The Wild and Unprecedented Severe Weather Year of 2011 Across the US

Wettest Year on Record at Detroit and 4th Wettest at Flint (*updated 12/31-DTX)

 

Nearly every weather event I write about: whether past, present or future deals with its affects across Southeast Lower Michigan. While this past year was exceptional locally for: *record/near record rainfall and occasionally temperature including this past Summer of 2011 and last Winter of 2010-11, it is nothing compared to some of the the severe weather (winter and summer) that happened across the country.

The following video courtesy of PBS news gives an excellent account of the wild and wacky weather across the country in 2011. This video includes interviews with NOAA and private entity, Weather Underground. These weather extremes are sure to spark even more debate on the reasons for such weather and Global Warming, including the driving factors...man or nature or both.

Coming in January 2012: 
Looking more in-depth into the "Wet Year of 2011"  
 
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian

Developing Eastern Lakes Low Pressure to Bring Some Snow to the Area

A awkward phasing of the jet streams over the eastern Great Lakes should ramp up a storm center over that region Tuesday. For the past several runs, models have come into a general agreement on the storm. While the storm will be born over the Eastern Lakes, the worst of the system will be further east in the Northeast and New England, then later maturing over Eastern Quebec. This familiar pattern, seen with assertiveness the past several winters, has generally been shy to visit thus far this winter.

The southern jet will supply a dose of energy and most of the moisture, while the northern jet brings it's own energy kick and more important for snow, colder air. Look for the colder air to phase into the southern stream in time enough to bring some accumulating wet snow to Southeast Lower Michigan. However, with the main moisture just clipping our area along with temperatures hovering in the lower to mid 30s on Tuesday, don't look for more than a light snowfall over the region.

As temperatures fall later Tuesday and winds increase, driving could become dicier but snowfall should taper in the evening. As the storm deepens over the Northeast Tuesday night however, colder northerly winds streaming across Lake Huron will gin up snow shower activity to the lee of the lake, mainly across the Thumb.

With the absence of major snow systems this winter thus far, I look for this one to provide the most snow seen thus far, albeit light, in the 1" to possibly 3" category and the majority of that over the eastern counties. As out weather pattern picks up some steam in the fast zonal flow, a clipper or two should race across the Lakes later in the week and provide some more possible light snows.

THE DR. JEKYLL / MR. HYDE WINTER OF 1899-1900

So the winter of 2011-12 thus far has been nothing to crow about, they thought the same thing back in the Winter of 1899-1900 through the end of January less snow fell /9.4"/ than thus far this winter with but then...

Take a look at the THE DR. JEKYLL / MR. HYDE WINTER OF 1899-1900 an article I wrote about during the millennium switch of 1999-2000

" PARTY LIKE ITS . . . 1899"

Written by: William R. Deedler, Weather Historian Southeast Michigan 12/99

With all the noise and fuss about the new millennium, curiosity about the weather in Southeast Lower Michigan during the last millennial change (999-1000) and the last turn of the century (1899-1900), lead me to dust off the old weather record books for Detroit. Unfortunately (and not surprisingly), weather records are not available from the start of the current millennium, but what about the last century? What was the winter of 1899-1900, including the holiday period of Christmas into New Years Day, like? Let's journey back in time and see how the 1900's began . . .

THE DR. JEKYLL / MR. HYDE WINTER OF 1899-1900
The winter of 1899-1900 started off on a pleasant, mild and dry note with little snow. Temperatures averaged only slightly above normal in December but more so in January, despite a cold snap at the beginning and end of the month. January, in fact, averaged about five degrees above normal in Detroit. Furthermore, snowfall was only about half the average through January. By the end of January, fewer than 10 inches /9.4/ of snow fell in Detroit, which normally sees a couple of feet by this time. The majority of the storm tracks held north of Southeast Lower Michigan through midwinter, and thus, cold outbreaks and snowstorms were kept to a minimum. Yet, if the inhabitants of Southeast Lower Michigan thought they were going to get off easily the winter of 1899-1900, they were in for one rude awakening, as the latter half of the winter bore no resemblance to the first half.

Sharply colder weather blasted into the region late in January, pushing low temperatures down into the single digits and even below zero /-2/ by the 31^st.      All but the first few days of January did the temperatures averaged above or well above normal, that is, until the 26^th through the 31^st when they averaged better than 12 degrees below normal. Keep in mind, on the average, the second half of January is coldest period during the winter, with average temperatures in the lower 20s (highs around 30 and lows in the lower teens).

