September. Heavy Rainfall Event/Flooding Possible 9/28-30th

[srainhoutx]

A bit worrisome to see the 12Z GFS continue to advertise a weak broad low pressure system developing next week in the Bay Of Campeche at the tail end of the boundary meandering for several days.

[srainhoutx]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1212 PM CDT THU SEP 13 2012

TXZ192-193-131800-
BASTROP-TRAVIS-
1212 PM CDT THU SEP 13 2012

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN BASTROP AND EASTERN
TRAVIS COUNTIES UNTIL 100 PM CDT...

AT 1206 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM NEAR WYLDWOOD...OR 10 MILES EAST OF AUSTIN
BERGSTROM INT AP...MOVING NORTH AT 10 MPH.

WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH
HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
ELGIN...
MANOR...
WEBBERVILLE...
STATE HIGHWAY 71...
FARM TO MARKET ROAD 969...

[Andrew]

PW values are increasing to the SW counties. 850mb transport values look pretty impressive also and would indicate that for areas farther north more moist air should filter in from the gulf.

pwtr.gif

tran.gif

[Andrew]

All factors point to the heaviest of rains setting up around central Texas NW of SE Texas. Both 850mb levels along with PW values are maxed out around there and with boundaries setting up around the area some localized heavy rains look possible.

[srainhoutx]

HGX issues Flood Advisory for Harris County.

FLOOD ADVISORY
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
347 PM CDT THU SEP 13 2012

TXC201-132245-
/O.NEW.KHGX.FA.Y.0115.120913T2047Z-120913T2245Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HARRIS TX-
347 PM CDT THU SEP 13 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR...
NORTHWESTERN HARRIS COUNTY IN SOUTHEAST TEXAS...

* UNTIL 545 PM CDT

* AT 342 PM CDT...DOPPLER RADAR INDICATED HEAVY RAIN DUE TO
THUNDERSTORMS. THIS WILL CAUSE URBAN AND SMALL STREAM FLOODING IN
THE ADVISORY AREA. UP TO 2 INCHES OF RAIN HAS FALLEN IN THE PAST
HOUR.

* SOME LOCATIONS THAT WILL EXPERIENCE MINOR FLOODING INCLUDE
JERSEY VILLAGE...HUNTERS CREEK VILLAGE...BUNKER HILL VILLAGE...
SPRING VALLEY...PINEY POINT VILLAGE...HEDWIG VILLAGE...AND
HILSHIRE VILLAGE.

[srainhoutx]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
341 PM CDT THU SEP 13 2012

TXZ229>234-239>247-140500-
LA SALLE-MCMULLEN-LIVE OAK-BEE-GOLIAD-VICTORIA-WEBB-DUVAL-
JIM WELLS-KLEBERG-NUECES-SAN PATRICIO-ARANSAS-REFUGIO-CALHOUN-
INCLUDING THE CITIES OF...COTULLA...CALLIHAM...CROSS...
LOMA ALTA...TILDEN...GEORGE WEST...THREE RIVERS...BEEVILLE...
GOLIAD...VICTORIA...LAREDO...FREER...BENAVIDES...SAN DIEGO...
ALICE...ORANGE GROVE...KINGSVILLE...CORPUS CHRISTI...PORTLAND...
INGLESIDE...ARANSAS PASS...SINTON...MATHIS...ROCKPORT...REFUGIO...
WOODSBORO...PORT LAVACA
341 PM CDT THU SEP 13 2012

...MUCH NEEDED RAINFALL EXPECTED OVER SOUTH TEXAS THROUGH THIS
WEEKEND...

