Weak El Nino This Winter? Much Ado About Nothing; Winter 2012-13 Outlook - Parts 1 - 3

Winter 2012-13 Outlook For Southeast Lower Michigan
Part - 1

After last winter's outlook fiasco; I must say I and nearly all who put together an outlook last season (at least that I saw), scampered away with their tails between their legs. Yes indeed, the Winter of 2011-12 left many a meteorologist and winter weather enthusiast crushed with repeated dashed hopes of basically, winter weather! Early in the game (in fact at climatologically, winters open) I theorized that we were in for a troublesome forecastable winter.  Later in the winter; in my mid winter update 1/22/12, I discussed the relevance between the winter weather that had occurred up to that point and those exact same issues.  

On the doorstep of the new winter at hand, already there are conflicting signals about El Nino that was "supposed" to develop this fall into early winter. Granted, it was likely to be weak anyway but to me; it's really was much ado about nothing. Therefore; I will go forward with the assumption that La Nada, or a Neutral ENSO phase (with Pacific SST 3-month average temperatures in area 3.4  between -0.5 and 0.5) is in the can for this winter. With that premise in mind; generally other winter producing elements will definitely overrule the ENSO phase and thus it's importance is negligible. I've always felt the ENSO phase, unless moderate to strong, is of lesser importance than many make it out to be, especially over the eastern half of the nation. More often than not; ENSO should be down on the list of important winter influencing factors for Southeast Lower Michigan and the Great Lakes, as a whole. We'll only use it as a "square one" or beginning of this discussion. (Note; interestingly upon just checking the CPC's ENSO page; they have just "discontinued" El Nino watch, so I guess we are on the same page, anyway). 

Studying the latest actual data from the Pacific SST's show the following;

Note; the determining area 3.4 showed a slight decrease in the above normal anomalies since September, while area 4 showed a bit warmer results. In addition; in areas 1 and 2, the SST anomalies just are hovering around normal. This is suggesting if there is any El Nino, it is/would be a west based El Nino  meaning any above normal SST's will continue to reside mainly over the western and possibly central areas of the Pacific (in areas 3 and 4  and  we'll get back to its importance later in the actual winter forecast section of my Outlook).

                                                                   Areas of SST's

As stated, the beginnings of the earlier predicted El Nino have certainly sputtered in the latest analysis and  most recent model projections; which are now converging on basically aa Neutral Winter. The CFSv2 model's most recent projection (as of 11/12) reveals the following:

This obviously shows one of the main reasons why CPC discontinued the "El Nino Watch"; simply because latest model projections say there isn't going to be one or at least not during this winter. Humorously; if anything besides a Neutral pattern, the CFSv2 model even intimates it may cool enough for possibly another weak La Nina by Spring 2013. Ah the models; got-a- love em! At this time, however, the general consensus of all the models shows a downsloping toward the Neutral phase as well but with less sloping downward for the winter than the CFSv2 above.

Longer term, the ENSO cycle is evident on the graph below. The sine-wave cyclical nature of the ENSO index is apparent from the sketched-in cycle I drew. Note; La Nina years dominated from the late 1940s into the mid 1970s; then mainly El Nino years took over from the late 1970s into the mid 2000s. Recently; the cycle has been shifting to the La Nina dominant phase again.

Typical upper air patterns seen during Enso-Neutral years since 1961 are displayed below and while this pattern may very well dominate this winter; these Neutral years do not take timing (meaning; the sequence of events leading up to the Neutral conditions) into consideration. Therefore; not all of these Neutral years are analogue years to this winter simply because they were Neutral.

Part -2

Influencing Factors for the Winter 2012-13

NAO/AO
In addition; probably THE most important element in this winter's forecast and its subsequent success (especially its temperature forecast) is the dominant phase of the North Atlantic Oscillation /NAO/ along with the Arctic Oscillation /AO/ phase. As seen in the climate history chart below; whether the prevailing and projected NAO/AO is positive, neutral or negative can certainly help determine the winter's temperature and lesser extent; snowfall outcome. As an example; just with the projected Neutral (or La Nada) pattern alone, reveals the array of possibilities (highlighted) is somewhat variable. As I stated several times in the past "with a Neutral ENSO, we are totally at the mercy of the NAO/AO along with other meteorological winter influencing variables." Keeping this in mind brings the likelihood of more volatile temperatures and weather under these conditions!

Predicting the NAO/AO still remains one most elusive "nuts to crack" in the meteorological world. Even out for a week or two can be a challenge. The web site I generally go to for the prediction of the NAO/AO is at the Climate Prediction Center /CPC/ found here. An interesting experimental web site I found in projecting the NAO, AO, PNA and SST's for three months while researching for the Winter Outlook is a web site run out of University at Albany/SUNY, Albany, NY. It is done by an industrious young graduate student there named Kyle MacRitchie.  I'm still relatively new to the site but the predictions are based on current ensemble forecast data that is projected out for three months. Remember; the projection takes information from daily ensemble data so; like the ensemble data, the projections further out are subject to change, sometimes daily. Kyle also includes an "esemble variance line" projection. This shows where the esemble data is too variable for somewhat; reliable projections. He also includes his definition of the NAO/AO/PNA/SST's projections. As an example; the latest run of the NAO/AO and PNA out for three months on November 17th, 2012 shows the following:

As one can see; while the NAO projection is variable in the general sine-wave pattern, the AO has been projected (and again, as of the Nov 17th data) to be generally negative. We'll keep watch on the data through the winter for long range projections occasionally along with updates, in upcoming blogs. One thing is interesting to note, at least at this time; is the pronounced negative AO projection throughout the winter (I'm sure that will change however, at least somewhat in the succeeding days and weeks).

