Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 5

[Srain]

Morning e-mail from Jeff:

 

Next storm system quickly arrives into the area Wed-Thurs with strong to severe thunderstorms possible.
 
Fast progressive upper air pattern will bring another upper level storm system and Pacific cold front into the area by Thursday. Cool front from last night has pushed into the NW Gulf this morning with a dry and cool air mass in place over SE TX. High clouds are already starting to stream ENE from central MX in response to the next digging trough out west. Front will stall over the NW Gulf today while moisture begins to return northward from both the Gulf and Pacific above the surface cold dome. Will see a rapid increase in cloud cover from SW to NE tonight as moisture surges northward above the cold dome. Skies will be cloudy be sunrise Wednesday with lifting of the incoming moist air mass over the cool dome producing periods of showers, light rain, fog and drizzle. Showers will become numerous by early afternoon as a lead short wave crosses the area helping to enhance lift. Additionally, the warm front will move northward and approach the coast by mid afternoon on Wednesday. Surface based instability appears limited, but there appears to be some elevated instability and thunderstorms may become more numerous as the day progresses near and north of the warm front. Not expecting much severe weather on Wednesday, but a few of the elevated storms could produce some hail.

 

As a surface low deepens over central TX on Wednesday night, the attached warm front downstream over the upper TX coast should progress inland and through much of SE TX by Thursday morning. Area will become under the influence of the warm sector, but also under the increasing influence of capping from the SSW. Approach of the main upper trough across NW TX into OK will push a cold front eastward across central TX and as this boundary encounters the warm and moist air mass east of I-35 expected thunderstorms to develop. Strong linear forcing is suggested indicating more of a line than discrete cells. However strong lift will also be overspread the northward moving warm front which should be along a line from near Temple to Lufkin Thursday morning. Convection will become increasingly surface based and the air mass will be highly sheared in the low level, so supercells with tornadoes will be possible along and near the warm frontal boundary which could be over our northern set of counties. One drawback for a significant severe weather outbreak appears to be limited instability with CAPE values of 800-1500 J/kg over the region. Low level shear is impressive however and storms that are able to root near the surface will have rotating updrafts.
 
South of the warm front across the warm sector and the rest of SE TX, the linear forcing along the advancing front combined with a strong upper level sub-tropical jet overhead should result in a line of thunderstorms or squall line to move across the area from W to E during the morning hours. There will be a severe threat with this line also…with the main threat being wind damage, but isolated tornadoes in any “notches” in the line will be possible given low level helicity values of 200-400 m^2/s^2. How far south this line of storms extends will depend on the intensity of the capping advecting NNE from S TX. Forecast models are not overly excessive with the cap, but time of day (early to mid morning) does not bode well for any heating as compared to yesterday when surface heating was able to weaken the cap and lift from a short wave enticed convection through the mid level warm layer. Will review the severe parameters again Wednesday AM as by this point there should be a decent handle on the threat and the most likely severe modes.

 

Cold front Thursday afternoon slows and stalls just offshore with clouds and possible showers lingering near the coast early Friday. GFS has come in wet on Saturday as this model amplifies another short wave and drops it across TX, but no other models currently suggest this scenario. For now will follow the dry guidance and keep skies partly cloudy and conditions dry unless the other major models begin to trend toward the wetter GFS solution.

 

 Severe Weather Outlook for Wednesday

Severe Weather Outlook for Thursday:

 

[Ed Lizard]

New 12Z NAM still a buzzkill IMBY.  Maybe not a buzzkill in Northern and Eastern Texas.  But up there, cool surface temps, down here, warm 700 mb nose.  Mondo shear/helicity, however.

 

Using handy 9Z SREFs MUCAPE 500 J/Kg, deep shear 40 knots and some precip product, Thursday morning happy zone somewhere between ACT and CLL, then happy zone shrinks, before picking up again in Southern Louisiana.

 

Waiting on new GFS, it has been keeping me a bit over a quarter full optimistic IMBY Thursday morning,

[Srain]

Morning e-mail from Jeff:

 

Next upper level storm system moving toward the state this morning.