The snow-making machine shifted into high gear in February, when right off the bat a snowstorm dumped nearly a foot /10" in Detroit/ of snow across the region on the 4^th. However, within a few days, the temperature soared to 62 degrees and was accompanied by nearly three quarters of an inch of rain. What had been 10 inches of snow on the ground the evening of the 4^th, was a mere trace just four days later, the evening of the 8^th. Colder weather returned the following day, freezing any standing water and creating numerous ice rinks. The colder weather, more or less, held for the balance of the month, along with periods of light snow. That is, until the last day (28^th), when another major snowstorm hit the area. A fine, dry snow started early in the morning (2:20 AM) of the 28^th and then fell heavily for most of the day. By 8 PM, thirteen inches of snow accumulated with temperatures ranging from the mid teens to mid 20s during the entire episode. At the close of February, twenty-eight inches of snow fell in Detroit for the month alone. This was nearly three times the amount measured in the winter through January and it was by no means over with yet!

The late February storm wound down on the morning of March 1st with a storm total of 14.6 inches. The busy storm track, however, held near Southeast Lower Michigan in March with still another snowstorm just three days later, on the 4^th. This time, light snow moved back into the region around dawn and continued all day, again heavy at times, until ending at dusk. About six and a half /6.6/ inches fell during the day along with temperatures falling from 33 degrees at 2 PM, down to 12 degrees at midnight. By this time, a snow depth of nearly 17 inches was observed. And, while winter should have been ending, it was in reality, just beginning.

A little over 24 hours later (during the forenoon hours of the 5^th), snow once again began in earnest and continued falling, moderate to heavy, all day. The temperature fell to a low of 7 degrees at 5 AM that morning just before the snow began, but never recovered during the day until the evening, when it rose through the teens. By 8 PM, another nine and a half inches of snow had inundated the area with 26 inches of snow measured on the ground. This 26-inch snow depth is the highest official snow depth ever recorded in Detroit. After the snow depth was measured (8 PM), the snow became mixed with, and then changed to sleet which continued falling until l2:30 AM on the 6th, when it changed to freezing rain. Still, another 3.5 inches of snow and sleet fell from 8 PM until the change over to freezing rain, giving a grand total of 19.6 inches for the three-day period. Also, with the additional 3.5 inches snow that fell, the snow depth probably ranged somewhere in the neighborhood of 28 inches (accounting for some settling and sleet), though no official maximum snow depth was mentioned. In fact, in that week period (Feb. 28^th-Mar. 6^th), more than 34 /34.2/ inches of snow fell on Downtown Detroit! This snowfall nearly equals the second most snow ever recorded for a MONTH in Detroit, which was during the snowy La Nina December of 1974 when 34.9 inches fell. Also, it is only about eight inches shy of the normal snowfall seen in an ENTIRE winter season /42 inches/.

Needless to say, travel by street car, railroad, horseback, river ferry or just plain walking was a monumental chore. In one note, it was mentioned that it took fours hours for a street car to travel from Downtown Detroit to Trenton (a nearby suburb of Detroit) and back, a trip that usually took an hour and a half with stops along the way. Several street cars burned out their motors trying to plow through incredible amounts of snow. The temperature continued to rise rapidly from the 18 degrees recorded at midnight on the 6^th, to an almost springlike 42 degrees just six hours later at 6 AM. This 24 degree rise in temperature was a result of warmer air surging into the area from the south. With the temperatures holding in the lower to mid 40s into early afternoon, the heavy snow cover soon started to become an extremely slushy mess. By 8 PM on the 6^th, the snow pack had melted down to 18 inches, dropping better than10 inches in less than 24 hours. Then, by midnight, the temperature fell below freezing to 23 degrees. This created more headaches for travelers with huge blocks of frozen slush and ice and thus, made navigation even more difficult and hazardous.

Temperatures continued to average well below normal into mid month and on St. Patrick's Day, the mercury plummeted to a record low of -2 ( Irish coffee was probably in high demand this St. Patrick's Day). If this weren't bad enough, the snow machine once again cranked daily from the 15^th through the 18^th, when nearly seven more inches of snow fell. The intra-month period of February 22nd-March 21st may very well have been Detroit's snowiest month /28-day/ time period. Exactly 44 inches of snow fell during that time, this handily beats out the CALENDAR month record for most snow, 38.4 inches, which occurred just eight years later in February 1908 and is also a few inches higher than the average snowfall /42 inches/ for an ENTIRE winter season.