Snow Cover
Other theories and ideas that influence the winter somewhat over the central and eastern US is the snow cover over the northern hemisphere mid-late fall. Extensive snow cover forming October into November would tend to help "refrigerate" the cold air masses originating over Siberia and the Polar region that moved south across Canada into the states. Maps of the snow cover have been available for several years now and a "norm" has been established since 1995. The snow cover this autumn "up north" has been quite extensive to the north and northwest (see map below as of Nov 5th; note the comparison to average, in green).

From Rutgers University Snow Lab:
Across North America, snow cover extent for October 2012 was above average. Canada had much above average snow cover during the month, while the contiguous U.S. experienced below-average snow cover. The North American snow cover extent was 696,000 square km (269,000 square miles) above the long-term average of 8.1 million square km (3.1 million square miles). For the continent, above-average snow cover was observed across the Canadian Rockies and Prairies, while the U.S. Rockies and much of Alaska experienced below-average snow cover.

The Pacific Decadal Oscillation

The Pacific Decadal Oscillation (PDO) is the long-term ocean fluctuation of the Pacific Ocean. The PDO waxes and wanes approximately every 20 to 30 years. The graph below shows the cyclical nature of the PDO (like the ENSO) with its warm and cool phases. Most scientists think we have just entered the “cool” phase (see below: PDO Cycle -red arrow- during mid 2000s). The cool phase is characterized by a cool wedge of lower than normal sea-surface heights/ocean temperatures in the eastern Pacific and a warm horseshoe pattern of higher than normal sea-surface heights connecting the north. The last time the PDO trended into the negative phase was also in the early 1950s, lasting into the mid 1970s. There is good evidence by the ENSO chart (above) that during the cooler phase, La Nina’s tend to be more commonplace and last longer.

                                                                            

                                                                           PDO Cycle

The cool water anomaly below shows the lingering effect of the year old La Niña back in April 2008. The much broader area of cooler than normal water temperatures off the coast of North America from Alaska (top center) to the equator is the classic feature of the cool phase of the Pacific Decadal Oscillation /PDO/ talked about, above. The cooler waters wrap in a horseshoe shape around a core of warmer than normal water temperatures. (In the warm phase, the pattern is reversed - Image is courtesy of NASA)

                                                                             April 2008

While we are assuming mainly Neutral phase for ENSO this winter; I would be remiss if I didn't discuss where El Nino conditions do prevail (highest above normal SST's) out in the Pacific and what influence that has on the States. Referring back to part-1 of my Winter outlook, I discussed where the warmest of waters where located; out over the western Pacific. The departure map below give an idea of how west based El Nino's affect the US.

Part - 3

The Analogues

My earliest of Winter Outlooks were predicated on the analogue years I decided upon by researching basically, hemispheric conditions were of a similar nature to the upcoming winter. Interestingly; local conditions also mimicked some of the years but not always with more precedence given to the similar "preseasons". In this particular Winter 2012-13 set of analogues; the winters followed a similar sequence of events (though timing may vary a bit) that were recently observed over the Eastern Pacific during the past few seasons. La Nina prevailed during the previous winter, spring and into the summer. The second half of the year saw a gradual return to Neutral conditions such as seen this fall. While data this fall did show a trend toward a weak El Nino, a prevailing weak El Nino for the upcoming winter was discounted for reasons discussed above.

       WINTER 2012-13 ANALOGUES

Local Comparisons/Results:

TEMPERATURES:

Clearly, the trend seen in this year’s analogue winters is the dominance of below normal temperatures. Taking recent past seasons into account; it is thought the coldest of winters are too cold for our recent trend and longer term winter trend. Another trend seen during the winters may prove helpful is that there tended to be a notable period of below normal temperatures with many of the seasons showing this more likely to occur during the first half of the winter (or first half of the cold season of mid Nov-mid Mar). Many (but not all) of they analogues did reflect a harsher first half of the winter as a trend. After taking into account all the data contained in this research and displayed here, a somerwhat colder winter seems likely. Also, considering the Neutral conditions expected; this leaves the door open for variances in temperatures with wide swings.

SNOWFALLS:

Season snowfall ranges of the winters tended to be closer to normal (or a bit above  when averaged across the region). The most notable trend in the snow and precipitation this go around also happens during the first half of the winter; when snowier conditions (total snowfall thru mid winter) are projected. Though I did not post Flint and Saginaw analogues at this time; central and northern areas of Southeast Lower Michigan seemed to have the better chance of at least normal snow; while areas further south over extreme Southeast Lower Michigan (basically south of a Detroit – Ann Arbor line) showed normal to below snowfall.  Of course, this is highly dependent on storm tracks and speaking of...

UPPER WIND PATTERNS/ STORM TRACKS

The upper wind pattern averaged for all analogues is a cold one for the Northeast quarter of the country.  This not surprising since there were only two "mild" winters in the study. I used a composite of the jet streams for the analogue Winters of 1951-52 and on for the storm tracks (see map above); being they were the most pronounced however; all winters indicated a similar trend.  

