Texas Winter 2013-2014

[Portastorm]

How today's weather has developed in Texas ... and how poorly some of the models performed in underestimating the cold air, let along the vorticity of the short wave rolling through the state ... this should all clue you in to NOT model hug for what lies ahead. As Ntxw and srainhoutx have cautioned, we have two more systems after this one in the next seven days. And the one for later next week has some pretty large potential to create widespread misery over a lot of real estate.

Trust those models and their text grid numbers are your own risk.

[SouthernMet]

Denton, Mineral Wells, Bridgeport all 29-31 degrees so accumulations on streets are starting now..

Decatur on the other hand is at 29degrees with a one
mile visibility & they have been getting precip for hours.


edit : (Power Emergency) Trenton & Whitewright - ALL POWER is out in Trenton & Whitewright. TXNM dose not anticipate restoration before 1pm.

[TheProfessor]

Here's an update from McCauley:

The winter storm approaches bringing a mix of rain/freezing rain/sleet/snow. Bridges and overpasses here in the Metroplex may get a little icy this afternoon, but as you can see, worse conditions will be to our north and northwest. Although temperatures are already near freezing here in the Metro, the temperatures aloft are running near 50 degrees. So as the rain falls, it will bring down some of this warmth, so do not expect a rapid fall in temperatures. It will all be over in the immediate DFW area before the sun goes down this evening.

But if that very heavy precip makes it to some place in the Metroplex, wouldn't that rapidly cool the air?

[Portastorm]

Here's an update from McCauley:

The winter storm approaches bringing a mix of rain/freezing rain/sleet/snow. Bridges and overpasses here in the Metroplex may get a little icy this afternoon, but as you can see, worse conditions will be to our north and northwest. Although temperatures are already near freezing here in the Metro, the temperatures aloft are running near 50 degrees. So as the rain falls, it will bring down some of this warmth, so do not expect a rapid fall in temperatures. It will all be over in the immediate DFW area before the sun goes down this evening.

But if that very heavy precip makes it to some place in the Metroplex, wouldn't that rapidly cool the air?

No, because the air immediately above the surface is much warmer, not much colder.

[gboudx]

Here's an update from McCauley:

The winter storm approaches bringing a mix of rain/freezing rain/sleet/snow. Bridges and overpasses here in the Metroplex may get a little icy this afternoon, but as you can see, worse conditions will be to our north and northwest. Although temperatures are already near freezing here in the Metro, the temperatures aloft are running near 50 degrees. So as the rain falls, it will bring down some of this warmth, so do not expect a rapid fall in temperatures. It will all be over in the immediate DFW area before the sun goes down this evening.

But if that very heavy precip makes it to some place in the Metroplex, wouldn't that rapidly cool the air?

Not really. I've seen too many wintry events ruined by warm air being drawn down by heavy rain. I believe it depends on the depth of the warm nose. The deeper the warm nose the more likely it won't cool down enough. But someone correct me if I'm wrong.

[Portastorm]

You're spot on, gboudx. Check out latest Tweet from @NWSFortWorth:

NWS Fort Worth ‏@NWSFortWorth 47s
Aircraft data from DAL has temps 37-40 at 3000-7000ft. This is warm enough to keep all rain/fzra in the metroplex for a while. #txwx #dfwwx

[Meteorcane]

Here's an update from McCauley:

The winter storm approaches bringing a mix of rain/freezing rain/sleet/snow. Bridges and overpasses here in the Metroplex may get a little icy this afternoon, but as you can see, worse conditions will be to our north and northwest. Although temperatures are already near freezing here in the Metro, the temperatures aloft are running near 50 degrees. So as the rain falls, it will bring down some of this warmth, so do not expect a rapid fall in temperatures. It will all be over in the immediate DFW area before the sun goes down this evening.

But if that very heavy precip makes it to some place in the Metroplex, wouldn't that rapidly cool the air?

There are two terms at play here, one is the evaporative cooling term that you mention, which if the subcloud layer was dry enough could produce cooling. The second term the one mentioned by McCauley is the vertical advection of temperature term. This term is usually not very significant unless significant updrafts/downdrafts are present. I doubt precip-induced downdrafts will be very strong in this case, however DT/DZ (change in temperature with height) is fairly large (and positive) in this case, which might make this term a little-larger and counteract the evaporative cooling affect.

