Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 6

[bubba hotep]

A -13.9°C at DFW, per today's 12z GFS, for next Wednesday would be some serious cold for so late in the month of February. That would push surface temps well down in the teens with highs probably not getting out of the 20s (of course all dependent on cloud cover). Maybe winter is back? I'm taking this very cautiously.

 

Coincidentally, tomorrow marks the 115 anniversary of our coldest ever recorded temperature of -8°F set in 1899 in one of the worst Arctic air outbreaks in United States history (that we know about).

 

It looks like wind would be the biggest obstacle to temps really bottoming out with clear skies, bitter 850s, and extremely dry air.  Also, it appears that the new GFS has a mid-range cold bias, but I am not aware of any hard data to support that claim. 

[aggiegeog]

It looks like wind would be the biggest obstacle to temps really bottoming out with clear skies, bitter 850s, and extremely dry air.  Also, it appears that the new GFS has a mid-range cold bias, but I am not aware of any hard data to support that claim. 

Agreed on the mid range GFS seeming to be too cold consistently. Though the idea of cold seems solid not so sure about <15F lows. Time to get back into model watching mode as we look to see how the 500mb pattern develops then by this weekend we can start to give a bit of credence to the surface values.

[DFWWeather]

I just realized and should clarify that the -13.9 C in my post above for DFW was at H85.

[Srain]

The 12Z Euro is coming in cold as well with the front arriving next Tuesday. Moisture is still the wild card, but there is some phasing of the Baja storm system and the shortwave dropping SE across New Mexico Tuesday night into Wednesday.

[bubba hotep]

I just realized and should clarify that the -13.9 C in my post above for DFW was at H85.

 

I got you, I was looking at 850s as the data rolled in and that jumped out at me.  

[bubba hotep]

This could be a wild ride watching the models in the coming days.  It wouldn't take huge changes in the northern stream or the movement of the Baja low to generate some really nice scenarios for Texas.  You know it is coming, that one model run with everything coming together to crush us only to be gone on the next run    

 

Also, I'm sure the severe weather types are perking up because of this systems potential. 

[bubba hotep]

From the FWD midday update:

 

A QUICK LOOK INTO NEXT WEEK PER THE GFS INDICATES IT WILL TURN MUCH
COLDER ON TUESDAY/WEDNESDAY BEHIND AN ARCTIC FRONT ON TUESDAY WITH A GOOD
CHANCE OF RAIN MONDAY THROUGH MONDAY NIGHT. THE PAST TWO GFS RUNS
DO BECOME COLD ENOUGH FOR SOME FROZEN PRECIPITATION ON TUESDAY. WE
WILL AWAIT TODAYS ECMWF RUN BEFORE COMMITTING TO THIS EVENT IN
THE AFTERNOON PACKAGE.

[Quixotic1]

This could be a wild ride watching the models in the coming days.  It wouldn't take huge changes in the northern stream or the movement of the Baja low to generate some really nice scenarios for Texas.  You know it is coming, that one model run with everything coming together to crush us only to be gone on the next run    

 

Also, I'm sure the severe weather types are perking up because of this systems potential. 

 

I've sworn off model watching until the end of March.  Thinking of moving to NE......

[DFWWeather]

The 12Z Euro is coming in cold as well with the front arriving next Tuesday. Moisture is still the wild card, but there is some phasing of the Baja storm system and the shortwave dropping SE across New Mexico Tuesday night into Wednesday.

 Yes, 12z ECMWF down to -13.6°C (H85) for next Wednesday at DFW, almost as cold as GFS. Interesting to note that the -15°C (H85) isotherm very close to the Metroplex. I don't know when the last time H85 temps actually verified that cold.

 

It looks like wind would be the biggest obstacle to temps really bottoming out with clear skies, bitter 850s, and extremely dry air.  Also, it appears that the new GFS has a mid-range cold bias, but I am not aware of any hard data to support that claim. 

 

Even with wind, H85 temps that cold should still get us to the teens (upper). Kinda like what happened in late Feb/early March 2002  (17°F with strong winds out of the north and sleet). Without clouds and wind, could easily see temperatures cratering to 10°F or lower with that kind of cold.

