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

[srainhoutx]

Now it's going to get interesting. The best I can tell the warm front is roughly from Eagle Pass through Beaumont and slowly moving N. The fly in th ointment is Olaf's mid level circulation and eventual future track. Nowcasting will likely be better than the forecasts at this point.

[vbhoutex]

That storm was presenting a pretty decent hook echo for a while to the NW of Ganado. Looks less pronounced mow, but people in the path need to be very alert since these can pop right back(id it was a tornado).

[srainhoutx]

Jason, pull up EWX on GR3 if possible.

[srainhoutx]

Jeff just sent an update...

Warm front across south Texas will return northward tonight with thunderstorms and heavy rainfall likely.

Currently a warm front extends from near Laredo to CRP to offshore of SW LA. Another boundary is present from near San Antonio to Port O Connor to offshore of High Island. Nasty HP supercell has developed on the latter boundary over Lavaca County and is now moving SE into Jackson and Wharton counties. Given radar DBZ of over 60 would expect a possibility of hail with this storm. Additional storms have developed over Matagorda and Brazoria counties and are moving ENE. Tropical tap from the remains of Olaf combined with increasing low level moisture from the western Gulf is supporting rich moisture advection over the top of the above mention boundaries resulting in waves of showers and thunderstorms. Disturbances within the sub-tropical flow are also helping to enhance lift and develop additional activity well to the north of the boundaries in place.

Pattern favors the slow northward migration of the warm front which should move onshore latter tonight. I am still a little concerned the models may be trying to lift this feature northward too fast given the development of rain cooled air to the north of the boundary...we shall see how that plays out. Will see numerous showers and thunderstorms track across the area. Low level wind shear is decent and a few of the storms will show some low level rotation along and near the warm front tonight so an isolated spin up is possible.

Main threat however remains the heavy rains as PWS climb well over 2.0 inches and storms train W to E in bands. Luckily storm motions for the most part have been fast enough so far to keep things from getting out of hand. However, as noted with the HP cell over Jackson County the large more organized storms along the boundaries are moving slow and dropping copious rainfall. Will maintain the widespread 1-3 inches tonight through Sunday with isolated 4-6 inches possible. Feel for the most part this rainfall can be handled although some watersheds will experience some run-off and rises and urban areas the usual street flooding.

Warm front should clear most of the area Sunday evening with subsidence behind a departing short wave and drier conditions developing. Air mass remains conditionally unstable for most of the week with mid level heights building and afternoon highs pushing into the 90's. Trigger temps. will be exceeded each afternoon and scattered storms may develop if the mid level subsidence is not too great. Another front approaches and stalls likely north of the region Tuesday night/Wednesday focusing the heavy rainfall threat back closer to the area.

Active pattern remains through the end of next week with yet another front expected Friday night with more storms and heavy rainfall. Luckily at this time this boundary looks to have a fairly good push and may actually blast through the area and into the Gulf with a dry air mass settling in behind. Will not buy into this just yet as progged front so far have stalled just offshore.

[vbhoutex]

:uarrow: Now it's going to get interesting. The best I can tell the warm front is roughly from Eagle Pass through Beaumont and slowly moving N. The fly in th ointment is Olaf's mid level circulation and eventual future track. Nowcasting will likely be better than the forecasts at this point.

I agree with you on that one Steve. We are heading out to Katy around 5 pm so I am watching all of this with heightened interest. The mid-level moisture is streaming in from Olaf already even though the core of the system isn't anywhere near TX yet. Could be a complicated forecasting weekend unless you use just one word-wet.
Just got the email from Jeff so you've got it well analysed Steve.

[srainhoutx]

HGX has Updated...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
327 PM CDT SAT OCT 3 2009