[srainhoutx]

.75 inches of sleet reported in Jacksboro (Jack County). Also FWD reports a light glazing of ice developing in the City of Denton.

[Meteorcane]

.75 inches of sleet reported in Jacksboro (Jack County). Also FWD reports a light glazing of ice developing in the City of Denton.

That high reflectivity band (which I assume is sleet based on radar classifcation) just to the W and NW of DFW looks nasty.

[srainhoutx]

MESOSCALE DISCUSSION 0054
NWS STORM PREDICTION CENTER NORMAN OK
1009 AM CST SUN FEB 02 2014

AREAS AFFECTED...SWRN/S-CNTRL/CNTRL OK AND WRN NORTH TX

CONCERNING...HEAVY SNOW

VALID 021609Z - 021815Z

SUMMARY...SNOW WILL BE TAPERING OFF FROM NW TO SE INTO EARLY
AFTERNOON...THOUGH LOCALIZED SNOW RATES TO 1 INCH/HR MAY PERSIST IN
PARTS OF S-CNTRL OK AND WRN NORTH TX FOR A COUPLE MORE HOURS.

DISCUSSION...COMPOSITE RADAR IMAGERY AND SFC OBSERVATIONS CONTINUE
TO INDICATE THE EROSION OF THE NWRN EDGE OF THE ONGOING SRN-PLAINS
PRECIPITATION SHIELD. THIS IS OCCURRING AS A MID-LEVEL DRY SLOT
PRECEDING AN UPSTREAM SHORTWAVE IMPULSE -- EMERGING OVER THE TX S
PLAINS PER MOISTURE-CHANNEL IMAGERY -- IS OVERTAKING THE LEADING
WARM CONVEYOR STRUCTURE. AS SUCH...SNOW WILL CONTINUE TO TAPER OFF
FROM NW TO SE THROUGH THE MORNING...ENDING AROUND 17Z IN THE
OKLAHOMA CITY TO FORT SILL CORRIDOR...AND AROUND 1730Z-1800Z IN
NORMAN. FARTHER SOUTH INTO S-CNTRL OK AND WRN NORTH TX...SNOWFALL
RATES TO 1 INCH/HOUR WILL LIKELY PERSIST FOR THE REMAINDER OF THE
MORNING BEFORE TAPERING OFF IN RESPONSE TO MID-LEVEL DRYING EARLY
THIS AFTERNOON. ANY ONGOING SLEET ACROSS PARTS OF WRN NORTH TX
SHOULD CHANGE TO SNOW IN THE NEXT HOUR OR TWO AS DEEP ASCENT
PRECEDING THE TROUGH ADIABATICALLY COOLS THE ELEVATED WARM NOSE
SAMPLED BY THE 12Z FWD RAOB.

..COHEN.. 02/02/2014


ATTN...WFO...FWD...OUN...SJT...

[srainhoutx]

SJT reports 2.5 inches of snow in Anson (Jones County)

[natlib]

Just about over in San Angelo.....a little icing on some elevated surfaces but the roads were nice and warm from our 85 degrees the other day so no problems driving. Hope the end of week system brings some of the white stuff.

[TheProfessor]

My point forecast now says 90% snow and sleet for this after new instead of wintry mix.

[orangeblood]

MESOSCALE DISCUSSION 0054
NWS STORM PREDICTION CENTER NORMAN OK
1009 AM CST SUN FEB 02 2014

AREAS AFFECTED...SWRN/S-CNTRL/CNTRL OK AND WRN NORTH TX

CONCERNING...HEAVY SNOW

VALID 021609Z - 021815Z

SUMMARY...SNOW WILL BE TAPERING OFF FROM NW TO SE INTO EARLY
AFTERNOON...THOUGH LOCALIZED SNOW RATES TO 1 INCH/HR MAY PERSIST IN
PARTS OF S-CNTRL OK AND WRN NORTH TX FOR A COUPLE MORE HOURS.

