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

[Srain]

The 12Z 4km NAM likes a QPF bomb just E of AMA along the I-40 Corridor...

[Srain]

Interesting to see the 12Z GFS continue to suggest some lift as a Clipper type system moves across Eastern Oklahoma/N Central/Central/SE/E Texas on E into Arkansas/Louisiana Friday night into Saturday. WSR (Winter Strom RECON) will fly the N Pacific SW of the Aleutian Islands tonight as scheduled and possibly again tomorrow night as well. The Updated HPC Medium Range Discussion explains well why the operational and ensembles are struggling with the evolving pattern. Hopefully that additional data will settle down the volatility seen in the medium range over the next few days.

 

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1110 AM EST MON 11 FEBRUARY 2013
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
         VALID 12/1100Z TO 13/1100Z FEBRUARY 2013
         WSPOD NUMBER.....12-073

 

I.  ATLANTIC REQUIREMENTS
    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

 

II. PACIFIC REQUIREMENTS
    1. FLIGHT ONE --NOAA 49--
       A. P23/ DROP 8 (47.0N 175.0W)/ 13/0000Z
       B  NOAA9 09WSC TRACK23
       C. 12/1900Z
       D. 18 DROPS ON TRACK AS PUBLISHED
       E. 41,000 TO 45,000 FT/ 13/0600Z

 

    2. SUCCEEDING DAY OUTLOOK: POSSIBLE
       A. P9/ DROP 7 / 14/0000Z

    3. REMARKS: TRACK P10 WILL BE FLOWN TODAY AS
       DETAILED ON WSPOD 12-072.

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1101 AM EST MON FEB 11 2013

 

VALID 12Z THU FEB 14 2013 - 12Z MON FEB 18 2013

 

MODELS SHOW RELATIVELY GOOD LARGE-SCALE EVOLUTION DAYS
3-7/THU-MON...WITH A HIGH AMPLITUDE TROUGH FORMING NEAR THE
MISSISSIPPI RIVER...WHILE PROGRESSIVE FLOW DEVELOPS ALONG THE WEST
COAST.  HOWEVER...MODEL DETAILS INCLUDING THE ANTICIPATED
TIMING/STRENGTH OF INDIVIDUAL SHORTWAVE TROUGHS ARE MORE UNCLEAR
THAN USUAL DUE TO THE LARGE NUMBER OF TROUGHS/RIDGES AND APPARENT
SENSITIVITY TO THE FLOW CROSSING JAPAN THAT RESEMBLES A ROSSBY
WAVE PACKET...BOTH OF WHICH CONTAIN ENOUGH ERROR THAT IS DIFFICULT
FOR EVEN THE HIGHEST-RESOLVING ENSEMBLES TO ADDRESS...AND ARE
CONFIRMED BY THE HIGHER THAN USUAL SOLUTION SPREAD THROUGH THE
ENTIRE PERIOD.  THEREFORE...CONFIDENCE IN THE DAY-TO-DAY SENSIBLE
WEATHER IS LOWER THAN AVERAGE.

 

BEGINNING WITH DAY 3/THU...THE UPPER TROUGH SHOULD BEGIN TO TAKE
SHAPE OVER THE PLAINS/MIDWEST IN RESPONSE TO THE WAVE PACKET OVER
JAPAN REACHING NORTH AMERICA...WITH THE 00Z GFS STRONGER THAN THE
00Z ECMWF WITH AN EMBEDDED SHORTWAVE TROUGH AFFECTING THE GREAT
LAKES...AND CLOSER/STRONGER THAN THE 00Z ECMWF WITH A SURFACE LOW
OFF THE NORTHEAST COAST.  IN BOTH CASES...THE GLOBAL ENSEMBLE
MEMBERS AND THEIR RESPECTIVE MEANS SUPPORT INTERMEDIATE SOLUTIONS.

 

BY DAY 5/SAT...HEIGHTS SHOULD LOWER ALONG THE WEST COAST DUE TO
PASSAGE OF A SHORTWAVE TROUGH...WHILE A NEW AREA OF LOW PRESSURE
BEGINS TO DEVELOP ALONG THE NORTHEAST/MID-ATLANTIC COAST.  THE
SOLUTION SPREAD BECOME HIGH BY THIS PERIOD...WITH THE 06Z GFS
REPRESENTATIVE OF SOME OF THE MORE EXTREME BUT NOT OUTLYING
ENSEMBLE MEMBERS WITH ITS FASTER SPEED ALONG THE WEST COAST AND
MORE AMPLIFIED/SLOWER PROGRESSION OF THE EASTERN TROUGH.