 

Quite an impressive cold spell should it verify! It would be a way to go out with a bang to an otherwise crappy winter.

 

But again, I will proceed with caution here, but starting to get a little hopeful!

[Srain]

The afternoon Update from the Climate Prediction Center has shifted the cold air further West and also has some interesting Analogs that many longtimers may remember for our Region. There is that 1976 showing up again.

 

 

 

[Quixotic1]

BTW, did you see why KGRK's radar is down?  A rattlesnake........in February.....

 

LOL

 

http://forecast.weather.gov/product.php?site=NWS&issuedby=grk&product=FTM

[Quixotic1]

Steve, I'd take the analog 2003 over 2006.  

[Srain]

Steve, I'd take the analog 2003 over 2006.  

You folks did well in 2003 across the Metroplex. The 1976 analog is one that catches my eye. There was a major snow event across E Texas into Louisiana that January into February and the temperatures were brutally cold across Louisiana down to New Orleans. The Mississippi froze over from near St. Louis on S to around Baton Rogue that February shutting down barge/ship traffic for a week or two.

[bubba hotep]

Steve, I'd take the analog 2003 over 2006.  

 

I've been a big fan of 2003 as a March analog for a while now.

 

ETA: I missed that the super ensemble was actually referencing a Feb '03 analog.  

 

ETA2: I have no clue what month it is! The first part of this post should have been, "big fan of 2003 as a Feb analog" and thus making the "ETA" unneeded   

[bubba hotep]

FWD notes in the afternoon discussion that they are initially thinking 1/2" of snow north of I-20 and heavier amounts as you move into Oklahoma.  They point out that the forecast will likely change with so many moving parts coming together.  We have seen pretty much every threat fall apart so far this winter, will the trend continue or will we finally see a system trend in our favor over the weekend   

[aggiegeog]

FWD notes in the afternoon discussion that they are initially thinking 1/2" of snow north of I-20 and heavier amounts as you move into Oklahoma.  They point out that the forecast will likely change with so many moving parts coming together.  We have seen pretty much every threat fall apart so far this winter, will the trend continue or will we finally see a system trend in our favor over the weekend   

SHV put snow in also. It is not often that NWS puts snow in the D6-7 forecasts for our area so that should lead to higher confidence in the potential event. It does look light right now  for our area, but wherever the upper low focuses moisture will see heavy snow. It may be a good thing for it to not be aimed at us yet as we all know models will shift so maybe we get another 2010 with very deep cold in place and moisture anything is possible.

[DoctorMu]

This could be a wild ride watching the models in the coming days.  It wouldn't take huge changes in the northern stream or the movement of the Baja low to generate some really nice scenarios for Texas.  You know it is coming, that one model run with everything coming together to crush us only to be gone on the next run    

 

Also, I'm sure the severe weather types are perking up because of this systems potential. 

 

Enjoying the Fantasy while it lasts:

 

 

 

[vwgrrc]

Not trying to be negative on this event.

 

But it really looks like the precip. will come to a halt right before it's cold enough to snow/sleet on next Tue evening!

[Quixotic1]

I've been a big fan of 2003 as a March analog for a while now.

ETA: I missed that the super ensemble was actually referencing a Feb '03 analog.

ETA2: I have no clue what month it is! The first part of this post should have been, "big fan of 2003 as a Feb analog" and thus making the "ETA" unneeded

I put 2006 instead of 1976 in my post about analogs. Take comfort.

[Srain]

Evening briefing from Jeff:

Another extended streak of very mild days in early February…but this will all be ending by this time next week as a 1048mb arctic high crashes down the plains.

Not much to speak about in the short range (through the weekend). A weak cold front will cross the area Wednesday and knock temperatures back down to near or slightly above normal for this time of year. Moisture is extremely limited and do not expect any rainfall with this front. Lows will fall into the 40’s Thursday and Friday with highs in the lower 60’s. Highs return to the 60’s and 70’s over the weekend, but clouds also begin to increase. Rain chances look to return by Monday of next week as warm air advection increases moisture off the Gulf of Mexico and mid/high level moisture streams into the region from the southwest.

