1/22/15

Update 1/23/15 - Parade of Clippers Only Systems Bringing Snow This Slow Season

-Update 1/23/15

Latest model information has been weakening the low pressure to move through the Ohio Valley on Sunday or drifting it further south. Therefore; only the southern third of Southeast Lower Michigan will see snow on Sunday and generally just an inch or two.

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Virtually all the snow received this paltry winter storm season over Southeast Lower Michigan has been the result of some Alberta Clipper type low pressure system. True; some impressive lake effect snows have resulted with the cold Arctic air sweeping over the Great Lakes but that's been local effects downwind of the Great Lakes, leaving only light amounts here.

Recent light snows this past few weeks have "nickled and dimed" the region enough to bring normal to even above normal snows to Southeast Lower Michigan for January...and we aren't done yet. The entire region is below normal for the winter but probably surprisingly, not that much. The prolific snow making month of November (and now January) helped out there with above normal snows. On average; the region has averaged just 2" - 6" below the normal snowfall expected thru this midwinter season. The main reason it seems like we've had less snow is that we haven't had any big snows (big meaning 6" or more) AND it was so snowy last winter. This winter's snow accumulation thus far is a far, far cry from last winter's when record snows were measured in most areas from the I-69 region (Flint to Port Huron) south across the Ann Arbor and Metro Detroit areas to the Ohio border!

As of the 22nd; 17 1/2 inches of snow /17.4"/ has been recorded at Detroit Metro Airport this snow season; 2.8" below normal  Flint has received more with 22 1/2 inches /22.5"/ but is still below its normal by 1.6". Further north around the Saginaw Valley, less snow has fallen this season with just 14.3", about 6" below normal.

Stronger Clipper This Weekend May Bring Better Snows Southeast Lower Michigan

Early but consecutive guidance on another upcoming Clipper Low Pressure system is that it will affect the area later this weekend. The low and storm center advances quickly southeast across the Upper Midwest and into the northern Ohio Valley, Sunday and Sunday night. Most guidance has been stronger with this system than the past several that affected the area - along with a bit better moisture supply. The devil is in the details as far as exact track and pressure differences with ensemble GFS members quite variable with both. Though, I would not be surprised if this system, like the last, tracks further north than the map below depicts and thus, it is used for a median track.


As this early time frame /Thursday evening/; look for the storm to bring a swath of light to moderate snowfall across Southeast Lower Michigan on Sunday. How much snowfall will depend on the exact track of the system. Clippers as a rule contain sharp lines of demarcation between snow and no snow on the southern extent of their track. Meaning; if the low tracks further north than the maps suggest below, less snow will fall particularly over extreme Southeast Lower Michigan...closest to the track. On the other side of this envisioned storm track; if she were to track further south then the Saginaw valley and other areas north would receive less snow. I'll fine tune the track into the weekend in updates but as it stands now; 2"-4" of snow is likely with even a higher core amount of 3"-5" possible. Again this is preliminary from what I'm seeing at this time but plan accordingly as this system has the potential to be weaker...or stronger at this early date.

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

1/17/15

Let's Take a Break from the Hibernating Cold to Look at Mom Nature at Her Grandest!

These pictures are just too beautiful and grand not to share! Try too look at them without doing the "ink-blot test"; you can't...each one reminds you of some beautiful spiritual, heavenly or earthly image. Mother Nature the Grand Dame Artist! Imagine this after a big blizzard, sort of a "winter rainbow" though nothing to do with the meteorological storm per se'.

Amazing aurora! An unexpected CME impact on Jan. 7 created a strong geomagnetic storm (G3 out of 5.) And beautiful aurora ensued! These images come from Ruslan Akhmetsafin in Russia, Aykhal; Greg Syverson in Prudhoe Bay Alaska; Arctic Fishing Adventures in Tromsö, Norway and more from Ruslan Akhmetsafin in Russia, Aykhal. All these were shared at spaceweather.com

For more on aurora's!









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

1/2/15

Update 1/8/15 - Another Strong Arctic Impulse To Make Being Outside & Travel Hazardous Into Tonight!

1/8/15 - Update

As mentioned in last post 

"Other impulses surging southeast in the cold cyclonic flow aloft will bring the risk of light snow or snow showers to the region thru the rest of the week but nothing extraordinary or heavy is expected at this time."

Latest data on another quickly moving Arctic impulse along with strong surface convergence zone over Wisconsin, indicates a band of mainly 1-3" with local amounts near 4" of snow are likely for the region. The snow will begin late this afternoon over western counties and be over much of  Southeast Lower Michigan by sunset. This band of snow will continue into the first half of the night as it plows thru the region rapidly from west to east. Considerable blowing and drifting will accompany the system as a reinforcement of Arctic air moves across the region.

As a result, hazardous travel will be in full force dark along with bitter cold wind chills as low as -15 to -25 with temperatures in the single digits above and below zero! It will be a wicked night outside as dangerously very cold wind chills accompanying the blustery, snowy conditions. Take care if you must go out and/or travel. Because of the relatively uneventful season thus far; this system should be our best (or worst, depending point of view) this season thus far.

