5/13/15

Change in Upper Air Pattern Mid-May Liable to Bring More Contrasting Temperatures and...

I my blog regarding May's weather outlook I stated; I expected a warmer than normal May and thus far, Southeast Lower Michigan is averaging 8 - 10 degrees above normal thru the 13th. In addition, on 5/2 when I wrote the blog I stated:

"Why there is still the risk of a frost or freeze, none looks likely in the next week to 10 days anyway and there's less than a 30% chance through the month with the above normal temperatures. I'll keep the blog updated if the risk does arise if colder air masses make their way out of Canada".

I stated that because even though I expected a warm May overall, sharply contrasting air masses have been the rule this spring and I expected May to be no exception. After days in the 80s (including record territory), sharply colder air from Canada has aggressively plowed back across the region, driving temperatures down some 30-35 degrees recently! While temperature swings of 30-40 degrees in the month of May happen, it's not as commonplace as its spring month counterparts of March and April across Southeast Lower Michigan.

Our upper air pattern has reverted back to "ridge-trough pattern" of April as opposed to primarily ridge the first two weeks of May. The projected pattern discussed on the 2nd served well the first two weeks of the month (or as stated  "next week to 10 days") with above to much above temperatures. In addition, I stated I would update if the need arises after that period and the need has come....

Remainder of May Outlook
After a cold start and risk of scattered frost across the region overnight into Thursday morning as a rather strong high pressure dominates, look for temperatures to start a moderate climb once again through the 60s and into the 70s and breaking into the 80s over the weekend. In addition, the risk of showers and thunderstorms will be on the increase as the warmer air rudely surges back into the region. With this contrasting pattern in the works the next few week, severe weather potential also rises.

Looking ahead, I expected this oscillating pattern to be more the rule than the exception through  much of the remainder of the month. While temperatures will average above normal for the month, enough cold air will also be able to make it down occasionally to bring the possibility of a frost and/or freeze.

The old adage of planting after Memorial Day (and it comes the earliest possible this year) still seems the best advice - especially in the more frost/freeze prone areas of Southeast Lower Michigan!

 

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


5/2/15

Analogues and Guidance Indicate a Warmer and Somewhat Drier May In Store for Southeast Lower Michigan

Thus far, the current spring pattern has evolved as indicated by both analogues and recent guidance. A colder than normal March evolved into a near normal to above in April as temperature patterns projected and in actuality; transitioned from below normal to above. The timing of the pattern change has been somewhat ahead of the timing of both spring analogues and models by about a week or two week. But, I'm not complaining after last winter and early spring with spring development, now in full force.

TEMPERATURES
Spring analogues for May called for a near normal May temperature-wise while latest guidance indicates above normal temperatures. With out timing of pattern changes seemingly ahead of past analogues, above normal temperatures are the best forecast. Typically May's average high temperatures start out in the mid 60s and warm to the mid 70s by the close. Overnight lows begin the month in the mid 40s and rise to the mid 50s by the close. Why there is still the risk of a frost or freeze, none looks likely in the next week to 10 days anyway and there's less than a 30% chance through the month with the above normal temperatures. I'll keep the blog updated if the risk does arise if colder air masses make their way out of Canada.


RAINFALL
Drier than normal or average spring conditions were projected by both the analogues and models, and continue to be upheld by latest precipitation guidance for May. Local analogues projected Spring rainfall would average at least an inch or two below normal across all of Southeast Lower Michigan. Thus far this spring through the end of April, precipitation has averaged around two inches below normal. Latest model projections continue the drier than average pattern with below normal rainfall. Note the CFSv2 is calling for a notable bull-eye of below normal rainfall to our south, over the Ohio Valley. Interesting since this is the area that has been most active with precipitation the past several seasons on average. May is generally one of our wetter months with around three inches of rain usually falling - therefore this dry pattern established bares watching for the growing season.

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














4/22/15

Record Breaking Late Season Snowstorm of April 23rd-25th 2005, The Incredible Snowstorm of May 9th 1923 and Lastly, The Unbelievable Late Snow of May 21-22, 1883

You  might be grumbling about today's snow flurries but just cast you mind back ten years ago!  While our weather this spring has been less than desirable, it has been worse; on tomorrow's date in history and later. Take a look at my write-ups on just three 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/!

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 equaled 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 air mass
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).
 
Unbelievable Snow of May 21-22, 1883  
 
Since this was so long ago; it was questioned at one time if it really occurred and 
if the snow amounts were legit or not. While at NWS, DTX, I was very curious
myself and dug back into the archaic records of nearly 132 years ago now,
to investigate the authenticity of such occurrence. Not only was there snowfall 
recorded between 7PM EST May 21-7AM EST May 22, 1883 but it was impressive
amounts being so very late in the spring!
 
Snow began to accumulate during the evening hours of the 21st, leaving a snowfall
of 2.3" by midnight (snowfall, not snow depth). The snow continued from midnight 
until the early morning hours of the 22nd, leaving an additional 2.7" snowfall 
recorded by 7AM the next morning. Therefore, there was a total of 5.0" of snowfall 
during that 12 hour period - the entire event. However; I don't ever recall seeing
a 5" snow depth on the ground the morning of the 22nd, as part of the snow melted
as it fell. Record lows of 32 degrees were reported both days, the evening of the
21st and early morning of the 22nd, mainly during the snowfall. In addition, a record
low maximum of just 41 degrees was recorded on the 22nd! Normal highs for that late 
in May are lower 70s while lows in the lower 50s! Therefore; the temperature average
for May 22nd, 1883 was 37 degrees or 25 degrees below normal /62/, extraordinary for any 
winter month - let alone late May! 
 
The Monthly Weather Review quotes Detroit as having snow on the 21st-22nd though
the amounts were not listed. I was able to pull up the daily morning weather maps
from May 21, 1883 and May 22, 1883; See for yourself, this storm along with its
development again bring up the Ohio Valley/Eastern Lakes Low development that 
matures over the East and Northeast part of the country. This type of pattern is
reminiscent of many of our major snowstorms, including the rare late season ones
discussed here.