ABUNDANT MOISTURE AHEAD OF A SLOW-MOVING COLD FRONT AND UPPER
LEVEL TROUGH WILL COMBINE TO PRODUCE SCATTERED TO AT TIMES
NUMEROUS SHOWERS AND THUNDERSTORMS TONIGHT THROUGH SUNDAY. THE
BEST CHANCES FOR RAINFALL WILL BE OVER THE RIO GRANDE PLAINS AND
WESTERN BRUSH COUNTRY TONIGHT AND FRIDAY MORNING...THEN SPREAD
EAST FRIDAY AFTERNOON AND FRIDAY NIGHT...WHEN THE BEST CHANCES FOR
RAIN WILL BE OVER ALL OF SOUTH TEXAS. THERE IS A VERY GOOD CHANCE
THAT SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER SOUTH
TEXAS ON SATURDAY...BEFORE SLIGHTLY DRIER AIR MOVES INTO THE AREA
BEGINNING ON SUNDAY AND DIMINISHES THE CHANCES FOR RAIN. AT THIS
TIME...THE CONCERN FOR SEVERE THUNDERSTORMS IS LOW...ALTHOUGH AN
ISOLATED STORM COULD APPROACH SEVERE LIMITS TONIGHT THROUGH FRIDAY
NIGHT.

DUE TO THE EXTENDED DURATION OF THE RAINFALL...AND THE VERY DRY
CONDITIONS OVER MOST OF SOUTH TEXAS...NO WIDESPREAD FLOODING IS
EXPECTED AT THIS TIME. AVERAGE RAINFALL AMOUNTS THROUGH SUNDAY ARE
EXPECTED TO RANGE FROM NEAR 2 INCHES NEAR THE COASTAL COUNTIES OF
SOUTH TEXAS...TO 3 OR MORE INCHES NEAR THE RIO GRANDE AND
NORTHWESTERN BRUSH COUNTRY. LOCALLY HIGHER AMOUNTS OF 6 OR MORE
INCHES WILL BE POSSIBLE. AS A RESULT...THERE COULD BE SOME
ISOLATED FLOODING DURING THIS TIME...WITH THE GREATEST POTENTIAL
OVER THE RIO GRANDE PLAINS AND WESTERN BRUSH COUNTRY WHERE
RAINFALL WILL BE GREATEST AND THE TERRAIN IN UNDULATING. IF SOME
AREAS RECEIVE EXCESSIVE RAINFALL BEFORE DRIER CONDITIONS BEGIN BY
LATE SUNDAY...THEN A FLASH FLOOD WATCH MAY BE ISSUED BY THIS
WEEKEND.

RESIDENTS...EMERGENCY MANAGERS...LAW ENFORCEMENT AND MEDIA OUTLETS
SHOULD CONTINUE TO MONITOR THE LATEST FORECASTS CONCERNING THIS
RAINFALL EVENT. MONITOR NOAA WEATHER RADIO FOR THE LATEST
INFORMATION...FORECASTS...AND POSSIBLE WARNINGS. YOU CAN ALSO
VISIT OUR WEBSITE AT: WWW.WEATHER.GOV/CORPUSCHRISTI

[srainhoutx]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
355 PM CDT THU SEP 13 2012

TXC031-053-091-209-259-299-453-491-132300-
/O.NEW.KEWX.FA.Y.0120.120913T2055Z-120913T2300Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HAYS-KENDALL-LLANO-TRAVIS-WILLIAMSON-BURNET-BLANCO-COMAL-
355 PM CDT THU SEP 13 2012

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED AN

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR...
BLANCO COUNTY...
EASTERN KENDALL COUNTY...
HAYS COUNTY...
NORTHERN COMAL COUNTY...
SOUTHEASTERN LLANO COUNTY...
SOUTHERN BURNET COUNTY...
SOUTHWESTERN WILLIAMSON COUNTY...
WESTERN TRAVIS COUNTY...