1/5/15 - Update

Latest indications have clipper moving faster than discussed back on the 2nd along with a more southern track. While dynamics are adequate for a band of moderate to heavy snow, it will be well south of Southeast Lower Michigan across central and southern Indiana and Ohio tonight into early Tuesday. 

Up here in Southeast Lower Michigan, I would look for little if any snowfall across the Saginaw Valley into the Thumb from the clipper. An inch or less is likely from the Flint to Port Huron areas south into Howell and east across Detroit's northern suburbs. The southern third of the region - roughly from Ann Arbor thru Detroit and points south - will generally see around an inch; possibly two near the Ohio border. Other impulses surging southeast in the cold cyclonic flow aloft will bring the risk of light snow or snow showers to the region thru the rest of the week but nothing extraordinary or heavy is expected at this time.

The big news this week will continue to be the Arctic cold along with a record or near record (for January & depending on locality in the Plains and Midwest) high pressure as it pushes into the Plains and Midwest. After, the high pressure core will weaken with time.  Detroit's barometric high pressure record for January sits at 31.03" /1050.8Mb/ occurring way back in January of 1927. The record of all time is just one hundredth more - 31.04" /1051.1 Mb/ which actually occurred twice; Feb 1934 and March of 1948. All three of these record high pressure readings are safe as the high pressure core will circumnavigate the Great Lakes and weaken.



Temperatures during the week will average well below normal with coldest readings in the single digits to near 10 for highs; while lowest fall into the single digits below zero to possibly as low as -10 to -13 under any intermittent clear skies in the south. Along with the coldest readings expected, another big factor at times will be the dangerously cold wind chills particularly ahead of the Arctic mound of high pressure Wednesday into Thursday.

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


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Original 1/2/15 -


In my last blog, I spoke of the weekend potential snowstorm's demise and issued the likely unfolding scenario of the system yesterday, New Year's Day.

" Here we are again with a storm taking aim on the Great Lakes - and here we are again -  likely to miss a significant snowfall. Why? The decided storm track will likely again be anti-climatic for Southeast Lower Michigan to experience a big storm. Latest indications are the low pressure will begin developing over eastern Texas, slide north northeast thru Western Arkansas, Missouri, southern Illinois and on northward across northwest Indiana into southwest Lower Michigan. From there, best track at this time appears to be over or near Battle Creek, Lansing and Saginaw then out over Lake Huron while she deepens. 

Does this mean all chances snow or even mixed precipitation have gone by the wayside? No. As the low approaches and pushes the warmer, moisture laden air over the cold air and landscape I look for a mix of snow, sleet and freezing rain to overspread Southeast Lower Michigan during the day Saturday; changing over the rain across the region by Saturday night then back to snow and snowshowers overnight. The best chance for any accumulations of snow will be again, like the last storm, over the Saginaw Valley at the onset and behind the system."

This system still looks too warm to bring any large amounts of snow to the region. That being said; the latest storm track is a bit further southeast and closer to my original thinking; east northeast across the Tri-state area of Indiana/Ohio/Michigan then onward over the southeast corner of Lower Michigan and into southwest Ontario. This southeast shift of track almost guarantees a period of mixed precipitation across Southeast Lower Michigan along with some snow accumulations at the onset and behind the system (as mentioned yesterday). 

While precipitation will begin as snow, sleet and/or freezing rain; any snow accumulations will be minor in the southern areas (Ann Arbor - Metro Detroit - Adrian - Monroe areas) mainly amounting to an inch or less. The bigger headache will be traveling during the morning and early afternoon hours everywhere where the combination of mixed precipitation and cold ground makes driving hazardous until temperatures climb above freezing. Further north into the Howell - Pontiac - Flint - Port Huron areas a couple inches of snow mixed with sleet and freezing rain may get a chance to accumulate an inch or two before the change to rain. Again the furthest north-northwest areas, into the Saginaw Valley and Thumb Region could see 2-3" of snow, sleet and freezing rain before mixing and changing 

to rain.

Impressive Strong Cold Air Advection Will Bring Coldest Air of the Season and Dangerous Wind Chills into Early Next Week !

Strong Arctic high pressures surging out of Canada this next week will bring impressive cold air advection and pressure gradients due to the high pressure cores. Central estimate pressure readings at this time of 1045 - 1057 MB /30.85 - 31.20 IN/ are expected to flood into the country. These strong high pressure readings and the tight gradients of cold air advection will bring dangerous low wind chills in the upcoming week; at times well below zero! Air temperatures of teens and single figures are likely much of the time, however coldest lows could fall below zero on some morning.

Take a look at this neat animation of the Polar Vortex split and Arctic conveyor belt from the North Pole vantage affecting the upcoming system for this week.