The dominant upper wind jet streams this winter are projected by the analogues and also have been seen in recent fall patterns; a predominant split flow with the Arctic/Polar jet  from Canada and the sub-tropical jet in the south, both are displayed in the warm colors on the above map storm track map. These two distinctive jet streams will dominant this winter and phase. Most winter see these tracks more or less during the winter but it is their dominance that makes or breaks a snowy winter.  The most dominant of the storm tracks expected this winter are (numbered in order of precedence):

 1- Alberta Clippers bore by the northern Pacific jet and/or the Polar/Arctic jet which will usher in polar or arctic air originating from western Canada or the Arctic.

2- Two other storm tracks will be induced by later phasing of jets over the Ohio valley or up the East Coast. This pattern has already been active this fall. The storm track up the East Coast was noted more in the Neutral winters than La Nina’s especially with a negative NAO when troughing more prevalent in the eastern half of the country.  It is these two tracks which bear watching to see if strong arctic pushes of air keep more snow to the south of the region.

3- The Southern Plains/ Texas Low which we be bore over that region by phasing of the Arctic/Polar jet  from Canada and the sub-tropical jet in the south.

Composites for the Winter Analogues

The composites of the analogue winters show a broad area of below normal readings over the north-central part of the country; east across the Lakes/Ohio Valley into the Northeast. With the upper wind pattern from those winters, this isn't at all surprising. Note in the precipitation composite, the distinct "below normal-normal precipitation" region north/south over the Ohio Valley. This intimates a storm track up through the Ohio Valley just west of the Appalachians. It's also interesting to note that the East Coast averaged a bit drier, I say "averaged" that dry region could be misleading as some years may too have been wetter. What it does say is that more often than not; a storm track was in the vicinity of the Ohio Valley to the Northeast. If this bears out again; where she places will have a definite affect on our precipitation and snowfall; at least from the southern tracks.

Solar Cycles in Analogue Years

Ever since writing my Outlooks back in the mid 1990's; I've been a supporter of more research on solar cycles influence on the earths climate and even shorter term patterns. Many article have been written on researching this same topic. Scientists studying climate change are interested in understanding the effects of variations in the total and spectral solar irradiance on Earth and its climate. More and more evidence has been published on the solar cycle and its direct affect on earth's climate. One such fascinating study was done by NCAR  back on 2009 on the effects of the 11 year solar cycle and ENSO.

From the article:

"The research may pave the way toward predictions of temperature and precipitation patterns at certain times during the approximately 11-year solar cycle. These results are striking in that they point to a scientifically feasible series of events that link the 11-year solar cycle with ENSO"

                                                           

In my analogue study; one of many items I look at is the past winter analogue seasons and attending solar cycle and correlate with our upcoming Neutral 2012-13 season and current placing in the solar cycle.

All years highlighted in light blue are "close" to our current time (red x); disregarding the lowest and highest years gives us 1904-05, 1976-77 as the closest analogue winters, solar cycle speaking. The winter's of 1956-57 and 1985-86 are a close second. Taking this one step further; all those winters were on the up cycle like our present winter. Both winters of 1904-05 and 1976-77 were cold, brutal winters. The Winter temperature average of 1904-05 was 20.5; while the Winter of 1976-77 was even worse at 19.8. Many of us lived through the Winter of '76-77 and do remember it vividly. The Winter's of 1956-57 was one of two "mild" winters with an average temperature of 28.9; while the winter of 1985-86 was again colder with an average of 23.6! So; out of the four closest analogue winter's; three out of four were cold and below normal. Before we get too carried away, solar cycles are most likely to have the least affect on our winter weather! With climate change so much in the news and importance; I would surmise studies will continue to go on as to their short term affects on weather. Therefore; this section is added for interest sake only and to me anyway, it is interesting.

Summarizing:

Temperatures Look for temperatures during the winter to average below normal /-3.0 to -0.5/ compared to the 30 year /1981-2010/ normals. While the trend of our winter analogues show mainly significantly below normal; it is felt the coldest of analogues are too cold and thus skewing the average down. However, at the same time, some of the cold outbreaks seen this winter may rival some of the outbreaks seen in recent winters and thus; a colder than average winter is likely. Considering the Neutral conditions expected; this leaves the door open for variances in temperatures with wide swings. The biggest caveat will be of course, the phase of the NAO/AO and where that ridge and trough dominants during the winter! If the ridge moves inland too much and continues to cross the country like it has for so many months; I'm in trouble. I'm banking on the mother-lode of cold (upper low in Canada) to help squelch the ridge. I must say; it is hard to go below normal after what happened last year but the evidence for at least normal to below temperatures is compelling. More often than not; my analogues have held me in "good stead" as the British say (to be of great use and benefit to someone) so on with the show!       Snowfall and Rainfall: Snowfall and rainfall ranges in the Winter analogues for 2012-13 are a little closer to normal over extreme Southeast Lower Michigan (when compared to many other years I've done). Therefore, while snowfalls last season were predominantly below to well below normal; this winter indications suggest the best snows will be closer to normal (within 5 inches of). Indications are the best snows will fall  across the northern areas of the region…or from Detroit’s northern suburbs across Flint and Port Huron and on into the Saginaw Valley and Thumb Region. Near normal to below snow is expected south of a line from Ann Arbor to Detroit. The analogue winters are strongly hinting toward a two-tier snowfall pattern this winter with the heaviest amounts to the north… along with an average chance for mixed precipitation the entire region. It will be interesting to see if these particulars bear out. (See more in: Storm Tracks) Some Winter Dates: Winter Begins early on:  December 21st,  2012 @  612 AM EST Christmas:   Tuesday December 25th2012 Holiday Cold  Full Moon:   Friday December 28th, 2012 @521 AM EST New Years:  Tuesday January 1st 2013 Ground Hogs Day:   Saturday February 2nd, 2013 Valentine’s Day:  Thursday February 14th, 2013

Next : Active weather brewing for the last week of November?   Look for the details late this week. Have a Happy Thanksgiving!