                           SURFACE MAP OF 5/21/1883 - 7AM

                SURFACE MAP OF 5/21/1883 /Cropped and analyzed-WRD/
 
 
The central pressure of the low had deepened close to 29.30"/992 MB /lowest 
pressure analyzed 29.34 IN outside of the center/ moving into West Virginia
the morning of the 21st. The sub 40 degree temperature isotherm is entered in a 
blue dashed line.
 
                             SURFACE MAP OF 5/22/1883 - 7AM
 
 
 
 
The central pressure of the low remained close to 29.40"/995 MB /lowest pressure 
analyzed 29.47 IN outside of the center/ in the Washington DC area the morning
of the 22nd. The sub 40 degree temperature isotherm is entered in a blue dashed
line. 
 
Of course, the 500 MB upper air map was non existent for the date but can be 
extrapolated and it must have been a mighty cold upper low to support that kind
of storm and snowfall so far south, a little better than a week before June. 
 
 
Making weather fun while we all learn, 
Bill Deedler -SEMI_WeatherHistorian
 

4/19/15

A Cool Week is In-Store for Southeast Lower Michigan - Hold Off Planting Vulnerable Plants This Earth Day Week

After a relative slow slow start to April warmth; the past couple of weeks have more than made up for the cool start to spring thus far. With March averaging 2 - 3 degrees below normal, the growing season was put on hold into early April. However since April 9th, temperatures have averaged consistently above or well above normal these past 10 days or so. So much so, that the average temperature thus far April is now averaging in the upper 40s to lower 50s - or about 4 degrees ABOVE normal. The last time freezing temperatures were seen and felt was early in April on the 6th at Detroit /32/, and the 11tth at Saginaw /32/ and 12th at Flint /also 32/. In fact, sometimes it has been safe to start planting hardier crops mid to late April. Cool weather crops such as peas, broccoli, cabbage, etc etc can be usually put in at least by late April.

Therefore; is it safe to plant?

I would definitely hold off planting anything frost/freeze sensitive that will germinate the next week to 10 days. A pronounced cool spell through this upcoming week anyway, will definitely take a bite out if that above normal average temperature accumulated this month. A return upper wind flow, back cross Polar will take  hold this week. This pattern is much like the bitter cold, cross Polar flow seen recently in mid to late winter. Of course, the air has moderated some since then and will continue as the solar angle increases with the spring but will still carry a punch. Frost, freezes and possibly even a period or two of snow flurries are all in our near term weather scenario. The outcome will depend on the actual coldness of the air mass over the region and whether or not cloud, cover dissipates overnight allowing for good radiational cooling along with local temperature affects.

 
As noted in my map above, Earth Day is this Wednesday. It is what it says, a day to reflect on our mother planet and to appreciate our life giving environment. Earth Day began in the early 1970s as we became more and more concerned about our pollution of environment and the longer term affects.

Earth Day Flag


Next up - Record Breaking Late Spring Snowstorms & What's May looking like?

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


4/8/15

-Update 4/9/15: Stormy April Beginning To Come To Fruition: Severe Weather Potential 4/9-10

Quick Update This Evening Into Friday - 4/9/15

Very little change from yesterday's blog with timing issues and low level stability major deterrents for an organized outbreak of severe weather. If anything; all things considered now, any organized severe weather looks doubtful with the strongest weather /winds/ coming in isolated strong storm/severe, ahead of and along the cold front overnight and toward morning. Widespread strong winds are expected after cold frontal passage near sunrise (as stated yesterday, see next paragraph below). Winds on Friday look to rev-up to between 25 - 40 MPH with gusts possible 40 - 50.


-4/8/15
Review
Overall with the data I've looked at as of the 18Z GFS Wed 4/8 run, I see the best (or worst if you prefer) of the strong weather, mainly west, southwest and south of Southeast Lower Michigan. This mainly because of late timing issues and somewhat out of alignment severe weather parameters.

Thunderstorms look likely, some elevated and some strong to possibly a few severe with gusty damaging winds, mainly from late afternoon into the over night hours with the evolving squall line. However, the strongest of winds could very well be behind the line of storms, the early part of Friday.

 Any notable changes, look for updates.
______________________________________________________________________________
It was just last week when I called for a stormier April and now we have out first potential severe weather event, Thursday into early the morning hours of Friday. It's been relatively calm too long and mainly due to the the overhang of cold, Polar air over the region. This brought the colder than average March but with the change of the month, came a change in the over weather and temperatures pattern and - the springtime conflict of air masses. With the strengthening heating of the atmosphere comes the usual air mass battle and resultant storms and severe weather.

It's been relatively calm across the country this spring as the cool, stabilizing residual Polar air masses continued to slide down across Canada into the eastern half of the country while this has brought a slow start to spring across much of the Great Lakes and Northeast, it also has kept severe weather basically at bay. In addition the near freezing waters of the northern Great Lakes basically, 30s to lower 40s over the southern Great Lakes have a remarkable effect of local and downwind areas. Today is an excellent example of the contrasting low level air masses across a rather small region of the country. The combination of a cold polar high pressure in southeast Canada and its attending northeast wind across the icy Great Lakes, show the strength of air masses in this classic early spring weather pattern. Meanwhile, much warmer (some places close to 40 degrees) bubbles up from the south and southwest as warm spring-like winds push rudely northeast into this cold, stable dome of air. Below, look at the contrasting temperatures of both air masses over the Great Lakes and Northern Ohio Valley.

Water Temperatures remain in the 30s to lower 40s over the Eastern Great Lakes.
(Click on ALL maps for larger depiction and clarity)















 Great Lakes Surface Map as of 5PM 4/8/15


Outstanding, all that's needed to mix up these opposing foe's is some sort of catalyst to come along and surge one air mass into the other. Cue surface/instability maps for Thu into Fri>>>>

During Thursday:
The warm front pushes north through the lower Great Lakes by early evening along with ushering in more unstable air and decent helecity (which aids in the development of tornadoes). Storm Relative Helicity (third map) along a warm front is generally where it is best available because of the clockwise turn of the air from the colder air mass to the north and east to the warmer air mass south and southwest. Therefore, east to southeast winds gradually turn to south and southwest in the lowest layers of the atmosphere. The Storm Relative Helicity Index map relates those numbers, the higher the number the more likely of tornadic storms using the scale below (third map). One very important caveat to remember however, is that strong instability (CAPE/LI/Bulk Shear among other parameters) is also needed. Many times, one of these parameters may blow the roof off (no pun intended) but with the absence of another, severe weather fails to materialize.