* UNTIL 600 PM CDT

* AT 349 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETECTED THUNDERSTORMS WITH HEAVY RAINFALL ACROSS THE ADVISORY
AREA. DOPPLER RADAR ESTIMATED LOCALIZED RAINFALL AMOUNTS OF
2 TO 4 INCHES OF RAIN HAS FALLEN ACROSS NORTHERN BLANCO...
SOUTHERN BURNET AND NORTHWESTERN TRAVIS COUNTIES. SCATTERED
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO MOVE EAST AROUND
10 MPH AND WILL BE CAPABLE OF PRODUCING ADDITIONAL RAINFALL
AMOUNTS OF UP TO ONE AND ONE HALF INCHES PER HOUR.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE MINOR FLOODING TO
OCCUR...ESPECIALLY ALONG SMALL STREAMS AND NEAR LOW WATER
CROSSINGS. SOME LOCATIONS THAT WILL EXPERIENCE MINOR FLOODING
INCLUDE...ANDERSON MILL...BLANCO...CANYON LAKE DAM...CEDAR PARK...
DRIPPING SPRINGS...KINGSLAND...MARBLE FALLS...ROUND MOUNTAIN...
TANGLEWOOD FOREST AND WIMBERLEY.

[srainhoutx]

From Nesdis...

SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 09/13/12 2217Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-683-1404
LATEST DATA USED: GOES:2202Z JS
.
LOCATION...W LOUISIANA/S CENT AND E TEXAS...
.
ATTN WFOS...LCH...SHV...HGX...FWD...CRP...EWX...SJT...MAF...
ATTN RFCS...LMRFC...WGRFC...
.
EVENT...CURRENTLY WATCHING AREA OF S CENT AND SW TX FROM N OF SAN ANTONIO
TO THE RIO GRANDE AND AREA OF E TX FOR LOCALIZED HEAVY RAINFALL.
.
SATELLITE ANALYSIS AND TRENDS...THE MERGER BETWEEN THE SFC FRONT/OUTFLOW
MOVING TO THE SE AND THE CELLS/OUTFLOW SPREADING NORTHWARD FROM THE
GULF HAS OCCURRED FOR A LARGE PORTION OF CENT TX RESULTING IN LOCALIZED
INTENSE RAINFALL RATES FOR A RELATIVELY SHORT PERIOD OF TIME. MUCH OF
THE ACTIVITY OVER CENT TX HAS BEGUN TO SLOWLY DIMINISH LEAVING BEHIND A
SHIELD OF MOSTLY MODERATE RAIN. HOWEVER, THERE ARE STILL SOME ADDITIONAL
CELL/OUTFLOW INTERACTIONS UPCOMING FOR S CENT TO SW TX AND FOR E TX
SPREADING INTO W LA DURING THE NEXT COUPLE OF HOURS. CURRENTLY WATCHING
ACTIVITY CONVERGING FROM MULTIPLE DIRECTIONS ON THE AREA STRETCHING
FROM JUST N OF SAN ANTONIO TO NEAR DEL RIO TX. HAVE ALREADY SEEN
SOME SIGNIFICANT CELL MERGERS AND OVERSHOOTING TOPS WITH SOME OF THE
ACTIVITY IN THIS REGION WHICH HAS YIELDED SATELLITE ESTIMATED RATES TO
NEAR 3"/HR. LOCALIZED ESTIMATED TOTALS OF AT LEAST 2-3" HAVE ALSO LIKELY
OCCURRED ESPECIALLY IN THE REGION FROM WILLIAMSON TO KENDALL COUNTIES
PER AUTOMATED SATELLITE ESTIMATES. FARTHER TO THE NE, THE OTHER LOCATION
FOR MERGING CELLS/OUTFLOW IS AFFECTING E TX WITH SIMILAR ESTIMATED RATES
BRIEFLY TO NEAR 3"/HR AND 2-3" TOTALS PARTICULARLY FROM VAN ZANDT TO
HARRISON/PANOLA COUNTIES.
.
AN ANNOTATED SATELLITE GRAPHIC SHOWING THE HEAVY PRECIPITATION THREAT AREA
SHOULD BE AVAILABLE ON THE INTERNET ADDRESS LISTED BELOW IN APPROXIMATELY
10-15 MINUTES.
.
SHORT TERM OUTLOOK VALID 2215-0115Z...MEDIUM TO HIGH CONFIDENCE FACTOR
IN SHORT
TERM OUTLOOK...FOR S CENT/SW TX...LATEST OBJECTIVELY DERIVED SFC MOISTURE
CONVERGENCE SHOWS MAX LOCATED BETWEEN SAN ANTONIO AND DEL RIO WHICH
IS WHERE THE CELLS/BOUNDARIES ARE SET TO INTERSECT OVER THE NEXT HOUR
OR SO. BELIEVE THE MOST INTENSE ACTIVITY WILL CONTINUE TO SHIFT SLOWLY
TO THE S AND SW DURING THE NEXT SEVERAL HOURS. FOR E TX/W LA...ADDITIONAL
CELL/OUTFLOW INTERACTIONS ARE ALSO LIKELY IN THIS AREA. SOME ERRATIC
CELL MOVEMENT MAY OCCUR FOR A TIME AS THESE INTERACTION OCCUR OVER E TX,
BUT AN OVERALL GRADUAL EASTWARD SHIFT FOR THE STRONGER/NEWER CELLS INTO
W LA SHOULD OCCUR OVER THE NEXT SEVERAL HOURS. THIS IS WHERE BETTER SE
LOW LEVEL INFLOW IS ORIGINATING AND IT IS ALSO A REGION WHICH HASN'T
BEEN WORKED OVER AS OF YET.