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

Balmy Veteran's Day, Bone-Chilling Monday!

A very strong cold front surging east across the Midwest Sunday afternoon will be pushing aggressively through Southeast Lower Michigan early on Monday. While temperatures ahead of the front will be flirting with record highs /71-Detroit; 68-Flint; 72-Saginaw/ in the mid to upper 60s (with even a few lower 70s)  this Veteran's afternoon; behind the front will be a much different story. Temperatures will plummet some 30+ degrees from this afternoon's readings to Monday afternoon's with temperatures dropping down into the 30s during the day! Also; rain accompanying the front may mix with/or change to a bit of sleet and snow showers before ending Monday. Moderate and gusty southerly winds will shift to southwest to west on Monday.

Expect high temperatures to average below the normal highs of around 50 degrees with readings only rising into the upper 30s to mid 40s until later in the week; while lows fall well down into the 20s on the coldest mornings.

Try to get out and enjoy the brief Indian Summer-like weather while it lasts!

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

Indian Summers

A popular article on Indian Summers I wrote back in 1996 and updated and posted last Autumn; enjoy!  

 

All You Ever Wanted to Know About Indian Summers (but were afraid to ask;-) 

 

Look for my Winter Outlook 2012-13 including the latest information and new formats for the up-coming winter in mid November.

10/31/12 Update - "Wicked Witch Of The East Sandy" Winds Down With Winds Down

The following are reported wind gusts to the NWS DTX as of Tuesday, October 30th. No other later reports are available as winds have diminished across the region.

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
400 PM EDT TUE OCT 30 2012

THE FOLLOWING ARE SOME PEAK WIND GUSTS REPORTED TO THE NATIONAL
WEATHER SERVICE TODAY...AS OF 400 PM...

PORT HOPE                        55 MPH     1129 PM...
YPSILANTI                        49 MPH     825 PM...
DETROIT CITY AIRPORT             49 MPH     918 AM...
PONTIAC                          48 MPH     936 PM...
ADRIAN                           48 MPH     1132 PM...
ANN ARBOR                        46 MPH     247 AM...
DETROIT METRO AIRPORT            46 MPH     1105 PM...
FLINT                            44 MPH     1116 PM...
SAGINAW                          39 MPH     1212 AM...

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

Update 10/29/12
Latest model guidance continues to advertise historic storm "Sandy" making landfall at or near the southern New Jersey coast according to the NHC. Pressure was pegged at 943 MB and also from the 11AM EDT discussion:

RECONNAISSANCE CENTER FIXES INDICATE THAT SANDY HAS BEEN GRADUALLY
TURNING TO THE LEFT AND IS NOW MOVING NORTH-NORTHWESTWARD OR ABOUT
330/16 KT. THE LATEST RECON FIXES HAVE BEEN FALLING ON THE PREVIOUS
FORECAST TRACK...AND SO HAVE THE LATEST 12Z NHC FORECAST MODELS.
THEREFORE...NO SIGNIFICANT CHANGES TO THE ADVISORY PREVIOUS TRACK
OR REASONING ARE REQUIRED. SANDY IS NOW LOCATED NORTH OF THE AXIS
OF A STRONG NEGATIVELY TILTED MID-/UPPER-LEVEL TROUGH...AND THE
HURRICANE SHOULD TURN NORTHWESTWARD VERY SOON. LANDFALL ALONG OR
JUST SOUTH OF THE SOUTHERN NEW JERSEY COAST IS EXPECTED LATE THIS
EVENING...AT WHICH TIME A TURN TO THE WEST-NORTHWEST IS EXPECTED.

For the latest on Sandy check out NOAA/NWS Storm Central.

For our neck of the woods; I updated wind forecast slightly (mainly near Lake Huron)...upped 45 - 50 mph to 45- 55 mph and gusts near 60 per NWS High Wind Warning downwind of Lake Huron.

Generally, a stiff north wind at 15 to 25 mph with gusts in excess of 30 mph will increase further to 25 to 35 mph with gusts as high as 45 - 55 mph over Southeast Lower Michigan later today into Tuesday. Strongest winds will be down wind of Lake Huron where possible 60 MPH may occur at the height of the storm. Most areas away from Lake Huron will see winds increase further to 25 to 35 mph with gusts as high as 45 - 50 mph over Southeast Lower Michigan later today into Tuesday per original forecast. In addition, latest indications and recent air samplings indicate enough cold air will be drawn and remain in the system to bring mixed precipitation (rain/sleet and snow) at times.

From the NWS DTX; go to Web Briefing on the storm

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

10/28/2012
As of 8 PM EDT; Hurricane Sandy continues to deepen /an extraordinary 950 MB or 28.05"/ this Sunday evening off the coast of North Carolina as it moves northeast around 15 mph. She is expected to move more north and then northwest toward the coast; coming inland actually around New York City sometime late Monday evening into Tuesday morning. Maximum sustained winds as of Sunday evening remain at a minimal hurricane strength at around 75 mph.