 

GFS 18Z SKEWt

beta.wxcaster.com/cgi-bin/parse_skewt_trace_all.cgi?model=GFS&STATIONID=DTW


DATA TABLE
    Helicity Amount of Rotation
> 100 Some storm rotation
>  250 Enough rotation to support supercell thunderstorms
    and some tornadoes
>  400 Enough rotation to support dangerous tornadic thunderstorms



5PM 4/8/15 - Helecity





 8PM 4/8/15 - Helecity


GFS 03z SKEWt

Note that while helicty remains potent, the atmosphere begins to stabilize as nightfall overtakes the region, particularity so early in the heating season. April severe weather events can be one of the most extreme events because of strong, almost winter-like dynamics (wind fields/energy) feeding the low pressure storm system. And, when strong winter-like dynamics meet up with spring or even summer-like air masses all hell can break loose.
11pm Thu - Helecity








The bulk shear here at 7AM Fri pushes through Southeast Lower Michigan just on the heels of the line of convection. Strong winds indicated aloft behind the line of storms will blast down to the surface behind the front bringing strong, gusty surface winds!


Review
Overall with the data I've looked at as of the 18Z GFS Wed 4/8 run, I see the best (or worst if you prefer) of the strong weather, mainly west, southwest and south of Southeast Lower Michigan. This mainly because of late timing issues and somewhat out of alignment severe weather parameters.

Thunderstorms look likely, some elevated and some strong to possibly a few severe with gusty damaging winds, mainly from late afternoon into the over night hours with the evolving squall line. However, the strongest of winds could very well be behind the line of storms, the early part of Friday.

Any notable changes, look for updates.


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

SPC Severe Weather Outlook Issued Wednesday afternoon





 SPC AC 081730

   DAY 2 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1230 PM CDT WED APR 08 2015

   VALID 091200Z - 101200Z

...THERE IS AN ENH RISK OF SVR TSTMS THURSDAY AFTERNOON AND EVENING ACROSS PARTS OF SOUTHERN GREAT LAKES REGION AND LOWER OHIO VALLEY...SOUTHWARD THROUGH THE OZARK PLATEAU AND ARKLATEX REGION...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE ENH RISK
AREA...ACROSS THE GREAT LAKES REGION AND OHIO      VALLEY...SOUTHWARD  INTO THE SOUTHEASTERN PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS AS FAR SOUTHEAST AS THE EDWARDS  PLATEAU AND ADJACENT PORTIONS OF THE RIO GRANDE VALLEY...

   ...SUMMARY...
 SEVERE THUNDERSTORMS ARE LIKELY THURSDAY INTO THURSDAY NIGHT ACROSS  SOUTHERN PORTIONS OF THE GREAT LAKES REGION...AND MUCH OF THE MIDDLE  MISSISSIPPI AND OHIO VALLEYS INTO THE SOUTHEASTERN PLAINS.  THIS WILL INCLUDE THE RISK FOR DAMAGING WIND GUSTS AND LARGE HAIL.  A  COUPLE OF STRONG TORNADOES ARE POSSIBLE.

   ...SYNOPSIS...
A SIGNIFICANT IMPULSE...WITHIN THE SOUTHERN BRANCH OF SPLIT
WESTERLIES EMERGING FROM THE MID-LATITUDE PACIFIC...IS FORECAST TO CONTINUE AN EAST NORTHEASTWARD ACCELERATION OUT OF THE GREAT BASIN DURING THIS PERIOD.  THIS FEATURE IS EXPECTED TO REACH THE CENTRAL  HIGH PLAINS BY 12Z THURSDAY...AND THE UPPER MIDWEST BY THURSDAY NIGHT...WHERE/WHEN MODELS SUGGEST THAT IT MAY INCREASINGLY PHASE WITH A SIGNIFICANT NORTHERN STREAM IMPULSE.  AS THIS OCCURS...MORE SUBSTANTIVE DEEPENING OF AN ASSOCIATED SURFACE CYCLONE...EMERGING FROM THE CENTRAL PLAINS...IS EXPECTED TO PROCEED ACROSS AND EAST  NORTHEAST OF THE GREAT LAKES REGION.

ALTHOUGH SUBSTANTIVE DEEPENING OF THE LOW IS NOT CURRENTLY FORECAST  AS IT TRACKS FROM THE MID MISSOURI VALLEY TOWARD LAKE MICHIGAN DURING THE DAY THURSDAY...IT STILL IS EXPECTED TO BE AT LEAST MODERATELY STRONG WITH LOWEST PRESSURES AT OR BELOW 1000 MB.  A TRAILING SURFACE COLD FRONT APPEARS LIKELY TO ADVANCE SOUTHWARD THROUGH THE MIDDLE MISSISSIPPI VALLEY AND PORTIONS OF THE OZARK PLATEAU AND SOUTHEASTERN PLAINS...WHERE IT WILL GRADUALLY OVERTAKE A WELL-DEFINED DRYLINE.  A WARM FRONT EAST OF THE LOW APPEARS LIKELY TO ADVANCE NORTHWARD THROUGH THE GREAT LAKES REGION...WHILE COLD AIR REMAINS DAMMED TO THE EAST OF MUCH OF THE NORTHERN AND CENTRAL APPALACHIANS.