Potent Clipper to Bring a Round of Snow and Wind Tuesday into Tuesday Night

A fast moving Alberta Clipper should push an area of snow across the upper Midwest into the Great Lakes and Ohio Valley, Tuesday into Tuesday night. While this system will be quickly moving and somewhat limited in moisture, it will deposit a swath of measurable snow across all or parts of the region.  I say somewhat limited on moisture because as a rule, these storm systems tend to be on the drier side. Early indications however, do show encouraging moisture amounts and snowfalls of possibly generally 1-3"or even 2-4". This is EARLY, so you know the scoop; don't count on those amounts until you see the definite track, moisture and whites of the flakes! ;-) You know how Mom Nature's been cheap with the snow this season as opposed to last! In any event; it WILL BE COLD this week!



While winter's been stubborn to take residence over the country and Great Lakes this cold season; this week should let everyone know what season it is!

Updates likely this upcoming week!


Have a Happy, Healthy and Prosperous New Year for 2015!

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



1/1/15

Another Potential Snowstorm Bites The Flurries

At the end of my last blog on December 27th, I stated the following...
 
"Near Term Outlook

As you can tell by some of the prognostic data presented here there is a change afoot this week anyway; and when there is a change in the overall pattern that usually involves a storm and colder air. Well again the models are dancing around with possibilities of a New Years weekend storm /3rd-4th/ and again it's everything from a major snowstorm to rain or freezing rain to nothing for us. Stay Tuned!" 

While mentioning a variety of outcomes possible with this system, many of us - me included- where hoping for the season's first major snowstorm as the models showed an array of possible scenarios. Some snow lovers who were stung just a week earlier with the snowstorm-no-show for a white Christmas, were leery of the model's promise of a storm New Year's weekend! I was not hopeful for the Christmas storm and was a little more juiced up for the second; but still was not at all satisfied with the prospects.

Here we are again with a storm taking aim on the Great Lakes - and here we are again -  likely to miss a significant snowfall. Why? The decided storm track will likely again be anti-climatic for Southeast Lower Michigan to experience a big storm. Latest indications are the low pressure will begin developing over eastern Texas, slide north northeast thru Western Arkansas, Missouri, southern Illinois and on northward across northwest Indiana into southwest Lower Michigan. From there, best track at this time appears to be over or near Battle Creek, Lansing and Saginaw then out over Lake Huron while she deepens.   



 



Does this mean all chances snow or even mixed precipitation have gone by the wayside? No. As the low approches and pushes the warmer, moisture laden air over the cold air and landscape I look for a mix of snow, sleet and freezing rain to overspread Southeast Lower Michigan during the day Saturday; changing over the rain across the region by Saturday night then back to snow and snowshowers overnight. The best chance for any accumulations of snow will be again, like the last storm, over the Saginaw Valley at the onset and behind the system.


Have a Happy, Healthy and Prosperous New Year for 2015!

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

12/27/14

So: Where's our Winter and Snow Thus Far??? Looking Back and Foward into the New Year of 2015

The cold season started out with a bang in November but then quickly went to a whimper in December, the true cold or winter month. This December has been well above average in the temperature department and has had little in the way of measurable snow. Officially in Detroit; just a trace of snow has fallen thru the 27th and it's liable to stay that way through the end of the month! It would be the second least snowfall ever recorded in Detroit since 1880 with only 1889 seeing NO snow. And, all this coming after last winter's record snowfall; I just tell people Mom Nature used up her snow allotment last winter ;-).

So, what's going on?  Well, I have a few hypotheses and a theory about that and it actually finds it's roots in my Winter Outlook when looking at the broad key players this winter.

Ok; then what am I posting about, what are the basic key players, the hypothesis's and resulting theory?

The key players or passengers as you will, in our jet stream "vehicle" since November: NAO/AO, North-Central Pacific Water Temperatures, EPO and El Nino  (in order of precedence).

NAO/AO: North Atlantic and Arctic Oscillations

Should be no question about this one, the main driver or pilot in our weather this late fall and early winter. Or is it? Is there another, while not the main driver - a "back-seat" driver?

First, note the NAO track record thus far this cold season: it's mainly encompassed in a positive phase. Also, see the NAO remains weakly positive thru most of January; but what of the AO?











Now the AO, Arctic Oscillation did show some life back in November and early December with negative phases and our temperatures in Southeast Lower Michigan acted accordingly by falling below normal. Note the decline or negative phase estimate the remainder of the winter and early spring. I wonder if that trajectory will verify?













North and Central Pacific Water Temperatures:

In my opinion or hypothesis, this and not the weak El Nino has been the co-pilot or "back-seat driver" thus far during the cold season and the "co-conspirator" (along with NAO/AO) as to why December has been mild and uneventful. The wide area of above normal temperatures across the general Pacific has been a major contributor the mild month.
In my Winter Outlook, I stated that the second area of warmer than average water temperatures stretching across the Pacific, north of the El Nino may be just as important as the up and coming El Nino. Here is my explanation and Map from the Outlook:

"It is still assumed however, that the weak El Nino will affect the cold season upper and surface wind flow by aiding and abetting the subtropical flow into the country. In addition, another item of importance is the large area of above normal water temperatures seen out in the mid Pacific north of the standard El Nino. I feel this too will also influence the sub-tropical jet, especially the late Autumn into early winter anyway (see Nov map below). By mid to late winter, the warmer waters all around the central Pacific are understandably projected to wane (Feb map). 

