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

[Ed Mahmoud]

I thought I heard thunder, radar looks clear in immediate Galleria area. I was either wrong, or something is just firing up and hasn't been sampled by 5 minute old scan.

[Ed Mahmoud]

Hi Southenrgale,

CRP = Corpus Christi - that's where the sounding took place.

Here are some tutorials that explain it better than I ever could --

High-level:

http://s214580749.websitehome.co.uk/tut ... ds-01.html

http://weather.unisys.com/upper_air/skew/details.html

More complicated:

http://www.eos.ubc.ca/courses/atsc201/A ... dings.html

Bumped up.

I'm hoping for an 18Z sounding from CRP and/or LCH.

[srainhoutx]

MESOSCALE DISCUSSION 0498
NWS STORM PREDICTION CENTER NORMAN OK
1210 PM CDT FRI APR 17 2009

AREAS AFFECTED...PORTIONS SE AND E-CENTRAL TX.

CONCERNING...HEAVY RAINFALL

VALID 171710Z - 171945Z

SLOW EWD MOTION OF INITIAL MCS...AND ESPECIALLY ITS MERGER WITH
SCATTERED-NUMEROUS TSTMS THAT HAVE DEVELOPED JUST TO ITS E BETWEEN
VCT-CLL...WILL CONTRIBUTE TO SUSTAINED PERIODS OF 1.5-2.5 INCH/HOUR
RAIN RATES. THIS THREAT WILL SHIFT EWD ACROSS I-10 CORRIDOR BETWEEN
SAT-HOU AND OVER HOU METRO...AS WELL AS OVER AREA BETWEEN
HOU-TYR...THROUGH MID-AFTERNOON. REF WWS 159-160 AND RELATED
MESOSCALE DISCUSSIONS FOR SVR THREAT.

SURFACE MESOANALYSIS CONTINUES TO INDICATE MARINE FRONTAL ZONE FROM
OFFSHORE SABINE PASS WNWWD ACROSS GLS BAY AND INTERSECTING
CONVECTION OVER AUSTIN COUNTY. AIR MASS ALONG AND S OF THIS
BOUNDARY WILL REMAIN CHARACTERIZED BY RICH MOISTURE...WITH SFC DEW
POINTS UPPER 60S TO LOW 70S...AND GPS PW DATA SHOWING VALUES
CONSISTENTLY AROUND 1.5 INCH. MODIFIED RAOBS AND RUC SOUNDINGS
INDICATE NEARLY-SATURATED RH -- FROM SFC TO NEARLY 700 MB. LOWER
PORTION OF THIS DEEP SLAB OF MOIST AIR WILL BE LIFTED ATOP FRONTAL
ZONE AMIDST 45-55 KT LLJ...WHICH ALSO WILL HELP TO ENHANCE
STORM-RELATIVE INFLOW..AS WELL AS PROXIMITY TO AXIS OF MAX 850 MB
MOISTURE TRANSPORT...AND ZONE OF DEEP LOW LEVEL CONVERGENCE/ASCENT.
MOISTURE...DEEP LIFT AND INSTABILITY...AND THEREFORE POTENTIAL FOR
HEAVY RAIN...ALL WILL DIMINISH ROUGHLY N OF I-20. FROM ABOUT 20 NM
S OF I-10 TOWARD COAST...THREAT BECOMES MORE CONDITIONAL AND SPOTTY
BECAUSE OF LACK OF SUSTAINED LOW LEVEL LIFT...ALTHOUGH SIMILAR RATES
ARE LIKELY FROM INDIVIDUAL/LOCALIZED CORES.

..EDWARDS.. 04/17/2009


ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

[srainhoutx]

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1213 PM CDT FRI APR 17 2009

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
CENTRAL AUSTIN COUNTY IN SOUTHEAST TEXAS...
NORTHEASTERN COLORADO COUNTY IN SOUTHEAST TEXAS...
WESTERN WALLER COUNTY IN SOUTHEAST TEXAS...
SOUTHEASTERN WASHINGTON COUNTY IN SOUTHEAST TEXAS...

* UNTIL 100 PM CDT

* AT 1212 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 11
MILES SOUTHWEST OF BELLVILLE...AND MOVING NORTHEAST AT 30 MPH.

* LOCATIONS IN THE SEVERE THUNDERSTORM WARNING INCLUDE BUT ARE NOT
LIMITED TO BRENHAM.

[srainhoutx]

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1221 PM CDT FRI APR 17 2009

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* TORNADO WARNING FOR...
CENTRAL AUSTIN COUNTY IN SOUTHEAST TEXAS...
NORTHEASTERN COLORADO COUNTY IN SOUTHEAST TEXAS...
WALLER COUNTY IN SOUTHEAST TEXAS...

* UNTIL 100 PM CDT

* AT 1219 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO THIS TORNADO
WAS LOCATED NEAR CAT SPRING... MOVING NORTHEAST AT 20 MPH.

* LOCATIONS IN THE TORNADO WARNING INCLUDE BUT ARE NOT LIMITED TO
MONAVILLE...PINE ISLAND...HEMPSTEAD AND BELLVILLE.

[southerngale]

Thanks, Jason & Ed. I'll read the tutorials and hopefully understand them. But please continue to give us the "nutshell" version.

[srainhoutx]

Thanks, Jason & Ed. I'll read the tutorials and hopefully understand them. But please continue to give us the "nutshell" version.

As requested southerngale...

Latest Update from Jeff Lindner....e-mail around 10:00 AM
Within the last 2 hours a band of very heavy rainfall has developed from about 45 miles N of Victoria to near west of College Station. Within the last hour rainfall rates have increased to near 1.5 inches over portions of Lee and Fayette counties and this activity will spread into Colorado, Austin and Washington Counties in the next 1-2 hours.



IR images show cooling cloud tops and GPS sounder shows PWS now in excess of 1.5-1.7 inches across the western ½ of our region. Very strong 850mb moisture convergence is noted from Matagorda Bay to near Austin and eastward into Wharton and Colorado counties. Excessive hourly rainfall rates of 1-3 inches will be possible as this band moves slowly toward the east while cells training south to north within the band.



Additionally, we may get a weather watch issued shortly for a large part of our area as thunderstorms are rapidly developing east of WW # 159 which bumps up against our western counties.

[southerngale]

Geez... you don't often see this many 90% chances in a forecast.
And only 70% for part of tomorrow... I'm sure that will please some folks in my area. lol


Hazardous Weather Outlook
Lake Wind Advisory
Tornado Watch

This Afternoon: Showers and thunderstorms. Some of the storms could produce heavy rain. High near 71. East wind around 20 mph, with gusts as high as 25 mph. Chance of precipitation is 90%.

Tonight: Showers and thunderstorms, mainly after 1am. Some storms could be severe, with damaging winds and heavy rain. Low around 67. Southeast wind between 15 and 20 mph, with gusts as high as 20 mph. Chance of precipitation is 90%.

Saturday: Showers and thunderstorms likely. Some storms could be severe, with damaging winds and heavy rain. Mostly cloudy, with a high near 79. South wind between 10 and 20 mph, with gusts as high as 25 mph. Chance of precipitation is 70%.

Saturday Night: Showers and possibly a thunderstorm before 1am, then showers and thunderstorms likely after 1am. Some storms could be severe, with damaging winds and heavy rain. Low around 64. South wind between 10 and 15 mph. Chance of precipitation is 90%.

[srainhoutx]

MESOSCALE DISCUSSION 0499
NWS STORM PREDICTION CENTER NORMAN OK
1238 PM CDT FRI APR 17 2009

AREAS AFFECTED...PORTIONS S TX.

CONCERNING...SEVERE THUNDERSTORM WATCH 159...

VALID 171738Z - 171815Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 159
CONTINUES.

NEW WW -- EITHER REPLACEMENT OR ADD-ON -- WILL BE REQUIRED BEFORE
SCHEDULED 18Z EXPIRATION OF WW 159...IN ORDER TO REFINE SVR THREAT
NEXT SEVERAL HOURS TO AREAS ALONG AND S OF CURRENT SRN SEGMENT OF
MCS.

DESPITE PERSISTENT LOW CLOUD OVER...INFLOW-LAYER AIR MASS FROM S OF
COMPLEX WILL CONTINUE TO EXPERIENCE STEADY HEATING FOR ANOTHER FEW
HOURS. THIS WILL COMBINE WITH SFC DEW POINTS NEAR 70 F TO BOOST
MLCAPE INTO 2000-2500 J/KG RANGE. ALTHOUGH STRONGEST LOW LEVEL
SHEAR WILL REMAIN FARTHER E -- IN CLOSER PROXIMITY TO LLJ MAX AND
WARM FRONT AND IN WW 160 -- 0-1 KM SRH 100-200 J/KG ACROSS THIS AREA
INDICATE SOME POTENTIAL FOR ROTATING STORMS AND RELATED HAIL THREAT.
TORNADO POTENTIAL CANNOT BE RULED OUT...BUT IS MODE DEPENDENT ON
STORM-SCALE PROCESSES THAN FARTHER E. FAVORABLE STORM-RELATIVE
INFLOW IS FCST TO CONTINUE ACROSS THIS REGION -- 25-35 KT IN LOWEST
2 KM AGL. REF HEAVY RAINFALL MESOSCALE DISCUSSION 498 FOR THAT
HAZARD.

..EDWARDS.. 04/17/2009


ATTN...WFO...HGX...CRP...EWX...

[srainhoutx]

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1245 PM CDT FRI APR 17 2009

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
NORTHWESTERN AUSTIN COUNTY IN SOUTHEAST TEXAS...
NORTHERN COLORADO COUNTY IN SOUTHEAST TEXAS...
WASHINGTON COUNTY IN SOUTHEAST TEXAS...

* UNTIL 345 PM CDT

* AT 1238 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THAT FLASH FLOODING WAS LIKELY FROM A BAND OF STRONG
THUNDERSTORMS LOCATED FROM WEIMAR TO INDUSTRY TO BRENHAM.
DOPPLER RADAR RAINFALL ESTIMATES INDICATE THAT 3 TO 6 INCHES
OF RAIN HAS FALLEN IN THIS AREA. AN ADDITIONAL 1 TO 3 INCHES
APPEAR LIKELY OVER THE NEXT 2 HOURS. 5 INCHES OF RAIN WAS
REPORTED IN WEIMAR. FM 155 SOUTH OF WEIMAR IS CLOSED DUE TO
FLOODING.

* LOCATIONS IN THE FLOOD WARNING INCLUDE BUT ARE NOT LIMITED TO
SHELBY...ROCK ISLAND...QUARRY...NEW ULM...LAKE SOMERVILLE DAM...
INDUSTRY...INDEPENDENCE...CAT SPRING...WEIMAR...COLUMBUS...
BURTON...BRENHAM AND BELLVILLE.

[Ed Mahmoud]

Funnel cloud with tornado warning being monitored by Bellville law enforcement. Heading in general direction of Hempstead...

[jasons2k]

Don't see that warning on GRLevel3. Strange..

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1250 PM CDT FRI APR 17 2009

TXC015-473-477-171815-
/O.CON.KHGX.TO.W.0011.000000T0000Z-090417T1815Z/
WASHINGTON TX-WALLER TX-AUSTIN TX-
1250 PM CDT FRI APR 17 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 115 PM CDT FOR AUSTIN...
WALLER AND WASHINGTON COUNTIES...

AT 1247 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
TORNADO. THIS TORNADO WAS LOCATED NEAR BELLVILLE...AND MOVING
NORTHEAST AT 15 MPH.

* LOCATIONS IN THE THE TORNADO WARNING INCLUDE BUT ARE NOT LIMITED TO
PINE ISLAND AND HEMPSTEAD

LAW ENFORCEMENT OFFICIALS HAVE REPORTED A FUNNEL CLOUD WITH THIS
STORM NEAR BELLVILLE. IF YOU ARE IN THE PATH OF THE STORM TAKE COVER
NOW.


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

[srainhoutx]

I am becoming more concerned that training storms will continue to develop and slowly move E across the Houston Metro as the day wears on. Storms are firing near Cotulla and extend ENE just S of I-10 into our western and northern counties. Jasons may be able to post an image from GR3.

[jasons2k]

Here they are - sorry about the background not covering the whole screen - I don't have time to do the switch-a-roo on my settings right now:


Shot at 2009-04-17

[jasons2k]

FYI - NONE of the posted warnings out right now are showing-up on GR3. Maybe that feed is down. I'll see if I can track down the issue...

[srainhoutx]

I'm hearing reports of some data port issues jasons. HGX Aviation Update...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1250 PM CDT FRI APR 17 2009

.DISCUSSION...
18Z TAF DISCUSSION.

&&

.AVIATION...
ON GOING TRENDS OF THE MCS OVER THE BRAZOS VALLEY INDICATE SLOW
MOVEMENT INTO THE I-45 COORIDOR. WILL SEE PREVAILING VCTS/TSRA
THROUGH THE EVENING HOURS PERHAPS LONGER DEPENDING ON HOW MUCH
INSTABILITY THE STORMS CAN TAP. INSTABILITY IS LIMITED ACROSS
AREAS NORTH OF I-10 BUT THIS UNSTABLE AIR COULD MOVE FURTHER
NORTH THIS AFTERNOON WITH STRONG LLJ PRESENT. WILL LIKELY SEE
+TSRA BUT WILL HOLD OFF ON MENTIONING HAIL/GR FOR NOW DUE TO
LIMITED INSTABILITY AT THE MOMENT. OVERNIGHT SHOULD SEE A LULL IN
ACTIVITY AND THEN SATURDAY SHOULD HAVE ANOTHER ROUND OF TSRA IN
THE LATE MORNING. POSSIBLE TO GET ANOTHER SQUALL LINE DEVELOPING
C TX OVERNIGHT WHICH WILL MOVE INTO THE AREA MUCH LIKE TODAY.
EXTENDED PART OF THE TAF TRIES TO INDICATE A HIGH POSSIBILITY OF
A SECOND ROUND OF STORMS. WINDS WILL LIKELY VEER FROM ESE TO MORE
SSE OVER THE NEXT 24 HRS.