AIDED BY THE PRESENCE OF MOIST AND POTENTIALLY UNSTABLE AIR IN THE WARM SECTOR OF THE CYCLONE...LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION SHOULD BE SUFFICIENT TO SUPPORT WIDESPREAD THUNDERSTORM  ACTIVITY...FROM THE MISSISSIPPI VALLEY AND SOUTHEASTERN PLAINS INTO THE APPALACHIANS...PERHAPS PORTIONS OF THE PIEDMONT TO THE EAST OF THE SOUTHERN APPALACHIANS.  IN THE PRESENCE OF MODERATELY STRONG...40-50 KT DEEP LAYER MEAN FLOW AND DEEP LAYER SHEAR...ANUMBER OF THESE STORMS MAY BECOME SEVERE.  MUCH OF THIS ACTIVITY  SEEMS LIKELY TO BE FOCUSED ON THE AFOREMENTIONED SURFACE BOUNDARIES...PARTICULARLY ALONG THE SOUTHEASTWARD SURGING
FRONT/DRYLINE ACROSS THE OHIO VALLEY INTO SOUTHEASTERN PLAINS BY  THURSDAY EVENING.

   ...GREAT LAKES/OHIO VALLEY INTO SOUTHEASTERN PLAINS...
MODELOUTPUT IS SUGGESTIVE THAT DEEPER/RICHER BOUNDARY LAYER  MOISTENING MAY BE CONFINED TO A RELATIVELY NARROW CORRIDOR IN  ADVANCE OF THE COLD FRONT.  AND CONSIDERABLE CONVECTIVE ACTIVITY MAY  BE ONGOING IN THE WARM SECTOR ACROSS PARTS OF THE MIDDLE MISSISSIPPI   AND OHIO VALLEYS AT THE OUTSET OF THE PERIOD.  BY 12Z THURSDAY...IT ALSO APPEARS THAT THERE MAY BE CONSIDERABLE STABILIZATION OF THE  BROAD AREA OF STEEP MID-LEVEL LAPSE RATES NOW PRESENT ACROSS THE  PLAINS INTO THE VICINITY OF THE APPALACHIANS.  THESE FACTORS...AMONG
OTHERS...MAY BE LIMITING FACTORS TO A POTENTIALLY MORE SUBSTANTIVE   SEVERE WEATHER RISK FOR THIS PERIOD.

  STILL...GIVEN THE LARGE-SCALE FORCING AND STRENGTH OF DEEP LAYER   FLOW/SHEAR...INCLUDING A RATHER BROAD AREA OF 40-50 KT SOUTH   SOUTHWESTERLY 850 MB FLOW DURING THE DAY...THE ENVIRONMENT WILL BE  CONDUCIVE TO ORGANIZED CONVECTIVE DEVELOPMENT...INCLUDING SUPERCELLS.  AND POCKETS OF STRONGER DESTABILIZATION COULD YIELD  SCATTERED AREAS WITH POTENTIAL FOR INTENSE SUPERCELLS CAPABLE OF   PRODUCING A STRONG TORNADO OR TWO...IN ADDITION TO VERY LARGE HAIL.

IT IS POSSIBLE THAT ONE OF THESE AREAS COULD DEVELOP NEAR THE WARM   FRONT...IN THE VICINITY OF THE SURFACE LOW...ACROSS PARTS OF   NORTHERN ILLINOIS...INCLUDING THE CHICAGO METRO AREA...
DURING THE MIDDAY AND AFTERNOON HOURS.  ANOTHER COULD DEVELOP NEAR  THE COLD FRONT/DRY LINE INTERSECTION...ACROSS PARTS OF THE OZARK  PLATEAU AND ARKLATEX REGION DURING THE LATE AFTERNOON AND EVENING.    HOWEVER...TOO MUCH UNCERTAINTY CURRENTLY EXISTS CONCERNING COVERAGE  AND AREA TO SUPPORT 10 PERCENT SIGNIFICANT SEVERE WEATHER  PROBABILITIES AT THE PRESENT TIME.   OTHERWISE...DAMAGING CONVECTIVE SURFACE GUSTS MAY EVENTUALLY BECOME  THE MOST PROMINENT SEVERE WEATHER THREAT WITH AN EVOLVING SQUALL  LINE ALONG/AHEAD OF THE COLD FRONT BY THURSDAY EVENING.

   ..KERR.. 04/08/2015

4/6/15

50TH ANNIVERSARY OF THE PALM SUNDAY TORNADO OUTBREAK OF 1965 AND RECALLING THE SUPER OUTBREAK OF 1974

After we just celebrated Easter Sunday and Passover this year; many meteorologists, severe weather buffs and weather enthusiasts will also recall three of the worst tornado outbreaks ever to affect the southern Great Lakes and/or the Ohio/Tennessee Valleys in April.

 

Fifty years ago this Saturday /11th/, in the Palm Sunday Outbreak 1965, even though just a child, I recall that the afternoon and evening's violent display of weather; once again sparked my interest in weather while riding back in the car from my grandparents in Marine City (along the St. Clair River). The churning, violent sky gave birth to vivid lightning as it cascaded across the sky. I remember my dad trying to tune into the AM radio stations to little avail as static from continuous strikes of lightning plagued the airways. Little did I know, decades later I would write about that terrible outbreak back in 2005 while in the NWS, updated in 2012 and 2015. 

 

In addition, I included the Super Outbreak of 1974 (anniversary, April 3) written by NOAA/NWS in that Palm Sunday Outbreak 1965 article (see below).  I remember the 1974 Outbreak much more vividly as I was in my first year with the NWS. Fortunately for us; Southeast Michigan was on the extreme northern fringe of that terrible Outbreak. And finally; up until April 27, 2011 which exceeded it, it was known as the worst tornado outbreak ever to hit the country. 

 

Coincidentally and rather eerily, I began my career with the NWS working part time early in 1974 when the April 3rd, 1974 Outbreak occurred and retired just days before the April 27th, 2011 Outbreak, that superseded it.

 

PALM SUNDAY TORNADO OUTBREAK
APRIL 11TH, 1965

Written by: William R. Deedler, Weather Historian
March, 2005,2012,2015

The Palm Sunday Tornado Outbreak occurred on April 11th, 1965 with the violent storms tearing through much of the Southern Great Lakes Region and Northern Ohio Valley. The worst hit states were Michigan, Indiana and Ohio. It is the third biggest tornado outbreak on record; 47 confirmed tornadoes resulted in 271 people killed and 3,400 people injured in just a twelve hour span. Damages from the storms mounted to more than 200 million dollars (1.5 billion/2015 dollars). Only the "Super Outbreaks" of April 3rd, 1974 and April 27th, 2011 were worse. This write-up is mainly from a Southeast Lower Michigan perspective with some data taken directly from the NWS Storm Data files.