The expected track I discussed several days ago continues to look good as she heads inland on Tuesday into Pennsylvania and then as far west as west/north-central New York state (see hurricane track above courtesy from the Hurricane Center). As mentioned in my last post; the model projection of the strong polar jet core aloft phasing into Sandy is already unfolding in the real time upper wind data. Sandy is expected to become extra-tropical before she moves inland and this extra-tropcial version will continue the brisk to strong winds and push precipitation to the west as she retrogrades as far west as the eastern Great Lakes by Tuesday. Even though Sandy is (and will remain) well east of Southeast Lower Michigan; it's biggest influence by way of buffeting gusty north winds will continue to rake the region right into Halloween (albeit; dying down somewhat by then). Generally, a stiff north wind at 15 to 25 mph with gusts in excess of 30 mph will increase further to 25 to 35 mph with gusts as high as 45 - 50 mph over Southeast Lower Michigan later Monday into Tuesday. Strongest winds will be down wind of Lake Huron.

Look for wind blown light rain to gradually spread west (with a north to south trajectory movement) over Southeast Lower Michigan by early Monday and continuing Monday night into Tuesday. There will still be the chance of more showery precipitation on Halloween. Chances of any frozen precipitation look slim as the air mass is becoming fairly homogeneous with temperatures in the lower levels of the atmosphere conducive for mainly rain. Even so; temperatures will be no picnic with readings oscillating from the mid to upper 30s at night to the lower to mid 40s during the daytime right into Halloween. The rain and very cool temperatures will make for several days of raw, cool weather for October's swan song.

Humongous storm as it is projected to look on Monday evening /18z Sun GFS run/ approaching New York City Monday evening; 8PM EDT 10/29/2012

 Then as she heads slowly west and unwinds a bit by Tuesday evening; 8PM EDT 10/30/2012

Finally on Halloween night as the "Wicked Witch from the East" (remnants of "Sandy") makes for one breezy and cool trick or treat evening; 8 PM EDT 10/31/2012

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

Previous post; 10/24/2012
Our extended meteorological models have been intimating some brew-haul of a storm developing over the Northeast quadrant of the U.S. between Tuesday and Thursday. Some earlier runs had the storm as early as Sunday or Monday but now general consensus in toward the Halloween holiday period. What makes this "model induced storm" so interesting is that is brings the remnants of tropical system "Sandy" far enough north and northwest while merging it with a strong polar jet streak. This polar jet streak will be responsible for bringing our Indiana Summer weather to an end on Saturday as it pushes a strong cold front through the region.

As all of this is still out in "la la land", changes will undoubtedly occur but at this time the models our hinting that the negative tilting trough that matures over the Lakes; will be powerful enough to grab "Sandy" and pivot it back far enough to the northwest to brush Southeast Lower Michigan by Halloween day with mixed precipitation. In any event; a huge storm blossoms over the Northeast with the GFS model projecting a 972 MB low over New York state by Halloween night. Again, this is way ahead and the way this thing has been dancing around in predictions; stay tuned for further updates and undoubtedly, some changes. At this time; it looks as though, much of the storm will be to our east.

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

10/8 Update; A Cold and Frosty Columbus Day Greets Inhabitants of Southeast Lower Michigan

Widespread frosts and areas of freezing temperatures engulfed Southeast Lower Michigan this Columbus morning under brilliant sunshine. Before that sunshine, temperatures dropped well down into the 20s and 30s at most locations. As would be expected; sheltered areas along with lake influenced areas escaped the worst of the cold. Check out the low temperatures on the NWS regional temperatures/precipitation table. Keep in mind the second table of several; reflects 24 hour low temperatures ending at midnight. Coldest temperatures were found around the Saline area where readings crated to the lower 20s!

000
ASUS63 KDTX 081503
RTPDTX
MORNING TEMPERATURE AND PRECIPITATION SUMMARY
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1103 AM EDT MON OCT 8 2012

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  1008  ES DH00/TAIRZX/DH07/TAIRZP/TA/PPDRZZ


:SOUTHEAST MICHIGAN -- TEMPERATURE AND PRECIPITATION STATIONS
:.......................................................
:       STATION              MAX / MIN  / 8 AM  / 24-HR
:        NAME                TEMP/ TEMP / TEMP  / PRECIP
:.......................................................
WHKM4: NWS WHITE LAKE      :   47 /  29  /  33  /    T
ARBM4: ANN ARBOR           :   46 /  30  /  30  / 0.06
ADG  : ADRIAN AIRPORT      :   48 /  28  /  31  / 0.02
BAX  :*BAD AXE AIRPORT     :   50 /  28  /  31  /
CFS  :*CARO AIRPORT-TUSCOLA:   50 /  26  /  29  /
DET  : DETROIT CITY AIRPORT:   51 /  35  /  36  /    T
DTW  : DETROIT METRO ARPT  :   50 /  33  /  34  /    T
FNT  : FLINT BISHOP AIRPORT:   51 /  29  /  34  / 0.01
ONZ  :*GROSSE ILE AIRPORT  :   50 /  39  /  41  /
OZW  :*HOWELL AIRPORT      :   47 /  33  /  34  /
DUH  :*LAMBERTVILLE AIRPORT:   49 /  32  /  32  /
D95  :*LAPEER DUPONT AIRPRT:   50 /  27  /  28  /
IKW  :*MIDLAND AIRPORT     :   49 /  26  /  30  /
TTF  :*MONROE AIRPORT      :   48 /  30  /  30  /
RNP  :*OWOSSO AIRPORT      :   50 /  33  /  38  /
PTK  : PONTIAC AIRPORT     :   48 /  31  /  31  /    T
P58  : PORT HOPE           :   52 /  34  /  34  / 0.00
PHN  :*PORT HURON AIRPORT  :   50 /  27  /  28  /
MBS  : SAGINAW - TRI-CITIES:   50 /  32  /  33  / 0.05
HYX  :*SAGINAW-HARRY BROWNE:   50 /  32  /  34  /
VLL  :*OAKLAND/TROY AIRPORT:   50 /  34  /  35  /
YIP  : YPSILANTI WILLOW RUN:   50 /  32  /  36  /    T
.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  1008  ES DH07/TAIRZX/TAIRZN/TA/PPDRZZ


