UPDATE 12/4/11 7:40 PM:
Today’s model runs have scaled back the winter weather impact for DFW, currently showing very minimal to non-existent winter weather here. Some models hint at non accumulating light snow flurries from midnight through afternoon Monday. Other models hint at very light snowfall from sunset Monday through Sunrise Tuesday. Neither of these scenarios result in a substantial impact to the Metroplex at this time. I think our first winter weather event of the season is now hardly worth mentioning.

UPDATE 12/3/11 3:00 PM:
The latest model runs push drier air in with the colder air, meaning when the cold air gets here the precipitation will have ended. Winter weather chances here now for Monday appear much less likely. This wobble in computer models is not surprising especially when you are dealing with just +1 and -1 temp inaccuracies making all the difference. I will keep an eye on this though, aren’t out of the woods yet.

The Dallas/Fort Worth Metroplex may get its first winter weather of the season early next week, as a strong cold front subducts warmer moist air over north Texas. The last few runs of the NAM and GFS models are now indicating that Monday any time after noon, winter weather may impact the Metroplex, with the northwestern areas much more favorable.

Each run of the computer models have the predictable wobble in timing and adjust temperatures by +1 or -1. With the forecast temperatures right at the freezing mark, obviously a +1 or -1 temperature difference makes all the difference between icy dangerous driving and standard rainfall.

Models the last 24 hours or so have consistently shown the potential for area wide rain to convert to a freezing rain or sleet mix, then possibly into a wet snow as Monday afternoon progresses. The freezing line would shift across the Metroplex from northwest to southeast during the day.

GFS computer model snow depth forecast for Tuesday 12/6/11 at 6:00am CST. 1-2 inches appear possible in D/FW.

Travel Impacts
Travel Monday afternoon and evening would of course be impacted, but the impacts may not be too substantial just yet as accumulation on the roads would be light and icing would be slow to occur. Monday overnight into Tuesday morning will present the beginning of the largest driving hazard. Overnight temps in the upper 20s combined with lightly traveled roads in DFW would greatly aid in road icing for Tuesday morning.

Tuesday during the day clouds will likely clear out and yield to sunshine, but temps are expected to stay in the low 30s due to strong cold air blowing in from the north all day. Sunshine Tuesday would likely help warm area roadways and melt accumulated ice during the daytime, but puddles may re-freeze overnight Tuesday into Wednesday morning as temps drop below freezing again. Travel late Tuesday into Wednesday morning may be hazardous as spotty patches of ice would likely remain on roadways. Wednesday temps will warm into the 40s and all remaining ice and snow should melt and evaporate.

Even minor winter weather events tend to have a pretty high impact on areas not hardened for winter weather like the Metroplex. I will continue to monitor any updates and provide them here!

A table of the top 10 snowiest winters, provided by the National Weather Service. This season ranked number 2, just half an inch behind breaking the record.

   1   17.6   1977-78
   2   17.1   2009-10*
   3   15.3   1963-64
   4   13.5   1923-24
   5   10.4   1976-77
   6    9.5   1909-10
   7    9.2   1916-17
   8    8.8   1947-48
   9    8.1   1937-38
  10    7.3   1965-66
        7.3   1941-42

The cause is undoubtedly related to El Nino, which has an indirect effect on allowing more Gulf moisture to make its way into the southern plains. This also causes the southern branch of the jet stream to bring pacific storm systems over the southern plains with greater frequency.

The National Weather Service wrote up a great summary of the numerous snowfall events this season, and can be found here

• http://www.srh.noaa.gov/fwd/?n=wintersnow09-10

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As you can see, the heaviest snow was concentrated within Collin County including a report in Frisco of 6 inches, and 8 inches reported in Allen. DFW Airport officially documented 1.3 inches of snowfall total from this event. The statement from the NWS included below.

The snow will not remain very long, as temperatures will quickly recover to the 60s on Monday and 70s by Tuesday. The next storm system will begin to affect the region on Wednesday evening, with thunderstorms likely. A shot of cooler air will follow as this system passes, but nowhere near this level of winter weather we just received.

...Spring snow for dfw...

Dfw Airport recorded 1.2 inches of snow on March 20th. This breaks
the previous daily record for March 20th of 0.4 inches set in 1970.
An additional 0.1 of an inch officially fell on March 21st and the 

event total is 1.3 inches. 

The additional 1.3 inches brings the 2009-2010 winter total to 17.1
inches. This ranks second of all time and came 0.5 inches shy of
tying the all-time record of 17.6 inches set in 1977-1978. 

This snow event was unseasonably late in the year. The last time an
inch or more fell at dfw later than March 20th was when 2 inches
fell on March 29th in 1937.

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Dallas/Fort Worth - snowiest seasons

   1   17.6   1977-78
   2   17.1   2009-10*
   3   15.3   1963-64
   4   13.5   1923-24
   5   10.4   1976-77
   6    9.5   1909-10
   7    9.2   1916-17

   8    8.8   1947-48
   9    8.1   1937-38
  10    7.3   1965-66
        7.3   1941-42
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The last freeze of the season is expected for the region Saturday night, so take action on Saturday to protect any sensitive vegetation since the growing season has already begun.

Below is a diagram detailing the average date of last freezes across the region… It looks like we are right around average here.