COLD MARCH LION PROCEEDS PALM SUNDAY STORMS

March of 1965 had been a cold and stormy spring month (several degrees below normal, ranking in the top twenty listings for coldest and snowiest Marches at some locations) in Southeast Lower Michigan with several rounds of heavy rain and snow which lasted into early April. There really had been no surge of warm spring weather to speak of that year until the first week of April, the week which preceded the second biggest tornado outbreak in recorded history. During that first week of April, temperatures surged quickly up to near 70 degrees on the 6th but then, just as quickly, they were knocked back down into the 40s again by yet another chilly air mass on the 8th. Palm Sunday weekend (10-11th) started out calm enough with temperatures actually rising up to near normal levels (mid 50s) under partly sunny skies on Saturday. Many meteorologist eyes, however, were focused on the strong mid and upper level jet stream surging across the Southern Plains into the Midwest later Saturday. In retrospect, this was the harbinger of the rough times that lay ahead, the vicious Palm Sunday Tornado outbreak.

PALM SUNDAY

500 MB chart from 7 am EST, April 11, 1965; click on image to enlarge The strong jet core extended throughout all levels of the atmosphere as of Palm Sunday morning. At 850 MB (5000 FT), a 50 to 60 knot west southwest wind could be found over the Southern Plains moving through Kansas into Missouri, while at the 700 MB (10,000 FT) level, a 70 knot wind maximum was surging northeast across the Texas Panhandle into Oklahoma. Higher up, from the 500 MB to 300 MB (18,000 - 30,000 FT) layer, incredibly strong maximum winds of 120-150 knots extended from the Desert Southwest into the Southern Plains.

Surface chart from 7 am EST, April 11, 1965; click on image to enlarge
At the same time, and in response to the strengthening upper level winds, a deepening surface low pressure system was taking shape over the Midwest. This intensifying low pressure, central pressure at 990 MB (or about 29.20") moved east northeast into Iowa by the forenoon hours of Palm Sunday. Its attending warm front surged northward into Southern Indiana and Ohio, while the 850 MB warm front pushed north into Southern Lower Michigan. As this warmer, more unstable air aloft approached Southern Lower Michigan, scattered thunderstorms were triggered during the pre-dawn hours. A thunderstorm was ongoing at both Detroit City and Metropolitan airports as of the 400 AM EST observation (Detroit City Airport was the official climate observing site for Detroit at the time and this was transferred to Metro Airport just a year later in April 1966).


500 MB chart from 7 pm EST, April 11, 1965; click on image to enlarge Temperatures climbed up through the 40s over Southern Lower Michigan during the forenoon hours of Sunday, while behind the warm front (along the Ohio River), readings rose into the mid 70s and were accompanied by dew points in the lower to mid 60s. Early in the day, the surface warm front surged rapidly northeast, aided by the strong south winds of 20 to 30 mph at the surface (and as mentioned earlier, much stronger aloft). During the early afternoon hours, the warm front pushed northeast into extreme Southeast Lower Michigan. With the passage of the front, skies broke out which allowed some sunshine to aid in raising the temperatures into the mid 60s to lower 70s by mid afternoon. Dew points followed right along for the ride, rising from the lower 40s early in the day, to the lower 60s by mid afternoon. This helped set the stage for the violent weather that was to explode shortly over the Lower Great Lakes and Northern Ohio Valley.

Map of tornado tracks; click on image to enlarge
The deepening low pressure system and attending fronts began spawning severe thunderstorms and tornadoes over Eastern Iowa, Extreme Southern Wisconsin and Extreme Northern Illinois early that Palm Sunday afternoon. Along with numerous severe thunderstorms, up to 13 major tornadoes swirled violently through that region. As the low pressure center pushed east northeast across Central Wisconsin, the strong jet core of upper winds began to surge northeast into the Lower Great Lakes Region. Severe thunderstorms blossomed out ahead of the swiftly moving cold front, which extended in an arc from the greater Chicago area south southeast across extreme western Indiana along the instability axis. The first tornadoes spawned in the tri-state area (Michigan-Indiana-Ohio) developed quickly and in rapid succession over Extreme Northern Indiana (see map of tornado tracks) starting 545 PM EST, then 613 PM, 618 PM, another at 625 PM and on and on.

It was also just about this time that severe thunderstorms moved onshore into Western Lower Michigan from Lake Michigan. The storms extended from Muskegon southward to the Holland area. At 630 PM EST, one tornado (F3) touched down in Kalamazoo County, while another tornado (F4) developed at 650 PM EST and moved across Ottawa and Kent counties. Still, another complex of severe storms ignited more strong tornadoes over Central Indiana, starting just after 6 PM EST.

CLOSER TO HOME: TERRIBLE TWOS

Detroit Radar (per NWS/DTW right; Fujita et al. MWR, 1970) showed a rapid increase in thunderstorms over West Central and Southwest Lower Michigan and Northern Indiana by late afternoon. Storm movement was pegged east northeast at around 70 mph! As these storms roared into South-Central Lower Michigan, two horrible twisters were spawned over Branch County, one at East Gilead at 715 PM EST and the other, just a half hour later, southwest of Kinderhook (or, nearly in the same spot as the first). The first tornado seemed to be the most intense and may have caused the most deaths. After striking East Gilead, the storm tracked across Coldwater Lake and damaged several homes along its path. It was about this time (1/2 hour later) that the second twister took off, also plowing across Branch County in nearly the same path as the first. Branch County was hardest hit with at least 19 people killed and about 200 injured, with just under 200 homes destroyed and $20 million (149 million/2015 dollars) in damages.

