SE TX/SW LA weather: Much cooler and WET after Tuesday

[Ed Mahmoud]

BTW, Sunday and Monday may be active weather days in SE Texas.



Cold mid-level temps shown on both GFS and Euro, may bring snow to low elevations in California, and besides lots of wind energy, cool mid-level temps may enhance hail chances down here...

[jasons2k]

Pretty decent line pushing through now...it looks like the gust front is racing ahead of the line a bit & some storms popping-up ahead of the main line.

[SamSagnella]

Code: Select all

BULLETIN - EAS ACTIVATION REQUESTED 
TORNADO WARNING 
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 
1111 AM CDT MON MAR 10 2008 
 
THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A 
 
* TORNADO WARNING FOR... 
  HARRIS COUNTY IN SOUTHEAST TEXAS 
  LIBERTY COUNTY IN SOUTHEAST TEXAS 
  MONTGOMERY COUNTY IN SOUTHEAST TEXAS 
 
* UNTIL 1145 AM CDT 
 
* AT 1107 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS TORNADO 
  WAS LOCATED NEAR SPRING...MOVING NORTHEAST AT 30 MPH. 
 
* LOCATIONS IMPACTED INCLUDE... 
  PORTER HEIGHTS... 
  KINGWOOD... 
  PATTON VILLAGE... 
  WOODBRANCH... 
  ROMAN FOREST... 
  SPLENDORA... 
  CLEVELAND...

http://kamala.cod.edu/offs/KHGX/0803101611.wfus54.html

[Ed Mahmoud]

Pretty decent line pushing through now...it looks like the gist front is racing ahead of the line a bit & some storms popping-up ahead of the main line.

Hey, that potential tornado is near my house.


Good thing nobody is home...

[Ed Mahmoud]

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1129 AM CDT MON MAR 10 2008

TXC201-291-339-101639-
/O.CAN.KHGX.TO.W.0008.000000T0000Z-080310T1645Z/
MONTGOMERY TX-LIBERTY TX-HARRIS TX-
1129 AM CDT MON MAR 10 2008

...THE TORNADO WARNING FOR HARRIS...LIBERTY AND MONTGOMERY COUNTIES
HAS BEEN CANCELLED...

...THE TORNADO WARNING FOR HARRIS...LIBERTY AND MONTGOMERY COUNTIES
HAS BEEN CANCELLED...

THE THUNDERSTORM WHICH PROMPTED THE TORNADO WARNING HAS WEAKENED AND
IS NO LONGER EXPECTED TO POSE AN IMMEDIATE THREAT TO LIFE OR
PROPERTY.

PLEASE REPORT SEVERE WEATHER TO THE COUNTY SHERIFF...LOCAL POLICE...
OR DEPARTMENT OF PUBLIC SAFETY. THEY WILL RELAY YOUR REPORT TO THE
NATIONAL WEATHER SERVICE.

LAT...LON 3040 9502 2998 9494 2997 9542 3020 9549
TIME...MOT...LOC 1629Z 241DEG 26KT 3018 9523

My house will survive...

[jasons2k]

From a few minutes ago

[jasons2k]

From NWS:

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1215 PM CDT MON MAR 10 2008

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
CHAMBERS COUNTY IN SOUTHEAST TEXAS...
SOUTHEASTERN HARRIS COUNTY IN SOUTHEAST TEXAS...

* UNTIL 100 PM CDT

* AT 1212 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
OF 60 MPH. THIS STORM WAS LOCATED NEAR GALENA PARK...AND MOVING
EAST AT 30 MPH.

* LOCATIONS IN THE THE SEVERE THUNDERSTORM WARNING INCLUDE BUT ARE
NOT LIMITED TO SMITH POINT...HOBBY AIRPORT...SOUTH HOUSTON...
SHOREACRES...PASADENA...OLD RIVER-WINFREE...MONT BELVIEU...LA
PORTE...HIGHLANDS...DEER PARK...CLOVERLEAF...CHANNELVIEW...BAYTOWN
AND ANAHUAC

STRONG WINDS MAY KNOCK DOWN TREES AND POWER LINES OR DAMAGE
BUILDINGS. TAKE COVER NOW!

PLEASE REPORT SEVERE WEATHER TO THE COUNTY SHERIFF...LOCAL POLICE...
OR DEPARTMENT OF PUBLIC SAFETY. THEY WILL RELAY YOUR REPORT TO THE
NATIONAL WEATHER SERVICE.

[JenBayles]

Yep, I cursed myself with my previous post. We got about 10 minutes of moderate rain, and now the sun is peeking through! Watching the radar, there was almost a perfect donut hole of light rain around the Bear Creek Dome as that line moved through. The Dome wins again.

[JonathanBelles]

1847 5 N ODEM SAN PATRICIO TX 2802 9759 DPS AND LOCAL EMERGENCY MANAGEMENT CONFIRM TORNADO TOUCH DOWN NEAR HIGHWAY 234 NORTH OF ODEM. (CRP)

1921 5 NW GREGORY SAN PATRICIO TX 2797 9735 KZTV TELEVISION NEWS CREW VIDEO TAPED A BRIEF TORNADO TOUCH DOWN NORTHWEST OF GREGORY. (CRP)

[KatDaddy]

...EAST TX/LOWER MS VALLEY...

LATEST MODEL GUIDANCE IS GRADUALLY TRENDING TOWARD A POTENTIAL
SEVERE WEATHER EVENT ACROSS EAST TX INTO THE LOWER MS VALLEY LATER
THIS WEEK. LARGE SCALE TROUGHING WILL EVOLVE OVER THE MIDDLE PARTS
OF THE COUNTRY WITH A CORE OF STRONGER MID-HIGH LEVEL FLOW EXPECTED
TO EXTEND FROM CA...SEWD INTO THE SRN ROCKIES/WEST TX. THIS PATTERN
EVOLUTION SHOULD WITH TIME INDUCE SFC CYCLOGENESIS ALONG A WEAK
FRONTAL ZONE SOMEWHERE OVER N TX/OK...BEFORE LIFTING NEWD. MODELS
DIFFER ON PLACEMENT AND MIGRATION OF SFC CYCLOGENESIS WHICH
ULTIMATELY LENDS CONSIDERABLE UNCERTAINTY TO THIS FORECAST.
MOISTURE/INSTABILITY RETURN WILL BE STRONGLY INFLUENCED BY
DEVELOPMENT AND INTENSITY OF LLJ IN RESPONSE TO MID-HIGH LEVEL WLYS.
AT THIS TIME IT APPEARS CONVECTIVE POTENTIAL...SOME OF IT
STRONG...WILL INCREASE SOMEWHERE ACROSS THE ERN PORTIONS OF
OK/TX/LOWER MS VALLEY BEGINNING THURSDAY...PERHAPS EVEN LATER IN THE
WEEK ON FRIDAY. NAM IS A BIT MORE AGGRESSIVE IN SFC LOW EJECTING
NEWD INTO AR LATE THURSDAY WHILE GFS IS SLOWER IN THIS EVOLUTION.
IF GFS IS MORE AGGRESSIVE IN FUTURE MODEL RUNS THEN A SLIGHT RISK
MAY BE REQUIRED FOR THIS REGION.

[Ed Mahmoud]

Re: SWODY3 "See Text: discussion

12Z WRF brings a decent little disturbance out of Mexico into Texas, just in time to spark some activity near HOU.



GFS much more subtle


WRF sounding shows very little instability in below 800 mb, and not much speed or directional shear where there is elevated instability, and the WRF is the more agressive model, so I'm not gung-ho on severe Thursday, yet.

[southerngale]

Nothing severe around here yesterday... a few thunderstorms and mostly just rain from early afternoon until sometime last night. The lighter stuff lingered forever, it seemed.

[Ed Mahmoud]

We're in a 30% (unhatched) hail risk area today. But I think Monday late into Tuesday will be a bigger deal. I've posted in severe weather thread my thoughts on that.

[jasons2k]

From Jeff Lindner:

A chance of strong to severe thunderstorms this afternoon and evening.

Discussion:

Upper trough moving into TX this morning with surface low pressure over SW OK and a strong low level jet over E TX. Highly modified Gulf air mass with low 60 degree dewpoints is starting to return to the coastal bend and will rapidly advect northward today as 50kt low level jet develops over SE and E TX. As surface low moves to the E this afternoon the W TX dryline will surge eastward deep into E TX. While capping is very strong…enough heating may be had by late afternoon along with surface forcing along the dryline to lift surface based energy through the capped layer and allowed thunderstorms to develop. Given the expected cap intensity advecting NE off the higher terrain of NE Mexico I suspect only a few storms will be able to develop and mainly along and E of US 59 and E of SH 288. It should be noted that both the NAM and GFS are showing more development this afternoon than their previous runs!

With that said any storm that is able to develop will go quickly severe given strong wind shear and unstable surface layer. Large hail and damaging winds will be the main threats with storms that area able to form. SPC has our eastern most counties outlooked in the Day 1 slight risk area. Expect no development over our SW counties where capping will be greatest.

Next item is high temperatures on Friday and Saturday as strong SW low level flow develops with downslope profile off the higher terrain of NE Mexico. Downslope winds will lead to compressional heating and expect low 100’s along the Rio Grande with low to mid 90’s into central and SC TX…maybe as far east as VCT. Locally we should see highs well into the 80’s with mid 80’s at IAH and possibly upper 80’s at CLL. Saturday looks warm also before a weak cool front moves through the area Saturday afternoon and cools highs back toward normal values for Sunday.

Early Next Week:

Big upper trough will carve into the SW US this weekend and begins its eastward track early next week in highly progressive US flow. Long period of return Gulf flow should result in a moderate to possibly highly unstable air mass by Monday. Looks like high rain chances are in the offing along with good severe potential. Close watch is needed on this system.

[Ed Mahmoud]

Re: Jeff Linder- (relevant parts quoted)

Discussion:

Upper trough moving into TX this morning with surface low pressure over SW OK and a strong low level jet over E TX. Highly modified Gulf air mass with low 60 degree dewpoints is starting to return to the coastal bend and will rapidly advect northward today as 50kt low level jet develops over SE and E TX. As surface low moves to the E this afternoon the W TX dryline will surge eastward deep into E TX. While capping is very strong…enough heating may be had by late afternoon along with surface forcing along the dryline to lift surface based energy through the capped layer and allowed thunderstorms to develop. Given the expected cap intensity advecting NE off the higher terrain of NE Mexico I suspect only a few storms will be able to develop and mainly along and E of US 59 and E of SH 288. It should be noted that both the NAM and GFS are showing more development this afternoon than their previous runs!

Early Next Week:

Big upper trough will carve into the SW US this weekend and begins its eastward track early next week in highly progressive US flow. Long period of return Gulf flow should result in a moderate to possibly highly unstable air mass by Monday. Looks like high rain chances are in the offing along with good severe potential. Close watch is needed on this system.

That is what I am saying. Considering it is really only 8:11 am (solar time), the low clouds are doing an ok job here at the Galleria of starting to lift and break up a tad, so maybe we'll get enough of that near Equinox sunshine to break the cap.


12Z WRF suggests cap might be breakable late this afternoon. Instability a tad meager, especially the lowest 2 km of the atmosphere if the forecast sounding is correct, but good mid-level instability. If we can get a degree or two warmer than the WRF is forecasting, strong storms would be a good bet.

[jasons2k]

The 60F Dewpoint Isotherm is just south of Houston now along the coastal counties. This will easily push north of us today. So, the moisture should be there. The big question is enough heat. Yep, the low clouds are breaking-up but there are plenty of mid-high level clouds to contend with. Looks like a day of watching the satellite loops to see if we can get any TCU far enough west of us.

[Ed Mahmoud]

The 60F Dewpoint Isotherm is just south of Houston now along the coastal counties. This will easily push north of us today. So, the moisture should be there. The big question is enough heat. Yep, the low clouds are breaking-up but there are plenty of mid-high level clouds to contend with. Looks like a day of watching the satellite loops to see if we can get any TCU far enough west of us.

Indeed.

Checked the AccuWx PPV WRF temp maps, the 20ºC (68ºF) isotherm right at Hooks at 0Z, it is already 57ºF, so it wouldn't take too much sun to exceed the WRF forecasted temps, and hence less CINH than forecast and higher CAPE.

[Ed Mahmoud]

1630 SWODY1 update trimmed our tornado chances below 5%, and our hail below 30%.

[Ed Mahmoud]

1631 visible image, still a mix of sun and clouds here around the Galleria

[jasons2k]

Yeah and the dryline is still WAY west of here...