 

Fast moving upper level pattern resulting in rapid day to day weather changes across the region. Mid and upper level cloud decks have spread across the area overnight as the lead short wave ahead of the main upper trough along the CA coast ejects over TX this morning. Showers have developed over much of northern into eastern TX with this feature. At the surface the old cold frontal boundary is breaking down over the Gulf of Mexico and starting to return northward as a warm front as surface pressures lower over NW TX. Will start to see cloud bases lower this morning into the afternoon hours and lift of the warm moist Gulf air mass over the surface cold dome continues to saturate the low level air mass from the top down. Fairly dry low level ESE flow is in progress along the upper TX coast this morning and his will result in much of the initial rainfall evaporating before reaching the ground. By mid to late afternoon, the low levels should become saturated with widespread drizzle and light rain developing and spreading northward out of the Gulf of Mexico.

 

Warm front will move inland tonight, but believe that the “juicy” tropical air mass will south of the region. While some sort of a warm front swings north across the region overnight, instability will be lacking although very strong shear will be in place. Lift from the main upper level trough and surface cold front arrives into the region in the 400-600am and expect an increase in showers and thunderstorms from west to east during the morning hours on Thursday. As for the severe potential, the lack of instability and ever so close mid level capping over the coastal bend and S TX has me favoring areas NE of a line from College Station to Conroe to Liberty to High Island for any isolated severe threats. While SPC is further SW with their outlook area, capping could be an issue for those areas SW of the Houston metro area. Main threat appears to be large hail and wind damage although would not rule out a tornado if any discrete cells can root near the surface and utilize the very favorable low level shear environment. Current thinking is that any tornado threat will be near/along the warm frontal boundary which should be very near our northern set of counties from Huntsville to Lake Livingston and with any cells that can develop ahead of the main line of storms.  Think the main line of storms will be a broken thin band with the heaviest and more solid part of the line passing along and north of I-10.
 
This system will exit east late Thursday, but the surface cold front slows and stalls near the coast. With an active sub-tropical jet overhead a few light showers may linger near the coastal locations into Friday morning before stronger surface high pressure forces the boundary offshore on Friday.

 

Fast moving flow aloft has the next system into the area by late Sunday/Monday but moisture return is looking limited with the fast moving nature and winds only turning off the Gulf on early Sunday giving a small window for moisture to move northward.
 
Severe Weather Outlook for Thursday:

[bubba hotep]

We had some pingers overnight and this morning

[Ed Lizard]

Based on 12Z modelling, I'm down to 3/16ths optimistic on either fun-derstorms or more than a couple of tenths of precip tomorrow.  NAM (12 km and 4 km) hates me, 9Z SREFS have less than 10% of members with 3 hour quarter inch rain IMBY.  What a waste, Almost have the SREFs have a SigTor aob 3 IMBY.

 

 

Even GFS starting to back off, seems to suggest 700 mb warm nose will supress fun in and near HOU area.  GFS offers hope up Huntsville way.

[Srain]

HGX releases the prelim report for the Shepherd, TX tornado event as an EF1...

 

http://www.srh.noaa.gov/hgx/?n=severe_2013_02_18

[Ed Lizard]

I see an extended period of general cool and boring weather in Texas lasting into at least early March.

 

Thank goodness for the Australia cyclone thread.

[Srain]

The progressive pattern will continue throughout the weekend into next week as storm systems march E across the North Pacific and head inland before turning S along a Western trough and eject E into the Southern Plains. The zonal split flow pattern appears to remain in place until the mid week time frame when ridging begins to develop to our W and a deep anomalous Eastern trough becomes anchored across the Plains to the East Coast.

