5/7/13

Update 5/13/13 - Alerted Cold Snap Lives Up to Forecast Days Ago!

5/13/13
Projected cold snap first warned about back on the 7th certainly lived up to its hype and then some with some areas actually dropping into the mid 20s. This air mass was even cold enough to match Detroit's record low /30/ first attained in 1971...long before any heat island became established around the airport...impressive! Also; that 30 tied for the coldest so late in the season at Detroit. Note, lows this morning across Southeast Lower Michigan after a very chilly and brisk Mother's day (highs).

 
MORNING TEMPERATURE AND PRECIPITATION SUMMARY
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
929 AM EDT MON MAY 13 2013

VALUES REPRESENT YESTERDAY`S HIGHS....LOW OVER THE LAST 12 HOURS
AND PRECIPITATION OVER THE LAST 24 HOURS ENDING AT 8 AM EDT


.BR DTX  0513  ES DH00/TAIRZX/DH07/TAIRZP/TA/PPDRZZ/SFDRZZ/SDIRZZ


:SOUTHEAST MICHIGAN -- TEMPERATURE AND PRECIPITATION STATIONS
:....................................................................
:       STATION               MAX / MIN  / 8 AM / 24-HR / SNOW/ SNOW
:        NAME                 TEMP/ TEMP / TEMP / PRECIP/ FALL/ DEPTH
:....................................................................
WHKM4: NWS WHITE LAKE      :   47 /  26  /  33  /    T  /    T / 0
123M4: ANN ARBOR           :   49 /  28  /  30  /    T  /    T / 0
ADG  : ADRIAN AIRPORT      :   50 /  28  /  36  / 0.00
BAX  :*BAD AXE AIRPORT     :   43 /  33  /  38  /
CFS  :*CARO AIRPORT-TUSCOLA:   45 /  31  /  35  /
DET  : DETROIT CITY AIRPORT:   50 /  32  /  37  /    T
DTW  : DETROIT METRO ARPT  :   52 /  30  /  36  /    T  /  0.0 / 0
FNT  : FLINT BISHOP AIRPORT:   49 /  29  /  36  /    T  /  0.0 / 0
ONZ  :*GROSSE ILE AIRPORT  :   50 /  34  /  37  /
OZW  :*HOWELL AIRPORT      :   47 /  28  /  36  /
DUH  :*LAMBERTVILLE AIRPORT:   48 /  28  /  37  /
D95  :*LAPEER DUPONT AIRPRT:   46 /  30  /  35  /
IKW  :*MIDLAND AIRPORT     :   45 /  29  /  37  /
TTF  :*MONROE AIRPORT      :   52 /  28  /  37  /
RNP  :*OWOSSO AIRPORT      :   48 /  30  /  38  /
PTK  : PONTIAC AIRPORT     :   49 /  30  /  35  /    T
P58  : PORT HOPE           :   44 /  36  /  38  / 0.00
PHN  :*PORT HURON AIRPORT  :   48 /  30  /  36  /
MBS  : SAGINAW - TRI-CITIES:   48 /  30  /  36  /    T  /    T / 0
HYX  :*SAGINAW-HARRY BROWNE:   46 /  32  /  36  /
VLL  :*OAKLAND/TROY AIRPORT:   49 /  34  /  37  /
YIP  : YPSILANTI WILLOW RUN:   53 /  30  /  37  / 0.00
.END


*THE TEMPERATURE DATA FOR THESE SITES ABOVE REPRESENT THE HIGHEST AND
 LOWEST TEMPERATURES THAT WERE REPORTED ON THE METAR OBSERVATIONS
 THAT TRANSMIT THREE TIMES AN HOUR AND MAY NOT REPRESENT THE ACTUAL
 HIGH OR LOW FOR THAT SITE. THESE SITES DO NOT MEASURE
 PRECIPITATION.
.....................................................................


THE FOLLOWING COOPERATIVE OBSERVER SITES REPORT FROM MIDNIGHT TO
MIDNIGHT THE PREVIOUS DAY.


.BR DTX  0513  ES DH07/TAIRZX/TAIRZN/TA/PPDRZZ/SFDRZZ/SDIRZZ


:SOUTHEAST MICHIGAN -- TEMPERATURE AND PRECIPITATION STATIONS
:....................................................................
:       STATION               MAX / MIN  / 12 AM /24-HR / SNOW/ SNOW
:        NAME                 TEMP/ TEMP / TEMP  /PRECIP/ FALL/ DEPTH
:....................................................................
ARNM4: ADRIAN              :   49 /  31  /  32  / 0.00 /  0.0 / 0
MILM4: MILFORD - GM GROUNDS:   46 /  29  /  29  / 0.03 /  0.0 / 0
MDLM4: MIDLAND             :   45 /  33  /  33  / 0.01 /    M / M
MTCM4: MT CLEMENS SELFRIDGE:   51 /  35  /  35  /    T /  0.0 / 0
PRHM4: PORT HURON          :   48 /  37  /  38  / 0.06 /    M / M
SGNM4: SAGINAW 5W          :   45 /  33  /  34  /    T /    T / 0
.....................................................................


COOPERATIVE OBSERVATIONS VALUES ARE FOR APPROXIMATELY THE PREVIOUS 24
HOURS FROM YESTERDAYS OBSERVATION TIME TO TODAY`S OBSERVATION TIME.


.BR DTX  0513  ES DH07/TAIRZX/TAIRZN/TA/PPDRZZ/SFDRZZ/SDIRZZ


:SOUTHEAST MICHIGAN -- TEMPERATURE AND PRECIPITATION STATIONS
:..................................................................
...
:       STATION           OB   /MAX / MIN  /OB  /24-HR /SNOW/SNOW
:        NAME             TIME /TEMP/ TEMP /TEMP/PRECIP/FALL/DEPTH
:..................................................................
...
: ***MIDLAND COUNTY***


: ***BAY COUNTY***
AUBM4:  AUBURN            :0630/ 46 /  27 /  30 /    T/   M/   M


: ***HURON COUNTY***
BDAM4:  BAD AXE           :0705/ 44 /  33 /  35 / 0.04/   M/   M
FLNM4:  FILION 5NNW       :0645/ 44 /  33 /  35 / 0.00/   M/   M
POAM4:  PORT AUSTIN       :0738/ 43 /  35 /  36 / 0.00/   M/   M
PHPM4:  PORT HOPE         :0800/ 44 /  33 /  37 / 0.02/ 0.2/   0


: ***SAGINAW COUNTY***
MERM4:  MERRIL 2E         :0800/ 47 /  29 /  37 /    T/   T/   M
SAGM4:  SAGINAW           :0800/ 47 /  30 /  34 / 0.00/ 0.0/   0


: ***TUSCOLA COUNTY***
CARM4:  CARO              :0750/ 44 /  29 /  32 / 0.00/   M/   M



: ***SANILAC COUNTY***
LEXM4:  LEXINGTON         :0735/ 47 /  31 /  34 /    T/   M/   M
MRLM4:  MARLETTE          :0645/ 45 /  30 /  31 / 0.00/   M/   M
SANM4:  SANDUSKY          :0705/ 46 /  32 /  32 / 0.03/   M/   M


: ***SHIAWASSEE COUNTY***
CORM4:  CORUNNA 2NE       :0600/ 48 /  29 /  29 /    T/   T/   0
DRNM4:  DURAND            :0800/ 47 /  30 /  37 /    T/   T/   0
OWSM4:  OWOSSO            :0700/ 47 /  28 /  29 /    T/   M/   M