:SOUTHEAST MICHIGAN -- TEMPERATURE AND PRECIPITATION STATIONS
:.......................................................
:       STATION               MAX / MIN  / 12 AM /24-HR
:        NAME                 TEMP/ TEMP / TEMP  /PRECIP
:.......................................................
ARNM4: ADRIAN              :   46 /  38  /  39  / 0.04
MILM4: MILFORD - GM GROUNDS:   45 /  34  /  36  / 0.03
MDLM4: MIDLAND             :   50 /  36  /  38  / 0.00
MTCM4: MT CLEMENS SELFRIDGE:   51 /  39  /  43  /    T
PRHM4: PORT HURON          :   53 /  37  /  42  / 0.00
SGNM4: SAGINAW 5W          :   50 /  35  /  35  / 0.00
.....................................................................


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


.BR DTX  1008  ES DH07/TAIRZX/TAIRZN/TA/PPDRZZ


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


: ***BAY COUNTY***
AUBM4:  AUBURN            :0630/   50 /  28  /  32  / 0.00


: ***HURON COUNTY***
BDAM4:  BAD AXE           :0700/   50 /  32  /  32  / 0.00
FLNM4:  FILION 5NNW       :0620/   51 /  32  /  32  / 0.00
POAM4:  PORT AUSTIN       :0740/   50 /  32  /  33  / 0.05
PHPM4:  PORT HOPE         :0800/   51 /  31  /  33  / 0.00


: ***SAGINAW COUNTY***
SAGM4:  SAGINAW           :0800/   51 /  31  /  32  / 0.00


: ***TUSCOLA COUNTY***
CARM4:  CARO              :0800/   51 /  31  /  32  / 0.00
VSSM4:  VASSAR            :0700/   51 /  26  /  27  / 0.00


: ***SANILAC COUNTY***
LEXM4:  LEXINGTON         :0730/   51 /  32  /  33  / 0.00
SANM4:  SANDUSKY          :0700/   50 /  33  /  33  / 0.00


: ***SHIAWASSEE COUNTY***
CORM4:  CORUNNA 2NE       :0600/   50 /  32  /  32  / 0.00
DRNM4:  DURAND            :0800/   50 /  32  /  36  /    T
OWSM4:  OWOSSO            :0700/   51 /  31  /  33  /    T


: ***GENESEE COUNTY***
BUNM4:  BURTON 4N         :0700/   52 /  27  /  28  /    T
FLTM4:  FLINT  7W         :0800/   49 /  30  /  34  /    T
LIDM4:  LINDEN            :1030/   47 /  31  /  41  / 0.00
GODM4:  GOODRICH          :0730/   51 /  30  /  31  / 0.03


: ***LAPEER COUNTY***
LPEM4:  LAPEER 2W         :0900/   51 /  28  /  33  / 0.00
LPRM4:  LAPEER            :0730/   50 /  30  /  30  / 0.00


: ***ST. CLAIR COUNTY***
AGCM4:  ALGONAC           :0835/   55 /  34  /  43  / 0.00
YALM4:  YALE              :0700/   52 /  31  /  32  / 0.00


: ***LIVINGSTON COUNTY***
HELM4:  HELL              :0930/   44 /  29  /  39  / 0.06
HOWM4:  HOWELL            :0800/   48 /  26  /  27  / 0.01
WHLM4:WHITMORE LK 1N      :0700/   45 /  29  /  29  / 0.00


: ***OAKLAND COUNTY***
FARM4:  FARMINGTON        :0730/   48 /  28  /  28  / 0.00
PONM4:  PONTIAC           :0811/   49 /  33  /  34  / 0.01
WSBM4:  WEST BLOOMFIELD   :0730/      /       /     / 0.05


: ***MACOMB COUNTY***
RICM4:  RICHMOND 4NNW     :0800/   55 /  27  /  30  / 0.00


: ***WASHTENAW COUNTY***
AASM4: ANN ARBOR-SOUTHEAST:0730/   48 /  28  /  28  / 0.03
AAWM4:  ANN ARBOR 1W      :0830/   47 /  29  /  33  / 0.02
MCHM4:  MANCHESTER        :0641/   45 /  28  /  28  / 0.02
SLNM4:  SALINE 4SW        :0800/   48 /  21  /  26  / 0.00
SALM4:  SALINE            :0800/   42 /  22  /  25  / 0.00