The below Pacific water temperatures pattern is now reminiscent of a positive PDO /PDO+/ along with the weak El Nino. Recently, negative PDO conditions have held sway out over this region. Below are the current November water temperatures including the positive PDO with warmer waters surrounding cooler waters in a horse-shoe shape".



Check out the dominant flow across that region and the U.S. this past 30 days in the boxed-in areas.





Mid November to mid December's 500H trajectory below shows very well the strong Pacific jet and also the cold polar vortex /500 Upper Low/ over eastern Canada. Both of which we've had a taste of since November...and battle is ON!




Meanwhile our third player or passenger /EPO/ has remained rather quiet this winter /Dec/ trip thus far, being mainly in a positive phase but it too seems to becoming restless.


EPO: Eastern Pacific Oscillation

Unlike last winter and main reason we were so cold last winter, the EPO has not been in a dominant negative phase. When in a negative phase, it encourages ridging along the west coast of Canada which connects with a cross polar projection of Arctic air and frequently works in conjunction with the NAO/AO but this conjunction as we saw last winter, is not always needed for a Arctic air delivery to U.S.

Note the phases of the actual observance of the EPO phase this fall and early winter on the top panel, of the EPO Index. However, more interesting developments are the change that is projected (and is actually happening as I write) on the successive 4, 7, 10 and 14 day forecast below. Check out the dates on the bottom then look again at the top panel. A strongly negative phase corresponds well with much of November, the cold month, the well below normal temperature month we just felt. See the change in the phase index in December? Nearly the whole month has been positive and that to a lesser extent, along with a positive NAO/AO and the warm waters in the Pacific; have all helped keep the bitter cold air in mainly Canada since early December.






El Nino:

The fourth "passenger" in this winters jet stream "vehicle" is of course the one everyone makes a fuss over, the boy child; El Nino. While he's been squakin and fussing some, he's terribly weak and really not even at "official" El Nino status yet.



From the Climate Prediction Center

Although the SST anomalies alone might imply weak El Niño conditions, the patterns of wind and rainfall anomalies generally do not clearly indicate a coupling of the atmosphere to the ocean. Therefore, despite movement toward El Niño from one month ago, the combined atmospheric and oceanic state remains ENSO-neutral.
 
Similar to last month, most models predict SST anomalies to be at weak El Niño levels during November-January 2014-15 and to continue above the El Niño threshold into early 2015 (Fig. 6). Assuming that El Niño fully emerges, the forecaster consensus favors a weak event. In summary, there is an approximately 65% chance of El Niño conditions during the Northern Hemisphere winter, which are expected to last into the Northern Hemisphere spring 2015 (click CPC/IRI consensus forecast for the chance of each outcome).

That is another great reason why this very mild and uneventful December is actually a "psuedo El Nino", there really isn't one but it's been like one. El Nino really hasn't had an influence on the States by most accounts, which leads me back to what I feel are the main drivers in this winter thus far: NAO/AO and the mild Pacific waters and strong jet across them.

Why Have the Models Been So Erratic (Lousy)?

So what gives for the immediate future and why have the models been all over the place with storm development and cold air delivery timing?  Well just look at what they are up against, two or three "passengers" trying to gain control over the weather pattern into the country. The "main driver" or pilot; NAO/AO is fighting against a stubborn "backseat driver" or co-pilot the Pacific Jet and mild above normal water temperatures. Yes the analogies are somewhat silly but very "apropos" given the radical and inconsistent behavior of the forecast models dealing with them.  After all, when people think about the chaos of driving and other "drivers", it is a common image yet it really does capture the multifaceted battle in the atmosphere. ;-)

Near Term Outlook

As you can tell by some of the prognostic data presented here there is a change afoot this week anyway; and when there is a change in the overall pattern that usually involves a storm and colder air. Well again the models are dancing around with possibilities of a New Years weekend storm /3rd-4th/ and again it's everything from a major snowstorm to rain or freezing rain to nothing for us. Stay Tuned! Also, after we'll look into what January is likely to have in store and compare its past - analogues - with this December and into January.

New Years Eve looks good weather-wise right now with only the drinkers and subsequent drivers to be concerned about!

Have a Happy, Healthy and Prosperous New Year for 2015!

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

12/21/14

Ghost of Christmases Past; The Whitest of Christmases and Other Christmases Past

The Whitest of Christmases and Other Christmases Past 
 
By: William R Deedler; Southeast Michigan Weather Historian
Date: 7AM Sunday Dec 21st, 2014
 

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, but not necessarily have to fall on Christmas. 

At this time /21st/, we have the likelihood of a storm but just a slight chance of a white Christmas across all of Southeast Lower Michigan from any residual snowfall late Christmas Eve into Christmas.  Over the years extreme Southeast Lower Michigan has average about 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 is falls on the day.  Now officially there must be an inch of snow on the ground Christmas MORNING at 7am. That is how the official "white Christmases" have been tallied n the past. So 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 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.