: ***GENESEE COUNTY***
BUNM4:  BURTON 4N         :M   /  M /  27 /  28 /    T/   M/   M
GODM4:  GOODRICH          :0730/ 47 /  29 /  31 / 0.01/   T/   0


: ***LAPEER COUNTY***
LPEM4:  LAPEER 2W         :0730/ 47 /  30 /  33 / 0.01/   T/   0
LPRM4:  LAPEER            :0730/ 47 /  30 /  32 / 0.00/   M/   M


: ***ST. CLAIR COUNTY***
YALM4:  YALE              :0655/ 45 /  30 /  31 /    T/   T/   0


: ***LIVINGSTON COUNTY***
HOWM4:  HOWELL            :0751/ 49 /  26 /  34 / 0.00/ 0.0/   0
WHLM4:WHITMORE LK 1N      :0700/ 48 /  26 /  27 / 0.00/ 0.0/   0


: ***OAKLAND COUNTY***
FARM4:  FARMINGTON        :0730/ 48 /  27 /  34 / 0.00/   M/   M
WSBM4:  WEST BLOOMFIELD   :0645/    /     /     /    T/   T/   0


: ***MACOMB COUNTY***
RICM4:  RICHMOND 4NNW     :0845/ 48 /  32 /  37 /    T/   T/   0


: ***WASHTENAW COUNTY***
AASM4: ANN ARBOR-SOUTHEAST:0730/ 50 /  27 /  33 /    T/   M/   M
AAWM4:  ANN ARBOR 1W      :0830/ 51 /  25 /  39 /    T/   T/   0
MCHM4:  MANCHESTER        :0705/ 48 /  28 /  28 / 0.00/   M/   M
SLNM4:  SALINE 4SW        :0800/ 50 /   M /  34 / 0.00/   M/   M
SALM4:  SALINE            :0800/ 50 /  27 /  33 / 0.04/   M/   M


: ***WAYNE COUNTY***
DBNM4:  DEARBORN          :0500/ 50 /  31 /  31 / 0.00/   M/   M
WYTM4:  WYANDOTTE         :0800/    /     /     /    T/   T/   0


: ***LENAWEE COUNTY***
MRIM4:  MORENCI           :0730/ 52 /  29 /  35 / 0.00/ 0.0/   0
TECM4:  TECUMSEH          :0630/ 51 /  30 /  30 / 0.00/   M/   M
TIPM4:  TIPTON 2WNW       :0800/ 48 /  29 /  36 / 0.00/   M/   M


: ***MONROE COUNTY***
DNDM4:  DUNDEE            :0650/ 49 /  30 /  31 / 0.00/   M/   M
MLIM4:  MILAN             :0738/ 49 /  29 /  34 / 0.00/   M/   M
MNRM4:  MONROE            :0900/ 50 /  27 /  39 / 0.00/   M/   M
NWPM4:  NEWPORT 4SSE      :0700/ 51 /  29 /  29 / 0.00/   M/   M
.END

5/12/13
The aggressive cold snap has come to fruition with just above low max's expected today with highs in the upper 40s to lower 50s.  As stated below, record low max's are in the lower to mid 40s and record lows overnight in the mid 20s to around 30 /Detroit - 44/1966, 30/1971; Flint 40/1966, 28/1946; Saginaw 42/1966, 26/1946 - note the record lows are for Monday morning/.   

Areas of frost and freezing temperatures are still expected overnight and if you have set out vulnerable vegetation, you may want to cover it. Seeds not germinated in the ground stand the best chance of surviving but are still vulnerable to a freeze.

A strong rebound in temperatures will come this week with readings rising through the 70s and into the lower to mid 80s by mid week.

________________________________________________________________________________  

5/8/13
Latest guidance continues the trend for the upcoming weekend into Monday. A rather potent cold front and subsequent air mass will dive across the Great Lakes and on into Southeast Lower on Saturday. Latest temperatures estimates are for lows in the 30s both Mother's Day morning and Monday; while highs drop sharply from the 60s Saturday to the upper 40s to lower 50s on Mother's Day. This is a somewhat impressive mini cold snap; rather sharp and quick hitting for just a couple of days. A brisk northerly wind will accompany the chill on Mother's Day.

For comparison; record low max's for Southeast Lower Michigan on Mother's Day, Sunday are in the lower to mid 40s while record lows on Sunday and Monday are in the upper 20s to lower 30s. Therefore; not too far away from record cold weather for the period.
_____________________________________________________________________
Original blog 5/7/13 1230am

It's interesting how we "backed-out" of winter this past month or so and on into spring.
Very much the same way we backed-out of autumn into winter; late and slowly. In the fall, even with each cooler wave of air it seemed warmer breezes returned and hung around much longer, refusing to give-way to winter. And again; the same thing could be said about spring as the colder, winter-like periods refused to give up the ship to spring.

So what now? Have to serious waves of colder air finally exhausted themselves? Are we free to assume spring air masses will rule the land? While the green-up is now in earnest as expected; is it safe to plant? I'd say yes for the most part BUT there seems to be one more hump to get by before there is more security in that statement. And that hump is the upcoming Mother's Day weekend or in which I'll refer to in meteorological terms and tongue-in-cheek as the "Mother's Day Curse"; or simply when Mother Nature gets to be "Mommy Dearest".

Mother's Day's is always the second Sunday of May which figures out to be anytime from May 8th to May 13th...Julian Day 128 - 133. I've noticed this "pattern" and I can't tell you how many times people complain to me about the "more than occasional" lousy weather on or around Mother's Day in Michigan. Is there any scientific data to back it up? The May 9th, 1923 snowstorm written about in my last blog would certainly fit the bill when Mom Nature certainly had a Mommy Dearest tantrum! How about the general temperatures in DTW data, any note of a pattern during that week or so?

A while back while I was at DTX, we ran DTW's (Detroit Metropolitan Arpt's) climatic data of the high temperatures only from 1958 to 2004, so not the entire Detroit climatic base. And, in this case (as with others) a graph or "picture" is worth a thousand words.

On the graph below we have; the highest category, termed "max" (record highs), "min" (record low maxs), means and standard deviations (%) of all those highs. In other words; the times the temperatures were at a certain standard deviation percentile or below. For example; looking at the graph below say at the 90th percentile at the highlighted interval, means 90 percent of the time the high temperatures either equaled or were less than the particular temperature in the left column. In this particular case, lower 80s are at the 90 percentile and thus, only 10% of the time the highs exceeded the lower 80s.


Again, during the time period mentioned above and highlighted on the graph; one can see the sideways to even down (especially the record low maxs which are shown on the graph as the min trace) of temperatures during the highlighted period, May 8th - 13th (Julian Day 128-133) or Mother's Day date possibilities.

The temperatures actually become a bit more erratic at that time. As mentioned, the most interesting and notable item that shows up is in the record low max's ("min"). See how the bottom blue min data line actually decreases from the first week of May; indicating a several degree slide in the record low maxs as slightly more potent cold air masses occurred during our point of interest - Mother's Day timing, 8th - 13th. Other data (traces) at the same highlighted time show a pause in rising temperatures even though we are proceeding toward the mid May time period. I know it's subtle "pause" but then compare it to the jump in all temperature fields (Max, 90th, 67th, Mean, 33rd, 10th and Min) the next six days from around day 134 to day 139. After; the same pattern roughly repeats all over again up then sideways, up then sideways. The period around Mother's Day happens to fall within that sideways (or even down a bit). Ultimately, the temperature pattern does becomes less variable as we "climb" into summer.