DISCUSSION...COMPOSITE RADAR IMAGERY AND SFC OBSERVATIONS CONTINUE
TO INDICATE THE EROSION OF THE NWRN EDGE OF THE ONGOING SRN-PLAINS
PRECIPITATION SHIELD. THIS IS OCCURRING AS A MID-LEVEL DRY SLOT
PRECEDING AN UPSTREAM SHORTWAVE IMPULSE -- EMERGING OVER THE TX S
PLAINS PER MOISTURE-CHANNEL IMAGERY -- IS OVERTAKING THE LEADING
WARM CONVEYOR STRUCTURE. AS SUCH...SNOW WILL CONTINUE TO TAPER OFF
FROM NW TO SE THROUGH THE MORNING...ENDING AROUND 17Z IN THE
OKLAHOMA CITY TO FORT SILL CORRIDOR...AND AROUND 1730Z-1800Z IN
NORMAN. FARTHER SOUTH INTO S-CNTRL OK AND WRN NORTH TX...SNOWFALL
RATES TO 1 INCH/HOUR WILL LIKELY PERSIST FOR THE REMAINDER OF THE
MORNING BEFORE TAPERING OFF IN RESPONSE TO MID-LEVEL DRYING EARLY
THIS AFTERNOON. ANY ONGOING SLEET ACROSS PARTS OF WRN NORTH TX
SHOULD CHANGE TO SNOW IN THE NEXT HOUR OR TWO AS DEEP ASCENT
PRECEDING THE TROUGH ADIABATICALLY COOLS THE ELEVATED WARM NOSE
SAMPLED BY THE 12Z FWD RAOB.

..COHEN.. 02/02/2014


ATTN...WFO...FWD...OUN...SJT...

This makes much more sense that what McCauley is throwing out there....freezing rain might be present at the onset but the warm nose should be cooled quite rapidly transitioning over to sleet, at least from DFW northwestward


The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

[Portastorm]

Careful though ... that will only work for those areas pretty much underneath the shortwave and it will occur when the precip is close to ending.

[dhweather]

Folks, we went through a historic occasion in the last 12 hours of special note for you North Texas members! Did you realize that your local NWS office (@NWSFortWorth) used Twitter to provide nonstop forecast reasoning, insights, and real-time observations on the weather? That's right ... the midnight shift specifically were the ones who used Twitter to open the window into their world.

To my knowledge no other Texas-based WFO has done such a thing. It was as if they brought you into their office, gave you a workstation alongside them, and openly discussed what they looked at and how they came to deciding on a forecast. Absolutely groundbreaking social media type stuff and certainly extraordinary for NWS!

I'm going to repeat this post throughout the day because I want folks in the NWS Dallas/Fort Worth area to know what an amazing bunch of government professionals they have working for them, besides Dennis Cavanaugh.

Go back and look at their tweets for yourself and see what I'm talking about. As I myself wrote on Twitter, those men and women on that midnight deserve a high five, or fist bump, or whatever accolade you think is appropriate.

Yes they are - fantastic.

[Lagreeneyes03]

It's been so much one or the other in DFW-VERY cold, no precip or precip and kind of cold. Why is it the extreme cold air can filter in so easily last week and not this week?

And how is it looking for the Thu/Fri/Sat event that was talked about earlier this week?

[Ntxw]

Folks, we went through a historic occasion in the last 12 hours of special note for you North Texas members! Did you realize that your local NWS office (@NWSFortWorth) used Twitter to provide nonstop forecast reasoning, insights, and real-time observations on the weather? That's right ... the midnight shift specifically were the ones who used Twitter to open the window into their world.

To my knowledge no other Texas-based WFO has done such a thing. It was as if they brought you into their office, gave you a workstation alongside them, and openly discussed what they looked at and how they came to deciding on a forecast. Absolutely groundbreaking social media type stuff and certainly extraordinary for NWS!

I'm going to repeat this post throughout the day because I want folks in the NWS Dallas/Fort Worth area to know what an amazing bunch of government professionals they have working for them, besides Dennis Cavanaugh.

Go back and look at their tweets for yourself and see what I'm talking about. As I myself wrote on Twitter, those men and women on that midnight deserve a high five, or fist bump, or whatever accolade you think is appropriate.

Yes they are - fantastic.

Thumbs up! FW is also one of the best in the country when it comes to severe weather along with OUN. We are lucky here in DFW to have a weather service who seems to enjoy the weather as much as they like to forecast it.

[WeatherNewbie]

Is that line of snow/sleet/fr rain actually going to move into the Metroplex? It seems to be moving almost exactly parallel to it at the moment.

[hriverajr]

I have noted that the system is moving through fairly quickly, also quite a dry slot developing. Remainder of event may be short lived. Sun already out here at Del Rio.