 

BY DAY 6/SUN...FOLLOWING THE INTERMEDIATE SCENARIO THAT MOST
CLOSELY RESEMBLES THE 00Z ECMWF ENSEMBLE MEAN...THE WEST COAST
TROUGH IS EXPECTED TO DIG ACROSS THE INTERMOUNTAIN WEST/ROCKIES
BEFORE REACHING THE PLAINS ON DAY 7/MON.  THE 00-06Z GEFS MEAN
SHOWS EXCELLENT AGREEMENT WITH THIS APPROACH...WHILE THE 00Z
GFS/ECMWF AGREE WITH THE PHASE BUT SUGGEST VERY DIFFERENT PMSL
FIELDS.  ALONG THE EAST COAST...THE 00Z GFS/ECMWF SHOW ACCEPTABLE
AGREEMENT WITH THE ECMWF ENSEMBLE MEAN'S LOW TRACK...BUT ARE
SLIGHTLY MORE OFFSHORE AND FASTER.  HAVE EXCLUDED THE 06Z GFS
SCENARIO FOR THE MOMENT WITH ITS MORE EXTREME INLAND AND DEEP LOW
TRACK THAT HAS SUPPORT FROM LESS THAN 10 PERCENT OF THE GLOBAL
ENSEMBLE MEMBERS.

 

JAMES

[bubba hotep]

Day after Valentine’s Day surprise for DFW?

ETA: Had the appropriate images attached to this msg but they didn't show up, oh well, y'all know where to look.

My snow sense is starting to tingle for Friday night. FWD seems to be dismissing the GFS even though it looks to be locking in on this little system. It may just be the weenie in me but it seems like the GFS has been pretty good vs the Euro this winter for our area. However, they both have done their fair share of flip flopping and thrashing around. Anyway, it will be interesting to see what camp the NAM sets up in this week.

[Srain]

A nice snow event unfolding for Amarillo, Dumas, Borger, Canadian on E across the I-40 Corridor with many reports of thunder snow and 2 inch per hour rates and an impressive deformation band developing.

The over night RECON over the N Pacific did make it into the 00Z data ingest (12 high altitude, 4-5 lower altitude drops) and after a some what stormy day things should settle down Wednesday into Thursday before a stronger push of Canadian air moves across the Region overnight Thursday. Friday should be breezy and much cooler. The guidance is still advertising a clipper like system dropping SSE along the W flank of the developing trough to our E bringing some lift and light precip (mostly light rain), some of which may be in the frozen form Friday night. Dallas/Ft Worth, Shreveport and even Houston/Galveston NWS have made mention of this, but are not expecting anything significant as the lower levels appear too warm for much to reach the ground. A stray flurry or ice pellet or two may be possible before the system moves E giving us a chilly Saturday.

[Srain]

Morning e-mail from Jeff:

 

Upper level storm system moving across NW TX this morning bringing fog and drizzle to much of eastern TX.
 
Surface low pressure near Victoria is lifting northeast this morning with a well defined warm front along the upper TX coast. Dewpoints are near or above 70 south of this front and in the upper 50’s near the coast. Dense fog has developed over much of the area due to the warm moist Gulf air mass gliding up and over the top of the very shallow surface cool dome. Do not think the warm front will make much if any northward progress today, but could push onshore near Galveston and High Island early this afternoon. Main thrust of lift associated with the upper level system has been aimed at N and NE TX this morning and short term guidance suggest only a few showers are likely this morning over SE TX with much better chances over Louisiana and points eastward.
 
Prefrontal trough now over the I-35 corridor will reach the coast by early to mid afternoon and this should disperse the fog and drizzle although clouds may be harder to break. Cannot rule out a few showers or even an isolated thunderstorms along this boundary…but lack of activity so far this morning is suggestive that anything will be weak and isolated. Actual cold front blasts through the area this evening with much colder conditions overnight into Wednesday. Lows will fall into the 40’s under gusty NW winds and highs on Wednesday will only reach 60. Clouds may linger into the first part of Wednesday as moisture is trapped under the frontal inversion.
 
High pressure will be in control Thursday and most of Friday before a fast moving “clipper” type weather system arrives Friday night. This interesting feature will be a very strong short wave on the backside (western flank) of a large eastern US upper level trough. The incoming amplitude and direction of movement of this feature is not overly supportive of rainfall production as it allows almost no time for Gulf moisture to return to the region. However the GFS model continues to generate post frontal light rainfall across the area late Friday night/Saturday morning. Think the drier guidance (CMC and ECMWF) is on the correct thinking, but just in case the GFS is correct, there could be a brief period of light rain/light snow mix over our far northern counties early Saturday morning as suggested by model critical thickness parameters and forecast soundings. Surface layer will be well above freezing so anything that falls will melt on contact. Quick hitting cold air intrusion could bring freezing temperatures to much of the area on Sunday morning before rapid return flow and southerly winds bring back moisture, warmer temperatures and humidity.

[Srain]

The 12Z GFS is suggesting possible 1-2 inch amounts for wintry mischief Friday night into early Saturday morning for areas near Temple/Waco/Hearne...