Mother's Day 2013

So, then how does this data relate to the upcoming Mother's Day? For that we have to look ahead at model guidance for our aforementioned period. General model consensus is for a sharpening colder trough to dig out of Canada for the upcoming weekend. The amplitude of this trough and cool surface high pressure to follow will bring colder, below average temperatures during the period roughly Saturday through Monday...or again, right around Mother's Day.




 


The bigger question at this time (and relating to our headline); will there be a risk of any frost/freeze with this air mass? At this early juncture; I'd say there will be just enough cold air at the surface, that we run the risk of some scattered frost and freezing temperatures but at this time, not a widespread heavy killing frost/freeze. Timing too is important and chilliest mornings are expected at this time to be Mother's Day morning and again, Monday morning.

Therefore make it simple; if you don't have to plant, especially tender vegetation, why risk it? Wait a few days because much warmer weather is projected to follow (sort of like our graph ;-)

Making weather fun while we all learn,
Bill Deedler - SEMI_WeatherHistorian



4/24/13

Record Breaking Late Season Snowstorm of April 23rd-25th 2005 and Incredible Snowstorm of May 9th 1923!


After 70 degree weather yesterday, yet again today it is snowing a various locations across Southeast Lower Michigan!  While our weather this spring has been much less than desirable, it has been worse; on this date in history and later. Take a look at my write-ups on just two of these memorable snows.

Record Breaking Late Season Snowstorm of April 23rd-25th 2005

 

With such an exceptionally variable and stormy winter it was actually fitting that the Winter of 2004-05 went out with a bang and not a whimper. If the persistent cold and snow during March wasn't enough to extend an already lengthy winter, Mother Nature really gave the inhabitants of Southeast Lower Michigan a sucker punch late in April.

A very nice stretch of sunny, dry (actually too dry) weather commenced late March into the first three weeks of April. This beautiful early spring weather reached a climax on the 19th when record highs were attained at all three climate stations (DTW/FNT/MBS). Ironically, not only did all three cities have record highs but it also was with the same temperature, 83 degrees. After the 19th, however, the weather was all downhill, accelerating big-time by the weekend. A series of cold fronts pushed south across the Michigan from the 20th to the 23rd, dropping temperatures some 40-50 degrees by the weekend /23-24th/!

 Preliminary Snowfall totals from the April 23rd-25th, 2005, near historic winter storm

An intense low pressure developed along an arctic cold front over the Upper Ohio Valley Saturday into Sunday and actually backed westward into the Eastern Lower Great Lakes (over Southwest Ontario - central pressure about 29.25" /986 MB/). This storm brought the worse late April weather seen in these parts in several decades. Snowfalls from the storm ranged wildly from a trace to as much as 16.5" with the heaviest falling across the highland areas from central Oakland County northeast into the Thumb Region (around Bad Axe). This very late snowstorm was the "icing on the cake" so to speak on what already had been a very snowy season. More information is available on April snows and total snowfall amounts from this storm. Incredibly, the May 9th, 1923 snowstorm which contained similar snow depths is over two weeks later!

The phasing of upper level jet steams, resulting in intensifying low pressure systems over Lower or Eastern Great Lakes have been responsible for some of our worst snowstorms; as evidenced by the above and following...

               ...Snowstorm of May 9th, 1923... 

Not since records have been kept in Southeast Lower Michigan      
(Detroit as far back as 1870), has the snowstorm of May 9th
in 1923 been equalled in season lateness and magnitude.

A strong cold front, of Arctic origin, pushed across Southeast
Michigan on the afternoon of the 8th, creating scattered thunder-
storms. The strength of the front was quite evident in Detroit.
The temperature plummeted from a near normal reading of 62
degrees at 100 pm to a winter like one of 34 degrees by 600 pm.
Behind the front, the stage was set for some startling weather    
developments for the month of May...even in Southeast Lower
Michigan. Rain mixed with snow fell across the area during the
evening of the 8th. Detroit received an estimated inch of snow
which melted on the ground before ending by midnight.

On the morning of the 9th, a low pressure area developed along
the front in northwest Ohio and moved over Lake Erie during the
afternoon. The developing low pulled warmer, moist air north from
the Ohio Valley and mixed with the unseasonably cold airmass
over Southeast Lower Michigan. As a result, a heavy, wet snow
began falling during the forenoon hours and continued through the
afternoon. Arguably, one of the most astonishing things (and
there were several) about the mid-spring snowstorm was that the
bulk of the snow fell during the time of day which is normally
considered "the heat of the day" or "afternoon heating" when
normal highs of the day are attained. The afternoon temperatures
never budged from the lower 30s (31-33) and was accompanied by
a stiff northwest wind, averaging 15 to 25 mph. Keep in mind,
the normal or average high for May 9th is 67...some 35 degrees
warmer! 

The snow ended by the evening in Detroit and at 800 pm, six
inches was reported on the ground. The story was even more
fantastic as one traveled west and north of Detroit across
Southeast Lower Michigan. Generally, six to nine inches fell 
west to the Ann Arbor area, northwest through Howell, north
across Pontiac and northeast up to Port Huron. Even more
incredible, snow depths of around a foot were reported at Flint
and Lansing north into the Saginaw Valley. Widespread damage was
reported to trees, power lines (many had a two inch circumference
of snow hanging on them) and telephone poles, especially in the
Saginaw Valley. Even so, economic damage was surprisingly small,
especially to spring vegetation. Evidently, the earlier spring
weather had been abnormally cold and this led to a late green up.
Substantial damage from the cold to vegetation and crops was
actually averted due to the insulation affect of the heavy, wet 
snow. Many May snow records (amounts and lateness in the season)
were shattered and stand firm to this day over Southeast Lower
Michigan.

By the next morning (10th), much of the snow had melted and by
the evening, it was just a memory. The official high in Detroit
on the 9th was 39, but that occurred just after midnight, before
the storm. The low was 31, which occurred in the afternoon during
the storm, giving a mean of 35 for the day and 21 degrees below
the normal of 56. Other May record snowfalls in Detroit pale in
comparison. In 1912, 1.5 inches fell on May 13th for the second
highest amount and the latest snow actually occurred the last day
of the month, May 31st, 1910 with a trace.

So, the next time you think it's too cold for this late in spring
or we can't possibly have a measurable snowfall in May across
Southeast Lower Michigan, you might want to THINK about it again
(or maybe not).
 
Making weather fun while we all learn, 
Bill Deedler -SEMI_WeatherHistorian
 


4/23/13

Finally an Extended Surge of Warm, Spring Weather To Encourge a Rapid Green Up!

One more cool down for the time being is all we'll have to endure before spring comes on more aggressively as we turn the calendar from April to May! Finally, Mom Nature will give us a surge of extended spring weather we have yet to see thus far. Latest indications are the colder, below normal temperatures plaguing much of the northern, central and Great Lakes region will hit the road for a longer time frame beginning by this weekend.