A slow moderation in temperatures took hold during the latter half of the month. Even so, March of 1900 still ranks as the 3^rd coldest March (tied with March 1885 and 1960) in Detroit since 1870. And not surprising, with the 30.2 inches of snow that fell during the month, March of 1900 is the snowiest March ever recorded (February of 1900 is the 4^th snowiest February). Snow also made an appearance in April /1.5 inches/ and even in May with a trace on May 4^th. So, despite the meager snowfall the first half of the winter, the snow that fell the second half more than made up for the deficiency. The total snowfall for the 1899-1900 season was 69.1 inches, which ranks as the fourth snowiest winter season in Detroit since 1880.

CHRISTMAS WEEK 1899 Christmas Eve 1899 began on a relatively benign weather note across Southeast Lower Michigan. A little light rain changed over to light snow during the evening with just three tenths /.3/ falling by midnight. Not quite enough to make it an official white Christmas (five tenths /.5/ or better of snow is needed on the ground) and only a trace fell on Christmas. By the looks of the temperatures, a cold front must have pushed through the area during the daytime hours of Christmas Eve. The temperature reached 34 degrees during the afternoon on Christmas Eve but then fell to 17 degrees by the midnight hour. In addition, that 17 degree reading at midnight was the HIGH temperature for Christmas Day with temperatures steady to slowly falling until bottoming out at 11 above. In spite of being chilly, Christmas Eve into Christmas Day in 1899 were, for the most part, cloudy non-eventful days, meteorologically speaking, with no big storms in sight.

The most obvious trend the last week of 1899 (see Chart-1) was the turn toward colder conditions, but with negligible precipitation (traces of snow). As the week drew to a close, lows were generally in the single digits with an actual "goose-egg" /0F/, reported on the morning of the 30th. Sky condition ranged from partly cloudy to cloudy, so there were periods of sunshine. 

CHRISTMAS WEEK 1899-1900 (DEC. 25TH - JAN. 1ST)
Date	High	Low	Precip.	Snowfall	Sky Cover
12/25/1899	17	11	T	T	Cloudy
12/26/1899	18	9	T	T	Ptcldy
12/27/1899	20	12	T	T	Ptcldy
12/28/1899	20	10	0.01	0.1	Ptcldy
12/29/1899	14	6	T	T	Ptcldy
12/30/1899	8	0	0	0	Ptcldy
12/31/1899	12	4	T	T	Cloudy
01/01/1900	19	5	T	T	Ptcldy

NEW YEARS EVE - DAY 1899-1900
Snow flurries fell virtually all of New Years Eve until shortly after the stroke of midnight (12:15 AM) but with only a trace accumulation. The sky remained cloudy New Years Eve into very early morning hours of New Years Day, until around 3 AM, when the sky cleared, allowing for a clear sunrise New Years Day. The morning low of 5 above was accompanied by only a trace of snow on the ground.
The first day of 1900 was cold, but relatively nice across Southeast Lower Michigan. Under partly sunny skies with a few flurries, the temperature crept up to only 19 degrees and the mean temperature of 14 degrees, averaged out to 17 degrees below normal. 

In addition,  Check out my post below on a possible change in the current weather pattern across the country into early-mid January

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Benign Weather Pattern to Become More Active as 2011 Bids Adeiu?

                             Written by: William R. Deedler, Weather Historian 12/25/2011

No one can deny the Winter of 2011-12 has been off to a very slow start with generally mild weather and just spurts of light snow, hardly worth mentioning. The main culprit has been the one thing mentioned in the Outlook that is elusive and problematic in forecasting. I also briefly mentioned it in a recent article and I would discuss the phenomena that can make or break a forecast, the NAO/AO.  And, more to the point this culprit, the NAO/AO, has been almost exclusively positive for several weeks which has resulted in a very mild beginning to the Winter of 2011-12.

From the Outlook:

The Ever Elusive NAO/AO

The other main ingredient in this winter’s weather (like any other) is of course, the trend of the North Atlantic Oscillation/Arctic Oscillation throughout the winter. Of course, this is the biggest challenge to the forecast and potentially, has the biggest bust potential. While trends with La Ninas and El Ninos are seen (and these are not always consistent, either) the NAO is highly elusive and generally trends are seen only a week or two out. Generally, our colder winters in the study reflect a predominately negative NAO.