[Srain]

It certainly appears we will stay in a very unsettled pattern into next week. Roller coaster temps and very changeable weather seems to be the theme looking into the Medium/Long range.

 

[msp]

HGX put sleet in the forecast for CLL!  First notable sign of winter in weeks.

[DoctorMu]

HGX put sleet in the forecast for CLL!  First notable sign of winter in weeks.

HGX has a snow/sleet teaser in Sat am

[Srain]

A break from the clouds and showers are ahead for a couple of day before a Canadian front arrives overnight Thursday into Friday chilling us down to the 30’s. The GFS has backed off the with available moisture from the ‘Clipper like’ short wave diving SE along the W flank of the developing East Coast trough while the Euro still suggests some lift albeit weak may squeeze out some very light rain and possibly a stray flurry or sleet pellet or two, but those chances did decrease for Friday night/early Saturday. A quick shot of cold air will be replaced by a return flow off the Gulf on Sunday as another storm systems dives S from the Pacific NW into the Great Basis. Showers and storms may be possible Monday night into Tuesday mainly across E Texas into Louisiana before yet another front passes.

 

The active pattern continues into next week with a very progressive flow off the Pacific and additional storms systems to our West developing and moving across the Southern tier of the US as the sub tropical jet remains active and the a general trough develops that cover most of the Lower 48 with a Ridge developing over the NE Pacific and system riding over the top of that ridge and heading S into the Great Basin tapping Pacific and Gulf moisture as the move E. It is note worthy that when we have a noisy sub tropical jet in the neighborhood, embedded upper air disturbance can become very unpredictable and difficult to forecast as we witnessed early this morning across our Coastal areas. The next 8-10 day appear to be the ‘coldest’ we’ll see this month (not colder than January) and with an active storm track, bouts of rain/storms and winter weather further N across the Southern Rockies/Southern Plains N of the Red River may well be in the offing.

 

 

[Srain]

lol...

 

 

[Quixotic1]

Maybe it's just me, but the models seem to have been performing more poorly than usual this winter.  Not just the details but the overall trends as well. 

[Srain]

Maybe it's just me, but the models seem to have been performing more poorly than usual this winter.  Not just the details but the overall trends as well. 

Additional WSR (Winter Storm RECON) has been tasked. Hopefully some clarity will be added to the uncertainty in the Medium Range.

 

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1215 PM EST WED 13 FEBRUARY 2013

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

         VALID 14/1100Z TO 15/1100Z FEBRUARY 2013

         WSPOD NUMBER.....12-075

I.  ATLANTIC REQUIREMENTS

    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS

    1. FLIGHT ONE -- NOAA 49

       A. P28/ DROP 10 (35.0N 150.0W)/ 15/0000Z

       B  NOAA9 11WSC TRACK28

       C. 14/1930Z

       D. 19 DROPS AS PUBLISHED ON TRACK

       E. 41,000 TO 45,000 FT/ 15/0600Z

    2. SUCCEEDING DAY OUTLOOK:  POSSIBLE

       P21/ DROP 10 (40.0N 135.0W)/ 16/00000Z

    3. REMARK: THE NOAA G-IV WILL FLY TRACK P-9 TODAY AS

       DETAILED IN WSPOD 12-074.

 

[Srain]

A bit of a temperature bust up here in NW Harris County. I had 33F with a moderate frost. Morning e-mail from Jeff:

 

Little variation in the weather pattern for the next few days before a more progressive pattern onsets by late in the weekend.
 
Surface high pressure overnight has resulted in temperatures falling to near the dewpoints this morning in the mid to upper 30’s for most areas although a few locations have touched the freezing mark…Conroe our typically cold location. Under sunny skies and light winds should see temperatures rebound into the upper 60’s this afternoon. Fast moving weather system over the Great Lakes will push another front through the area Friday with gusty NW winds developing and colder air spilling southward. Strong short wave in the developing NW flow aloft will swing across the state Friday night. Moisture is extremely limited with both the NAM and GFS models showing mainly a batch of mid level moisture above a very dry surface to 800mb layer. While it is possible that the strong lift being generated with the short wave could produce a few showers it appears unlikely at the moment. Critical thickness values would be marginally supportive of a sleet pellet or snowflake from about midnight Friday through about 900am Saturday morning, but again with such little moisture to work with I am leaning heavily toward more mid level clouds than actual precipitation reaching the ground. Skies will clear Saturday afternoon as fast moving surface high pressure builds into the region. Highs on Saturday will struggle to reach 60. With skies clear and winds going calm on Saturday night expect a light freeze for areas north of HWY 105 and in/around the typically cold locations but lows should be no colder than this morning. However with the warmth of late some vegetation has begun to break dormancy and fragile buds/blooms may need some protection.
 