The warm, spring-like weather of today will once again go by the wayside as another aggressive cold front (the last in the series, for awhile anyway) moves through the region overnight and returns the region to below normal temperatures for a few days. But alas, have faith as latest extended model trends show the colder air to retract back to the northwest over Alaska, Western Canada and the Pacific Northwest during the coming weekend into next week (see 500 MB Jet maps below). After that however; extended guidance diverges on the first weekend of May; so get out and enjoy the much deserved warmer, spring weather as temperatures jump back into the 60s and 70s and possibly some 80s.



Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
 
 

4/16/13

Update 4/18/13; Severe Weather Reported

 Severe Weather April 18 2013 From the NWS


A strong cold front moved through Southeast Michigan on Thursday, April 18th. The front produced severe thunderstorms, heavy rain and
damaging winds.



_________________________________________________________________________
4/17/13 - 130 PM: Update
Little change to yesterday's blog as ingredients are progged to come together for the risk of strong to severe storms Thursday into early Friday. As we move closer to the time; a few important items have begun to become clearer.

12z 8am Thursday 4/18 -  Friday 12z 8am Fri 4/19
The highest severe threat for strong to damaging severe winds appears to be midday Thursday into Thursday evening. Refer to narrative and maps below for Thursday as confidence in modeling of the atmosphere is increasing with each successive run. Winds will average 20 to 30 mph with gusts possible in excess of 55 mph in the strongest of thunderstorms. Wind criteria for a severe thunderstorm is 58 mph along with 1" hail. At this time; the main threat from these storms would be wind damage. Because of the strong dynamics and shear in the atmosphere a risk of a few tornadoes can't be rule out.

In addition; also indicated below is concern for strong winds with the passage of the cold front around dawn Friday and moderate to strong gusty prevailing winds on Friday behind the front. Wind gusts of 40-50 mph are possible around frontal passage and after on Friday.

The Storm Prediction Center has now /130 PM Wed/ included all of Southeast Lower Michigan in it's severe threat for the above time period; 8AM EDT THU-8AM EDT FRI.



< Day 1 Outlook Day 3 Outlook >
Apr 17, 2013 1730 UTC Day 2 Convective Outlook
Updated: Wed Apr 17 17:17:50 UTC 2013  (Print Version)
Probabilistic to Categorical Outlook Conversion Table
Categorical Probabilistic
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions
 http://www.spc.noaa.gov/products/outlook/day2probotlk_1730_any.gif
  
Categorical Day2 1730Z Outlook
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 98,699 13,128,064 Chicago, IL...Memphis, TN...Joliet, IL...South Bend, IN...Decatur, IL...
SLIGHT 348,105 52,217,566 Houston, TX...Indianapolis, IN...Columbus, OH...Detroit, MI...Nashville, TN...
 Forecast Discussion
   SPC AC 171715
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1215 PM CDT WED APR 17 2013
   
   VALID 181200Z - 191200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS FOR SWRN LOWER MI...ERN/SRN
   IL...WRN/NRN IND...SERN MO...FAR WRN KY/TN...ERN AR...NWRN MS...FAR
   NERN LA...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES TO THE
   WRN/CNTRL GULF COAST...
   
   ...SIGNIFICANT SEVERE WEATHER EPISODE CONSISTING OF POTENTIALLY
   WIDESPREAD DAMAGING WINDS AND SEVERAL TORNADOES APPEARS INCREASINGLY
   LIKELY ON THU...
   
   ...SYNOPSIS...
   AN AMPLIFIED UPPER-LEVEL TROUGH CENTERED FROM THE NRN PLAINS TO THE
   SOUTHWEST AT 12Z/THU WILL PROGRESS EWD ACROSS THE UPPER MS VALLEY TO
   THE SRN PLAINS THROUGH EARLY FRI. A VIGOROUS SHORTWAVE IMPULSE WILL
   EJECT FROM THE CNTRL PLAINS TO WI/IL WITH AN INTENSE AND
   STRENGTHENING MID-LEVEL SPEED MAX /AOA 100 KT/ OVERSPREADING THE
   MIDWEST. AT THE SURFACE...CYCLOGENESIS WILL CONTINUE FROM THE IA/IL
   BORDER NEWD TOWARDS NRN LK MI. AN ATTENDANT COLD FRONT WILL SWEEP
   EWD LIKELY REACHING LK MI TO THE LOWER MS VALLEY BY THU EVENING. A
   WARM FRONT WILL ATTEMPT TO ADVANCE NWD IN LOWER MI...WITH LOWER
   CONFIDENCE IN HOW FAR N IT WILL EXTEND WITH ABUNDANT CONVECTION
   EXPECTED N OF THE BOUNDARY.
   
   ...GREAT LAKES TO THE WRN/CNTRL GULF COAST...
   FAIRLY EXTENSIVE BANDS OF CONVECTION SHOULD BE ONGOING AT 12Z/THU
   ALONG BOTH FRONTAL ZONES. DIURNAL HEATING WITHIN A RICHLY MOIST AIR
   MASS FROM THE WRN GULF INTO THE MIDWEST CHARACTERIZED BY 60S TO
   LOWER 70S SURFACE DEW POINTS AMIDST A REMNANT EML PLUME EMANATING
   N/NEWD ACROSS THE S-CNTRL CONUS...SHOULD RESULT IN A MODERATELY
   UNSTABLE WARM SECTOR WITH MLCAPE REACHING 1000-2000 J/KG.
   LOWER-LEVEL SHEAR/HODOGRAPHS WILL BE IMPRESSIVELY LARGE WITH NRN
   EXTENT ACROSS THE BULK OF THE WARM SECTOR. THESE FACTORS COMBINED
   WITH STRONGLY FORCED ASCENT WILL LIKELY YIELD AN EXTENSIVE QLCS THAT
   WILL INTENSIFY AND INCREASE IN FORWARD SPEED DURING THE LATE MORNING
   THROUGH THE AFTERNOON. BOWING SEGMENTS AND EMBEDDED SUPERCELLS WILL
   BE FAVORED...ESPECIALLY WITH NRN EXTENT GIVEN THE DEGREE OF SHEAR.
   POTENTIAL WILL ALSO EXIST FOR DISCRETE SUPERCELLS DEVELOPING AHEAD
   OF THE QLCS AS MLCIN BECOMES MINIMAL. THIS WOULD SEEM TO BE MORE
   PREVALENT WITH SRN EXTENT WHERE LARGE-SCALE ASCENT WILL BE
   PROGRESSIVELY WEAKER. SWATHS OF WIDESPREAD DAMAGING WINDS APPEAR
   PROBABLE ALONG WITH A ROBUST TORNADO RISK /SOME OF WHICH COULD BE
   SIGNIFICANT/. THE OVERALL SEVERE THREAT WILL LIKELY DIMINISH BY LATE
   EVENING/OVERNIGHT AS THE SURFACE MOISTURE PLUME IS PINCHED OFF WITH
   NRN EXTENT GIVEN DOWNSLOPE DRYING OFF THE SRN APPALACHIANS INTO THE
   CNTRL/UPPER OH VALLEY.
   
   ..GRAMS.. 04/17/2013

__________________________________________________________________________
4/16/13 - 330 PM
As mentioned in my previous blog; I'd keep my eye peeled for any potentially rough weather in our near future and Thursday into midday Friday may fit the bill at this early stage. In addition and partly because of our recent flooding; some local lowland and river flooding may again be realized with heaviest rains.
 