: ***WAYNE COUNTY***
DBNM4:  DEARBORN          :0900/   53 /  34  /  37  /    T
WYTM4:  WYANDOTTE         :0800/      /       /     / 0.01


: ***LENAWEE COUNTY***
BLIM4:  BLISSFIELD 1SW    :0707/   48 /  29  /  29  /    T
MRIM4:  MORENCI           :0730/   51 /  28  /  28  / 0.00
TECM4:  TECUMSEH          :0630/   47 /  30  /  32  / 0.05
TIPM4:  TIPTON 2WNW       :0800/   48 /  27  /  29  / 0.08


: ***MONROE COUNTY***
DNDM4:  DUNDEE            :0645/   47 /  32  /  32  / 0.03
MLIM4:  MILAN             :0757/   45 /  31  /  31  / 0.06
MNRM4:  MONROE            :0730/   49 /  31  /  31  /    T
NWPM4:  NEWPORT 4SSE      :0700/   50 /  35  /  37  / 0.00
.END


* ALL DATA ABOVE IS PRELIMINARY AND HAS NOT UNDERGONE FINAL QUALITY
CONTROL BY THE NATIONAL CLIMATIC DATA CENTER /NCDC/.  THEREFORE...
THIS DATA IS SUBJECT TO REVISION.  FINAL AND CERTIFIED CLIMATE DATA
CAN BE ACCESSED AT WWW.NCDC.NOAA.GOV.

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

10/6-8 Update
Little change from previous thinking as coldest overnights will be Saturday night into Sunday and then, Sunday night into Monday. While this air mass is certainly old enough for frost/freezing conditions; patchy clouds and steady wind off of the warmer Great Lakes can work against it. With partial to mostly clear skies and lighter winds; low temperatures have to potential to drop as low as the mid 20s to mid 30s. Areas away from the city of Detroit and Great Lake/ shores are at greatest risk for both frost and freezing conditions.

All persons with vulnerable plants outside may want to bring them indoors, shelter or at the least; water them to give them some protection from the cold. Autumn color enthusiast should note this weekend's cold, breezy air mass will hasten leaf change and encourage leaf drop. The fall color show across Southeast Lower Michigan should peak within the next week to ten days.

This will not be the last in the series of cold plunges in the upcoming week as a "sister" cold air mass is waiting in the wings to surge out of Canada by mid-week. Early indications are this air mass will be as cold, if not colder than the one this weekend and will contribute in closing down this season's growing season.

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

10/3 Update
The impressive cold air and dynamics with this early October blast is on track to flood into Southeast Lower Michigan beginning this Friday with the coldest of air engulfing the region, generally over the weekend. The risk of frost and freeze still appears great; especially if skies clear and winds lighten up some. Under these frost/freeze inducing conditions; the coldest morning when temperatures could fall as low as the mid 20s to mid 30s appears to be Sunday or Monday morning but I will update as we move into the weekend.

The upper air and surface projections of this blast are very impressive for early October. Note the -35C
temperature /500 MB;18kft/ in that western cold core swinging into the Dakotas Friday morning! Of course, the 540 MB low parked aloft over the shores of Lake Superior is nothing to sneeze at either! 

Then by Sunday morning; The whole eastern half of the country is engulfed in the cold on this 500 MB/18kft
map. What really struck me was the projected fairly large cold core of  -35C to -40C temperatures west of James Bay Canada. This is the first week of October, people!

Meanwhile; at the surface where it really matters to us gardeners and nurseries, etc etc....
Note the widespread cold air already over southern Canada extending across much of the North-Central and upper Midwest region of the U.S. with much of this region is in the 20s/30s.

Now, the impressive cold air and upper air dynamics with this sharp October blast has been duplicated (and then some) in the recent past; especially the past decade.

From my Autumn summary of 2009 (and sounds eerily similar to expectations with this October's blast)...

With the change in month, came the abrupt temporary change in autumn’s overall pattern. A strong amplified upper air pattern brought pre‐season Polar cold resulting in temperatures hovering in record cold territory during the first half of the October. Most areas saw a killing frost/freeze by the second weekend of October (roughly a week ahead of schedule, depending on location) but interestingly (especially considering the strength of the cold) none of the three official climate sights reported snow in October.

Another sharp cold blast that hit October of 2006  was by far, the worst October cold snap of recent memory also containing early record snows; From my October 2006 write-up 

The most dismal weather seemed to come at the peak autumn color show across the region. No doubt the worst of weather in October (and likely the fall) came mid-month on the 12th with a record breaking cold blast of Arctic air. The storm had an uncanny resemblance to very old record setting storm itself, back on October 13th, 1909. Both systems contained impressively deep centers / around 29.00”/ and air straight out of cold core depths of the Arctic. They also took similar tracks and blasted same region with heavy snow, lake effect snow and again, exceptional cold for October. Blustery heavy snow showers bombarded the land with visibilities, at times, dropping to white out conditions.