By the recent data, the positive trace of the AO and NAO is easy to see on this graph. The Arctic Oscillation has been pretty much exclusively positive the past three months, while the broader NAO has been mainly positive to occasional neutral during the same time period. Basically, the bitter cold Arctic air has been held further north than it's usual position as the jet stream has been contracted closer to the Pole. I like to use the analogy the freezer door has been basically slammed shut with just the occasional brief opening to let out a bit of frosty cold. This type of pattern results in a nicely charged bitter cold Arctic air mass up further north that only gets fully re-charged as the winter drags on.

 

It is also discernible by the ensemble model graph projections, that the oscillations are projected to slowly fall toward a weakly positive or even neutral stance in the next week or two. The problems interpreted here are two fold, one: are the projections correct and two: what will be the outcome? The first is the most important as far as a possible change in the offing. The ensemble members have been gradually intimating a gradual breakdown in the stubbornly positive stance of the NAO/AO for several days now, but is it believable? At this point, I feel a gradual weakening is likely, at least enough to bring a more active pattern across the country. I've noted many times in the past when the NAO/AO drifted toward a neutral stance after being in a substantially positive or negative mode, the storm track became active. Simply put, this change indicates the dominant air masses across the northern hemisphere are about to get more "mixed or stirred up". In the case of going from positive to a neutral or negative phase, the Arctic intrusions dig more substantially south and thus, create more storm development. 

In our present case, the mild temperate weather has held sway for much of December with only weak intrusions of Polar air masses. With this type of change projected, albeit it may be somewhat subtle, it should stir up the atmosphere up enough to at least get more action. Where and what the main action will be will be followed closely to relate in my blog. Stay Tuned.
 

Coming in January 2012: 
Looking more in-depth into the "Wet Year of 2011"  
 
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian

Ghosts of Christmases Past???

The Whitest of Christmases and Other Christmases Past 
By: William R Deedler; Southeast Michigan Weather Historian

Date: Saturday Dec 22nd, 2012

Frequently during the Christmas Season, meteorologists are asked; Are we going to have white Christmas?  Usually the chance of a white Christmas across all of Southeast Lower Michigan is around 50 percent. Generally, it is agreed among meteorologists that in order to "officially" have a white Christmas, an average of an inch of snow must cover the ground, but not necessarily have to fall on Christmas. 

At this time /22nd/, it looks like it will depend where you are in Southeast Lower Michigan as to whether or not you will enjoy a white Christmas this year. The heavens are going to make us wait to see as our only "hope" for additional snow will come appropriately enough, Christmas Eve. A low pressure system is slated to move thru the Upper Ohio Valley and how far north it tracks will determine any snowfall over Southeast Lower Michigan on the 24th. It does look as though some snow may make it into Southeast Lower Michigan. Officially, an inch of snow must cover the ground at 7am on Christmas morning for it to be deemed a "white" Christmas. 

Last Christmas /2011/ was a relatively mild Christmas with temperatures in the 40s and no snow on the ground; so no white Christmas. However back in 2010; residents across the Detroit area did enjoy a white Christmas with generally 1” to 6” of snow across as temperatures hovered in the 20s. However in 2009, much of the Detroit area south did not have a white Christmas but points north across Flint, Saginaw and the thumb region generally had a 1” to 3” snow cover. Back in 2008, we saw a “sloppy, melting white” Christmas. That white Christmas involved the melting of a heavy snow cover from past snows that accumulated throughout December. The best of the snowstorms came before Christmas on the 19^th (with another, lesser intense snow falling on the doorstep of Christmas, 23^rd -24^th). After, however, the heavy snow cover melted in earnest as milder air overspread the region Christmas Eve right through the 26th. Christmas of 2007, saw temperatures rise into the mid 40s to mid 50s a couple of days prior to Christmas and that, combined with light rain, pretty much took care of any hopes for a white Christmas as then, like the later Christmas of 2008, the  previous heavy snow cover melted (but this time in its entirety before Christmas). Some scattered light snow did return, skirting the landscape on Christmas Eve but most areas around Southeast Lower Michigan still only had a trace of snow for Christmas. At White Lake and Saginaw, however, the official inch of snow to make it a white Christmas was barely attained in 2007