Upper air pattern of late that has been locked in place with cold arctic air aimed at the NE US with frequent winter storms and ridging over the SW US into the southern plains resulting in the dry and warm weather locally. This streak of mild and dry weather will end by early to mid next week as the ridge over the SW US repositions off the US west coast and amplifies into Alaska. A very cold air mass currently resides over NW Canada with temperatures in the -25F to -35F range. The west coast ridge punching into the Alaska will force a large downstream central US trough which will unleash a strong arctic high pressure cell out of NW Canada into the central plains early next week. Medium range models are in decent agreement on the developing upper air pattern which adds confidence that some fairly cold air will be heading southward by the middle of next week. Since we are still about 7 days out will not attempt to resolve low temperatures and just how cold it might get. Current guidance suggests sub-freezing temperatures are certainly possible all the way to the coast.

Other item of interest is a short wave which drops through the longwave trough and across TX in the Tuesday/Wednesday time period. Suspect cold arctic air mass will either be moving into the region or already in place as this shortwave moves across. Not sure at this point if there will be enough moisture to squeeze out any precipitation, but thermal profiles suggest a wintry mix would be possible over portions of the area if moisture is available.

[Srain]

A dry cold front has arrived and temperatures today will be cooler than yesterday. The temperatures will be near normal for this time of year and some moderating is likely into the weekend before a backdoor front arrives Sunday.

The Major weather headliner will be the strong Arctic front arriving early next week. The overnight guidance continues to be at odds with the GFS being about 18 to 24 progressive ejecting the Baja Storm across Texas with limited light precipitation ending before the coldest air arrives. The European model is slower suggesting light QPF continues after the cold air arrives suggesting p-type issues and much colder air work in tandem creating wintry mischief across a large portion of the Lone Star State into Louisiana. There is a slight hint of a Coastal trough/low attempting to develop on Monday along the Lower Texas Coast, but great uncertainty continues in what the sensible weather may hold moisture wise. It does appear that we will get a significant late Winter cold shot and areas North of the Coastal set of Counties could see freezing temperatures Tuesday night into early Wednesday. Highs may struggle to reach the mid to upper 30's for highs on Wednesday. This is a complex and complicated forecast, so expect day to day changes as we get additional information. Typically these Baja upper lows create tremendous forecasting challenges and with potential phasing of a strong shortwave dropping S across the Great Basin/Southern Rockies, the uncertainty should continue into the weekend as the computer models attempt to resolve all the moving parts and what our sensible weather will actually be. It is noteworthy that the ensembles are further West with the shortwave trough than the operational GFS which is more inline with the European solution. Regardless, the string of Spring like weather appears to be coming to an abrupt halt reminding us that it is still February and Winter. The ensembles are in rather good agreement that temperatures will be around 2 Standard Deviations below normal Tuesday into Thursday next week.

 

 

[bubba hotep]

The overnight model trends were encouraging for Texas and it appears that there is room for something big to come together (or a total bust).

[Srain]

55 Years ago today a nice snowstorm impacted SE Texas and Houston. I recently received some old photos from my Mom of me playing in the snow during that event. I guess I need to scan them and share what a real snowstorm looked like in the Houston Area... 

 

 

[bubba hotep]

A dry cold front has arrived and temperatures today will be cooler than yesterday. The temperatures will be near normal for this time of year and some moderating is likely into the weekend before a backdoor front arrives Sunday.

The Major weather headliner will be the strong Arctic front arriving early next week. The overnight guidance continues to be at odds with the GFS being about 18 to 24 progressive ejecting the Baja Storm across Texas with limited light precipitation ending before the coldest air arrives. The European model is slower suggesting light QPF continues after the cold air arrives suggesting p-type issues and much colder air work in tandem creating wintry mischief across a large portion of the Lone Star State into Louisiana. There is a slight hint of a Coastal trough/low attempting to develop on Monday along the Lower Texas Coast, but great uncertainty continues in what the sensible weather may hold moisture wise. It does appear that we will get a significant late Winter cold shot and areas North of the Coastal set of Counties could see freezing temperatures Tuesday night into early Wednesday. Highs may struggle to reach the mid to upper 30's for highs on Wednesday. This is a complex and complicated forecast, so expect day to day changes as we get additional information. Typically these Baja upper lows create tremendous forecasting challenges and with potential phasing of a strong shortwave dropping S across the Great Basin/Southern Rockies, the uncertainty should continue into the weekend as the computer models attempt to resolve all the moving parts and what our sensible weather will actually be. It is noteworthy that the ensembles are further West with the shortwave trough than the operational GFS which is more inline with the European solution. Regardless, the string of Spring like weather appears to be coming to an abrupt halt reminding us that it is still February and Winter. The ensembles are in rather good agreement that temperatures will be around 2 Standard Deviations below normal Tuesday into Thursday next week.