[srainhoutx]

The slow moving frontal boundary remains to our N and W from near San Antonio to The Ft Worth area with a weakening MCS to our W near San Antonio/Austin area moving ENE along the boundary. PW's have increased to the 2.2 range across SE Texas and shower/storms are moving inland while rains to the W shift slowly E. Daytime heating and increased Gulf moisture heading inland should produce heavy rainfall W of I-45 this afternoon and tonight as the boundary sags S into our area and stalls. Areas along the 290 corridor in NW Harris County received 3+ inches yesterday from a training storm complex and we may we see a repeat of that today with storm totals in the 2-4 inch range with isolated higher amounts nearing 5-6 inches.

The upper air disturbance is further W just entering New Mexico and should continue to provide high precip chances on Saturday. A Coastal low may develop and ride the stalled boundary during late Saturday into Sunday as the upper air disturbance slowly heads E across TX. Some guidance ( the Euro ) deepen the 500mb low and drop it SE into Central/SE TX on Sunday and slowly shift it E into Louisiana on Monday. Dry air may push into the area Monday, but another short wave and Pacific front heads SE Tuesday that may bring additional showers before we finally dry out later next week.

[srainhoutx]

For our neighbors in Central Texas:

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
603 AM CDT FRI SEP 14 2012

TXZ171>173-183>194-202>209-217>225-228-141400-
LLANO-BURNET-WILLIAMSON-VAL VERDE-EDWARDS-REAL-KERR-BANDERA-
GILLESPIE-KENDALL-BLANCO-HAYS-TRAVIS-BASTROP-LEE-KINNEY-UVALDE-
MEDINA-BEXAR-COMAL-GUADALUPE-CALDWELL-FAYETTE-MAVERICK-ZAVALA-
FRIO-ATASCOSA-WILSON-KARNES-GONZALES-DE WITT-LAVACA-DIMMIT-
INCLUDING THE CITIES OF...LLANO...BURNET...GEORGETOWN...DEL RIO...
ROCKSPRINGS...LEAKEY...KERRVILLE...BANDERA...FREDERICKSBURG...
BOERNE...BLANCO...SAN MARCOS...AUSTIN...BASTROP...GIDDINGS...
BRACKETTVILLE...UVALDE...HONDO...SAN ANTONIO...NEW BRAUNFELS...
SEGUIN...LOCKHART...LA GRANGE...EAGLE PASS...CRYSTAL CITY...
PEARSALL...PLEASANTON...FLORESVILLE...KARNES CITY...GONZALES...
CUERO...HALLETTSVILLE...CARRIZO SPRINGS
603 AM CDT FRI SEP 14 2012

...GOOD CHANCE OF RAIN WILL CONTINUE THROUGH SUNDAY...