.DISCUSSION...
WARM FRONT STARTING TO MOVE NORTHEAST ACROSS OUR SOUTHWEST ZONES.
ENOUGH LOW LEVEL SHEAR EXIST SOUTH OF BOUNDARY WITH POSSIBLE ISOLATED
SUPERCELL DEVELOPMENT. GFS INDICATE VORT MAX FROM REMAINS OF OLAF REACHING
OUR REGION SUNDAY. DEEPENING MOIST LAYER EXPECTED OVERNIGHT AS
FRONTAL BOUNDARY MOVES NORTH. GFS BUFR PROGGED SOUNDINGS INDICATE PW
VALUES GONG UP TO NEAR 2.5 INCHES OVER REGION SUNDAY. SURFACE
BOUNDARY INDICATED TO MOVE TO JUST NORTH OF OUR CWFA SUNDAY
MORNING WITH A WEAK SURFACE LOW DEVELOPING OVER LOUISIANA ALONG
BOUNDARY. TRAILING END OF THIS BOUNDARY WILL SAG SUNDAY NIGHT
ACROSS OUR NORTHERN ZONES WHILE WEAKENING. BOTH ECMWF AND GFS
INDICATE THIS SCENARIO. ASSOCIATED UPPER LEVEL VORT MAX INDICATED
HOWEVER TO MOVE EAST OF OUR REGION SUNDAY NIGHT. SURFACE BOUNDARY
WILL MOVE NORTH OUT OF OUR REGION WHILE WEAKENING AND BECOMING
DIFFUSE ON MONDAY. ANOTHER COLD FRONT WILL APPROACH OUR REGION
TUESDAY NIGHT. THIS FRONT MAY APPROACH THE FAR NORTHERN PORTIONS
OF CWFA EARLY WEDNESDAY AND THEN PUSH BACK NORTH. SURFACE HIGH
PUSHING THIS FRONT WILL MOVE TO EAST AND NORTHEAST OF TEXAS DUE TO
WSW STEERING CURRENT ALOFT. UPPER LOW DEVELOPING OVER SW CONUS
TUESDAY NIGHT WILL OPEN UP AND COMBINE WITH LARGE UPPER TROUGH
MOVING ACROSS NW CONUS ON THURSDAY. THIS WILL PULL A STRONG
SURFACE HIGH FROM NW CANADA SOUTHEASTWARD. ECMWF IS MORE
AGGRESSIVE WITH THIS FEATURE INDICATING FRONTAL BOUNDARY REACHING
THE TX PANHANDLE ON THURSDAY. BOTH GFS AND ECMWF DO BRING THIS
FRONT ACROSS OUR CWFA NEXT WEEKEND WITH A 1034 HIGH PRESSURE
CENTER PUSHING THE BOUNDARY. 37

[vbhoutex]

That storm was presenting a pretty decent hook echo for a while to the NW of Ganado. Looks less pronounced mow, but people in the path need to be very alert since these can pop right back(id it was a tornado).

Following up on this. I haven't heard nay reports on this, but there was a very pronounced hook echo as it went through Ganado. Hopefully there was no touchdown. No evidence of a hook at this time.

[jasons2k]

Radars coming to life:


Shot at 2009-10-03


Shot at 2009-10-03

[srainhoutx]

HGX Radar is down again...

NOUS64 KHGX 032109
FTMHGX
Message Date: Oct 03 2009 21:09:24

KHGX 88D IS DOWN AND ET STAFF WILL BE IN SHORTLY TO ASCERTAIN THE ISSUE. 2100Z 10/3/09 PROCHAZKA

[jasons2k]

Reverted back to TIAH TDWR:


Shot at 2009-10-03

[srainhoutx]

May need to keep on eye to our W. Cell E of Seguin has gone severe and entire area appears to be moving E. Also see another rotating Super Cell NW of Alice in S TX.

[srainhoutx]

ZCZC NFDSPENES ALL
SPENES
TXZ000-
.
SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 10/03/09 2211Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-763-8678
LATEST DATA USED: GOES-12: 2202Z BELGE
.
LOCATION...TEXAS...
.
ATTN WFOS...SHV...HGX...FWD...CRP...EWX...SJT...
ATTN RFCS...WGRFC...
.
EVENT...INCREASING CONVECTION OVER SE TX.
.
SATELLITE ANALYSIS AND TRENDS...LATEST IR STLT IMAGERY HAS BEEN SHOWING
INCREASING COLD TOP CONVECTION ACROSS PORTIONS OF SE TX IN RESPONSE TO
FRNTL BNDRY DRAPED ACROSS THE REGION. OBJECTIVE ANALYSIS INDICATES AN
AREA OF MAX MOISTURE CONVERGENCE WHERE CONVECTION IS INITIATING. MOISTURE
HAS BEEN ON THE INCREASE THROUGHOUT THE DAY AS TD OLAF MOVES EASTWARD
WITH CURRENT PWATS AOA 2" ACROSS SE TX.
.
MOST IMMEDIATE CONCERN FOR HVY RAINFALL IS INVOF GONZALES/GUADALUPE
COUNTIES AS THE CELL OVER GUADALUPE COUNTY MERGES WITH SEA-BREEZE
INITIATED CONVECTION. THIS CAN RESULT IN RAINFALL RATES IN EXCESS OF
2"/HR PER MANUAL SATELLITE ESTIMATES. WILL CONTINUE TO MONITOR...

http://www.ssd.noaa.gov/PS/PCPN/

[srainhoutx]

FYI: HGX Radar back up.