Timing isn't the issue this year it's more technical than that; while precipitation is likely before and maybe on Christmas - how much of it falls as snow /need an inch/ is the big question. As of the 21st, it looks like most of the precipitation will be rain before Christmas and maybe just snow showers  Christmas Eve and Day. Also, like many years before,  it may depend where you are in Southeast Lower Michigan as to whether or not you will enjoy a white Christmas this year (similar to last year). 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.

Previous recent Christmases
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 114 (including 1900) Christmases in Detroit, 54 (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 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 2015! 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

12/15/14

Update-12/24/14>>>Extended Models Intimating Notable Pattern Change Christmas Week - HO HO HO?

12/24/14-Update 230p
Very little change from earlier thinking, any residual moisture behind this system will fall as rain and snow showers. Temperatures will be contrary to any snow accumulations except possibly in the Saginaw Valley where moisture will be last to leave and temperatures first to fall. Any light accumulations would be on grassy areas in that area and mainly an inch or less. Overnight lows will fall into the 30s to around 40 and hover in that range Christmas Day.

Latest Indications Point To a Wet Christmas Eve & Light Snow and Snow Showers For Christmas Day  

A reasonable pattern evolution of the Christmas week storm is unfolding for the Great Lakes and Southeast Lower Michigan. The storm development previously blogged below, remains intact while the Great Lakes tract depicted as one of the possibilities, the most likely winner. 

Jet structure and max winds depict a large negatively tilted trough developing over the region on the 23rd into the 24th, Christmas Eve. At the surface, a deep cyclone will develop along a slow moving - quasi stationary cold front extending from the Gulf States northward into Lower Michigan during the day on Christmas Eve. This deepening storm center will pull substantial moisture and moderate warmth northward into the Great Lakes and Southeast Lower Michigan in the form of rain on the 24th and then light snow and snow showers Christmas Day. With any luck, we'll see enough snow showers on Christmas for a "snow in the air" Christmas but I wouldn't count on an official "white Christmas" this year - at least as things look now. I wish I could be more hopeful for a white Christmas but possibly enough moisture will remain behind the system in the seasonably colder air to generate the inch needed /per GFS/, so will update as the time rolls on closer. Speaking of "White Christmas" look for my annual "Ghost of Christmases Past; The Whitest of Christmases and Other Christmases Past, shortly. 

Surface Maps Particulars

Note the European is faster and further north with the low over Lower Michigan by Christmas Eve 7AM, whereas the GFS brings the center into the region by Christmas Eve 7PM.




Then by Christmas morning on Thursday, the Euro has the center of the storm
well up into Canada where as the GFS holds more moisture and energy aloft along with the surface reflection over the Great Lakes and thus, a better chance for light snow and snowshowers.




Look for a further update early this week.
  
Merry Christmas & A Happy and Healthy New Year
_______________________________________________________________________

12/15/14 - Initial Post

Meteorologists and Weather Enthusiasts have seen it before, too many times to count in extended model la la land, an overhaul or notable change of the prevailing pattern being suggested a week to 10 days out. This time, the pattern change is rather strongly intimated by the GFS and European model right around Christmas - or at least Christmas week /22nd-28th/. Each day something new and different pops up; a snowstorm for the East Coast, the Midwest or the Ohio Valley and Great Lakes followed by a sharp cold blast in its wake. The only thing for "certain" is that an overall Jet Stream pattern change will evolve sometime the latter part of December and that will likely create a mess for someone (more further below) around the holiday.

Autumn into Early Winter 

No one has to be told it's been a rather tranquil and boring beginning of the meteorological winter /Dec-Feb/ and this coming after a rip-snortin' unusually cold, blustery and busy November (which had its deep cold roots in place by Halloween time). Looking back, the pattern this fall into early winter was well projected by upper air and surface patterns of the past with similar hemispheric traits in the Autumn Outlook.

Fall is cited for its wild swings in temperatures and this fall certainly should be no different as impressive upper lows in Canada dive south and southeast into the U.S. The aggressiveness of this overall, now common-place pattern shows little change in the last year. Both upper air and analogues also do suggest typical to strong cold outbreaks along with some contrasting upper ridging to bring classic Indian Summer weather.

Oscillations of upper and related surface patterns with a preference toward troughing and cooler than normal weather should be balanced out somewhat, leaving us with an average or normal fall with notable sharply contrasting patterns. I look for temperatures to average around normal...or within two degrees of the normal. 

As it turned out; temperatures this past autumn did fall well within the projected spread of the selected analogues and Outlook across Southeast Lower Michigan averaging exactly a degree /-1.0/ below normal at 49.8 /norm 50.8/. September and October averaged near to slightly above normal where as our cold November, averaged well below normal.

This "now suitable, now brutal" kind of weather regime was projected to persist into the winter with strongly oscillating weather patterns resulting in cold, mild, stormy and tranquil kind of winter. I bring this all up because as you know; recently we've had a few weeks of the rather tranquil weather to start off December and the winter thus far - BUT there is a change afoot!

 

Back to the present and future...