 

The next storm system will eject out of the Desert SW late Sunday and move across Texas/Oklahoma bringing bouts of wintry weather in the cold sector and light showers and isolated elevated storms across portions of E Texas on E into Louisiana where modest moisture returns from the Gulf may make it inland. It should be noted that the track of this storm is a bit further S than what we have been experiencing so far the season due to the blocking regime across Greenland stretching W to Ontario and -AO/+PNA. The sub tropical jet remains entrenched over the Southern half of Texas and Louisiana on E throughout the upcoming period.

 

Looking into the medium range time frame of late February, there continues to be indications that unseasonably chilly air may well be possible for the Eastern half of Texas on E where temps may well fall to the 10-15 degrees below normal range. With a dry N to NW flow aloft riding over the building Western Ridge, rain chance appear limited. The fly in the ointment will be the close proximity of the noisy sub tropical jet and any embedded upper air disturbance that may affect the Coastal areas. Winter Storm RECON continues across the Gulf of Alaska where 16 drops were included in the 00Z suite of computer guidance and additional missions are tasked for tonight to further aid the Global models. Also of note is the possibility of a major East Coast storm next week and that will need to need to be monitored.

 

Ensembles Early Next Week:

 

Ensembles Mid Next Week:

 

 

[wxmx]

I see an extended period of general cool and boring weather in Texas lasting into at least early March.

 

Thank goodness for the Australia cyclone thread.

Unless you can fill your glass up to 3/16s full with what the 0/12z CMC and 12z Euro are showing

[Srain]

Unless you can fill your glass up to 3/16s full with what the 0/12z CMC and 12z Euro are showing

 

[Ed Lizard]

Unless you can fill your glass up to 3/16s full with what the 0/12z CMC and 12z Euro are showing

 

There is just something wrong about liking cold weather as March approaches.

[DoctorMu]

LOL The Frozen Tundra of Love Field

[Srain]

It certainly appears a very chilly start to March is ahead with freezing to near freezing temps well S into Texas and Louisiana. We will need to monitor these trends as freezing temps may come awfully close to the Coastal Counties late next week into next weekend.

 

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
200 AM EST SAT FEB 23 2013

VALID 12Z TUE FEB 26 2013 - 12Z SAT MAR 02 2013

 

...OVERALL PATTERN AND SENSIBLE WEATHER THREATS/HIGHLIGHTS...

 

THE MODELS AND ENSEMBLES POINT TO AN ACTIVE AND TRANSITIONAL
MEDIUM RANGE FLOW PATTERN STARTING TUE/WED INTO THU WITH THE
LIFTING OF A WELL ORGANIZED MID-UPPER LEVEL TROUGH AND SURFACE LOW
SYSTEM/WINTER WEATHER SWATH FROM THE MID-MS VALLEY TO THE
MIDWEST/GREAT LAKES/NE US AS MOISTURE WRAPS INTO THE SYSTEM...ALSO
THEN ENHANCED BY LAKE EFFECT.  A TRAILING COLD FRONT APPROACH
ACROSS THE SE/ERN US WILL ALSO FOCUS PRECIPITATION.

 

MEANHWILE...ANOTHER DYNAMIC MID-UPPER LEVEL SHORTWAVE TROUGH DIGS
WINTER PCPN SEWD OVER THE WRN US MON/TUE BEFORE EJECTING EWD
ACROSS THE CENTRAL AND ERN STATES WED/THU...POSSIBLY LEADING TO
SOME EAST COASTAL SURFACE LOW RESPONSE. ANOTHER TROUGH IN THIS
SERIES IS ON ITS HEALS BACK ACROSS THE WEST MIDWEEK...BUT EXPECTED
RAPID UPSTREAM FLOW AMPLIFICATION OUT FROM THE ERN PACIFIC HAS
GOOD GUIDANCE SUPPORT TO LEAD TO DEVELOPMENT OF AN AMPLIFIED WRN
US MID-UPPER LEVEL RIDGE BY LATE NEXT WEEK. THIS MAY FORCE THE
LEAD IMPULSE TO AMPLIFY WITH NRN STREAM ENERGY INTO QUITE AN
AMPLIFIED AND COLD E-CENTRAL US MID-UPPER LEVEL TROUGH IN A
POSITIVE PNA PATTERN. DOWNSTREAM...TRENDS CONTINUED TOWARD AN
INCREASINGLY BLOCKY (NEGATIVE) NAO PATTERN EMERGING IN THE NRN
ATLANTIC HEADING INTO NEXT WEEKEND WITH HIGH LATITUDE HEIGHT RISES
FEEDING WWD ACROSS SRN GREENLAND TOWARD ERN CANADA.