[srainhoutx]

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
102 PM CDT FRI APR 17 2009

..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..

1047 AM HAIL WEIMAR 29.70N 96.78W
04/17/2009 M0.50 INCH COLORADO TX EMERGENCY MNGR

MARBLE SIZED HAIL REPORTED IN WEIMAR.

1248 PM HEAVY RAIN WEIMAR 29.70N 96.78W
04/17/2009 M5.00 INCH COLORADO TX COUNTY OFFICIAL

TWO ROADS CLOSED INCLUDING FM 155...JUST SOUTH OF WEIMAR.

[jasons2k]

Another tornado warning on the way soon??


Shot at 2009-04-17

[srainhoutx]

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
138 PM CDT FRI APR 17 2009

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
EASTERN AUSTIN COUNTY IN SOUTHEAST TEXAS...
NORTHWESTERN HARRIS COUNTY IN SOUTHEAST TEXAS...
WALLER COUNTY IN SOUTHEAST TEXAS...
SOUTHEASTERN WASHINGTON COUNTY IN SOUTHEAST TEXAS...

* UNTIL 215 PM CDT

* AT 136 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR
BELLVILLE...AND MOVING EAST AT 15 MPH.

* LOCATIONS IN THE SEVERE THUNDERSTORM WARNING INCLUDE BUT ARE NOT
LIMITED TO WALLER...SEALY...PRAIRIE VIEW...HEMPSTEAD AND
BROOKSHIRE.

[srainhoutx]

Update from Jeff Lindner...

Flash Flood event rapidly unfolding across SE TX. Extremely dangerous flooding situation has quickly develop this afternoon. Rainfall in the last 4 hours of 6-9 inches has fallen over portions of Austin and Fayette counties. Major flooding is in progress in many locations across these counties and spreading eastward into Harris, Waller, and Montgomery counties.

MESOSCALE DISCUSSION 0501
NWS STORM PREDICTION CENTER NORMAN OK
0145 PM CDT FRI APR 17 2009

AREAS AFFECTED...PORTIONS SE TX.

CONCERNING...TORNADO WATCH 160...

VALID 171845Z - 172045Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 160 CONTINUES.

THOSE PORTIONS OF THIS WW BENEATH AND AHEAD OF ONGOING MCS SHOULD BE
CONTINUED FOR TIME BEING.

SFC MESOANALYSIS SHOWS MARINE FRONT NOW QUASISTATIONARY FROM
OFFSHORE SABINE PASS WNWWD ACROSS SRN GLS BAY AREA TO ITS
INTERSECTION WITH CONVECTIVE COMPLEX OVER AUSTIN COUNTY. LOW LEVEL
SHEAR IS FAVORABLE...AND WILL REMAIN SO...INVOF FRONTAL ZONE. STG
LLJ OF 50-55 KT REMAINS EVIDENT IN HGX/LCH VWP...PERHAPS EXAGGERATED
SOMEWHAT BY MOTION OF BIRDS/BUGS IN THAT LAYER...BASED ON
SEMICIRCULAR ANNULUS OF REFLECTIVITY IN THAT LAYER FROM HGX RADAR
AND COMPARISONS WITH PRE-STORM LDB PROFILER WINDS AND AREA RUC
SOUNDINGS. STILL...45-50 KT FLOW IS LIKELY WITHIN APPROXIMATELY 1
KM AGL...KEEPING HODOGRAPHS ENLARGED AND 300-400 J/KG SRH IN THAT
LAYER. THICKENING ANVIL CLOUD COVER HAS MITIGATED SFC
HEATING...CONTRIBUTING TO TENDENCY OF SBCINH TO INCREASE EWD ACROSS
WW AREA INTO LA...AND MAKING EWD EXTENT OF SVR THREAT MORE
UNCERTAIN/CONDITIONAL. STILL...MODIFIED RUC SOUNDINGS SUGGEST
1000-1500 J/KG MLCAPE OVER AND JUST S OF FRONT. TORNADO POTENTIAL
HAS BECOME MORE CONDITIONAL GIVEN INCREASED CINH AND MESSY STORM
STRUCTURES...BUT DOES STILL EXIST...ESPECIALLY WHERE STORMS CROSS
THROUGH FRONTAL ZONE. SVR POTENTIAL IS FCST TO DIMINISH WITH NWD
EXTENT FROM FRONT AS INFLOW-LAYER PARCELS BECOME
PROGRESSIVELY/GRADUALLY MORE ELEVATED...AND AS MUCAPE DECREASES.

..EDWARDS.. 04/17/2009


ATTN...WFO...LCH...HGX...CRP...EWX...