May Weather Discussions. Drougnt Continues For Houston

[srainhoutx]

A day of watching the radar and the meso discussions/watch boxes march E. Morning e-mail from Jeff:

Chance for severe weather this afternoon and evening across the entire region.

Good shot at much needed rainfall.

Disturbance yesterday produced a taste of what is about to unfold in the next 12 hours across the region with many places seeing more rainfall yesterday than in the past 2 months. Next upper air disturbance is currently crossing the Rio Grande and already numerous severe thunderstorms are ongoing west of San Antonio and north of Del Rio…our activity for late today.

Local meso high pressure cell is in place this morning from short wave passage yesterday and overnight. This high will weaken and shift eastward today allowing he air mass over SE TX and the coastal bend to become very unstable. At last mid level capping has weakened due to southerly track of the approaching shot wave making the atmosphere more favorable for surface based thunderstorms. ENE moving NE Mexico disturbance will cross the region during maximum heating this afternoon favoring severe thunderstorms. Forecasted high temperatures in the upper 80’s will yield tremendous low level instability on the order of 3000-4000 J/kg while mid levels cool allowing steep lapse rates (the rate of rise of surface based air parcels) the steeper the rate the faster the surface air will rise vertically. Good inflow from the Gulf of Mexico is noted which will pump mid 70 degree dewpoint air mass into the disturbance and keep moisture profiles favorable. It all points to a good shot at rainfall.

Severe:
Cannot deny the parameters are in place for severe weather mainly wind damage and hail. 4KM WRF model continues to show the current cluster of storms growing upscale into a forward propagating MCS/large scale bow echo as it plows ESE into the mean low level flow over the region. This meso model has been showing this for the past several runs and the setup is similar to the event yesterday afternoon over N TX which resulted in a large scale bow echo and widespread wind damage. Will hit the wind threat the hardest as that is tending toward where the models are showing with their forecasted convective evolution patterns. Expect the current activity to grow upscale into a linear MCS over the next 2-4 hours and then begin to bow forward between Corpus Christi and San Antonio. Damaging wind threat will greatly increase as the leading edge begins to bow out toward the east and meso low (comma head) forms on the northern end of the complex. Cold pool generation will race eastward with the complex acting as a mini cold front and helping to sustain/maximize lift. Line/bow should reach our western counties by early to mid afternoon and sweep across the entire region from mid afternoon to mid evening. Main threat will be damaging winds of 50-70mph. Dry and brittle trees limbs will likely suffer damage even from non severe winds.

Rainfall:
Best shot at rainfall the entire area has seen and the feeling is pretty high that everyone will see at least some rainfall. Best chances will be west of I-45 where Gulf of Mexico ridge is the weakest. Will go with widespread .5-1.0 inch west of I-45 with isolated amounts up to 2.0 inches. If a fast moving bow echo develops these totals may be a touch high as the forward speed of the activity will greatly limit the duration of the event. East of I-45 totals will likely average about .5 of an inch lower.

Note: Convection yesterday W of Waco, TX was able to produce 8-10 inches of rainfall (flash flooding). There is some possibility that the main punch of the complex/bow echo may leave behind a stalling outflow boundary along US 59 or near the coast this evening. Should this happen very close attention will have to be paid to potential cell training or cell redevelopment overnight as a low level jet tries to re-establish across the region ahead of the main cold front Friday morning. Slow moving convection on any trailing outflow boundaries will be prodigious rainfall producers and could produce rapid flash flooding even with the excessively dry grounds.

Extended:
Cold front will move across the region Friday morning, but main activity and moisture should be shunted eastward with the disturbance overnight. Much drier and cooler air mass will filter into the region making for a sunny and cool (for May) weekend and early next week. Highs near 80 and lows in the upper 50’s will be a treat for this time of year.

Drought:
Yesterday marked the 58th day without rainfall at Hobby Airport…the streak should end today.

[Andrew]

The storms are tracking at a rate that would get them here around the evening so perfect timing for strong storms. If the cap can loosen somewhat more things can get crazy fast.

[Mr. T]

Severe thunderstorm watch for all of SE TX

It just might rain today

Too bad after this it looks dry for yet another extended period

[srainhoutx]

Woohoo!

[srainhoutx]

For our neighbors in Central Texas...

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING FOR
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1024 AM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
NORTHWESTERN CALDWELL COUNTY...
EASTERN HAYS COUNTY...
TRAVIS COUNTY...
SOUTHERN WILLIAMSON COUNTY...