Then in OCTOBER 2004 

NEAR RECORD COLD FIRST WEEK OFFSET BY INDIAN SUMMER WEATHER THE LAST WEEK

October had been a cool month, especially in the beginning when temperatures fell into the mid 30s with several mornings during the first week having some frosty conditions. A low of 35 degrees on 5th at Detroit Metro - and 25 degrees here at White Lake - was accompanied by a killing frost and hard freeze in Detroit's north/west suburbs. Later on the 17th/18th, another plunge of polar air brought temperature back down into the 30s and for the most part, ended the growing season for 2004 across the remainder of Southeast Lower Michigan. Big changes in the upper wind flow to a predominant southwest flow took place during the last third of the month and brought much warmer weather to the region. Temperatures pushed well up into the 60s throughout the last week of the month and peaked at 75 degrees on the 30th (second highest tem

October 2003
October opened in the depths of some of the unseasonably cold air that arrived late in September. A strong polar high pressure pushed the cold air south into the area from Northern Canada. So cold was it on the 1st, that several locations noted snow flakes mixed in with rain showers. While that was the case here at the NWS in White Lake, it was not officially at Detroit Metro Airport. If snow had been observed there, it would have tied the earliest date for snowfall officially observed at Detroit /Oct 1st 1974/. The chill hung around for the nearly the entire first week of the month. High temperatures held down in the 50s, while lows fell into the upper 20s to upper 30s. 

 OCTOBER OF 2002 
WILL BE REMEMBERED ACROSS SOUTHEAST LOWER MICHIGAN FOR ITS NOTABLE CONTRASTING TEMPERATURE PATTERN. THE MONTH ARRIVED LIKE SEPTEMBER ENDED WITH UNSEASONABLY WARM WEATHER PRODUCING RECORD OR NEAR RECORD WARMTH. A HIGH TEMPERATURE AT DETROIT METRO AIRPORT OF 86 ON THE 1ST CAME WITHIN 2 DEGREES OF THE RECORD /88/. THAT HIGH OF 86 CHALLENGED BUT WAS UNABLE TO BREAK THE RECORD HIGH THAT CONTINUES TO STAND FOR OVER A CENTURY...SET WAY BACK IN 1897. THE LOW OF 66 AND AVERAGE TEMPERATURE OF 76 WERE...HOWEVER...THE WARMEST TEMPERATURES EVER SEEN ON OCTOBER 1ST. ANOTHER HIGH IN THE 80S /81/ CAME ON THE 4TH AND WAS A GOOD 15 DEGREES ABOVE NORMAL. THE SUMMER-LIKE WEATHER WITH TEMPERATURES IN THE 80S WAS ENDED ON THE 4TH BY A STRONG COLD FRONT THAT CHURNED-UP A SQUALL-LINE OF SHOWERS AND WIND GUSTS UP TO AROUND 45 MPH. 

 BIG CHANGE CAME MID MONTH AS THE UPPER WIND PATTERN SHIFTED FROM A DOMINANT SOUTHWESTERLY FLOW TO NORTHWESTERLY. THE COLDER SECOND HALF OF OCTOBER CAUSED THE AVERAGE TEMPERATURE TO DROP OVER TEN DEGREES TO 50 DEGREES BY MONTH'S END! THE WELL ABOVE NORMAL COOLING DEGREE DEPARTURE FOR THE MONTH...DESPITE THE BELOW NORMAL MONTHLY AVERAGE TEMPERATURE...FURTHER UNDERLINES THE CONTRASTING TEMPERATURE PATTERN OF THE MONTH. IN SPITE OF THE COLDER SECOND HALF OF OCTOBER...NO RECORD LOWS WERE SET. FROST AND FREEZES DID...HOWEVER...PRETTY MUCH ARRIVE ON SCHEDULE ACROSS SOUTHEAST LOWER MICHIGAN BY MID MONTH. THE FIRST FREEZING TEMPERATURE /30 DEGREES/ AT DETROIT METRO AIRPORT WAS RECORDED ON THE 14TH. 

However, on the Flip-side;

We've also seen some impressive warmth lately in October as evidenced by the 70s/80s last year in the first half of October 2011. A record high of 90! on yours truly's birthday; October 8th 2007 at Detroit Record highs also occurred at both Flint and Saginaw for a couple of days at that time. Here is more on that warm stretch that actually held for the first six weeks of fall 2007!

October 2007 was near the top with the 6th warmest on record at Detroit with a record base of 137 Octobers /1871/, impressive! Over at Flint with a +8.1 departure, October 2007 became the 4th warmest on record since 1942, while at Saginaw with a +7.3 departure, placed October in 6th warmest since 1899.  The best stretch of warm weather came from the 7^th through the 11^th when temperatures surged into the 70s and 80s, and then again from the 23^rd into the 27^th, when readings rose into the mid 60s to mid 70s. Temperature averaged around 10 to 15 degrees above normal during these warm spells. 

October of 2005 also saw record warmth during the first week of the month with record highs in the upper 80s at both Detroit and Saginaw.

Yes, October around here is by nature, a changeable, feast or famine month especially when it comes to temperatures. But; just a little more so in the past decade...hmmmm.

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

_____________________________________________________________________________
Previous blog on October Frost/Freeze potential

9/30/2012
Just a brief heads up for the first weekend of October:

Latest indications are a stronger cold blast is slated to push southeast out of Canada late this week into the weekend; which is similar timing to the last one. Very early indications are this one may very well have more punch with it as far as cold enough temperatures to bring a more substantial frost and freeze to all of Southeast Lower Michigan.

We are coming up to the time when Southeast Lower Michigan on average, experiences a killing frost/freeze; generally the second to third week of October. Therefore, if this pans out; we will be a little ahead of schedule. Stay Tuned....