 

...GUIDANCE EVALUATION AND WEATHER SYSTEM PREFERENCES...

 

MODEL AND ENSEMBLE MEAN GUIDANCE HAS OVERALL CONVERGED UPON A MORE
COMMON/BETTER CLUSTERED MID-LARGE SCALE SOLUTION FOR MUCH OF THE
FORECAST DOMAIN NEXT WEEK COMPARED TO THE LAST FEW DAYS WITH THE
LAST COUPLE GFS/GEFS RUNS MORE IN LINE/LESS PROGRESSIVE.  LOWER
FORECAST SPREAD BOLSTERS FORECASTER CONFIDENCE DESPITE A
TRANSITIONAL PATTERN.  THE ECMWF ENSEMBLE MEAN EVEN SO HAS PROVEN
THE MOST RUN TO RUN CONSISTENT THROUGH MEDIUM RANGE TIME SCALES
RECENTLY AND NOW SITS ON THE SLIGHTLY SLOWER/MORE AMPLIFIED SIDE
OF THE FULL ENVELOPE OF GUIDANCE ALOFT.  THIS SOLUTION REMAINS
WELL SUPPORTED BY UPSTREAM AMPLITUDE OVER THE PACIFIC AS DEPICTED
IN RECENT WATER VAPOR IMAGERY LOOPS.

 

SCHICHTEL

 

[DoctorMu]

Yo, Adrian! "Rocky" is starting to dig deep in the panhandle. Wichita Falls is going to see some action. Fort Worth? We'll see - should be an interesting 24-36 hrs.

[bubba hotep]

Yo, Adrian! "Rocky" is starting to dig deep in the panhandle. Wichita Falls is going to see some action. Fort Worth? We'll see - should be an interesting 24-36 hrs.

It wouldn't take much of a south trend for me to see some snow but DFW proper is probably out of the game... But maybe not

[Srain]

Morning e-mail from Jeff:

 

A powerful winter storm over the central plains this morning with bring a strong cold frontal passage to the area over the next few hours.
 
Strong cold front is currently plowing through central TX and is nearing our western counties early this morning as a full scale blizzard is in progress over the TX panhandle into Oklahoma and Kansas. Main surface low over NW TX will deepen today blasting the cold front through the area by late morning. Strong forcing along the front should generate a thin line of showers and thunderstorms which will move rapidly west to east across the area. Instability and less capping east of I-45 will support a marginal severe threat with strong winds being the primary concern.
 
Deepening surface low will result in a very tight pressure gradient across the region by early afternoon with WNW winds increasing to 20-30mph with frequent gust to 40-45mph. A wind advisory is in effect starting at noon and will continue into the early evening hours. Winds of this magnitude may cause tree limbs to fall on power lines and down dead trees from the 2011 drought.
 
Other item this afternoon will be fire weather as strong winds couple with very dry air to produce critical fire weather conditions. A Red Flag Warning is in effect for this afternoon for all counties, but feel the highest fire danger will be along and west of a line from College Station to Wharton where rainfall over the past several weeks has been lower compared to locations near the coast and E of I-45. With such strong winds expected, any fire that develops will burn quickly out of control. 
 
After today mainly clear and cool weather for the rest of the week. Another cool front will move across the region on Thursday, but little moisture will mean generally no rainfall. This front will bring a bout of colder weather for Friday-weekend with lows into the low to mid 30’s and highs in the 50’s to near 60.

 

[Ed Lizard]

World's dullest cold front approaching.  Low RH and high winds means critical fire conditions in Deep South Texas.