Further back, Christmas of 2006, was also mild and therefore, there was no white Christmas. Back in 2005, we just barely squeaked out a white Christmas (at Detroit Metro Airport, anyway) as a mild spell moved in just before Christmas along with rain, melting the snow down from 4” to 1” by Christmas.  Originally, there had been 8” of snow on the ground on the 15^th. Besides last year, the last really scenic (no slop) white Christmas occurred in 2004. A snowstorm brought heavy snow (ranging from 8”at Detroit to around 4” in Saginaw and Flint) on the 23^rd, which left the region with a nice white cover for Christmas. It was also a cold Christmas also with highs only in the teens and overnight lows below zero. 

www.ncdc.noaa.gov/img/climate/extremes/2001/december/white_pg.gif

Looking over historical weather records of Christmases past since 1900, a wide range of weather conditions were found. While most people would like to believe that Christmas in the Detroit area should be snowy-white and picturesque, more often than not, they're not. Over the past 112 (including 1900) Christmases in Detroit, 53 (47%) have been what would be called "white" with an inch or better of snow on the ground. Keep in mind however, these records are for Detroit; farther north in Flint, the chance of a white Christmas jumps to 56 percent, while in Saginaw and the Thumb region it rises to 61 percent.

Based on the Detroit records, the Santa award for the "whitest" (most snow on the ground) and also the second snowiest Christmas (snow falling on Christmas) goes to the Christmas of 1951! Just over a foot /13 inches/ of snow was recorded on ground late Christmas day with 6.2 inches of the snow falling on Christmas. Temperatures held well below freezing (HI-26/LOW-18), so what snow did fall, remained. A close second to the "whitest" Christmas, occurred the Christmas after the big stock market crash in 1929. Eleven and a half inches of snow was measured December 25th, 1929 at Detroit but only three tenths /.3/ fell on Christmas. Recently, the Christmas of 2000 was very white indeed, but as to how much of a white Christmas (snow depths) is where the confusion came in. Let me elaborate, officially at Detroit Metro Airport, just six inches of snow was recorded on the ground at 7AM Christmas Day. However, just about anywhere west/north and in the city of Detroit itself, amounts were considerably higher with generally 8 to at least 15 inches. At the National Weather Service in White Lake, 15 inches was observed on the ground Christmas morning. No additional snow fell on Christmas Day (nor was anymore really wanted with the surplus already at hand). In any event, for Detroit and surrounding communities, the six inches at Detroit Metro Airport is the official snow depth used for the area.

The snowiest Christmas (most snow falling on Christmas), occurred in 1915 when 6.4 inches fell with a snow depth of seven inches on the ground. The timing of this snowfall was impeccable for Christmas with it actually starting Christmas Eve around sunset. Then, it continued to snow through the night into Christmas day. Actually, even more than the 6.4 inches fell from the entire storm with an additional 1.6 inches falling on Christmas Eve. This gave a snowstorm total of eight inches.  A little light rain did mix with the snow during the forenoon hours of Christmas but with a high temperature of only 33, it did little to mar the "Christmas card" scene. Speaking of "Christmas card" scenes, another heavy wet snowfall blanketed the area just after the turn of the century early on Christmas in 1901. The scene is described in the historical weather books as follows:

    "Night of the 24 - 25 cloudy; moist snow continued,

     heaviest between hours of 1:30 and 4:30 am, ended

     at 6 am. amount of precipitation .62 inches. The

     street cars ran all night to keep the tracks open.

     the snow adhered to trees etc, and made a very

     beautiful scene. Depth of snow on ground at 8 am,

     5.5 inches".

 This "Norman Rockwell Christmas scene" was further enhanced by a heavy coating of frost deposited on the buildings and windows Christmas Eve due to the moisture-laden air. But just like memories of some Christmases past, this majestic Christmas scene quickly faded (melted) during the day as temperatures climbed to 41 degrees, leaving just slush , slop and water. During the Christmases of 2002 and 2003, the weather was similar to both of the white Christmases mentioned above /1901 & 1915/. Here again in 2003, snow started falling Christmas Eve and lasted into at least part of, if not all of Christmas Day. On Christmas Day 2003, snowfalls ranged from at least an inch in the far southeast corner of Lower Michigan to as much as six inches across Detroit's northern suburbs, extending northward across Flint and Saginaw. On Christmas Day of 2002, total snowfall at Detroit Metro Airport was measured at 6.4” inches for both days (Christmas Eve and Christmas) with 3.4” of it falling on Christmas Day, itself. Across all of Southeast Lower Michigan snowfalls generally ranged from four to seven inches. A picture perfect Christmas was created both years with the freshly fallen snow. Like the Christmas snowstorms of 1901 and 1915, the snow Christmas 2002 was also somewhat heavy and wet with high temperatures in the lower 30s and lows only in the mid 20s.