Discussion
A powerful jet stream aloft, instability at the surface all wrapped around a deep low pressure system and sharp cold front spell trouble for much of the mid part of the country and into the Great lakes and Ohio/Tennessee Valley mid to late week. What really has me concerned in the strong jet aloft; we're talking 70 knots - 100 knots of wind just off the surface to around 18,000 FT /500 MB/. Even if the instability is marginal and the fronts push through at lesser favorable times; this system STILL looks potent, take a look..

First off; Thursday afternoon with out first system>>>

As modeled by the GFS as of 12z Tuesday; a strong upper wind max/80k-500 mb/ will help usher in the elevated thunderstorm complex expected to develop Wednesday night and push through Southeast Lower Michigan Wednesday night into Thursday afternoon. The right-rear quadrant of this max jet is projected to cross this region sometime Thursday afternoon. This will give storm development an added "kick" along with instability which is projected to rise with daytime heating with lifted index's ranging in neighborhood of -3 > -6. Caution; remember this is model projected and you know where that sometimes leaves us! Actual instability will largely depend on several factors; surface heating (i.e. sunshine), colder air present aloft at the time just to name a few. These periodic thunderstorms will primarily be elevated (not surface instability based) as they advance through the region Wednesday night into early Thursday. Severity will depend largely on available instability aloft and potential surface based instability thrown into the action along with projected wind max "kicking -in"!  Negatives include; time of day, little added surface instability along with the max leaving the region a bit earlier which would help negate severe potential.

                                                                                                Thursday Midday


Then on Friday early in the day (below maps); the main surface system along with wind max is slated to storm through the region. Again; the yellow highlighted discussion of model projected above applies here, also. Timing of the system and limited instability is unfavorable for "classic severe weather". However, with the powerful cold front being aided by a 70 knot - 100 knot jet core just aloft; this still would have the potential for a potent squall line of wind were the winds realized by any decent updrafts along the front, thunder or not! Strong gusty winds look favorable later also behind the system as it wraps up to the north.
                                                                                                      Friday Forenoon





Again this is two to three days out and this atmosphere and attending severe weather is yet to be better sampled. In any event; stay tuned for updated info on this potential first notable severe weather event of the season.

For the latest on severe weather potential for the US click here!
 

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian


4/10/13

The Battles Of Spring Are In The Air!

Finally some spring-like thunderstorms pulsed through Southeast Lower Michigan this second week of April. Along with the storms; very heavy rains soaked the mainly dormant landscape. Just a hint of green has been activated by the spring rains thus far, and mainly just grassy areas at that. Late you say? It's almost laughable when think back to last year at this time when our spring green-up was already over a month old. But last year of course was the truest of anomalies; the warmest March and early spring on record. Also while you're thinking back, you might remember, April settled down back closer to normal and averaged cooler than March! Extraordinary indeed! In addition, you might also remember the cold air masses in April that brought the killing frosts and freezes and heavily damaged the fruit crops. Well hopefully, we'll have none of that this year as we slowly warm and the growth appears, somewhat more gradual. After all, which is better; exhaust the cold air now or wait till the buds/flowers are on the fruit trees and spring growth is in full term?

But what of this spring? What spring you may ask? Oh it's there but you have to look closer for it. It's a whole different kind of spring...the inverse of last year...closer to our "normal spring" but thus far, it has indeed been colder and later. While March ended up 2 to 2 1/2 degrees below normal; April thus far has been worse! During the first third of the month /10 days/, temperatures have averaged as much as 3 to nearly 5 degrees below normal with the biggest departures up around the Saginaw Valley and Thumb District. Yes, when mother nature pays back; she can be a....   


The Great Lakes continue their icy chill as domes of cold, residual Siberian and Arctic air surge down, nearly unabated across the northern and even central states at times. This Arctic air continues to be funneled down across the Lakes; accentuating the typically early spring icy waters of the Great Lakes. And, as you can see by the widespread 30s to around 40 degree water temperatures as we approach mid April; the Great Lakes at this time of year do absolutely nothing in aiding our spring warm-up.

 
Arguably; no other weather map displays the spring air mass battle more appropriately than our present surface map for 8pm this evening; Wed Apr 10th. The battle line is clearly drawn, seen and heard by way of strong thunderstorms and very heavy rains along the quasi-stationary front draped west to east across the Lower Lakes/Upper Ohio Valley. Cold, residual Arctic air continues to be funneled down across the Great Lakes while at the same time, spring's warm southerly winds in response to an increasingly stronger spring sun, push northward up through the deep south and into the Ohio Valley! The resultant, strong baro-clinic zone also denoted by the sharp east/west temperature contrast across the region is exceptional; 30s and 40s to the north and 50s, 60s and 70s around and immediately to the south...all in a very tight area of landscape. 



The clash of the seasonal air masses; winter to the north and spring to the south indeed is in the air and will be for the next few weeks anyway as the cold, winter-like air masses slowly warm and moderate as they clash with springtime warmth. Our extended maps indicate this with a rather busy weather period for the next 10 to 14 days. I'll be on watch for more notable Mother Nature rou's or tantrums in the meantime.

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian

4/8/13

"January through March"; The Real Winter of 2012-13

Without a doubt, the Winter of 2012-13 was late in getting started and even statistically,  better suited the months of January through March rather than the standard climate months of December through February. In fact, March's average temperatures at all three climatological sites ended up colder than December's temperatures, something not seen often. Normals for Southeast Lower Michigan in December average in the upper 20s to around 30; while normals for March average in the mid 30s. Last December saw temperatures average in the mid 30s across the entire region (DTW - 35.9; FNT - 33.5; MBS - 34.1 for a Southeast Lower Michigan average of 34.5) which as you can see, match March's normals of mid 30s well.

In the reverse, this past March of 2013 saw temperatures average in the lower to mid 30s (DTW - 34.6; FNT - 32.2; MBS - 31.3 for an average of 32.7) nearly two degrees below December 2012's average temperature for Southeast Lower Michigan of 34.5! Not quite as cold as December's normal temperatures but still represented December better than December's 2012 actual temperatures did.

While normally March gradually warms up as the month unfolds, this really didn't happen until the last six days of the month when readings averaged normal to above. Two thirds of the month average below normal with the largest departures ironically coming when spring was to commence; the 20th and 21st with temperatures averaging 13.5 degrees below normal.  On the flip side to this cold, just two exceptionally mild days stole about a degree below monthly departure (in other words; the departure for the month would have been 3.0 - 3.5 degrees below normal, rather than 2.0 - 2.5 below). A storm center that pushed north of the region on the 10th/11th and pulled unseasonably mild air into the area with temperatures rising into the mid 50s to mid 60s...averaging 14 degrees above normal.

While snowfall around the region is still possible; chances diminish quite notably from early April to late April. And; despite the mild winter, snowfalls up through the first week of April actually performed admirably. Detroit has recorded 47.6" exactly 6.0" /norm- 41.6" thus far/ above normal and right on the normal-above normal threshold used in analogues. Normal snowfall for the entire season at Detroit; 42.7". Snowfall at Flint was a few inches below the normal thus far with 43.6" recorded, normal for the entire season stands at 47.4" and thus, -3.8" thus far.  Saginaw recorded 43.4" (just .2" different from Flint) and season normal stands at 46.1".