* UNTIL 130 PM CDT.

* AT 1023 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETERMINED THAT RAINFALL ESTIMATES FROM DOPPLER RADAR INDICATE
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE AUSTIN TO
SAN MARCOS AREAS.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
ANDERSON MILL...AUSTIN...AUSTIN BERGSTROM INT AP...CEDAR PARK...
GEORGETOWN...PFLUGERVILLE...ROUND ROCK...SAN MARCOS...SERENADA...
TANGLEWOOD FOREST...TAYLOR...WINDEMERE...BEE CAVE...BUDA...
COUPLAND...DRIFTWOOD...GEORGETOWN DAM...HUTTO...KYLE...LAKEWAY...
LEANDER...LIBERTY HILL...MANOR...MANSFIELD DAM...MARTINDALE...
MUSTANG RIDGE...NIEDERWALD...ONION CREEK...ROLLINGWOOD AND UHLAND.

RAINFALL AMOUNTS BETWEEN ONE AND TWO INCHES CAN BE EXPECTED IN LESS
THAN ONE HOUR WHICH WILL CAUSE FLASH FLOODING ON LOW WATER CROSSINGS
ESPECIALLY IN METROPOLITAN AREAS.

[srainhoutx]

Remember that roads are going to be mighty slick since we gone so long without rain. It looks like the afternoon is going to be active. Enjoy the rain and stay safe out there.

[unome]

http://forecast.weather.gov/product.php ... glossary=1



000
FXUS64 KHGX 121524
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1024 AM CDT THU MAY 12 2011

.UPDATE...
A NEARLY 200 MILE N-S LINE OF CONVECTION APPROACHING AND PASSING
THE I-35 CORRIDOR THIS MORNING...WITH SCATTERED CELLS AHEAD OF IT
AFFECTING OUR NORTHWESTERN ZONES. THIS SOUTH CENTRAL TEXAS MCS
WILL TRACK EASTWARD AND SHOULD REACH OUR WESTERN FRINGES AROUND
NOON... WITH CELLULAR FILL-IN AHEAD OF IT INTO THE EVENING HOURS.
THE UPPER LEVELS ARE STILL CONDUCIVE TO MUCH OF THE AREA RECEIVING
RAIN...WITH ISOLATED THUNDER WITH A LOCAL SEVERE THREAT. 12/12Z
ANALYSIS STILL DEPICTS A SPLITTING 25H JET OVER EAST TEXAS...WITH
A LFQ RESIDING OVER MATAGORDA BAY. DOWNSTREAM ENVIRONMENT HAS THE
DEEPEST MOISTURE CENTERED AROUND CRP (1.8 INCH PWAT) WITH STEEP
MID-LEVEL LAPSE RATES ABOVE WEAK 7H CAPPING. AS CONVECTIVE TEMPERATURES
IN THE LOWER-MIDDLE 80S ARE MET...AREA CAN EXPECT JUST SCATTERED
CONVECTION TO BEGIN TO RIDE UP FROM THE WSW. STRONGEST STORMS HAVE
THE POTENTIAL TO BECOME SEVERE WITH LARGE HAIL BEING THE MAIN THREAT.
THE WINDOW OF BEST OPPORTUNITY WILL BE FROM MID-LATE AFTERNOON
INTO THE LATE EVENING...OR GENERALLY WHEN THE UPPER TROUGH AXIS
SWINGS INTO NORTH CENTRAL TEXAS. 31

.CLIMATE...
DUE TO ACTIVE WEATHER...TODAY`S DROUGHT STATEMENT WILL BE ISSUED
TOMORROW. 43

[srainhoutx]

And so it begins for our area. Some minor flooding concerns due to the slow movement of these storms...

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1117 AM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
BRAZOS COUNTY IN SOUTHEAST TEXAS...
EASTERN BURLESON COUNTY IN SOUTHEAST TEXAS...

* UNTIL NOON CDT

* AT 1112 AM CDT...NATIONAL WEATHER SERVICE RADAR REPORTED A LINE OF
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE HAIL.
THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM COLLEGE
STATION TO 11 MILES SOUTHWEST OF COLLEGE STATION...AND MOVING
NORTHEAST AT 15 MPH.