A RAIN MAKING WEATHER SYSTEM OVER THE SOUTHWEST U.S. TODAY
WILL MOVE SLOWLY EAST TO WEST TEXAS SATURDAY...AND THEN
ACROSS SOUTH CENTRAL TEXAS ON SUNDAY.

THIS WILL CAUSE A GOOD CHANCE FOR SHOWERS OR THUNDERSTORMS
TODAY THROUGH SATURDAY AND SUNDAY...AS A SERIES OF DISTURBANCES
PASS OVER THE REGION IN ADVANCE OF THE LOW OVER THE SOUTHWEST U.S.
THE FINAL PERIOD OF RAIN IS EXPECTED ON SUNDAY...AS THE LOW MOVES
OVER SOUTH CENTRAL TEXAS FROM THE WEST. LOCALLY HEAVY RAIN IS
POSSIBLE WITH THESE WEATHER PATTERNS THROUGH SUNDAY. RAINFALL
AMOUNTS OF 1 TO 2 INCHES IS EXPECTED...WITH ISOLATED RAIN AMOUNTS
OF 3 TO 5 INCHES. THIS MAY CAUSE MINOR FLOODING ACROSS STREETS...
UNDERPASSES...LOW WATER CROSSINGS AND ALONG SMALL STREAMS AND
RIVERS.

DRIER WEATHER IS EXPECTED SUNDAY NIGHT AND MONDAY...AS THE RAIN
MAKING WEATHER SYSTEM MOVES EAST OF SOUTH CENTRAL TEXAS.
A MOSTLY SUNNY DAY IS EXPECTED MONDAY.

[srainhoutx]

Morning e-mail from Jeff:

Slow moving cool front currently depicted in the surface observations along a line from NW LA to just north of College Station to south of San Antonio this morning. Meso low noted in radar images over C TX moving ENE at the present time while showers and thunderstorms are spreading northward into the coastal plains from the NW Gulf of Mexico. Moisture has increased over the region compared to yesterday with PWS in the 1.9-2.2 inch range and soundings nearly saturated. Water vapor images reveal mid and high level moisture tap spreading NE from TS Kristy in the EPAC off the western coast of Mexico. Storms yesterday were once again prodigious lightning producers and also produced some very heavy rainfall. Several locations picked up 1 inch of rainfall in 15 minutes or less and a few locations totaled nearly 4 inches. This proves this air mass is capable of some excessive rainfall in a short period of time especially if storm motions slow.

Set up over the area is starting to resemble some similarities to past fall flooding events with a stalling surface front, deep tropical Gulf moisture, upper trough slowly moving in from the west, and the EPAC tropical system tap. Thus far rains have remained fairly scattered, but with the frontal boundary entering the region today expect more organized rainfall. Additionally storm motions will be slowing as steering currents weaken. Frontal boundary should progress very slowly toward the coast tonight into Saturday and may limp offshore. Moisture levels will remain high as the upper trough remains west of the area. This trough begins to move eastward Saturday night/Sunday with increasing jet stream dynamics aloft. Still some timing differences in the models on when the main trough moves across the state and provides good lift and good chance of rainfall…currently looking like Sunday into Sunday night. Some sort of coastal low looks to develop along the boundary over the Gulf waters and this will help to spread rainfall along the coast and inland ahead of the upper trough.

Should start to clear and dry things out on Monday, but a secondary trough drops into the region by Tuesday with a potentially decent frontal passage. Not overly confident on the timing and moisture may linger into Monday producing scattered showers/thunderstorms.