CLIMATOLOGICAL WINTER 2012-2013 (DEC, JAN, FEB) STATS/RANKINGS - NWS
 
---------------------------------------------------------------------

PRECIPITATION

              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   8.92"    6.44"   +2.48"     11TH WETTEST
FLINT AREA     8.04"    5.03"   +3.01"      6TH WETTEST
SAGINAW        7.14"    5.24"   +1.90"     16TH WETTEST


AVERAGE TEMPERATURE

              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   30.4     27.9     +2.5      17TH WARMEST
FLINT AREA     28.5     24.9     +3.6      10TH WARMEST
SAGINAW        28.5     24.7     +3.8      10TH WARMEST


AVERAGE HIGH TEMPERATURE! 
              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   37.5     34.4     +3.1    T-16TH WARMEST
FLINT AREA     36.2     32.2     +4.0     T-8TH WARMEST
SAGINAW        35.2     31.4     +3.8          N/A*


AVERAGE LOW TEMPERATURE

              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   24.0     21.4     +2.6      21ST WARMEST
FLINT AREA     20.9     17.7     +3.2      14TH WARMEST
SAGINAW        21.7     18.0     +3.7          N/A*


DETROIT AREA HAS A CLIMATE RECORD DATING TO NOVEMBER 1874
FLINT AREA HAS A CLIMATE RECORD DATING TO JANUARY 1921
SAGINAW HAS A CLIMATE RECORD DATING TO JANUARY 1912

*RANKINGS OUTSIDE THE TOP 20 FOR SAGINAW ARE CURRENTLY UNAVAILABLE
DUE TO ONGOING UPDATES FOR THE SAGINAW AREA DATABASE
_______________________________________________________________
 
 
Next up on the Winter of 2012-13; I'll take a look at the analogue 
performance and what analogue(s) performed the best in relevance to
this winter and associated spring projections.
 
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
 
  

3/27/13

Easter to Close Cold March With a New Polar Blast On Our Doorstep; But Before Then...

Below average temperatures have dominated this March across Southeast Lower Michigan (and much of the region east of Rockies for that matter) but this Easter weekend (the last few days of March) will go out closer to normal...but it won't last! Mother Nature should give inhabitants of Southeast Lower Michigan a bit of a reprieve this Easter weekend with closer to normal temperatures with highs around 50 to possibly even mid 50s with enough sunshine both Holy Saturday and Easter Sunday.

Look for temperatures for Easter services to be in the 40s and again; lower to mid 50s for highs on Easter before before the gates come crashing down by Monday; appropriately named April Fool's Day. And, anyone who believed winter left for good will be made a fool of by Mom Nature on Monday and Tuesday as temperatures plunge back down into 30s to around 40. Again; well below the normal of lower to mid 50s by the turn of the month. And, with the opening Tiger's game in Minneapolis (or had it been Detroit, for that matter) on April Fool's Day, you KNOW you're just asking for trouble; what were they thinking?



Unfortunately Easter won't be completely unmarred; there will be a chance of showers with the next wave of colder air and snow showers on April Fool's Day.

So why has there been such a slow start to spring? I discussed some of that in my last few blogs; Spring Outlook and Negative Arctic Oscillation. Things are beginning to look up as we enter the second month of spring and we'll take a look at the rest of spring including a rather decent analogue year thus far this past winter and early spring, next week.

Have a good Easter!
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian

3/19/13

Extremely Negative Arctic Oscillation Draining Arctic Air Into The Great Lakes and East Upon Spring's Fanfare


Earlier in my Spring Outlook I wrote the reasons why I expected much of March to be colder than average. I see absolutely no reason to adjust that prediction (though some moderation is possible by the weekend) as a strong blocking pattern in the upper wind pattern continues to hold sway over the Eastern North American continent. This blocking pattern in conjunction (and mainly the result of) with an an extremity negative Arctic Oscillation /AO/. Word from the Weather Prediction Center /WPC/ today confirms that with following discussion;

NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1102 AM EDT TUE MAR 19 2013

VALID 12Z FRI MAR 22 2013 - 12Z TUE MAR 26 2013

MULTI-DAY MODEL AVERAGES DEPICT A SPLIT FLOW OVER NORTH AMERICA AT
THE MEDIUM RANGE, WITH CONTINENTAL POLAR AND ARCTIC AIR FEEDING
INTO THE CENTRAL AND EASTERN STATES, AND A PACIFIC JET DIVING
THROUGH THE WEST AND ACROSS THE DEEP SOUTH. THE EXTREME AMPLITUDE
AND PERSISTENCE OF THE NORTHERN STREAM OWES TO THE NEAR-RECORD
NEGATIVE ARCTIC OSCILLATION--EXPECTED TO BOTTOM OUT AT THE SHORT
RANGE. 
 
  Note the latest projection of the AO for the rest of March. The extremely negative AO is projected this week, ironically bottoming-out right around the first day of spring!

 
What do I mean by "strong blocking pattern" in the upper wind pattern? See Map -1

                                                                                                                Map -1

First Day of Spring? More Like the First Day of Winter! 

On March 20, 2013, at precisely 7:02 A.M. EDT, the Sun will cross directly over the Earth's equator. This moment is known as the vernal equinox in the Northern Hemisphere.

Ironically; the following projection /Map -2/ of the upper air pattern /5,000 ft/ Thursday morning the first full day /24 hrs/ of spring across North America in the east is a pitiful rendition of a spring time weather map. Actually, if one were to look at it and asked; what first calendar day of a season does this look like? "Winter" would be pretty much the unanimous reply! Note; I highlighted the -15c /+5f/ air pockets at 5,000 ft...one where it should be over the polar region and the other where it shouldn't...over the Great Lakes and Southeast Lower Michigan /black dot/. Note; the freezing line 0c /32f/ extends far south into the Southeast Gulf states. 

Temperatures across Southeast Lower Michigan are/will be more typical mid January through the remainder of the week with again; some moderation due this weekend. With that moderation; latest models are intimating another storm system to form over the mid Mississippi Valley with its sights set on the Ohio Valley and possibly the southern Lakes region early next week. We also know the errors of the models lately have been in this area; so prudence will prevail at this time. ;-)

                                                                                                           Map - 2
 
 
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian

3/17/13

MILD MARCH MADNESS - 1945

I wrote this article BEFORE last March's record warmth. Still,
it is a very interesting account of that March of 1945...and 
also, the spring that followed it! Ironically, a similar wide-
spread severe crop damage occurred back in April of 1945 like 
last April's; due to cold and frosts. And, that was only a
portion of that spring's (not to mention the previous winter's)
weather issues! Enjoy... 
 
                 MILD MARCH MADNESS - 1945   

When looking through the month of March records in Southeast
Lower Michigan, one can't help but notice March 1945. The
temperature departure alone is awesome. March of 1945 made 
the record books as the warmest March ever, before and since 
(1870-1996) in Detroit. The average temperature of 47.9 (all
right, let's cheat and say 48 degrees) is extraordinary in 
itself when considering the current normal, or average,
temperature in Detroit for March is 35.7 degrees. In 1945
however, the normal was even lower at 33.0 degrees (normals 
for Detroit have been rising through the years). March of 
1945's average or mean temperature not only surpassed the 
current March's normal temperature by more than 12 degrees
(+12.2), the 1945 normal by nearly 15 degrees (+14.9) but
even bettered the current April's normal by about a half
degree (normal mean for April in Detroit is 47.3).