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

A TRAINED WEATHER SPOTTER IN SOUTHWESTERN COLLEGE STATION REPORTED
NICKEL SIZED HAIL AT 1110 AM CDT.

[srainhoutx]

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1132 AM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* TORNADO WARNING FOR...
EXTREME SOUTH CENTRAL FAYETTE COUNTY...
NORTHEASTERN GONZALES COUNTY...
NORTHWESTERN LAVACA COUNTY...

* UNTIL NOON CDT.

* AT 1128 AM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE
THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 6 MILES WEST OF
MOULTON...MOVING EAST AT 40 MPH.

* SOME LOCATIONS IN THE WARNING INCLUDE MOULTON AND HALLETTSVILLE.

[unome]

http://imapweather.com/fullscreen/ is showing a tornado vortex signature near Karnes City / Falls City, moving East at 45mph

(of course, that does not mean one has been spotted)

[srainhoutx]

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1131 AM CDT THU MAY 12 2011

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

1110 AM HAIL COLLEGE STATION 30.60N 96.31W
05/12/2011 M0.88 INCH BRAZOS TX TRAINED SPOTTER

NICKEL SIZE HAIL REPORTED AT 911 WILLOW POND IN
SOUTHWESTERN COLLEGE STATION.

[srainhoutx]

MESOSCALE DISCUSSION 0756
NWS STORM PREDICTION CENTER NORMAN OK
1143 AM CDT THU MAY 12 2011

AREAS AFFECTED...N-CNTRL THROUGH SRN TX

CONCERNING...SEVERE THUNDERSTORM WATCH 288...289...

VALID 121643Z - 121815Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
288...289...CONTINUES.

THREAT FOR DAMAGING WIND AND ISOLATED LARGE HAIL WILL PERSIST MAINLY
ACROSS SERN THROUGH SRN TX NEXT FEW HOURS.

EXTENSIVE FORWARD PROPAGATING SQUALL LINE SHOULD CONTINUE THROUGH
REMAINDER OF SERN AND SRN TX SUPPORTED BY A DESTABILIZING BOUNDARY
LAYER. LATEST OBJECTIVE ANALYSIS INDICATE MLCAPE FROM 1500 J/KG OVER
SERN TX TO 2500+ J/KG OVER SRN TX ALONG WITH STEEP LAPSE RATES. VWP
DATA IMMEDIATELY BEHIND THE LINE SHOW A 40 KT WLY REAR INFLOW JET
WHICH WILL MAINTAIN STRONG CONVERGENCE ALONG GUST FRONT AND AUGMENT
DAMAGING WIND POTENTIAL. EXTENT OF FURTHER DEVELOPMENT ALONG NRN END
OF OUTFLOW BOUNDARY INTO N-CNTRL AND NERN TX REMAINS MORE UNCERTAIN.

..DIAL.. 05/12/2011


ATTN...WFO...HGX...FWD...CRP...EWX...BRO...

[srainhoutx]

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1146 AM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN AUSTIN COUNTY IN SOUTHEAST TEXAS...
SOUTHERN BURLESON COUNTY IN SOUTHEAST TEXAS...
WASHINGTON COUNTY IN SOUTHEAST TEXAS...

* UNTIL 1230 PM CDT

* AT 1141 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS LINE WAS
CENTERED 15 MILES SOUTHWEST OF LAKE SOMERVILLE DAM...OR 11 MILES
EAST OF GIDDINGS...AND MOVING EAST AT 40 MPH.

* LOCATIONS IN THE SEVERE THUNDERSTORM WARNING INCLUDE BUT ARE NOT
LIMITED TO SOMERVILLE...BRENHAM...SHELBY AND BURTON.

[srainhoutx]

Colorado County has a Severe Thunderstorm Warning now

[unome]

from SPC http://www.spc.noaa.gov/products/md/md0756.html



MESOSCALE DISCUSSION 0756
NWS STORM PREDICTION CENTER NORMAN OK
1143 AM CDT THU MAY 12 2011

AREAS AFFECTED...N-CNTRL THROUGH SRN TX

CONCERNING...SEVERE THUNDERSTORM WATCH 288...289...

VALID 121643Z - 121815Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
288...289...CONTINUES.

THREAT FOR DAMAGING WIND AND ISOLATED LARGE HAIL WILL PERSIST MAINLY
ACROSS SERN THROUGH SRN TX NEXT FEW HOURS.