The tornadoes then sped quickly across Hillsdale County, both tracking just south of the town of Hillsdale. So identical where the tornado paths at this point, that the second tornado actually leveled much of the remaining standing parts of homes hit by the first tornado! At least 11 people were killed in Hillsdale County by these storms along with at least $7 million (52 million/2015 dollars) in damages, including the 177 homes leveled. As the tornadoes crossed into Lenawee County, about 100 vacation homes (cottages) were torn apart on Devil's Lake at Manitou Beach but fortunately, being early April, most were vacant at the time. However, just south of Manitou Beach, the Manitou Beach Baptist Church was destroyed, burying 26 people alive under its debris. Miraculously, only one man died later from his injuries sustained at the church. Five miles south of Manitou Beach, a family in a home did not fare as well with six members of the family perishing in the storm!

Wind gusts recorded in Tecumseh, MI; click on image to enlarge The damage path from these terrible two tornadoes extended at one point up to four miles wide, though some of this damage might well have been also due to straight line winds. At least 14 people were killed in Lenawee County with damages amounting to $5 million (37 million/2015 dollars) and 189 homes destroyed. In the four counties, 44 people were killed along with 612 injured with property damages amounting to around $32 million (238 million/2015 dollars). These tornadoes were ranked an F4 on the Fujita Scale and their total paths were about 90 miles long. The tornadoes dissipated over extreme Northern Monroe County east of Milan. During these two monsters lives, over a thousand (1026) buildings were damaged along with countless vehicles (cars, trucks, boats, etc). With all the destruction that these two tornadoes brought to the area, we were fortunate to capture the wind gusts on a rather resilient wind gust recorder at Tecumseh in Lenawee County.

OTHER TORNADO "FAMILY" MEMBERS CAUSE HAVOC IN SOUTHEAST LOWER MICHIGAN

Another F4 tornado touched down at 815 PM EST and roared across Clinton County into Shiawassee. The path of this tornado was about 20 miles long at extended from just south of Dewitt (in Southern Clinton County), east northeast to Bennington (or just southwest of Owosso). A nine-year old girl was killed and six homes were destroyed in Clinton County, while three more homes were destroyed in Shiawassee County.

As 9 PM EST approached, two weaker F2 tornadoes appeared farther north in Bay and Tuscola counties. One tornado touched down at 850 PM EST in Bay County at Portsmouth Township and tore the roofs off some buildings and destroyed a few barns and trailers before moving out over Saginaw Bay. At 9 PM EST, another F2 tornado dropped down out of the sky over Tuscola County; it then moved east northeast for 10 miles ending at the town of Unionville. Some barns and a lumberyard were demolished along the ten mile path. There were no deaths and only two injuries with these two tornadoes.

A final tornado (another killer F4) touched down near the Michigan/Ohio State line (mainly on the north side of Toledo) at approximately 930 PM EST. The storm tracked east northeast and caught the extreme southeast tip of Monroe County. The worst damage from this tornado occurred on the north side of Toledo with 16 people killed in Ohio and two in Michigan. About 50 homes were destroyed along with a bus that was picked up and slammed down on I-75, killing four people. Damages with this tornado amounted to around $25 million (186 million/2015 dollars).

Much of the Detroit Metro Area observed strong to severe thunderstorms with very heavy rainfall as the intense low pressure system and strong cold front surged through Lower Michigan that night. Both Detroit City and Metropolitan Airports received about 1.5 inches of rain, whereas Flint measured just a quarter of an inch (.25). As the system moved into Canada, it put an end to the severe weather (well, almost). Very strong isobaric winds encompassed the region behind the storm center on Monday morning, the 12th, with Detroit City Airport (which at that time, housed the wind gust equipment) clocking a west northwest wind gust at 55 mph!

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

4/1/15

March Was Pretty Much Cool, Calm and Collected But What About April? And, Are We Done With Snow?

-4/3/15 Quick Update for overnight and Easter:

Occasional light rain will become mixed with and change to snow overnight with any accumulation an inch or less on grassy areas. Easter looks similar especially across the metro Detroit northward in Southeast Lower Michigan. Temperatures will be below normal over the weekend.

--------------

4/1/15

March was a rather unusually calm month over the region with well below normal precipitation and snow along with below normal temperatures. The pattern followed previous analogue patterns discussed in my Spring Outlook and my forecast. March was anticipated to contain below normal temperatures and precipitation.

Temperatures:  Below into mid Spring (March-April)
Snowfall:          Snowfall should end up around normal to above over the
                        southern sections of Southeast Lower Michigan and normal to
                        locally below northern sections for the cold season.

Precipitation:   Normal to below.

That's not to say the month didn't contain some nice spring days but the colder than normal days out did any warmer with readings averaging two to three degrees below normal. This is certainly better than last March when March averaged eight and a half degrees below normal with much more snowfall /12.5"/ at Detroit.
 
Temperatures / Precipitation / Snowfall for March 2015 
DETROIT
Average Mean Temp 34.5/-2.7
Precipitation .80/-1.48
Snowfall 2.8"/-4.7


April's Outlook: Stormy?

Latest model trends and past analogues suggest things are about to become busier across the Great Lakes as the predominant southern storm track lifts northward with the springtime warmth. As like last year; spring has gotten off to a later start across the Great Lakes with the jet stream staying mainly south and subsequently, warmer temperatures and precipitation on average also stayed south. This is not unusual, especially when the latter part of winter was so bitterly cold and the Great Lakes reaching 88% ice covered late February. When we are surrounded by a giant bowl of ice, it's bound to affect low level warmth early spring.

First things first; Upcoming Easter Period

Over the past few weeks; all guidance had been intimating a change late in March into early April in the jet stream and relating surface patterns. Stronger warmer and contrasting cold patterns, very typical of March into April was forecast to finally arrive bringing a stormier pattern that had been lacking in March. This had been on tap to begin with earnest the advent of April including Easter week and weekend. The main issues of course have been what, when and where as with all weather phenomenon.

Thunderstorms? It's been awhile...
 
Look for more spring-like days in the very near term Wednesday and especially, Thursday as a strong warming behind a warm front will push temperatures well into the 60s and possibly lower 70s. Unfortunately, a equally strong cold front will create a band of showers and scattered thunderstorms on Thursday. It's been quite awhile since we had thunderstorms across the region; in fact one has to look back to October! Both Detroit and Flint officially last reported a thunderstorm on October 28th while Saginaw hasn't seen one since October 3rd...all over five months. On average, Southeast Lower Michigan experiences two or three thunderstorm days during that five month cool period.


If you think we are done with snowfall, think again...

Yes, no sooner do we get a better taste of spring and we are slammed with colder air and the risk of snow, measurable snow. Latest indications which has the definite support of climate statistics say no; we aren't done with snow. On the climatological statistical side of things, we average at least a few inches of snow over Southeast Lower Michigan in April. We've had some decent (or indecent depending your point of view) snowstorms in April with the largest ever recorded in Detroit April 6th, 1886 with 24.5". On the model side of things; we may get our chance to get measurable snow Friday night (no, nothing like 1886) and possibly even again, Easter Sunday itself. At this time, Friday night into Saturday morning shows the best chance for snow across Southeast Lower Michigan as a wave of low pressure slides northeast through the upper Ohio Valley, along the cold front that is expected through here early Friday. Some models push it further south however, so it still isn't written in snow. ;-)



I'll update when things look more certain as these times approach for Easter Weekend.

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

3/10/15

Second Cold Winter is in the Books! So Let's Look at Those Cold Temperature Statistics

Our second cold winter is in the books across Southeast Lower Michigan; so let's look at those cold statistics and compare them to last winter's. In addition, I'll compare the actual temperature statistics of this winter to my Winter Outlook's forecast issued last fall. Some of the things worth noting is that even though this past Winter of 2014-15 did average higher than the Winter of 2013-14; it was still a cold enough winter to land in the top 20 coldest winters list of Southeast Lower Michigan. The bowels of the cold occurred in February which was an incredibly cold month by any winter month standards, placing in the top five spots for coldest Februaries and all time months. It was the second very notable cold February in a row for Southeast Lower Michigan. In addition, by far February was most notable winter month for snowfall. Ironically, last winter it was January that was the most notable for cold and snow. I'll discuss more about the snowfall and storms in an update on the winter after the snow season ends.

Winter 2014-15 Temperature Statistics

Location Winter 2014-15 Coldest Winter Since
2014-15 Ranking All-time Coldest
Detroit
23.0/-4.9
1977-78
18th-T 18.8 (1903-04)
Flint
21.7/-3.3
1978-79 17th 16.7 (1976-77)
Saginaw
21.5/-3.2
1978-79
20th 15.7 (1962-63)

T denotes Winter 2014-15 tied with 1958-59

                                   Winter 2013-14 Temperature Statistics
Location Winter 2013-14 Coldest Winter Since
2013-14 Ranking All-time Coldest
Detroit 20.9 1977-78
8th 18.8 (1903-04)
Flint 19.0 1978-79 5th 16.7 (1976-77)
Saginaw 18.2 1978-79
7th 15.7 (1962-63)

  

Top 20 Coldest/Warmest Februaries in Southeast Lower Michigan
 
Rank Detroit Area* Flint Bishop** Saginaw Area***
Coldest Warmest Coldest Warmest Coldest Warmest
Temp Year Temp Year Temp Year Temp Year Temp Year Temp Year
1 12.2 1875 39.5 1882 11.3 2015 34.5 1998 11.5 2015 33.4 1998
2 14.1 2015 36.7 1998 12.8 1979 31.8 1983 12.1 1979 31.5 1984
3 14.8 1934 33.8 1930 13.4 1978 31.2 1984 13.0 1914 30.7 1932
4 16.0 1936 33.6 1877 14.9 1963 31.1 1930 13.2 1963 30.7 1930
5 16.1 1904 33.5 1954 16.0 2014 31.1 1932 13.4 1934 30.6 1931
6 16.3 1978 33.3 1984 16.4 1936 31.1 1927 13.6 1978 30.5 1999
7 16.4 1979 33.3 1976 17.1 1934 31.0 2012 13.6 1936 30.3 2012
8 16.5 1901 33.0 1932 17.3 2007 31.0 1976 14.3 1917 29.9 1954
9 17.2 1885 32.9 2002 18.3 1967 31.0 1931 15.5 2014 29.1 1983
10 17.6 1914 32.8 1931 18.4 1994 30.9 1999 16.8 2007 29.0 1938
11 17.9 1905 32.7 1999 18.5 1923 30.8 1954 16.9 1962 28.9 1976
12 17.9 1895 32.6 2012 18.7 1958 30.1 1938 16.9 1994 28.8 2002
13 18.3 1912 32.6 1890 19.9 1942 30.0 2002 16.9 1912 28.3 2000
14 18.8 1963 32.1 1953 20.0 1962 29.4 1992 17.1 1923 28.2 1921
15 19.3 2007 32.1 1880 20.0 1959 29.3 2000 17.4 1916 28.1 1927
16 19.4 2014 31.8 2000 20.1 1988 29.2 1991 17.8 1920 28.1 1915
17 19.5 1917 31.8 1927 20.2 1982 28.8 1953 18.5 2003 28.0 1991
18 19.8 1899 31.6 1983 20.3 1980 28.7 1987 18.6 1967 28.0 1987
19 19.8 1889 31.2 1991 20.3 1929 28.2 1981 18.9 1958 27.7 1992
20 20.7 1982 31.2 1938 20.5 2003 27.9 1925 18.9 1913 27.7 1937
* Detroit Area temperature records date back to January 1874.
** Flint Bishop temperature records date back to January 1921.
*** Saginaw Area temperature records date back to January 1912.


While the listing of the coldest months has yet to be updated at the NWS to include February 2015, it is easy to see where each site would place with the February temperatures available. Detroit's average of 14.1 would place this past February in fifth place. Flint's average of 11.3 secures a second coldest month placement while Saginaw's reading of 11.5 degrees just jumps ahead of 11.6/Jan 1963 for third place.