NW upper air flow becomes more westerly by Sunday as a very fast progressive pattern develops over the southern US. Quick moving storm system about every 2-3 days will be the result with the first expected to arrive on Monday. Cold surface high pressure will rapidly shift eastward on Sunday with strong southerly flow developing across the area. South winds of 15-25mph will begin to pump Gulf moisture northward ahead of the Monday system. Moisture return looks fairly shallow and possibly capped with this system, but strong dynamics could help overcome these negatives and produce a few strong thunderstorms Monday afternoon/night. Fast moving system will be east of the area on Tuesday with a couple of dry clear days before the next system heads into the southern plains by the end of next week.

 

Note: The National Hurricane Center has released their report on Hurricane Sandy (a 157 pager the longest ever), but is full of excellent data and reasoning on the forecasting and operational decisions made during the hurricane event and changes that will be taking place operationally during such complex storm events: http://www.srh.noaa.gov/images/hgx/stormdata/Sandy.pdf

[DoctorMu]

The clipper was a bust as well. We received some of the mid-level cloudiness in the am, but no precip of any kind.

Can't complain too much about 62°F and mostly sunny. No A/C or sprinkler system running...

[Quixotic1]

The earliest date for the last freeze officially for FWD is February 5th set back in 2000. Our last freeze was on February 1st. With a forecast of 33 tonight, I'm starting to get a little worried about that record falling.

[Ed Lizard]

The earliest date for the last freeze officially for FWD is February 5th set back in 2000. Our last freeze was on February 1st. With a forecast of 33 tonight, I'm starting to get a little worried about that record falling.

Heavy frost yesterday morning and a light frost this morning.  Sadly, Winter is not over.  Hoping 17 G-IV drop sondes this afternoon in the Pacific lend clarity to potential exciting Wednesday night/Thursday event on 0Z models.

[DoctorMu]

Oddly, no frost in CLL.

The clipper moisture arriveth...but alas no cold

My hope each winter is for a nice week or two of frigid weather to knock down the insects. We could use that this year with the drought waning a bit.

[bubba hotep]

Oddly, no frost in CLL.

The clipper moisture arriveth...but alas no cold

My hope each winter is for a nice week or two of frigid weather to knock down the insects. We could use that this year with the drought waning a bit.

 

I was obviously overly on the clipper earlier in the week but reality set in by Wed.

 

I figured moisture would be an issue but thought we would have the temps.  We ended up with a brief period of light rain and 40s...

[Quixotic1]

Heavy frost yesterday morning and a light frost this morning. Sadly, Winter is not over. Hoping 17 G-IV drop sondes this afternoon in the Pacific lend clarity to potential exciting Wednesday night/Thursday event on 0Z models.

obviously my chicken little routine brought about maximum radiational cooling allowing dfw to hit 30 this morning. so in fact, the sky is not falling (unless you live in russia)

my next trick will be to sacrifice my lawn to the gods of winter by fertilizing

[Ed Lizard]

Still glass quarter full.  6 am sounding has somewhat cool surface, meager low level lapse rates, but pretty impressive mid level instability and wild and crazy shear, and over half an inch falls per GFS 6 hours following.

If it warms a coupla degrees before storms move through MBY, and the approaching system weakens the warm nose a touch, excitement potential for Thursday morning.

[Ed Lizard]

Still glass quarter full.  6 am sounding has somewhat cool surface, meager low level lapse rates, but pretty impressive mid level instability and wild and crazy shear, and over half an inch falls per GFS 6 hours following.

If it warms a coupla degrees before storms move through MBY, and the approaching system weakens the warm nose a touch, excitement potential for Thursday morning.

 

New GFS sounding looks similar.  Precip forecasts suggests decent storms (could be elevated) not too far North and East of IMBY. Maybe along what seems to be a subtle warm front.

[Srain]

One last day for our Region to dazzle our guests for the NBA All Star Weekend festivities with Chamber of Commerce weather before changes begin as those guest depart. A very progressive and stormy pattern develops for our Region this week into the weekend as an active storm pattern with its origins across the N Pacific ride up and over a NE Pacific Ridge and dive SE into the Great Basin develops and tropical moisture from the Eastern Pacific and a noisy sub tropical jet become the main weather drivers during the next 10-12 days.  SE Ridge become anchored across Florida and Cuba limiting intrusions of modified Continental air into the Gulf setting the stage for a series of stalling frontal boundaries and waves of embedded short wave energy sliding along those stalled boundaries allowing deep Gulf moisture to pool across the NW Gulf. Meanwhile to the W, multiple deep storm systems wrap up and move across the Rockies and Great Plains on E as a blocking regime develops over the NW Atlantic. While cold air in Canada will may some intrusions S into the Continental United States, the main theme will likely be Blizzard conditions across Colorado, Wyoming, Nebraska, South and North Dakota with freezing rain/sleet likely across the Mid West into the Mid Atlantic States.