 

02122015 00Z GEFS gfs-ens_z500a_namer_23.png

 

02122015 00Z Euro ENS ecmwf-ens_z500a_namer_7.png

 

It seems like the last couple of Baja ULL ended up ejecting out on a more southerly track than what was depicted by the models in the medium range, IIRC.  Now, if the models do trend to a more southerly track with the Baja ULL do we get a less organized system or does the northern stream short wave dig deeper shifting the heavier snow south?  Lots of possibilities still on the table.  

[DFWWeather]

Looks like the 12z GFS today is starting winter precip earlier with a fairly good shot of significant icing from sleet Monday night into Tuesday for DFW followed by changeover to snow on Tuesday. However, am a bit concerned of the significant moderation of the cold airmass. No where near as cold as prior runs. Gone from H85 temp of -13.9°C to barely -5.0°C. Hope this trend doesn't continue.

[bubba hotep]

Well, not surprising at all, the models continue to flop around with 12z runs coming in drier and warmer.  We may not see them lock in on a solution until pretty late in the game with this kind of a setup.  

 

My takeaway from the last 24 hours of model runs is that a winter weather solution for DFW is very much a possibility.  Most of our systems this winter have been long shot / thread the needle type systems with only the random model run here and there showing winter weather. We could still bust and get nothing but I am feeling pretty good about seeing something frozen out of this system. 

[DFWWeather]

Well, not surprising at all, the models continue to flop around with 12z runs coming in drier and warmer.  We may not see them lock in on a solution until pretty late in the game with this kind of a setup.  

 

My takeaway from the last 24 hours of model runs is that a winter weather solution for DFW is very much a possibility.  Most of our systems this winter have been long shot / thread the needle type systems with only the random model run here and there showing winter weather. We could still bust and get nothing but I am feeling pretty good about seeing something frozen out of this system. 

Yeah, 12z ECMWF coming in wetter like the GFS with fairly significant icing potential for DFW. It also starts frozen precip earlier. Seeing a strong sleet potential on both models before changeover to all snow. ECMWF has moderated from -10.4°C (H85) at 0z to -9.0°C at 12z. Still quite a bit colder than the GFS which increases my confidence of winter weather. With the overrunning warmer air  from the upper-low might explain the moderation of the H85 temps?

 

Looks like, per the afternoon AFD from DFW, that they are down playing this whole event and going with much warmer scenario (per GFS) and not much in the way of wintry precip. Already talking about 60s by end of the week. Looks like another crapbag system per all the other systems in this otherwise crappy winter.

[vwgrrc]

Oh yes. Down play is much safer for this winter.

 

Hope ECMWF keep the significant icing potential!

 

 

Looks like, per the afternoon AFD from DFW, that they are down playing this whole event and going with much warmer scenario (per GFS) and not much in the way of wintry precip. Already talking about 60s by end of the week. Looks like another crapbag system per all the other systems in this otherwise crappy winter.

[vwgrrc]

 

At this time, we expect any snow accumulations to remain less than 1 inch due to warm surface temperatures. We are not anticipating significant impacts or amounts due to the snow.

[ams30721us]

A much more reasonable and smart discussion from NWS SHV this afternoon. 