Well, you might ask "Did this LAMB of a month start out and 
end that way?" Yes, right from the start there were no LIONS
to be seen this March. During the first few days of the month,
temperatures averaged about 10 degrees above normal, while 
near the end of the month, readings averaged 15 to as much as
30 degrees above normal(see Table-1). Other temperature facts
during the month which are just as outstanding are: only one 
day during the month averaged below normal and that was only 
by 2 degrees, over half the month's (17 days) high temperatures
were 60 or better with nine of those days rising to 70 or better
and one even climbing above the 80-degree mark (82)! Keep in
mind, the current normal high for March is only 44.4 degrees.

As one might expect, with all the warm weather there would 
be some record high temperatures established and there were... 
six (Table-1). It's also interesting to note that the highest
mean temperature during the month, 68 degrees on the 28th, is
normal for the first day of summer, while the high that day of
82 is about normal for the 4th of July!

Abundant sunshine during the month (66% vs the normal of 51%)
certainly aided strongly in establishing this record warm month.
Even though sunshine was above normal for the month, rainfall 
was also, with three and a half inches falling. With above 
normal heat and rainfall during the month, one might also think
that it would be an active thunderstorm/severe weather month.
The observations at Detroit indicate otherwise, with only two
days having thunderstorms. The thunderstorm activity remained
heavily concentrated to the south in the Ohio Valley.

Speaking of the weather pattern, lets take a look at the general
weather pattern that created such an unseasonably warm month.
Needless to say, with such a warm March, all the real Arctic
cold remained bottled up in Canada. This was due to a strong
west-southwesterly flow across the U.S. from the Pacific. This
strong predominant flow of mild maritime air kept any Arctic 
cold high pressure areas well north of the region. The high
pressure areas that did move across the area were of Pacific
origin and thus, contained milder air. 

The strong west southwesterly jet stream across the country
also kept an active storm track in place, but it was mainly 
west and south of Southeast Lower Michigan. Several low 
pressure areas and attending frontal systems moved east
northeast across the Ohio River region and dumped copious 
amounts of rain, creating severe flooding in that area (not
unlike the early March storm track pattern of this year). 
Rainfall amounts of eight to 14 inches in March were common 
from the Arkansas area northeast across Kentucky and Ohio 
into Pennsylvania. In fact, at least up until that time, 
March of 1945 was the wettest month ever in Ohio. The low
pressure systems that moved west of Southeast Lower Michigan,
pulled very warm (for March) air north from the deep South
into the Great Lakes States.

The strong west-southwesterly flow over the country developed
a weak, but fairly persistent, ridge of high pressure over the 
eastern third of the country. Therefore, for you meteorological
buffs, the 500 MB heights averaged above normal (540-542 meters
over the southern Great Lakes). At the 850 MB level (5,000 ft),
the average 0'C isotherm (32'f) was well north of Southeast 
Lower Michigan, lying east-west across the tip of Northern 
Lower Michigan.      

In the end, it seems like Mother Nature always manages to
balance things out, as was the case this time. One can't
help but wonder if the people of the time felt a "payback"
was in the works for such a early, warm Spring. The Winter
and Spring of 1945 certainly brought their share of weather
extremes across the Great Lakes and Ohio Valley. 

In addition to the warm March and severe flooding in the Ohio
Valley, the following was obtained from the "Monthly Weather
Review" Publication:


     The year 1945 was notable for the severe cold
     weather, record snowfall, and continuous snow 
     cover in the eastern portion of the country until
     February; an abnormally warm March east of the
     Rockies; and unfavorably cool, wet weather for much
     of the remainder of the year- especially April, May
     and June- in the central and northeastern sections. 
     
     
     Abnormal warmth prevailed during March over
     practically the entire region east of the Rocky
     Mountains. Temperatures averaged higher than for any
     previous March on record for the States of Indiana,
     Ohio, Michigan, New York, New England, New Jersey,
     North and South Carolina. The month was extremely
     wet in central parts of the country, especially the
     Ohio and Mississippi Valleys, where disastrous
     floods occurred. Unusual warmth and generally
     adequate moisture caused vegetation to advance
     rapidly over practically the entire region east of
     the Rockies and by the end of March, the season was
     from 2 weeks to a month ahead of normal.
     
     The possibility of dangerous freezing, with
     vegetation, especially fruit, at such a critical
     stage of development so early in the season, became
     a reality when from April 4-7 and on the 23rd cold
     weather overspread central and eastern sections of
     the county and brought severe frosts and freezing
     southward as far as Oklahoma, Arkansas, the Ohio
     Valley and many southern Appalachian regions, with
     considerable damage to fruit and early gardens.
     
     Continued wet weather from Oklahoma and Arkansas 
     to the Great Lakes, seriously delayed seeding and
     development of crops, notably corn. One of the 
     worst April snowstorms of record occurred in Iowa
     and some adjacent states on the 3rd and 4th. May 
     was unfavorably cool...especially in the northern
     interior, with frosts in sections of the southern
     Lakes Region as late as the 24th and 30th. An
     unusual May snowstorm moved across the more northern
     states with falls up to 8 inches in Iowa on the 9th,
     and 10 inches to 2 feet in New England on the 10th
     and 11th.
     
And there were the usual severe events and tornadoes but still,
a quite eventful and somewhat extraordinary Spring indeed! 

By the way, What was the second warmest March on record in
Detroit you might ask?  Believe or not...the next year, 1946!


-----------------------------------------------------------------
TABLE - 1           DETROIT MI -  MARCH 1945
-----------------------------------------------------------------
DATE   MAX  MIN  MEAN  DEPART      DATE   MAX  MIN  MEAN  DEPART
_________________________________________________________________
3/01   44   23    34    + 6        3/17 # 75   44    60    +27 
3/02   42   38    40    +12        3/18   63   41    52    +18
3/03   53   29    41    +13        3/19   70   49    60    +26
3/04   40   25    32    + 4        3/20   61   37    49    +15
3/05   63   32    48    +19        3/21   45   35    40    + 5
3/06   53   27    40    +11 >(.3)  3/22   54   31    42    + 7
3/07   36   21    28 ** - 2        3/23 # 73   40    56    +20
3/08   39   24    32    + 2        3/24   63   39    51    +15
3/09   45   27    36    + 6        3/25 # 78   43    60    +24
3/10   38   29    34    + 4        3/26   73   51    62    +25
3/11   45   25    35    + 4        3/27 # 79   53    66    +29
3/12   52   35    44    +13        3/28 #*82   55    68    +30
3/13   53   30    42    +10        3/29   65   44    54    +16
3/14   67   36    52    +20        3/30   62   42    52    +13
3/15   70   46    58    +26        3/31   60   45    52    +13
3/16 # 74   56    65    +32

> ONLY SNOWFALL RECORDED                                   
# RECORD HIGH (STILL STANDING, EXCEPT 3/23 TIED IN 1994)
* HIGHEST TEMPERATURE EVER RECORDED IN MARCH
**ONLY DAY BELOW NORMAL IN MARCH
  
 Average    Average              Normal        Departure
High Temp   Low Temp   Mean   (1945) (1997)  (1945)  (1997)
 
  58.6       37.2      47.9    33.0   35.7    +14.9  +12.2 

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian


3/12/13

Updated 3/13 - Winter Arrived Late This Year; Will Spring?