 

Further S in the warm sector, rain and increasing chances for storms which may well become severe will be the major weather headline of the week. Our Region will be on the warm side of the storm systems which will begin to take shape tomorrow and extend into the coming work week and may well extend into the late next weekend time frame. One thing of note is the areas that have been affected by lingering drought conditions across the Central Plains may well benefit from such a stormy pattern. Across Texas, the first storm appears rather weak and brings the best chance of rains across NE Texas into Arkansas and Louisiana, Monday night into Tuesday with the first Pacific front to cross the area.

 

That front will stall along the Coastal areas and retreat N as a much stronger storm develops late Tuesday into Wednesday in Arizona and begins to slowly march ENE across Northern New Mexico with a trough axis becoming neutral to negative tilted by late Wednesday into Thursday. The dynamic with this storm are very impressive with 150+ kt winds in the 250mb level and 100+ kt at the 500mb level as well as strong lee side cyclogenesis expected across the Panhandles of TX/OK and Western Kansas. A squall line will likely develop across W Texas and slowly march E on late Wednesday into Thursday. The greatest threat for severe weather appears to be for areas E of the I-35 Corridor on Thursday with the highest chance of rotating super cells and tornadoes across E Texas, Louisiana and Mississippi.

 

A third very potent storm system is suggested by computer models to enter our region next weekend continuing the very active and storm pattern.

DAY 2 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1150 PM CST SAT FEB 16 2013
  
   VALID 181200Z - 191200Z
  
   ...NO SVR TSTM AREAS FORECAST...
  
   ...SYNOPSIS...
   MODELS CONTINUE TO INDICATE THE EVOLUTION OF A SIGNIFICANT
   LARGE-SCALE TROUGH EAST OF THE ROCKIES DURING THIS FORECAST PERIOD.
   THIS IS EXPECTED IN ASSOCIATION WITH THE PHASING OF A COUPLE OF
   SHORT WAVE IMPULSES...WITHIN A SPLIT BELT OF WESTERLIES EMERGING
   FROM THE MID LATITUDE PACIFIC...AND PERHAPS ANOTHER IMPULSE WITHIN A
   BELT OF WESTERLIES EMERGING FROM THE SUBTROPICAL EASTERN PACIFIC.
   THIS FEATURE IS FORECAST TO TURN EAST OF THE MISSISSIPPI VALLEY BY
   LATE MONDAY NIGHT...AS A STRONG DIGGING UPSTREAM SHORT WAVE IMPULSE
   CONTRIBUTES TO THE EVOLUTION OF ANOTHER LARGE-SCALE TROUGH ALONG THE
   PACIFIC COAST.
  
   IN ASSOCIATION WITH THE LEAD WAVE...SURFACE LOW PRESSURE IS EXPECTED
   TO CONSOLIDATE AND DEEPEN OVER THE GREAT LAKES REGION BY THE LATTER
   HALF OF THE PERIOD...WITH A TRAILING SURFACE COLD FRONT SURGING
   SOUTHEAST OF THE NORTHERN PLAINS...THROUGH MUCH OF THE UPPER HALF OF
   THE MISSISSIPPI VALLEY.  ANOTHER COLD FRONT...OF PACIFIC
   ORIGINS...IS EXPECTED TO ADVANCE SOUTH AND EAST OF THE CENTRAL AND
   SOUTHERN PLAINS...PERHAPS OVERTAKING A DEVELOPING/SHARPENING DRY
   LINE ACROSS THE ARKLATEX REGION DURING THE LATE AFTERNOON HOURS.
  
   A VERY STRONG SOUTHERLY 850 MB JET /50-70+ KT/ APPEARS LIKELY TO
   FORM AHEAD OF THE COLD FRONT...BUT MOSTLY WELL INLAND OF WESTERN AND
   CENTRAL GULF COASTAL AREAS...WHERE FLOW OFF THE GULF OF MEXICO IS
   FORECAST TO REMAIN RATHER MODEST.  GIVEN THIS...AND A WESTERN GULF
   OF MEXICO BOUNDARY LAYER STILL IN THE EARLY STAGES OF RECOVERY FROM
   RECENT COOLING/DRYING...IT STILL APPEARS PROBABLE THAT INLAND
   MOISTURE RETURN WILL REMAIN WEAK IN MAGNITUDE.  SUFFICIENT
   DESTABILIZATION FOR THUNDERSTORM ACTIVITY PROBABLY WILL OCCUR
   MONDAY/MONDAY NIGHT ACROSS THE LOWER MISSISSIPPI VALLEY...AND
   PERHAPS AS FAR NORTH AS THE GREAT LAKES REGION.  MOST OF
   THIS...HOWEVER...IS EXPECTED TO BE ASSOCIATED WITH THE DEVELOPMENT
   OF A PRE-FRONTAL CORRIDOR OF VERY WEAK CAPE...ABOVE A RESIDUAL COOL
   AND STABLE SURFACE BASED LAYER.  AS A RESULT SEVERE WEATHER
   POTENTIAL APPEARS NEGLIGIBLE FOR MOST AREAS.
  