[JenBayles]

I don't mind saying I'm getting a bit nervous looking at the forecast and blooming radars in TX. We're finally back in our house after the April flood, but still not completely put together. The past couple of storms that have moved through thankfully went quickly. I'm not so certain about tonight and tomorrow.

We did manage to get Harris County Flood Control to perform a survey of our drainage creek (Langham) a few weeks ago. Results are due any time now. If the survey proves what we think it will, then the work of desnagging and desilting of the creek will be yet another battle to get Commissioner's Court to fund the work. I am so unimpressed with our county governmental officials, but that's an entirely different topic on which I could write a book!

[CajunMama]

Jen, having flooded myself back in '93...the fear never goes away. It lessens but never goes away. We've come close several times but each time it the rain has stopped short of us flooding.

[srainhoutx]

Hey Jen. Good to see you back posting. I feel your pain, as you know. Welcome back and don't be a stranger and keep us informed. We've missed ya.

[srainhoutx]

EXCESSIVE RAINFALL DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
910 PM EDT SAT OCT 03 2009

...VALID 03Z SUN OCT 04 2009 - 00Z MON OCT 05 2009...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
BPT 30 SW BPT BYY 35 WSW VCT 15 SW SKF 25 WNW ERV 15 WSW 6R9
15 E 05F 20 ESE INJ GVT 20 ENE DEQ 40 NNW GLH 10 SSW GLH
20 W MLU 20 N JAS BPT.


LOCALIZED EXCESSIVE RAINS ARE POSSIBLE ACROSS THE OUTLOOK AREA
WHERE MESOSCALE FORCING..THE LIFT ASOCTD WITH THE QUICK MOVG UPPER
SYSTEM ASOCTD WITH OLAF..AND ADNL SHRTWV ENERGY EMBEDDED IN THE
SRN PORTION OF THE WLYS WILL INTERACT/TRIGGER SGFNT CNVCTV RAINS.
BAROCLINIC BAND LYING ALONG THE WRN GULF COAST IS EXPECTED TO
GRADUALLY LIFT NWD THIS PD TOWARD NRN TX AND THE AR/LA BORDER
REGION BY SUN AFTN. MODELS SHOW STRENGTHENING 30-40 KT SWLY 85H
FLOW DVLPG ACRS ERN TX..WITH PWS INCREASING TO OVER 2.25 INCHES
ACRS MUCH OF ERN TX AND PARTS OF THE LOWER MS VALLEY TONIGHT AND
SUN. IN ADDITION..THE HI/MID LEVEL MSTR STREAMING EWD FROM OLAF
WILL CONTINUE TO HELP SATURATE THE ATMOS THRU A FAIRLY DEEP LAYER
ACRS THIS REGION INCREASING THE POTENTIAL FOR INTENSE RNFL RATES.
INCREASINGLY DIFFLUENT JET WILL AID THE LIFTING PROCESS AND WILL
HELP LEAD TO WIDESPREAD MDT TO HEAVY RAINS. WIDESPREAD 2.00 INCH
RNFL AMTS ARE EXPECTED WITH LOCALIZED TOTALS IN EXCESS OF 5.00
INCHES BEING POSSIBLE THRU THE FCST PD.

KORTY

[jeff]

Starting to look like a classic flash flood set up with HP supercells doing their thing. Noting radar trends over SE TX suggest some sort of possible meso low N of KVCT near anchored convection with rapid development of near shore convection in the last 30 minutes pulling northward.

Little question the flash flood threat is high given PWS heading over 2.0 inches (200% of early October normals). Proof of capability of this air mass is noted on KCRP radar estimated from the cell that dropped nearly 5-7 inches of rain in a few hourly over Bee County.

[srainhoutx]

Thanks Jeff. We follow your updates regularly. The Olaf remnants certainly are the wild card in forecasting challenges ahead.

[southerngale]

Jeff, is that primarily for the Houston area or do we face the same flash flood threat over here? I've been sick for days and completely out of it. I had no idea that it might even rain until today.