Top 20 Coldest/Warmest Months in Southeast Lower Michigan
 
Rank Detroit Area* Flint Bishop** Saginaw Area***
Coldest Warmest Coldest Warmest Coldest Warmest
Temp Year Temp Year Temp Year Temp Year Temp Year Temp Year
1 12.2 Feb-1875 79.0 Jul-1955 10.9 Jan-1977 78.0 Jul-1921 9.4 Jan-1912 77.5 Jul-1921
2 12.8 Jan-1977 79.0 Jul-1921 12.8 Feb-1979 77.7 Jul-1935 10.4 Jan-1918 76.8 Jul-1916
3 13.1 Jan-1912 77.9 Jul-1916 13.1 Jan-1963 76.7 Jul-1934 11.6 Jan-1963 76.2 Jul-1935
4 13.2 Jan-1918 77.7 Jul-1931 13.4 Feb-1978 76.5 Jul-1955 11.7 Feb-1904 76.0 Jul-1931

14.8 Feb-1934 77.1 Aug-1995 13.8 Jan-1994 76.1 Jul-1931 12.1 Jan-1994 75.9 Jul-1955
    5  -  14.1 Feb-2015                     2 - 11.3                              3 - 11.5


Even with considerably less snow than our all out snowy winter of 2013-14; all cities managed to place in the snowiest list for February. Again, more on the snow side of the winter in successive blogs.

Top 20 Snowiest/Snowless Februaries in Southeast Lower Michigan
 
Rank Detroit Area* Flint Bishop** Saginaw Area***
Snowiest Snowless Snowiest Snowless Snowiest Snowless
Total Year Total Year Total Year Total Year Total Year Total Year
1 38.4 1908 0.0 1998 31.7 2011 0.4 1998 34.2 2008 0.0 1987
2 31.7 2011 0.7 1953 29.4 2008 1.4 1992 29.4 2011 0.1 1984
3 28.4 1881 0.9 2004 21.8 2014 2.2 1987 23.4 1935 0.5 1998
4 28.0 1900 1.5 1895 21.2 2010 2.4 1953 22.2 2013 1.4 1983
5 27.6 1926 1.6 1906 20.8 1990 2.4 1937 20.3 1965 1.9 1977
6 27.0 2010 2.0 1987 20.6 1986 2.9 1969 20.0 1912 2.0 1932
7 26.4 2015 2.1 1882 20.1 1994 2.9 1943 19.8 1985 2.1 1980
8 24.2 2008 2.2 1915 19.7 1965 3.0 1979 18.6 1926 2.2 1947
9 23.5 2013 2.3 1969 19.6 1988 3.0 1934 18.4 1990 2.4 1942
10 23.4 2014 2.4 1992 18.3 1946 3.5 1945 18.3 2010 2.5 1969
11 20.8 1986 2.4 1937 17.4 2015 3.6 1984 18.0 2005 2.6 1928
12 19.6 1898 2.5 1966 17.2 1960 3.6 1938 17.7 1924 3.1 1995
13 19.2 2003 2.6 1891 17.0 1924 3.8 1977 17.5 1950 3.2 1919
14 19.2 1988 2.7 1943 16.7 1973 4.1 1928 17.1 1956 3.4 1958
15 18.0 1893 2.8 1968 16.6 2013 4.5 1957 17.0 2014 3.5 1963
16 17.1 1994 2.8 1925 16.5 1926 4.8 1983 17.0 2012 3.7 1957
17 16.9 1985 2.9 2001 16.3 1967 4.9 1932 16.2 2015 3.7 1917
18 16.5 1936 3.1 1949 16.1 1993 5.0 2001 16.2 1962 3.8 1913
19 16.4 1901 3.1 1919 16.1 1962 5.1 1921 16.2 1946 4.0 1964
20 15.8 1965 3.3 1886 15.7 2006 5.3 1958 16.0 1954 4.1 1938
* Detroit Area snowfall records date back to January 1880.
** Flint Bishop snowfall records date back to January 1921.
*** Saginaw Area snowfall records date back to January 1912.


             Best performing analogues with 1884-85 and 1977-78 star performers




My Winter Outlook Call back in November (from Winter Outlook for Southeast Lower Michigan)

Temperatures: Below Normal /-1.0 to -4.0 degrees of the norm/

Temperatures are more variable in this winter's analogues and guidance as opposed to last winter when nearly all headlined a cold winter. That being said, normal to below normal temperatures dominate this winter again in the analogues and is suggested in other meteorological data presented here and why the below normal temperature range of -1 to -4 degrees. The largest below normal departures this winter are projected to be south and southeast of the Great Lakes. In addition; recent past seasons along with very recent unfolding conditions and the subset of preferred analogues also predict  another colder than average winter. Analogue timing of the coldest parts of the winter varies but majority suggest temperatures most likely to be below normal mid and late winter.

Average winter temperature for Southeast Lower Michigan for the winter of 2014-15 using the three climate sites came in at 22.1 which is 3.8 below normal.

All Ten Analogue Composite Map Issued in November 2014



Five Good Call Analogue Composite Map Issued in Nov 2014 for Winter 14-15

(only three years avail for composite, 1884-85 & Dec1894 N/A)



While winter turned out cold in all five winters (looking at my analogues & three winter map), it's interesting how mild or warm the five Decembers were in all five winters (Dec 1884 & 1895 maps N/A) giving more credence to the strong likeness and accurate projections for temperature trends to this past winter.



While both January and February were colder than normal in the East, February definitely was the stand out this year and in the past. Remember, the map below doesn't include February 1885, one of our coldest Februaries in the analogues. The coldest blue anomaly approaches -10.0 normal on average for these four Februaries in the Ohio Valley, Southern Lakes and Northeast while warm weather with above to well above normal anomalies prevailed in the West.


Two Best Call Analogue Composite Maps Issued in November 2014

Unfortunately, only one of the two best analogue maps is available since the winter of 1884-85 is N/A but a great analogue none the less - as was 1977-78. Also as an added  bonus, while not nearly the strength or magnitude of Blizzard of January 26-27, 1978; this past winter also contained quite a notable snowstorm on Feb 1-2nd that brought the third biggest snowstorm amount to Metro Detroit ever (and even more than the aforementioned Blizzard of '78) with 16.7". This storm largely helped consummate the 7th snowiest February on record with 26.4" in Detroit.



More later on other noteworthy items about the Winter of 2014-15, including the final tally of snowfall for the winter.


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