   ...PARTS OF ERN TX AND THE ARKLATEX INTO SRN AR...
   MODELS DO SUGGEST THAT WEAK BOUNDARY LAYER DESTABILIZATION COULD
   DEVELOP IN A NARROW PRE-FRONTAL CORRIDOR...ALONG THE DEVELOPING DRY
   LINE BY LATE AFTERNOON.  MID/UPPER 50S SURFACE DEW POINTS MAY RETURN
   AS FAR NORTH AS THE ARKLATEX...CONTRIBUTING TO CAPE GENERALLY ON THE
   ORDER OF 500 J/KG OR LESS...WITH SLIGHTLY HIGHER DEW POINTS AND CAPE
   FARTHER TO THE SOUTH.  VARIABILITY EXISTS AMONG THE MODELS
   CONCERNING THE DETAILS OF THE PHASING OF THE SHORT WAVE IMPULSES
   ...AND ASSOCIATED MID/UPPER FORCING FOR UPWARD VERTICAL MOTION
   ACROSS THE REGION.  HOWEVER...A WINDOW OF OPPORTUNITY APPEARS TO
   EXIST FOR LATE AFTERNOON BOUNDARY LAYER BASED STORM
   DEVELOPMENT...BEFORE THE FRONT OVERTAKES THE DRY LINE.  AND...IF
   THIS OCCURS...THE ENVIRONMENT MAY BE AT LEAST MARGINALLY CONDUCIVE
   TO THE DEVELOPMENT OF A SUPERCELL OR TWO.
  
   ..KERR.. 02/17/2013

DAY 3 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0156 AM CST SUN FEB 17 2013
  
   VALID 191200Z - 201200Z
  
   ...NO SVR TSTM AREAS FORECAST...
  
   ...SYNOPSIS...
   AS ANOTHER SIGNIFICANT SHORT WAVE IMPULSE SHIFTS EASTWARD ACROSS THE
   NORTHEAST PACIFIC...JUST AHEAD OF THE CREST OF A BROAD... BUILDING
   UPPER RIDGE...AN UPPER TROUGH...AMPLIFYING NEAR THE PACIFIC COAST AT
   12Z TUESDAY...IS FORECAST TO TURN INLAND ACROSS CALIFORNIA.  THE
   LATTER FEATURE APPEARS LIKELY TO REACH THE GREAT BASIN AND SOUTHERN
   PLATEAU BY 12Z WEDNESDAY...AND MAY GRADUALLY BEGIN TO COME IN PHASE
   WITH A SIGNIFICANT IMPULSE EMERGING FROM THE SUBTROPICAL EASTERN
   PACIFIC.  AS THIS OCCURS...AND MID-LEVEL HEIGHTS BEGIN TO RISE
   ACROSS THE WESTERN GULF STATES...A LOW/MID- LEVEL CYCLONE EMBEDDED
   WITHIN A DEAMPLIFYING UPPER TROUGH IS FORECAST TO SHIFT FROM THE
   GREAT LAKES THROUGH THE NORTHEAST.  MEANWHILE...AN ASSOCIATED COLD
   FRONT SHOULD STALL ACROSS THE FLORIDA PENINSULA/NORTHERN GULF OF
   MEXICO AND DEEP SOUTH TEXAS... WHILE ADVANCING EAST OF MUCH OF THE
   REMAINDER OF THE ATLANTIC SEABOARD.  TO THE SOUTH OF THE FRONT...THE
   BOUNDARY LAYER OVER THE GULF OF MEXICO WILL CONTINUE TO GRADUALLY
   RECOVER FROM RECENT COOLING/DRYING...AND A SOUTHERLY RETURN FLOW MAY
   BEGIN TO DEVELOP OFF THE WESTERN GULF OF MEXICO...CONTRIBUTING TO
   MOISTENING ABOVE THE SURFACE FRONT ACROSS MUCH OF TEXAS INTO THE RED
   RIVER VALLEY.  THIS MAY BECOME SUPPORTIVE OF SCATTERED THUNDERSTORM
   ACTIVITY LATE TUESDAY AND TUESDAY NIGHT...BUT DESTABILIZATION ABOVE
   THE STABLE SURFACE LAYER IS NOT CURRENTLY EXPECTED TO BECOME
   SUFFICIENT FOR AN APPRECIABLE RISK FOR LARGE HAIL.
  