*Updated 3/13 to include Great Lakes water temperatures
 
Let cut right to the chase; meteorological winter made a liar out of me since I predicted normal to below normal temperatures in Southeast Lower Michigan for the Winter of 2012-13. Early on; most guidance suggested it and analogues backed it up, so what happened? Nothing...other than winter come late to the party and screwed up my temperature forecast ;-). As mentioned many times in my outlooks and discussions, timing is one of the biggest problems in forecasts... particularly monthly and seasonal. Many of the analogues had the pattern pegged (above normal temperatures early winter to below mid & late) but none were as mild as the Winter of 2012-13.

Averaged out; temperatures for the meteorological winter (December through February) came in above normal across Southeast Lower Michigan (scroll down to data from the NWS). In fact, December into mid January averaged well above. However, as the second half of the meteorological winter (mid January - February) evolved; the pattern I was looking for to dominate through much of the winter did in fact, materialize. And, with the exception of the "few day heat wave" at the close of the January; mid January on into early March really "began" winter with normal to below normal temperatures (dark blue temperature trace). In February, not only did temperatures average normal to below across Southeast Lower Michigan but much of the region got pestered (or treated depending on one's view) with frequent snows...making it also, a snowy month. It's really not so unusual for winter to not get a foothold on the region until around Christmas but mid January, mom nature has some explaining.

It is one thing to discuss the winter temperatures, another to actually visualize it...therefore, a picture is worth a thousand words...or at least a paragraph or two. ;-)


It's easy to see how temperatures (above the mean yellow normal line) for much of January averaged above normal. A change of the trend (temperatures below the mean yellow normal line) began when the first real cold snap of the winter pushed temperatures down to near zero during the 21st-23rd (5,-1,5 @ DTW and colder elsewhere). Quickly after; there was one more warm surge on the 29-30th (57, 62 @ DTW) only to come crashing back down to the single figures Feb 1st, 3rd (9, 5 @ DTW). Many of the meteorological inclined can visualize the amplified and progressive upper air pattern creating the temperature fluctuations at that time.

Ah well, if January through March had been our meteorological winter; maybe a hit instead of a miss? Many of my comrades share with me the difficulty in predicting this past winter season three months out and sometimes, the weather for just three days.  It seems all across the country mom nature kept weatherman on their toes (and sometimes, biting their nails ;-). But that's the past and on to the future....after a few statistics.


The following are the temperature and precipitation statistics for the three climate locations in Southeast Lower Michigan. Snowfall is not included since theoretically, it's not over for the winter.

                             Winter 2012-13 Statistics *

                AVERAGE TEMPERATURE

              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   30.4     27.9     +2.5      17TH WARMEST
FLINT AREA     28.5     24.9     +3.6      10TH WARMEST
SAGINAW        28.5     24.7     +3.8      10TH WARMEST
 
                   AVERAGE HIGH TEMPERATURE

              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   37.5     34.4     +3.1    T-16TH WARMEST
FLINT AREA     36.2     32.2     +4.0     T-8TH WARMEST
SAGINAW        35.2     31.4     +3.8          N/A 


                   AVERAGE LOW TEMPERATURE

              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   24.0     21.4     +2.6      21ST WARMEST
FLINT AREA     20.9     17.7     +3.2      14TH WARMEST
SAGINAW        21.7     18.0     +3.7          N/A 


                       PRECIPITATION

              ACTUAL   NORMAL  DEPARTURE     RANKING
DETROIT AREA   8.92"    6.44"   +2.48"     11TH WETTEST
FLINT AREA     8.04"    5.03"   +3.01"      6TH WETTEST
SAGINAW        7.14"    5.24"   +1.90"     16TH WETTEST
 
* Data supplied from the National Weather Service White Lk. /DTX/
 
 
Spring 2013 Outlook

Since winter got a late start, does that automatically mean spring will too? Not necessarily, but in this case I think there will be likely some truth to that statement. However, that doesn't automatically mean that temperatures for spring on the whole, will average below normal. 

ENSO remains in a neutral pattern across the Pacific therefore, it will have little if any effect on our spring weather across Southeast Lower Michigan. The main players this spring will be the phase dominance of the NAO/AO, the PDO and PNA relating to the jet stream positioning and placements of long wave troughs and ridges.

Spring especially has that "curse" of being extremely changeable therefore, trends and pattern formations are even more fickle than winter. Being so changeable, projections for the season can be quite a challenge. I will discuss what prevailing temperatures and precipitation I expect along with reasoning. In future blogs, as in the past, I also plan to discuss notable changes and trends that will affect our spring weather .

Temperatures

I look for temperatures to average around normal to below during early spring as our late winter hangs over into much of March and possibly, even parts of April. That is not to say we won't have beautiful, warm spring days such as like Sunday (3/10) but overall temperatures early spring should still average around normal to below. For the latter half or so of spring on average, temperatures should have preference for above normal readings. All in all, I look for temperatures to average within 2 degrees of normal for the spring season.

Reasoning for the cooler than average early spring;
1 - Arctic Oscillation /AO/ recent preference for neutral to negative oscillation phase
Since mid winter our cyclical northern friend/foe has been oscillating between around average to below average and as one can see here, still shows a preference for that in the coming weeks. The second plot is an experimental projection of the Arctic Oscillation. Be advised; both these models change frequently and it is the prevailing trend we are concerned with when examining them.
Note both plots show an extreme negative Arctic Oscillation /as low as -4/ in the short term mid month. It will be interesting to see if this bears out.




2 -The more inclusive, North Atlantic Oscillation /NAO/ also shows a decided preference for a neutral to negatively phased oscillation.

3- The residual cold air stored over the Canadian/Polar regions which is aided by deep snow cover and relatively low sun angle early spring, acting like a freezer.

*4 - Great Lakes Water Temperatures /Added - 3/13/13 /

I wanted to also share the Great Lake's water and ice content as of 3/13/13 and adding to list of reasoning's for cool early spring. I was able to get the latest data from a the wonderful site /GLSEA/ which is part of the Great Lakes Environmental Research Lab /GLERL/. As you can see, several of the recent winter's water temperatures are on these charts. What I found interesting is the recent decrease in water temperatures so late this season, so much so, that now the water temperatures are really close to the colder winters we had in the recent past. In addition; note the big change (drop) from earlier this season for Lake's Michigan, Huron and Erie.



-Lake Michigan is colder than last year and 2010 and on par with 2011.
-Lake Huron is also colder than last year and 2010; and now very close to the remaining years.



-Most interesting of all is Lake Erie as it is the coldest now as it was in the coldest years. This would be due to it shallowness and our coldest part of the winter arriving late in the season.


Some Model Temperature Projections for Spring:
(As you can see, just these three have somewhat differing opinions and sometimes Southeast Lower Michigan seems to be caught in the middle)







Precipitation/Severe Weather

Rainfall should average around normal to above across the region as confrontation zones set up along the fairly active spring pattern induced by a fluctuating NAO and semi-permanent ridge over the southeast part of the country. The interaction will induce normal to above normal rainfall. Generally, in this sort of pattern; severe weather would be expected to be active. This will greatly depend on how dominant a particular phase of the NAO is this spring along with attending jet cores and available instability per event. A strongly negative /NAO-/ would tend to hold the more active severe weather to our south, whereas a more variable NAO oscillation would tend to allow more warmth, instability and stormy periods. I'll keep a lookout for possible upcoming active severe weather episodes.

Model projections for precipitation



Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian