12/22/22

Winter Storm to Blow Through With Less Snow Fan-Fare /Update 3PM Thu 12/22/22/

The Pre-Christmas storm is still expected along and back behind the the Arctic front moving through overnight into Friday. Warmer air ahead of the storm center will allow more rain to fall and less snow on the back-side of the system. Majority of models bring the change over around midnight Thursday and create icy road conditions and strong winds Friday morning into Friday.

What's still threatening with the system is the strong, frigid winds accompanying the backside of the storm. Wind gusts will be strongest on Friday and Friday night; possibly reaching the 40 - 50 mph range. Major concern will still be flash freezing on the roads creating hazardous driving conditions along with local power outages, certainly a risk.

Yesterday I stated; 

I've posted parts of the the GFS and Euro /12z/ just to give an idea of the range of weather conditions projected at this time /Wed-2pm/. At this time I'd side closer to the European expectations for weather conditions and local snow amounts with GFS greater than and also less than the European.Variability in intensity, location, movement resulting in duration and precipitation (snow ratios) is causing a variation in model output.

This is the case with guidance; I still prefer the European and snowfall totals have come down a notch for a few reasons. The system is moving faster; a subtle dry-slot behind the occlusion is a risk and more rain is expected ahead of the low/front. Even lower amounts of snow are showing up on a few models in the metro Detroit area /1-2"/; we'll see if this materializes. The range and intensities of this system for days has been a nightmare on the models. 

Checking latest preferred Euro guidance:

 

 

Generally 2-4" of snow is expected around the Metro Detroit area with 4-6" over the western/highland regions and downwind of lake Huron. Some pockets of higher snow amounts are possible; especially with Lake Effect snow into Saturday.   


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


 

 


12/21/22

Major Winter Storm to Impact The Great Lakes Region Including Southeast Lower Michigan Pre-Christmas Period

Traveling during the period overnight Thursday /22nd/ into early Christmas Eve /24th/ will be challenging especially Friday into Friday night. Sharply colder air will blast the region early Friday as the storm center intensifies and "bombs out" over the Southern Great Lakes. To be considered a bombogenensis event the central pressure of the low pressure would have to deepen 24 MB in 24 hours by definition. It should come close to or exceed that as the center gets into the region. 

What's really threatening with the system is the strong, frigid winds accompanying the storm. Wind gusts will be strongest on Friday and Friday night; possibly reaching the 45 - 55 mph range. Major concern will be flash freezing on the roads creating hazardous driving conditions along with damaging winds and local power outages, certainly a risk.

While most snow amounts shouldn't be on the higher side (better than a foot) as with most major storms over Southeast Lower Michigan; snow totals likely will range from 4" - 9" with the highest amounts over the western/highland regions and downwind of lake Huron. I've posted parts of the the GFS and Euro /12z/ just to give an idea of the range of weather conditions projected at this time /Wed-2pm/. At this time I'd side closer to the European expectations for weather conditions and local snow amounts with GFS greater than and also less than the European.

It should be noted here that this is under the assumption the low will be progressive and move fairly quickly through the Southern and Eastern Great Lakes. I am concerned about the low pressure deepening and holding a bit longer over the Eastern Great Lakes/Southeast Lower Michigan/Lake Huron region. This would enhance snowfall with Lake Effect snow with the bitter cold wind extending from the Lake down across the Thumb Region Southward into parts of Metro Detroit. The Great Lakes are relatively warm with the normal to mild fall and the lack of intense storms; resulting in somewhat less temperature mixing of deeper waters. The relatively warmer Lakes are a favored region; especially in the fall into winter for low pressure intensification and thus; breeding ground for these storms.

Variability in intensity, location, movement resulting in,duration and precipitation (snow ratios) is causing a variation in model output.  In any event; the Arctic blast will cause extensive blowing and drifting snow with local ground blizzard (little of no snow falling) conditions creating whiteouts with limited visibilities.

 GFS Thursday Eve thru Christmas Day

 EURO Thursday Eve thru Christmas Day


GFS Upper Wind Jet Structure Thursday Eve thru Christmas Day 


EURO Upper Wind Jet Structure Thursday Eve thru Christmas Day 

GFS Snowfall Thursday Eve thru Christmas Day

EURO Snowfall Thursday Eve thru  Christmas Day



Look for an update Thursday and Friday before the Christmas Holiday


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

12/19/22

 The Whitest of Christmases and Other Christmases Past and Chances for a White Christmas - 2022

Frequently during the Christmas Season, meteorologists are asked; Are we going to have white Christmas?  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 Christmas morning /7AM/, but not necessarily have to fall on Christmas. 

At this time /Monday/; December 19th 2022 chances of a white Christmas across all of Southeast Lower Michigan continue "to change with every model run" (I love it, this was the line I sent out last year). Seriously; as of the latest run trend; all areas should see the needed inch of snow on the ground Christmas morning. 
 
❅❅❅ ⛄ A major winter storm is brewing on all models for later this week as Christmas approaches ~ snow and rain, then snow, strong winds and hazardous, icy traveling conditions. More on the storm in the next few days when the sampling of the atmosphere mid week gets better. ⛄❅❅❅ 
 
Last Christmas /2021/ we ended up with no white Christmas. Christmas 2020; we lucked out with generally an inch or two of snow falling over the region on Christmas Eve into Christmas morning. A nice picture-perfect light snow cover.
 