Many meteorological indicators are pointing to a colder and stormy pattern with this change, certainly not uncommon and pretty much expected. It's the questions of where (and thus who), what and when that have to be answered.  The NAO and AO both are pointing to radical hemispheric change later in the month while the PNA remains weakly positive (or suggests troughing east of the Rockies). Both the NAO and especially AO are rather extreme with their collapse into negative territory (likelihood of colder weather). There still are variances in the overall decline from positive to negative and thus, problems in forecasting are strongly affected.

 

 

 

It is easy to see as both oscillations advanced into their positive phases beginning in December, the month became more tranquil and progressively milder over Southeast Lower Michigan, the Great Lakes and East. And generally, when there is a notable change like this projected there is a storm-a-brewin for someone and some part of the country. Here's some scenarios spit out by the GFS & European models for Christmas time.

 

Dec 15th 00z GFS, Snowstorm for the Eastern Lakes Christmas Eve 12/24>>>

 

This morning's, Dec 15th 12z GFS run (note the storm is again over the Eastern Lakes but it's now Friday morning 12/26)


 

The Dec 15th 12z Euro has a different view, she puts most of her eggs in a Northwestern Lakes Low Christmas Eve Day with a second forming just west of the Appalachians but as you can see (second map below), it undoubtedly makes headway toward the Northeast Coast just in time for Christmas

 

 

Of course, there is a lot of time between now and Christmas week and thus, numerous scenarios will be created in model la la land. In the meantime, it would be prudent to keep abreast of this change in the weather projections since it is definitely a heavily traveled time.

 

As the time gets closer I'll look at what's the most likely scenario - and where and when.

 

Merry Christmas & A Happy and Healthy New Year

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

12/3/14

40TH Anniversary of Detroit's Highest Snowfall in Modern Times!

This week marks the 40th anniversary of Detroit's biggest snowfall in amounts in modern times; December 1st, 1974 - including surface maps. The biggest snowfall of all time was way back on April 6th, 1886. Back in 2000; I wrote what I called "A Tale of Two Storms" which paralleled the two biggest snowstorms (in amount) to ever hit Metro Detroit. The second storm in the article, I will never forget as I worked it during my first year as a novice with the NWS. To this day, I have yet to see a storm quite like it; as far as the magnitude it snowed and for such a long period of time! Enjoy!  Here are reviews of both storms:

THE TALE OF TWO STORMS
By: William R Deedler, Southeast Michigan Weather Historian

Initially, I had intended to write about Detroit's biggest snowstorm ever recorded (24.5") but while researching the storm (which occurred way back on April 6th, 1886), I was struck by the uncanny similarities between that storm and Detroit's second biggest snowstorm (19.3") which occurred nearly a century later on December 1st, 1974. Besides the obvious similar snowfall amount between the two systems, other significant parallels could also be drawn. In addition,  while I was obviously not around to observe the first huge storm, I did have the opportunity to witness the second first-hand, in my earliest days with the National Weather Service. Unfortunately, weather maps for the1886 storm are unavailable, unlike the 1974 storm (below). With the aid of surface observations and weather journals however, at least an estimate of the surface and upper air data can be made. Perusing through the carefully scrolled weather journals of the late 1800's, one can't help but be amazed and "taken back" by the simplistic, yet stylish way of which they were written. In addition to hourly weather observations and climatic statistics, each day contains usually a short synopsis of the weather experienced for that day. It is the weather logs from late on April 5th - April 7th, 1886 that really commands ones attention and awe.
 
APRIL 1886 -
By early April 1886, some residents of Southeast Lower Michigan had most likely started on spring outdoor activities. High temperatures frequently pushed well into the 50s from mid March on; the last hint of snow fell nearly two weeks before on the 23rd. No doubt the growing season's new green vegetation was well underway.
 
The weather days proceeding the massive and incredible snowstorm hinted little of what was yet to come; however, there were some subtle signs of trouble brewing. The first was a fresh, brisk northeast wind that blew continuously for nearly three days prior to 6th (generally, an easterly wind along with a falling barometer in this region, foretells of foul weather approaching the area). On the 4th into the 5th, observations including temperatures, wind flow and pressure changes indicated an unseasonably cold high pressure system pushing slowly into Southern Canada and the Northern Great Lakes. This persistent and strengthening northeast wind along with an extended period of steady, then slowly falling barometric pressure, during the three-day period (3rd, 4th and 5th), indicates this high was a fairly strong, resilient and a blocking type of high pressure. A second and more foreboding sign of what was to come was indeed a rapidly falling barometric pressure later on the 5th, which foretold of the major storm approaching Southeast Lower Michigan. The surface observations late on the 5th indicated a low pressure and storm center approaching the Southern Great Lakes from the south or southwest (most likely from Illinois, Indiana or Ohio) as the cold high to the north slowly retreated.
 