   ..KERR.. 02/17/2013

 

DAY 4-8 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0347 AM CST SUN FEB 17 2013
  
   VALID 201200Z - 251200Z
  
   ...DISCUSSION...
   THE LATEST MEDIUM RANGE FORECAST GUIDANCE MAINTAINS GENERAL TRENDS
   OF THE PAST SEVERAL DAYS CONCERNING A MAJOR UPPER TROUGH AND
   ASSOCIATED STRONG JET STREAK THAT APPEAR LIKELY TO EMERGE FROM THE
   SOUTHWESTERN U.S. BY THE MIDDLE OF THE COMING WORK WEEK.  THE TROUGH
   AXIS STILL APPEARS LIKELY TO TAKE ON A NEGATIVE TILT AS IT
   PROGRESSES ACROSS THE SOUTHERN ROCKIES INTO THE CENTRAL AND SOUTHERN
   PLAINS BY 12Z THURSDAY...BEFORE LIFTING NORTHEASTWARD AND
   DEAMPLIFYING ACROSS THE UPPER MIDWEST ON FRIDAY.  PRIMARY SURFACE
   CYCLOGENESIS IS EXPECTED ACROSS EASTERN COLORADO INTO WESTERN
   KANSAS...BUT MODELS INDICATE SECONDARY WAVE DEVELOPMENT FROM PARTS
   OF NORTHWEST INTO EASTERN TEXAS WEDNESDAY NIGHT.  THIS MAY
   EVENTUALLY BECOME THE FOCUS FOR AN EVOLVING SQUALL LINE...AND
   INCREASING SEVERE WEATHER POTENTIAL...AS FORCING ENCOUNTERS BETTER
   MOISTURE RETURN OFF THE GULF OF MEXICO.  HIGHEST SEVERE
   PROBABILITIES STILL APPEAR TO EXIST ON THURSDAY...AS THE WAVE AND
   ASSOCIATED SQUALL LINE DEVELOP EASTWARD ALONG A WARM FRONT ACROSS
   THE LOWER MISSISSIPPI VALLEY.  SURFACE DEW POINTS IN THE WARM SECTOR
   OF THE WAVE MAY REACH THE MID 60S ACROSS PARTS OF SOUTHEAST TEXAS
   INTO SOUTHERN LOUISIANA AND MISSISSIPPI.  ASSOCIATED BOUNDARY LAYER
   DESTABILIZATION ON THE SOUTHERN PERIPHERY OF THE DIFLUENT HIGH LEVEL
   FLOW AND MID-LEVEL HEIGHT FALLS COULD BECOME SUPPORTIVE OF DISCRETE
   SUPERCELLS NEAR/AHEAD OF THE SQUALL LINE... WITH A RISK FOR
   TORNADOES...IN ADDITION TO DAMAGING WIND GUSTS.
  
   ..KERR.. 02/17/2013

[Ed Lizard]

12Z GFS & Euro have a Sunday/Monday signal for possiuble fun-derstorms, and the Thursday morning IMBY sounding has less of a 700 mb warm nose, great mid level instability and lots of shear, and even if storms are elevated, while low levels aren't unstable, not mondo-stable either, so maybe some 50 knot gusts mixing down?

[Srain]

Morning e-mail from Jeff:

 

Highly progressive flow will result in rapid weather changes over the next several days.
 
An upper level trough currently moving into the central plains will push a cool front into the area late today into tonight. Prior to this a strong low level jet on the order of 30-40kts just above the surface will transport a modified Gulf air mass into the region today. Once the sun is up we will begin to see vertical mixing of the stronger winds aloft toward the surface. Expect easily sustained winds of 20-25mph from mid morning through mid afternoon with gust in the 30-35mph range. A Wind Advisory has been issued for all SE TX counties for today for strong south winds. As moisture increase today a few streamer showers will be possible under a building capping inversion in the mid levels of the atmosphere. Cool front arrives tonight and crosses the region by morning. Overall lack of instability due to poor quality moisture return off the Gulf and stubborn mid level capping suggest strong sheared environment will go untapped. Think the best we will do is a thin line of showers along the front with better chances for a strong or possibly severe storm over the Houston, Walker, Trinity, Polk, San Jacinto county region as with the past several frontal passages.
 
Area will see brief surface high pressure progress across the region on Tuesday before the next system begins to arrive on Wednesday and Thursday. Surface boundary off the coast will begin to lift northward as a warm front on Wednesday. Strong isentropic lift will develop over the top of this boundary and expect widespread low clouds, fog, light rain and drizzle to develop early Wednesday morning. Weak waves in the southern stream sub-tropical jet will support an enhancement of activity possibly Wednesday afternoon with a few thunderstorms possible. Warm front will clear north of SE TX Wednesday night as the region awaits the arrival of a Pacific cold front early Thursday. While moisture return does look more plentiful with this system, instability may be lacking yet again and capping could once again be an issue. While models are more supportive of a line of thunderstorms…some severe on Thursday morning…I think it is best to hold back on any severe concerns at this point as there are a few big negatives that will have to be overcome…especially that stubborn capping inversion that has been ever so persistent this late winter due to the storm track being slightly too far north. However with that said this system does bear close watch as shear will be very strong and if the cap can be overcome rotating updrafts would be possible especially near the warm front which will be straddling our north/northeast counties.
 
Thursday front slows near the coast as some additional energy digs into the trough over the plains. Front should finally get enough push to move well offshore by Friday with skies clearing. Once again, the fast progressive flow brings another system toward the area by late in the weekend or early next week. 

[Ed Lizard]

SWODY 1 has Northeast Texas in a (low end) SLIGHT RISK area.

 

Little showers to the Northeast of HOU already, 19Z  RAP forecast soundings at CXO would indicate potential for thunder, not much CAPE but...

[Ed Lizard]

Whatchu talking about Willis...

 

TXC339-407-471-182000-
/O.CON.KHGX.TO.W.0001.000000T0000Z-130218T2000Z/
SAN JACINTO TX-MONTGOMERY TX-WALKER TX-
137 PM CST MON FEB 18 2013

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 200 PM CST FOR
SOUTHWESTERN SAN JACINTO...NORTHEASTERN MONTGOMERY AND EXTREME
SOUTHEASTERN WALKER COUNTIES...

AT 132 PM CST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED
NEAR WILLIS...MOVING NORTHEAST AT 35 MPH.

LOCATIONS IMPACTED INCLUDE...
WILLIS.

[Ed Lizard]

BULLETIN - EAS ACTIVATION REQUESTED

TORNADO WARNING

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX

146 PM CST MON FEB 18 2013

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* TORNADO WARNING FOR...

SOUTHEASTERN SAN JACINTO COUNTY IN SOUTHEAST TEXAS...

EXTREME NORTHWESTERN LIBERTY COUNTY IN SOUTHEAST TEXAS...

SOUTHWESTERN POLK COUNTY IN SOUTHEAST TEXAS...

* UNTIL 215 PM CST

* AT 143 PM CST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM

CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED 8

MILES NORTHWEST OF CLEVELAND...AND MOVING NORTHEAST AT 35 MPH.

* LOCATIONS IMPACTED INCLUDE...

LIVINGSTON...SHEPHERD...COLDSPRING AND GOODRICH.

[Srain]

MESOSCALE DISCUSSION 0167
   NWS STORM PREDICTION CENTER NORMAN OK
   0208 PM CST MON FEB 18 2013
  
   AREAS AFFECTED...SE TX/SW LA
  
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
  
   VALID 182008Z - 182115Z
  
   PROBABILITY OF WATCH ISSUANCE...20 PERCENT
  
   SUMMARY...TSTMS ARE EXPECTED TO CONTINUE THROUGH THE AFTERNOON
   ACROSS SE TX WHILE MOVING NEWD INTO SW LA. STORMS MAY BE STRONG
   ENOUGH TO PRODUCE SOME ISOLATED SVR HAIL/WINDS BUT THE THREAT SHOULD
   BE TRANSIENT...LEADING TO A LOW PROBABILITY OF WATCH ISSUANCE.
   ADDITIONALLY...A BRIEF TORNADO OR TWO CANNOT BE RULED OUT BE THE
   THREAT APPEARS VERY LOW AT THIS TIME.
  
   DISCUSSION...TSTMS HAVE GRADUALLY STRENGTHENED WITHIN THE WAA REGIME
   ACROSS SE TX. CLOUD COVER AND WARM PROFILES HAVE LIMITED INSTABILITY
   THUS FAR BUT MID-LEVEL COOLING ASSOCIATED WITH THE APPROACHING
   MID-LEVEL TROUGH IS LIKELY CONTRIBUTING TO AT LEAST SOME
   DESTABILIZATION. RECENT MESOANALYSIS DEPICTS SBCAPE AROUND 500 J/KG
   AND MLCAPE AROUND 250 J/KG. THIS LACK OF INSTABILITY WILL LIKELY
   KEEP STORMS SHALLOW AND THE OVERALL SEVERE THREAT LOW.
   HOWEVER...DESPITE THIS MODEST INSTABILITY...THE STRONGLY SHEARED
   ENVIRONMENT WILL FAVOR ROTATING UPDRAFTS WITH THE POTENTIAL TO
   PRODUCE ISOLATED SVR HAIL/WINDS...PARTICULARLY WITH ANY CELL
   MERGERS. RECENT RADAR IMAGERY REFLECTS THIS POSSIBILITY WITH
   ROTATING STORMS NOTED IN MONTGOMERY AND SAN JACINTO COUNTIES IN SE
   TX. ADDITIONALLY...GIVEN THE STRONG SHEAR...A BRIEF/TRANSIENT
   TORNADO CANNOT BE RULED OUT BUT THE PROBABILITY IS LOW.
  
   ..MOSIER/HART.. 02/18/2013
  
  
   ATTN...WFO...LCH...SHV...HGX...

[Ed Lizard]

No warning, but rotation increasing between BW8 and I-610 just West of 290.