Probably one of the slushiest and sloppiest Christmas Days happened in 1973. What started out as a white Christmas with a heavy 7 inch snow cover, quickly melted to a meager 2” slush mess by nightfall. To add insult to injury, it rained nearly a half an inch during the day.The wettest Christmas on record occurred in 1945 when 1.16 inches of rain fell. The rain actually began Christmas Eve as a light freezing rain and continued freezing until nearly dawn on Christmas, when the temperature pushed above freezing. Until the ice melted, a few tenths of an inch of ice coated everything by Christmas dawn. Needless to say, walking and driving early the Christmas of 1945 was treacherous but Santa was in and out of town in a flash!

Without a doubt, and still in the memories of long term inhabitants of Southeast Lower Michigan, is the warmest Christmas on record, the Christmas of 1982. It was as though the whole area was shipped to Florida for the holiday! The official record high at Detroit was 64 degrees, while Flint did one degree better at 65! These readings are about normal for Tallahassee, Florida! Scenes of shirt sleeved people with shorts running or riding bikes, instead of visions of sugar plums, made the Christmas of 1982 to some Michigan Christmas traditionalist, very hard to take.  This spring-like day was complete with scattered showers and, of all things, thunderstorms! Ironically, the bitterest cold Christmas came just a year later in 1983! Maybe a payback from Mother Nature for the warm weather we were treated to, the Christmas past? The temperature plummeted Christmas eve to a record low of -9 at Detroit and was accompanied by a stiff west wind averaging 25 to 30 mph, creating life threatening wind chills at times of near 40 below zero! Santa certainly brought the North Pole with him the Christmas of 1983, when he made his rounds very early that morning. In addition to the record low Christmas eve, another record low /-10/ was established during the very early morning hours of Christmas.

These Christmases past discussed are more the extreme than the norm across extreme Southeast Lower Michigan. But they do show the variable weather that can occur at Christmas (or any other time for that matter). The "normal" (or average) highs in extreme Southeast Lower Michigan Christmas Day are in the lower 30s, while lows average in the upper teens. 

As Christmas Day approaches check back here on my blog for any last minute updates regarding the holiday forecast and the potential for more snow after Christmas. 


And now, I'd like to wish all who read this a very Merry Christmas and/or Holiday Season and the best in 2013! I plan on continuing my blog for the new year if the fates allow and look forward in reaching out to more people (and hear their comments and ideas) across the globe.

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

Potential New Snow System To Affect Southeast Lower Michigan /Update/

              Written by: William R. Deedler, Weather Historian 12/2/2011 (Updated 12/4)

A strong positively tilted low pressure trough will push in the western part of the country over the weekend and slow the progression of a cold front sliding across the mid part of the country by early next week. The recent model trend from the 12/2&3 - NAM /12z and latest 00Z/ indicate the front will push just east of Southeast Michigan and then stall or slow to a crawl while extending southwest into eastern Oklahoma and western Arkansas.

Weak waves of low pressure along with a surplus of moisture will ignite a streak of snow and rain which will extend from Texas into the southern Great Lakes by early next week. Snow accumulations could be notable if the front stalls long enough as it gets hung up under the strong southwesterly jet. The latest 12/3 - GFS /00Z/ model also has the front slowing but the best moisture still hangs just to the south and east of Southeast Michigan. Stay Tuned.

This is a very recent development in this system as the models had for several days, pushed the entire boundary further east with little overrunning precipitation under the baroclinic zone. This system is a "sling-shot" type of system I talked about in my Outlook and were one of the more prevalent type of snow makers for Southeast Lower Michigan during my analogue winters.

From the Outlook

I mentioned the "sling-shot" pattern in my earlier discussion in regard to the jet stream. Plain and simple, by looking at the storm track map you can see how the Arctic/Polar jet prefers to take a dive southward (southeast or even southwest) to the lee of the southern Rocky Mountains in these analogue winters. This in turn, loads the storm "sling-shot "and shoots it east northeast toward the Great Lakes and then "somebody gets stung in the....";-).  Who gets stung remains to be seen as the pattern evolves.

