Significant Winter Weather Event

From the National Weather Service in Ft. Worth:

SURFACE LOW IS CURRENTLY LOCATED ACROSS THE BIG BEND REGION AND
WILL BEGIN TO RAPIDLY MOVE NORTHEAST OVER THE NEXT FEW HOURS.
MEANWHILE...WIDESPREAD SHOWERS AND THUNDERSTORMS HAVE DEVELOPED IN
RESPONSE TO INCREASING LARGE SCALE ASCENT SPREADING EAST AHEAD OF
THE UPPER LOW. EXPECT THIS ACTIVITY TO CONTINUE TO INCREASE IN
COVERAGE THROUGH MIDNIGHT. LIGHTNING HAS BEEN ON THE INCREASE AND
THERE WILL BE SUFFICIENT ELEVATED INSTABILITY TO SUPPORT AN
ISOLATED SEVERE HAIL THREAT FOR THE NEXT SEVERAL HOURS. AS THE
SURFACE LOW DEEPENS AND MOVES NORTHEAST...MUCH COLDER AIR WILL
CONTINUE TO POUR SOUTHWARD ACROSS NORTH TEXAS. THERE APPEARS TO BE
A PERIOD OF TWO OR THREE HOURS WHERE SOME MODERATE FREEZING RAIN
COULD OCCUR...MAINLY ACROSS THE NORTHWEST COUNTIES FROM NEAR
GRAHAM TO BOWIE. LATEST FORECAST SOUNDINGS FROM BOTH THE 00Z NAM
AND 02Z RUC INDICATE THAT THE 1000-850MB LAYER WILL COOL QUICKLY
TO BELOW FREEZING SOMETIME AFTER MIDNIGHT...HOWEVER A STOUT WARM
NOSE WILL PERSIST AROUND 800MB INTO THE EARLY MORNING HOURS
TUESDAY. THE LATEST RUC ALSO INDICATES AS MUCH AS 350J/KG OF
ELEVATED INSTABILITY ATOP THE COLD AIR. THIS PROFILE SUGGESTS THAT
SOME IMPRESSIVE CONVECTIVE SLEET SHOWERS WILL BE POSSIBLE LATER
TONIGHT INTO THE EARLY MORNING HOURS. CANT RULE OUT THUNDER SLEET
FOR SEVERAL HOURS AS WELL. THERMAL PROFILES ARE MORE FAVORABLE FOR
SNOW MAINLY ACROSS THE NORTHWEST COUNTIES. THIS IS ALSO WHERE THE
LATEST NAM CONTINUES TO INDICATE STRONGEST FRONTOGENETIC ZONE AND
POTENTIAL FOR BANDED PRECIP TO SET UP.

GIVEN THE LATEST DATA...WILL LEAVE THE WARNINGS IN EFFECT AS
IS...BUT CHANGE THE PREDOMINANT PRECIPITATION TYPE TO SLEET AND
ISOLATED THUNDERSTORMS FOR MUCH OF THE AREA. WILL HAVE THE PURE
SNOW CONFINED TO THE NORTHWEST COUNTIES AND RED RIVER COUNTIES
THROUGH MORNING. LATER IN THE DAY ON TUESDAY...WE COULD SEE ALL
SNOW OVER MUCH OF NORTH TEXAS...BUT PRECIP SHOULD BE WINDING DOWN.
IN ADDITION...WILL BUMP UP ACCUMULATIONS IN THE METROPLEX TO 2 TO
3 INCHES...MAINLY SLEET ACCUMULATION.

Although many things are still uncertain at this point it appears that this storm has the potential 

to be one of the more significant winter storms I have experienced.On top of that temperatures next week 

are expected to be the coldest I have ever experienced in Texas.The Low temperature Thursday 

morning is expected to be right around 10 degrees... a very impressive hard freeze! 

(At least by my standards). 

Winter Storm Maybe Tuesday?

This image pretty much summarizes thinking at this time.

The GFS doesn't have the front coming in until Tuesday afternoon which is considered to be too slow by the good people at the Ft. Worth WFO. 

Here is the 500 mb relative vorticity for noon on Tuesday according to the GFS. The trough is very strong and given that the highest vorticity maximum is still on the back side it isn't done digging.

At this point the GFS has a lot of precipitation breaking out across Texas and Oklahoma, but by the time temperatures drop below freezing Tuesday night moist of the precipitation is ended.
However given the amount of precipitation and given that it is not due strictly to lifting along the front but from the large trough digging into the west a significant icing event could occur if the front is 6 to 12 hours faster in this case.

Looks like a potentially nasty storm for Oklahoma and the Texas Panhandle at least.

Here is the 1000 - 500mb thickness. The critical 540 line (generally considered to be the rain snow line) is still pretty far north of the Red River according to the GFS.  

Here is an image from the ECMWF... looks quite a bit different. Its much faster with just about everything and even stronger with the trough. High pressure is already building deep into South Texas and northern gulf which indicates the front has already pushed deep into South Texas by 6am Tuesday. Not sure, but it probably doesn't have as much precipitation in North Texas guessing  by how far south the trough has dug  (not to mention its speed).

Winter Weather 1/9/2011

Didn't get any pictures of this event but it was pretty neat any way.
Snow began to fall Sunday morning around 10 am in the southern part of Collin County and continued for much of the afternoon. We received 2 or 3 inches which for a Dallas area snow is not bad at all.
The slightly anoying thing is that temps were 1 to 2 degrees above what they were forecasted to be over the metroplex which didn't allow for a quick change over to snow. By the time snow did begin to fall the upper disturbance responsible for the snow began to weaken as well as move east of the area. It seemed that a stronger disturbance took shape off to the east and a lot more snow occurred over in East Texas and beyond. It seems like I have noticed this trend many times before... where a wrap around snow band forms just to the west of us and as it approaches quickly diminishes in intensity.

Of course, now with all the cold air in place and the arctic left open  to unload more of these frigid airmasses into the central US, I have been looking ahead to see when the next winter precip maker will arrive. Nothing really catches my attention for a while but both the ECMWF and GFS continue to unload large high pressure systems from the west side of Canada down into the central US. Both the GFS and ECMWF occasionally sweep a disturbance across the area ahead of one of these very cold airmasses and as long as these keep showing up a chance exists for more ice.

In memory of the record breaking snowfall of February 11th 2010 here are a few images for your enjoyment (since I didn't take any this time around).