Christmas /2019/ no white Christmas was to be had - and also back in 2018; around Metro Detroit there was no white Christmas. In fact; temperatures pushed up into the 40s and 50s in the few days following Christmas. Further north from the Flint area into the Saginaw Valley and Thumb Region however; a inch or two remained on the ground for a white Christmas across that region.

Over the years, extreme Southeast Lower Michigan has averaged just under a 50 percent chance for a white Christmas.  Some years it's already on the ground, some years not, some years it melts while other years it falls on the day. However, theoretically, you could actually have nothing on the ground Christmas morning and have a snowstorm dump a foot on the region during the day and still have NO official white Christmas under the standing morning rule. It works the other way too; you could have a several inches on the ground at 7am 12/25 but warmer air and/or rain melts it away by afternoon or evening and still officially have a white Christmas.

Four years ago /2017/; an unexpected white Christmas was had in spades as low pressure system overachieved; developing robustly over the southern Great Lake/northern Ohio Valley. The system developed into a notable little snowstorm falling mainly on Christmas Eve over the southeast area as seen in this map, bringing snow for a picturesque, classic Christmas scene. The only negative - and a notable one - was the lousy driving conditions Christmas Eve into early Christmas Day but with improving conditions later for Christmas dinnertime.


For more on the system from the NWS; see here.

In 2016; even with mild weather with temperatures in the 30s; Southeast Lower Michigan was able to hold on to a white Christmas as the snow (generally 2-5") slowly melted. In fact; the day after Christmas, warm air surged into the region and pushed temperatures into mainly the 50s and took care of any remaining snow! Back in December /2015/; it was a mild and snowless Christmas with a high temperatures near 50. Of course, the year before, /2014/ contained our record breaking warm El Nino December, therefore the hopes for a white Christmas were low anyway. Back on Christmas 2014, the chances for a white Christmas were very similar to 2015 with record setting low amounts of snow for the month (in the top 5 snowless). Officially on 12/25/14 at 7am; no snow was on the ground with a trace of light rain on the date. Only a TRACE of snow had fallen up to that day in December /0.1 for the entire month/.  Most areas over the remainder of Southeast Lower Michigan had a few tenths of snow Christmas eve or Christmas but with less than the amount needed and mild temperatures rising into the upper 30s to around 40...none of the area saw a white Christmas.

More Previous Christmases back to 2004:

In 2013;  even with all the snowfall throughout last winter, officially on 12/25/13 at 7am Detroit Metro Airport had only a TRACE of snow on the ground. Most areas into the remainder of Southeast Lower Michigan had some residual snow and ice on the ground for a white Christmas. Back in 2012, enough snow did fall at Detroit Metro Arpt (an inch of fresh snow Christmas Eve) to make it an official white Christmas was on the ground as of 7AM. The necessary inch or more was also on the ground at both Flint and Saginaw. Ironically the day after Christmas, the best snowstorm of the winter season hit the region...a day late and several inches short for Christmas. A year earlier in 2011, it 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 Southeast Lower Michigan did enjoy a white Christmas with generally 1” to 6” of snow across as temperatures hovered in the 20s. Then further back 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 19th (with another, lesser intense snow falling on the doorstep of Christmas, 23rd -24th). 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.

Going back further to the Christmas of 2006; it was also mild and therefore, there was no white Christmas. 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 morning. Originally, there had been 8” of snow on the ground on the 15th. The last really scenic (no slop)  with fresh white snow for Christmas occurred in 2004. A snowstorm brought heavy snow (ranging from 8”at Detroit to around 4” in Saginaw and Flint) on the 23rd, 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. 


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 121 (including 1900) Christmases in Detroit, 57 (or 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.

  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 2000 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.

And now, I'd like to wish all who read this a very Merry Christmas and/or Holiday Season and the best in 2023!  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

12/2/22

Now That One Of The Driest Autumn's Has Passed - What Does The Computer Guidance Say For The Winter?

Mom Nature gives and takes away - and that's certainly the case this past fall (and year). In recent years; the abundance of precipitation at least partially, resulted in the Great Lake flooding levels. On that note; Great Lake and adjoining rivers levels have notably receded in the last year or two. See an update on the Lake Levels, October 2022. The drop in precipitation so far this year is the most seen in several years in metro Detroit. Last time we were significantly below normal was in 2012 for Detroit with 27.12" (still not even close to this year's thus far; 21.97") and Flint at 22.61" a ways from 2010 /25.57"/  thus far.  Saginaw just over 2010 /25.57"/ with current total /25.97"/. The last time Detroit's precipitation was this low was 20 years ago in 2002 /22.14"/. Again note; these are all entire year's totals and all should be over current annual totals. Finally; little change has been noted the first few days of December.

 


 

LATEST COMPUTER GUIDANCE ON WINTER 2022-23 


CFSv2

 

FOREIGN MODELS

EUROPEAN /ECMWF/


BRITISH MET /UK/


MULTI MODELS (BRITISH MET /UK/, EUROPEAN /ECMWF/, DWD - GERMAN, METRO FRANCE, ITALY, NCEP, JMA - JAPAN)


 CHINA    

                    

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