Check out the 500MB and Surface and you can visualize these vort maxs pivoting around the Southwest Trough and being "shot" northeast toward the Lakes. It is still very early to run for the snow shovels and also (like stated in my most recent post), the models have some trouble with forecasting the jet that feeds these systems from the Pacific, so this is just a heads ups at this time!  
------------------

**Update**

From above-

The latest 12/3 - GFS /00Z/ model also has the front slowing but the best moisture still hangs just to the south and east of Southeast Michigan. It is still very early to run for the snow shovels and also (like stated in my most recent post), the models have some trouble with forecasting the jet that feeds these systems from the Pacific, so this is just a heads ups. Stay Tuned.

**All recent models trends have now (12/4) shifted back to the earlier GFS/Euro trend consensus of keeping the axis of precipitation pushing slowly east as colder but drier air infiltrates Southeast Lower Michigan. While some light snow is still expected on the backside of this system, amounts will be light. The upper low spun up over the Southwest will also shift east with time and will be moving into the Ohio Valley later in the week but at this time, the system is slated to stay south of our region.**

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

  Earlier  NAM 12/3-00Z Model Run Fri Night for Monday Night @ 72hrs

                           


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

Are We In For One Troublesome Forecastable Winter?

Written by: William R. Deedler, Weather Historian 12/01/2011

In answer to the question of the headline: "Well, I really would hope not but analogue data indicating the interactions of the main jet streams involving strong wind maxs, does make one wonder".

Straight up: 

As we can see by the projected analogue winter jet streams, the problem readily shows up in the northern Pacific. Not only is this where a couple of jets are likely to phase/not phase this winter but also where observational data is scant. Much of the surface and aloft data is lost over the Pacific once it leaves Eurasia (including Japan) but thank our heavens above (no pun intended, well maybe a little) in the advancement of technology for satellite data (and upgrades). 

A big boom to forecasting came in the 1970s when satellite advancement really began to take off from its infancy in the 1960s. I recall at the WSFO at Detroit Metro Airport (at the time) what a ground breaking product this was and this was especially true for the local WSFO/WSO's in the Great Lakes what with: winter ice coverage and Lake Effect snows, synoptic rain and snow systems and severe weather. One could hardly wait at times for a recent picture to come out of the satellite machine (LOL) which currently is just another standard but important tool for forecasting!  Then, fairly quickly at the WSFO's, the micro-scale satellite interest expanded to a macro-scale interest over the US and points west, south and east with the Pacific Ocean, Gulf of Mexico and the Atlantic all having important watchable satellite data.

Back to the subject at hand:

As it is said, a picture is worth a thousand words and referring back to a few of the map pictures from my projected analogue jet stream and storm tracks in my Outlook, depicts nicely what we are up against.

The interaction of the Pacific and Polar/Arctic jets along with phasing location and timing; will have large repercussions on the downstream subsequent weather development this winter across the States. Of course, to a large extent, this happens most winters depending on the ENSO cycle, etc, etc as discussed in the Outlook. However, with the analogue data from this particular set of winters chosen, I feel tends to zero in on the perspective trouble spots and likely outcome. In addition, throw in at times the sub-tropical Pacific jet nosing in its beak for good measure and the complexity only grows. And to top it all off; the surface and aloft weather data you receive from many of these locations is very limited (if non-existent) and again, why satellite is such a valuable tool.

Analyzing the aloft data from the analogues, gives a valuable clue as to where the dominant storm tracks and subsequent forecast problems will likely arise. And, one eye on recent weather maps (surface and aloft) and the other on our analogue map projections reveals we are in the right place. 

Latest data from extended models is hinting at another dive of cold Pacific and Polar air over the western and central US next week; and possibly Arctic orientation air diving in the same location after that. Of course, this is too far out to get any sort of a grasp of its reality but December is beginning to show more of a mixed weather pattern as winter evolves (and the way analogues suggested).

December:

Along with write ups and updates on notable weather affecting Southeast Lower Michigan and the Great Lakes and posting my well received Christmases Past article;  I'll explore another troublesome area of forecasting...the ever elusive NAO/AO.

                                                                          Happy Holidays and may you have a

                                                                          prosperous and healthy New Year!

Making weather fun while we all learn  
Bill Deedler -SEMI_WeatherHistorian