EXTENSIVE FORWARD PROPAGATING SQUALL LINE SHOULD CONTINUE THROUGH
REMAINDER OF SERN AND SRN TX SUPPORTED BY A DESTABILIZING BOUNDARY
LAYER. LATEST OBJECTIVE ANALYSIS INDICATE MLCAPE FROM 1500 J/KG OVER
SERN TX TO 2500+ J/KG OVER SRN TX ALONG WITH STEEP LAPSE RATES. VWP
DATA IMMEDIATELY BEHIND THE LINE SHOW A 40 KT WLY REAR INFLOW JET
WHICH WILL MAINTAIN STRONG CONVERGENCE ALONG GUST FRONT AND AUGMENT
DAMAGING WIND POTENTIAL. EXTENT OF FURTHER DEVELOPMENT ALONG NRN END
OF OUTFLOW BOUNDARY INTO N-CNTRL AND NERN TX REMAINS MORE UNCERTAIN.

..DIAL.. 05/12/2011


ATTN...WFO...HGX...FWD...CRP...EWX...BRO...

LAT...LON 27629952 28609814 29669711 30749685 32279699 32369565
30039475 28229663 26869885 27629952

[srainhoutx]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1153 AM CDT THU MAY 12 2011

TXZ176-177-196-198-121730-
BRAZOS-GRIMES-MADISON-WALKER-
1153 AM CDT THU MAY 12 2011

...SIGNIFICANT WEATHER ADVISORY...

AT 1151 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 22 MILES SOUTHWEST OF MADISONVILLE...MOVING
NORTHEAST AT 20 MPH.

NICKEL SIZE HAIL AND WINDS UP TO 50 MPH ARE POSSIBLE WITH THIS STORM.

LOCATIONS IN THE PATH OF THIS STORM INCLUDE...IOLA...BEDIAS...AND
MADISONVILLE.

[tireman4]

Here it comes...........!

[srainhoutx]

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1230 PM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
AUSTIN COUNTY IN SOUTHEAST TEXAS...
SOUTHEASTERN BRAZOS COUNTY IN SOUTHEAST TEXAS...
EASTERN BURLESON COUNTY IN SOUTHEAST TEXAS...
NORTHWESTERN FORT BEND COUNTY IN SOUTHEAST TEXAS...
SOUTHERN GRIMES COUNTY IN SOUTHEAST TEXAS...
NORTHWESTERN HARRIS COUNTY IN SOUTHEAST TEXAS...
WALLER COUNTY IN SOUTHEAST TEXAS...
EASTERN WASHINGTON COUNTY IN SOUTHEAST TEXAS...

* UNTIL 115 PM CDT

* AT 1225 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS
IN EXCESS OF 60 MPH. THIS LINE WAS CENTERED 14 MILES NORTHWEST OF
HEMPSTEAD...OR 8 MILES NORTHEAST OF BRENHAM...AND MOVING EAST AT 40
MPH.

* LOCATIONS IN THE SEVERE THUNDERSTORM WARNING INCLUDE BUT ARE NOT
LIMITED TO WALLIS...WALLER...SIMONTON...SEALY...PRAIRIE VIEW...
NAVASOTA...KATY...BROOKSHIRE AND BELLVILLE.

[srainhoutx]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1229 PM CDT THU MAY 12 2011

TXC041-051-185-477-121930-
/O.NEW.KHGX.FA.Y.0002.110512T1729Z-110512T1930Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BRAZOS TX-GRIMES TX-WASHINGTON TX-BURLESON TX-
1229 PM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED AN

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR...
BRAZOS COUNTY IN SOUTHEAST TEXAS...
BURLESON COUNTY IN SOUTHEAST TEXAS...
NORTHERN GRIMES COUNTY IN SOUTHEAST TEXAS...
WESTERN WASHINGTON COUNTY IN SOUTHEAST TEXAS...

* UNTIL 230 PM CDT

* AT 1227 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN HAS FALLING ALONG A LINE EXTENDING FROM 7 MILES
NORTHWEST OF CARLOS TO 9 MILES WEST OF BURTON.

* RADAR TOTAL RAINFALL ESTIMATED 3 TO 5 INCHES OF RAIN BETWEEN IOLA
AND CALDWELL.

[jasons2k]

Happy happy joy joy! Today is finally our day. It's a nice, solid line coming through during the afternoon hours, and no 'junk showers' ahead of it to mess things up. We're ready!!