The afternoon high on the 5th reached only 38 degrees (about 15 degrees below normal) and then held nearly steady into the evening. Increasing high cirrostratus clouds mingled with the sunset but then, quickly lowered to altostratus and nimbostratus as midnight approached. Light snow began to fly just after midnight and remained light until becoming heavy during the predawn hours. Note the following taken from the actual Detroit Weather Log dated April 6th, 1886:
"Snow began at 12:30 AM and fell light until about 4:30 AM when it began to fall heavy and a tremendous fall of snow continued all day, ending at 9:00 PM. The fall at 7:00 AM was 4.6" and at 3:00 PM was 17.1" and at 11:00 PM, 2.4" making the total of 24.1 inches melted from the snow gauge. The rain gauge was soon snowed full and was practically useless. Total fall of the snow on the level was 24.5 inches. The snow was badly drifted by the heavy gale. The drifts in some places were 12 feet high and the snow in the street was from 10" to 40" inches deep. A heavy north gale set in at 1:45 AM and raged in fury all day reaching 40 miles north at 2:15 PM and continued all the remainder of the day. Its force with the snow was appalling. It blew the snow in fine particles against the face, cutting like a knife."
The synopsis continues with a description of numerous street cars that were abandoned, strewn about and laying in all sorts of positions. As one might expect with the snow falling in April, the snow contained a high water content (2.43") and, therefore, it was very heavy and packed down well. Obviously, wading through the snow to get around on foot was extremely difficult - so much so that it became necessary to use crowbars and ice picks just to clean a path on the street. Maneuvering through, or just moving the snow, was such a monumental chore that even several ton railroad cars were "held prisoner in their houses". On the train tracks, freight cars were immobilized and abandoned across all of Southeast Lower Michigan. Temperatures held in the upper 20s to around 30 through the entire snowfall, with over two feet of snow reported on the ground. The strong northeast to north gale sculptured towering drifts of snow up to 12 feet high across the landscape .The howling wind averaged over 30 mph during the 24 hour period. The lowest barometric pressure reading noted was 29.60 inches at 11:00 AM on the 6th. This reading isn't too terribly deep or severe (the lowest pressure ever observed in Detroit was 28.34 inches during the late January blizzard of 1978), but the pressure was taken only five times daily (7:00 AM, 11:00 AM, 3:00 PM, 7:00 PM and 11:00 PM), so it likely fell lower As the center of the low pressure drifted further north into the Great Lakes on the 7th, milder air from the south was drawn into Southeast Lower Michigan. The sky cleared as the wind shifted to the south and the temperature rose to 40 degrees, in spite of the very heavy snow cover. In the days following the storm, temperatures managed to push up well into the 50s and even reached the mid 70s by mid month, after all, this was April, right?
 
This storm stands as Detroit's biggest and severest snowstorm and is well summarized by the following quote in the journal and actually would still stand to this day. . .
"The storm was unprecedented in fierceness, snowfall and blockades in the history of the service and the oldest inhabitants can recall nothing to equal it".
DECEMBER 1974 -
It would be nearly a century later before a very similar storm, a sort of "meteorological clone" would arrive and again leave the region snowbound with the second highest snowfall (19.3" as compared to 24.5") ever recorded in metropolitan Detroit in a single storm. While there were several similarities between the two storms, one obvious difference was their timing in the snow season. Also, it is interesting to note here, that neither storm occurred during what is officially called "winter." While the 1974 storm occurred in late fall at the forefront of the 1974-75 winter season, the April 1886 storm showed up on the doorstep of spring.

Besides the similar heavy snowfall between the storms, there is the likeness of the surface observations taken before and during each storm. As its predecessor, the 1974 storm was proceeded by a few days of persistent northeast winds along with an initially rising barometric pressure, then after, an extended period of steady pressure readings before giving way, slowly at first, to falling pressure. Also, like the 1886 storm, temperatures crept up into the mid to upper 30s on both the 29th and 30th (though these highs were not anywhere near as below normal as in the April 1886 storm). On the 30th, the northeast wind averaged around 19 mph with peak gusts close to 30 mph. The persistent strong northeast wind with just a slow climb in daytime temperature was a result of a large stationary polar ridge axis of high pressure that extended in a horseshoe shape (an Omega High) from the Great Plains, north into the Dakotas, then east across Lake Superior into Quebec, Canada and finally south along the East Coast. The high's strength and position also recalls that of the1886's high pressure mentioned previously.
The development and track of this super snowstorm was complicated and quite a hassle for forecasters that Thanksgiving weekend. The primitive forecast models (when compared to the more sophisticated and better resolution of today's models) had quite a time in predicting the track of the storm and its intensity. Even up to the day of the storm, the forecast models continued to weaken the center of the storm as it moved into Kentucky and Ohio, while intensifying a new storm along the East coast. On Saturday, November 30th, a strong closed-off 500 MB Low advanced into the Mid-Mississippi Valley, while at the same time, at the surface, an inverted trough of low pressure extended from a low over the northern Gulf of Mexico, north northwest to a second low over Missouri. The consensus of the forecast models was to bring the 500 MB and surface low generally east, into the Ohio Valley and weakening both. In the meantime, the Gulf Low was forecast to track north northeast up the East Coast and intensify; thus, becoming the main low and storm center of the entire system. This was the accepted forecast scenario with the data available at the time and could hardly be argued otherwise. Actually, this predicted path and subsequent weakening of the Ohio Valley low as the East Coast storm intensifies or "bombs-out" is what generally happens. The models failed in forecasting the weakening trend of the Ohio Valley system. The 500 MB Low and the surface low not only did not weaken, they actually intensified and became vertically stacked in the atmosphere. Generally, when this happens the system tends to hold on to its intensity longer and slow down in movement, both of which proved detrimental to the computer forecast.
 