Rainfall:
Some areas really were nailed yesterday with excessive rainfall, but most of these locations were localized and thus far widespread heavy rainfall has not occurred in our region. With that said, the current air mass is capable for some quick 2-3 inches in an hour or less and with the potential for storm motions to slow and become more organized along/near the frontal boundary does raise some red flags in the flooding department. Feel the best chances of excessive rainfall today will be west of I-45 and then toward the coast over the weekend (S of I-10). An additional 1-3 inches can be expected with isolated amounts up to 5 inches possible.

[Portastorm]

I've received about 1.45 inches in the last 24-30 hours in southwest Austin. Very welcomed rain!

[texoz]

From the Austin-American Statesman this morning:

"Areas west of Austin had some of the highest overnight rainfall totals, according to Pat McDonald, meteorologist for the National Weather Service. Leander had 7.66 inches of rain by 7 a.m., McDonald said, while Johnson City saw 6.8 inches, Lago Vista saw 5.5 inches, Marble Falls had 5.3 and Jonestown registered 4.5 inches."

http://www.statesman.com/blogs/content/ ... conti.html

Additional heavy rains in these areas could be a problem.

[wxman57]

I've received about 1.45 inches in the last 24-30 hours in southwest Austin. Very welcomed rain!

Good to hear, Portastorm. Prior to August, I've been averaging close to 8 inches/month. Total for the year is over 53" now, which is about average for a whole year here in Houston. However, not much rain the past 4 weeks so my grass was turning brown. The inch I've had the past few days helps.

[jasons2k]

Interesting late morning discussion from the NWS. They analyze the cold front a bit furher north than what Jeff has in his email. They are also not too optimistic about rain chances today but the last few visible frames show we've been clearing-out around the Houston area setting us up for redevelopment this afternoon. It will be interesting to see how it plays out.

I sure can use the rain - I haven't had anywhere close to what you've had Wxman -- I'm closer to 35 inches for the year with very little this summer, except for the two massive dumpings all at once. I've been having to water a lot more than the monthly rain totals would lead one to believe.

[srainhoutx]

The high resolution rapid refresh meso models (HRRR/15Z & RAP/16Z) are sniffing rather strong storms developing near 18Z to our SW and along the Coastal Counties moving N into the evening hours.

[mckinne63]

It's getting cloudy and very windy in Stafford. I just was outside and temps feel like they have cooled own by 10+ degrees. Ooh...just checked my computer screen and it says it is 73 degrees!

[srainhoutx]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
223 PM CDT FRI SEP 14 2012

TXC157-142115-
/O.NEW.KHGX.FA.Y.0116.120914T1923Z-120914T2115Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FORT BEND TX-
223 PM CDT FRI SEP 14 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR...
SOUTHEASTERN FORT BEND COUNTY IN SOUTHEAST TEXAS...

* UNTIL 415 PM CDT

* AT 214 PM CDT...DOPPLER RADAR INDICATED HEAVY RAIN THAT WILL
CAUSE URBAN AND SMALL STREAM FLOODING IN THE ADVISORY AREA. UP TO
TWO TO THREE INCHES OF RAIN HAS FALLEN IN THE PAST HOUR.

* SOME LOCATIONS THAT WILL EXPERIENCE MINOR FLOODING INCLUDE
MISSOURI CITY...STAFFORD...FRESNO AND THOMPSONS.

ADDITIONAL RAINFALL OF ONE TO TWO INCHES IS EXPECTED OVER THE AREA.
THIS ADDITIONAL RAIN WILL MAKE MINOR FLOODING.

[mckinne63]

It's raining here, but it is light rain. Hearing thunder, but I think the strong cells are just above us. As best I can tell by looking at the radar on the KHOU radars. Will take what we can get!

[jasons2k]

I don't know how this happens - a solid line moves across and rain every where but here.