 

 

 

BIGGEST IMPACT IN THIS FORECAST PACKAGE CONTINUES TO CENTER AROUND
THE SUNDAY-WEDNESDAY TIMEFRAME. A BACKDOOR COLD FRONT WILL MOVE
INTO THE AREA ON SUNDAY AND SHOULD BECOME STATIONARY SOUTH OF
I-20 BY THE AFTERNOON. A LONG WAVE UPPER TROUGH WILL ALSO BEGIN TO
DIVE SEWD ACROSS MUCH OF THE CONUS WITH A STRONG SRN SHORTWAVE
TROUGH DIVING THROUGH THE FOUR CORNERS AND INTO W TX. LARGE SCALE
ASCENT AHEAD OF THIS TROUGH AND A COUPLE OF OTHER WEAKER LEAD
IMPULSES WILL HELP TO DEVELOP WIDESPREAD PRECIP ACROSS THE REGION
WHICH WILL BEGIN TO AFFECT OUR AREA SUNDAY NIGHT. A SHALLOW COLD
AIRMASS WILL ALSO MOVE INTO THE REGION SUNDAY NIGHT/MONDAY
MORNING. NEAR OR BELOW FREEZING TEMPS WILL BE LIKELY NORTH OF A
LINE FROM CLARKSVILLE...TO KTXK...TO KELD. FCST SOUNDINGS INDICATE
THERE WILL BE A STRONG WARM LAYER ALOFT. THEREFORE...ANY SNOW/ICE
THAT FALLS SHOULD COMPLETELY MELT AND THEN FREEZING ON CONTACT
WITH THE SURFACE. IN OTHER WORDS...FREEZING RAIN SHOULD BE THE
DOMINANT PRECIP TYPE IN AREAS WHERE TEMPS FALL BELOW 32 DEGREES F.
SOME VERY LIGHT ACCUMULATIONS WILL BE POSSIBLE BUT GROUNDS TEMPS
ARE STILL RUNNING IN THE MID 50S. ELEVATED SUFACES AND ROADWAYS
WOULD BE THE MOST VULNERABLE TO ANY ICING.

A TRANSITION BACK TO ALL LIQUID RAIN IS EXPECTED BY NOON MONDAY.
ANOTHER CHANGE TO SNOW AND SLEET WILL BE POSSIBLE ACROSS THE
HIGHEST TERRAIN OF SE OK/SW AR MONDAY NIGHT/TUESDAY MORNING. A
STRONG ARCTIC FRONT WITH A DEEP COLD AIRMASS IS FINALLY EXPECTED
TO PUSH ACROSS THE AREA ON TUESDAY. TEMPS WILL LIKELY FALL DURING
THE DAY TUESDAY FOLLOWING THE FRONT. PRECIP SHOULD CHANGE ONCE
AGAIN TO A RAIN/SNOW MIX FOLLOWED BY ALL SNOW AS THE VERY COLD AIR
DEEPENS. PRECIP SHOULD FINALLY END AND EXIT THE AREA EARLY
WEDNESDAY MORNING.

WHILE THE MEDIUM RANGE MODELS ARE SHOWING GOOD AGREEMENT WITH EACH
OTHER...THEIR RUN-TO-RUN CONSISTENCY HAS BEEN VERY POOR. IN
PREVIOUS RUNS...THE MODELS TRACKED THE SFC LOW GENERALLY ALONG THE
RED RIVER BETWEEN OK/TX KEEPING MOST OF THE CWA IN THE WARM SECTOR
FOR MOST OF THE EVENT AND DELAYING ANY WINTRY PRECIP UNTIL LATE
TUESDAY WHEN THE ARCTIC FRONT ARRIVES. TODAY...THE MODELS ARE
DROPPING THE SFC LOW SOUTH OF THE CWA AND ALONG THE GULF COAST.
THIS IS RESULTING IN SLIGHTLY COLDER SFC TEMPS BUT THE VERTICAL
PROFILE IS STILL TO WARM FOR WINTRY PRECIP FOR THE MAJORITY OF
THE EVENT.

IT IS IMPORTANT TO NOTE THAT SMALL LOCATION DIFFERENCES IN THESE
FEATURES CAN RESULT IN LARGE DIFFERENCES IN TEMPERATURES AND LARGE
DIFFERENCES IN PRECIP TYPES/AMOUNTS. AT THIS TIME FRAME...THERE IS
A LOT OF ROOM FOR CHANGE IN THE FORECAST ESPECIALLY GIVEN THE POOR
RUN-TO-RUN CONSISTENCY IN THE MODEL GUIDANCE. /09/