Light snow moved into extreme Southeast Lower Michigan during the predawn hours between 5:00 AM and 7:00 AM. Even at the 5:00 AM forecast issuance, it looked as if just one to three inches of snow would blanket extreme Southeast Lower Michigan for this event. However, by sunrise, already up to three inches of snow covered the region and the snow was not getting any lighter. A stiff northeaster' also accompanied this storm, though not as severely as the 1886 storm, averaging 20 to 30 mph with gusts above 30 mph. By sunrise, an area of snow had settled over extreme Southeast Lower Michigan. On radar during the forenoon hours, bands of heavier snow appeared over Northern Ohio and Lake Erie, trekking west-northwest toward Michigan. By now, the forecasters knew the forecast was in trouble and updated the forecast to read "six or more" inches of snow.

The 500 MB Low and associated energy to support the surface system drifted east over Kentucky, while the surface low that was over Missouri drifted east right along with it. A huge conveyor belt of moisture had set up in the atmosphere extending from the Gulf of Mexico and the Western Atlantic, east into the Ohio Valley and Southern Great Lakes. Not only had the storm tapped the usual Gulf moisture; now Atlantic moisture started to be drawn into the mix. After analyzing surface data from the 1886 storm, it is strongly suspected that this too was the case at that time. Huge moisture plumes from both the Atlantic and Gulf of Mexico fed the1974 storm and likely, the1886 storm, with nearly duplicate surface observations before and during the event.

Bands of snow (much of it moderate to heavy) continued to be produced across the Eastern Great Lake States on the "conveyor-belt" through the afternoon, with the heaviest snow falling across extreme Southern Ontario, extreme Southeast Lower Michigan and extreme Northwest Ohio. By mid afternoon, already between six and ten inches of snow was on ground across much of extreme Southeast Lower Michigan, with generally eight to ten inches in the metro Detroit area. Visibilities were frequently near zero and moderate northeast winds blew the heavy, wet snow into at least three to five foot drifts. Another notable item observed during the storm was frequency of large snow flakes. Generally in the majority of snowstorms there may be a period or two of heavy snow with large flakes and a quick accumulation of snow. During this storm however, there were several periods, or waves, of heavy snow with continuous large flakes and very low visibilities, migrating in from the east over the region.



 
The surface low drifted north northeast from Kentucky into West Virginia by Sunday evening on the 1st and gradually matured and occluded. It still remained however, the dominant low (which was not forecasted by the forecast models), while the second low on east coast moved north at the triple point (at the point where the occluded, warm and cold front of the system met) and never really developed. As darkness fell, generally up to a foot and a half of snow smothered the metro Detroit area, with six to twelve inches elsewhere in extreme Southeast Lower Michigan. During the evening the snowfall became lighter and by midnight, 18.4" was officially observed at Detroit Metro Airport. Another nine tenths of an inch fell early on the 2nd, for a grand total of 19.3" (19.2" of it falling in 24 hours) with Flint reporting a snowstorm total of 8.1". As the low drifted northward, milder air filtered into the region and the snow became mixed with, and then changed to drizzle.

Coincidentally, the next day (Monday, December 2nd, 1974), the temperature also warmed to 40 degrees in the afternoon, but the wind remained more northerly rather that shifting to the south (as on April 7th, 1886). This was due to the fact that the center of the low tracked further east of Southeast Lower Michigan into Pennsylvania, rather than into the suspected Great Lakes area in 1886.
 
Some other accounts of the storm:





http://www.annarbor.com/news/top-10-storm-snowfall-totals-for-the-ann-arbor-area/

http://www.theoaklandpress.com/general-news/20130208/10-worst-snowstorms-in-metro-detroit-history

http://www.toledohistorybox.com/2010/12/01/snowstorm-buries-toledo-december-1-1974/


From a reader -

Attn: Bill Deedler re: snowstorm Dec 1, 1974

Sir, I remember that storm well: I was visiting a friend in Kalamazoo. She watched the fledgling Weather Channel early in the morning when she awoke to lightly falling snow. She told me to leave early because the snow would fall first there. Little did I know that the farther east I drove back to Ann Arbor, the snow would get worse and worse. A normal trip of maybe 2 hours turned into 5 hours. It took me an hour to exit I-94 up the State Street exit, at times pushing my car myself. When I finally arrived at my apartment, I got stuck outside. I left it there. Cold, wet, tired, frustrated and alone, I got a phone call from a friend whose parents took him back to U of M early that morning. He walked 3 miles in 18 inches of blowing snow to comfort me. I married that man and am still happily married to him to this day. I will never forget December 1st!!

Sincerely, Judi -  Allen Park, MI
Any other accounts, I can publish in Comments section below.

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