 

 

[Terpeast]

Check out the video on this weather blog, Amarillo TX is ripping!

[wxmx]

-EPO forecasts and signals for a late season arctic blast are increasing.

[Srain]

-EPO forecasts and signals for a late season arctic blast are increasing.

 

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD

1023 AM EST MON FEB 25 2013

VALID 12Z THU FEB 28 2013 - 12Z MON MAR 04 2013

...GUIDANCE EVALUATION AND FORECAST CONFIDENCE ASSESSMENT...

HPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS HAVE

BEEN PRIMARILY DERIVED FROM A 50-50 BLEND OF THE 00Z ECMWF/ECMWF

ENSEMBLE MEAN. THIS AMPLIFIED SOLUTION FITS RECENT GUIDANCE TRENDS

AND WATER VAPOR LOOPS... DOWNPLAYS SOME SMALLER SCALE FORECAST

VARIANCE... AND OFFERS GOOD HPC CONTINUITY AND REASONABLY GOOD

FORECAST CONFIDENCE. THE GFS/GEFS RUNS OFFER A SIMILAR BUT NOT

IDENTICAL SOLUTION THAT GENERALLY EITHER OUTPACED OR LAGGED THE

GREATER CLUSTERING OF THE ECMWF ENSEMBLES WITH THE UKMET AND

OCCASIONALLY THE CANADIAN MODEL... WITH THE 06Z GFS MUCH MORE OUT

OF STEP THAN ITS 00Z RUN.

...OVERALL FLOW PATTERN AND SENSIBLE WEATHER HIGHLIGHTS/THREATS...

A SHORT RANGE WINTER STORM PROGRESSES OUT FROM THE NERN US TOWARD

THE CANADIAN MARITIMES THU INTO FRI. THIS WILL SUPPORT LINGERING

WRAP-BACK SNOWS WITH MAX AMOUNTS OVER NRN NEW ENGLAND...

ESPECIALLY OVER FAVORED TERRAIN. LAKE EFFECT SHOULD PERSIST

THROUGH THE WEEKEND IN COLD FLOW IN THE WAKE OF THE LOW... WITH

LINGERING RAINS OVER SRN FL NEAR A TRAILING SLOWLY MOVING COLD

FRONT.

UPSTREAM...A DYNAMIC SHORTWAVE IMPULSE WITH LIMITED MOISTURE WILL

DROP SEWD THROUGH THE WRN US THU/D3. DIGGING ENERGY WILL FEED MORE

SHARPLY INTO THE S-CENTRAL US BY FRI TO THE LEE OF A RAPIDLY

AMPLIFYING MID-UPPER LEVEL E-CENTRAL PACIFIC TROUGH AND WRN US

RIDGE COUPLET DEVELOPING UPSTREAM. THIS LEADS TO QUITE AN

AMPLIFIED WRN US RIDGE AND COLD ERN US TROUGH... POSITIVE PNA

PATTERN... BY SAT/D5 JUST AS HEIGHT RISES FEED WESTWARD FROM

GREENLAND INTO ERN CANADA AT HIGHER LATITUDES. THIS MAY LEAD TO

ERN US COASTAL LOW POTENTIAL SAT-MON AND HPC MANUAL PROGS SHOW

MODERATE DEVELOPMENT BUT THE PATTERN FAVORS OFFSHORE DEVELOPMENT.

500MB STANDARDIZED HEIGHT ANOMALIES ARE FCST TO DROP TO -3.5 OR SO

CENTERED OVER FLORIDA OVER THE WEEKEND WITH SFC TEMPS 10-15 DEG F

BELOW NORMAL. TEMPERATURES IN THE WEST SHOULD BALANCE WITH HIGHS

WELL INTO THE 80S IN THE SW DESERTS.