I will send more details as needed later…

Snowfall for our region will begin around 3am, and last through until 6pm. Temperatures will sit near or at freezing, so accumulations will be light to moderate. Icing will be possible on bridges during the day, while well traveled roadways may not be too adversely affected. Temperatures overnight will reach the high 20s so icing on bridges and untraveled roadways will become likely and hinder travel for Wednesday morning. Temps for Wednesday will reach the mid 40s so accumulations will likely melt clear away.

Some additional things to mention here however… I'm sure alot of you have noticed that this season's snowfall forecasts have been somewhat inaccurate. December 24th's forecast was 1-2 inches, with 3.0 inches actually falling; February 11's forecast was less than 1 inch only 24 hours before the snow began falling, with the end result being 12.5 inches. So, take snowfall estimates with a grain of salt as they tend to be subject to huge errors, and anticipate the worst.

Secondly, DFW airport's winter season snowfall record could easily be broken with this Tuesday's snowfall event. Currently the 2009-2010 season sits at 15.7 inches of snowfall total placing us in the number 2 spot. With just an additional 2.0 inches of snow we would become the snowiest year in Dallas' history!

Finally I will close with a comment from the most recent forecast discussion provided by the National Weather Service: EL NINO WINTERS…YOU GOTTA LOVE THEM.

Thursday’s snowfall has brought our seasonal snowfall total to 14.4 inches, the 3rd snowiest winter on record for DFW. Had there been no other snowfall events this entire season, our winter would have still made the top five snowiest, wow! Below are snowfall totals reported as of 11:30pm 2/11/10.

The impacts from this snowfall will be felt quite heavily the morning of Friday February 12th with heavy snowfall accumulations on area roads, plus icing on roadways and bridges. Afternoon temperatures for Friday have been revised downward to 38 degrees. This means snow will melt significantly but not all of it will melt before re-freezing overnight through Saturday. Expect icing conditions Saturday morning as well. Saturday high temps will reach the 50s and any remaining snow will melt off.

Additionally, I walked around and snapped some great pictures with my camera this evening. I have attached the updated gallery below.

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Public Information Statement issued by the National Weather Service as of Midnight 2/12/10:

...Snow event one for the record books...

At midnight...dfw Airport had recorded 11.2 inches of snow today.
This breaks the previous daily record for February 11 of 1.4 inches
set in 1988. This also breaks the previous 24-hour record for
February...7.5 inches on February 17, 1978 and February 25, 1924.

This is the greatest calendar-day snowfall total on record for
Dallas/Fort Worth. The previous record was 7.8 inches on January 15,
1964 and January 14, 1917.

This brings the seasonal snowfall total to 14.4 inches...which is
the 3rd highest seasonal total on record for Dallas/Fort Worth. This
is the snowiest winter in 32 seasons (since 1977-1978).

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Dallas/Fort Worth - snowiest seasons

   1   17.6   1977-78
   2   15.3   1963-64
   3   14.4   2009-10*
   4   13.5   1923-24
   5   10.4   1976-77
   6    9.5   1909-10
   7    9.2   1916-17
   8    8.8   1947-48
   9    8.1   1937-38
  10    7.3   1965-66
        7.3   1941-42

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Dallas/Fort Worth - most snow in February

   1   13.5   1978
   2   11.2   2010*
   3    7.5   1924

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Dallas/Fort Worth - greatest 24-hour snowfall totals

   1   12.1   January 15-16, 1964
   2   11.2   February 12, 2010*
   3    8.2   January 14-15, 1917
   4    7.5   February 17, 1978
        7.5   February 25, 1924
   6    6.0   March 13, 1924
   7    5.5   December 9, 1898
   8    5.0   November 22, 1937
        5.0   January 5, 1910
  10    4.7   November 13, 1976

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...Snow event one for the record books...

At 7 PM...dfw Airport had recorded 7.9 inches of snow today. This
breaks the previous daily record for February 11 of 1.4 inches set
in 1988. This also breaks the previous 24-hour record for
February...7.5 inches on February 17, 1978 and February 25, 1924.

This is the greatest calendar-day snowfall total on record for
Dallas/Fort Worth. The previous record was 7.8 inches on January 15,
1964 and January 14, 1917.

This brings the seasonal snowfall total to 11.1 inches...which is
the 4th highest seasonal total on record for Dallas/Fort Worth. This
is the snowiest winter in 32 seasons (since 1977-1978).

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Dallas/Fort Worth - snowiest seasons

   1   17.6   1977-78
   2   15.3   1963-64
   3   13.5   1923-24
   4   11.1   2009-10*
   5   10.4   1976-77
   6    9.5   1909-10
   7    9.2   1916-17
   8    8.8   1947-48
   9    8.1   1937-38
  10    7.3   1965-66
        7.3   1941-42

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Dallas/Fort Worth - most snow in February

   1   13.5   1978
   2    7.9   2010*
   3    7.5   1924

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Dallas/Fort Worth - greatest 24-hour snowfall totals

   1   12.1   January 15-16, 1964
   2    8.2   January 14-15, 1917
   3    7.9   February 11, 2010*
   4    7.5   February 17, 1978
        7.5   February 25, 1924
   6    6.0   March 13, 1924
   7    5.5   December 9, 1898
   8    5.0   November 22, 1937
        5.0   January 5, 1910
  10    4.7   November 13, 1976

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