MEANWHILE WELL UPSTREAM... AMPLIFIED ERN PACIFIC MID-UPPER LEVEL

TROUGH ENERGY REACHING THE NWRN US NEXT WEEKEND WILL WORK INTO THE

LEAD WRN US MID-UPPER LEVEL RIDGE AND FAVOR ANOTHER CHANCE FOR

ORGANIZED PCPN. GUIDANCE OFTEN BREAKS DOWN AMPLIFIED BLOCKY RIDGES

TOO RAPIDLY WITH APPROACHING TROUGHS...BUT HPC MANUAL PROGS AT

LEAST TAKE INTO ACCOUNT THAT THE SPECIFIC SYSTEM INVOLVED OFFERS

QUITE A BIT OF MUSCLE NOW OFF JAPAN. BELIEVE THE MAJORITY OF THE

ENERGY SHOULD FUNNEL INTO VANCOUVER ISLAND BEFORE DIVING THROUGH

THE HIGH PLAINS MON/D7... THOUGH THE DETERMINISTIC ECMWF LIES ON

THE STRONGER SIDE OF THE ENSEMBLES BY CLOSING OFF AN UPPER LOW BUT

OTHERWISE STILL CORRELATES WELL WITH ITS MEAN.

SCHICHTEL/FRACASSO

 

[Quixotic1]

Check out the video on this weather blog, Amarillo TX is ripping!

Now THAT is a blizzard.  great googly moogly. 

[Ed Lizard]

Now THAT is a blizzard.  great googly moogly. 

 

 

Moar

 

[Portastorm]

-EPO forecasts and signals for a late season arctic blast are increasing.

 

Litany of sadness in Austin, Texas:  10 minutes of sleet mixed with rain being the collective total for the last two "winters" ... probably two dozen dry fropas since last fall ...  I'm about all out of hope.  Throw in an active STJ with your arctic blast and all will be forgotten! 

[Quixotic1]

Moar

 

 

Closest I've seen to that is Christmas Eve 2009.  4" of snow but the wind never made it above 38.

[wxmx]

Litany of sadness in Austin, Texas:  10 minutes of sleet mixed with rain being the collective total for the last two "winters" ... probably two dozen dry fropas since last fall ...  I'm about all out of hope.  Throw in an active STJ with your arctic blast and all will be forgotten! 

At least you're "just" having trouble with moisture. Coldest here so far this winter has been 2C. I don't remember when was the last sub freezing obs in March, but not in the last 19 years I have lived here. To compound things, less than a 0.75" precip has fallen in the last 3 months. I was about to bail for the Thu-Sat cold front (mountain trip), but the 12z Euro has dragged me back in.

[Quixotic1]

At least you're "just" having trouble with moisture. Coldest here so far this winter has been 2C. I don't remember when was the last sub freezing obs in March, but not in the last 19 years I have lived here. To compound things, less than a 0.75" precip has fallen in the last 3 months. I was about to bail for the Thu-Sat cold front (mountain trip), but the 12z Euro has dragged me back in.

Best of luck this weekend.  

[DoctorMu]

At least you're "just" having trouble with moisture. Coldest here so far this winter has been 2C. I don't remember when was the last sub freezing obs in March, but not in the last 19 years I have lived here. To compound things, less than a 0.75" precip has fallen in the last 3 months. I was about to bail for the Thu-Sat cold front (mountain trip), but the 12z Euro has dragged me back in.

 

We've had only a handful of light frosts, and most were in December.  A long range forecast suggests we may not see 70°F until March 15.  Crazy stuff.

 

The paltry precipitation here as well since early January (when we had 6 in from an ULL is also troubling and potentially setting up more drought.

[Quixotic1]

a few flakes falling here in frisco

[wxmx]

We've had only a handful of light frosts, and most were in December.  A long range forecast suggests we may not see 70°F until March 15.  Crazy stuff.

 

The paltry precipitation here as well since early January (when we had 6 in from an ULL is also troubling and potentially setting up more drought.

Drought + strong winds + low humidity from fropa today = mountain set ablaze

 

[bubba hotep]

a few flakes falling here in frisco

A few out here a bit ago