SE TX/SW LA Discussion Thread - Heavy Rainfall Threat

[jasons2k]

From the previous thread:

Sorry it took me so long to put this up - I was driving home...

[JenBayles]

Just bringing this thread up to date:

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
327 PM CDT WED MAY 2 2007

TXZ163-164-176>179-195>200-210>214-226-227-235>238-032030-
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-MADISON-MATAGORDA-
MONTGOMERY-POLK-SAN JACINTO-TRINITY-WALKER-WALLER-WASHINGTON-
WHARTON-
327 PM CDT WED MAY 2 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

STRONG THUNDERSTORMS AND LOCALLY HEAVY RAIN POSSIBLE LATER TONIGHT

.DAY ONE...TONIGHT
ANOTHER MCS OVER CENTRAL TEXAS WILL PUSH EAST LATER THIS
THIS EVENING. IF THE MCS HOLDS TOGETHER...THERE IS SOME POTENTIAL
FOR A FEW OF THE STORMS TO PRODUCE WIND DAMAGE...MAINLY WEST OF A
BRENHAM TO CROCKETT LINE. LATER TONIGHT...ANOTHER MCS WILL DEVELOP
OVER CENTRAL TEXAS ALONG AN OUTFLOW BOUNDARY. THIS SYSTEM WILL
RACE EAST BETWEEN MIDNIGHT AND 6 AM. THESE STORMS WILL LIKELY BE
SEVERE AND DAMAGING WINDS...ISOLATED TORNADOES AND LARGE HAIL ARE
EXPECTED. WIDESPREAD RAINFALL AMOUNTS WILL AVERAGE 1 TO 2 INCHES
OVERNIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY
THE REMNANTS OF WEDNESDAY EVENINGS MCS WILL BE ONGOING AROUND
SUNRISE. THE RISK FOR SEVERE WEATHER WILL BE DIMINISHING DURING
THE MORNING. DEPENDING ON WHERE MESO-SCALE BOUNDARIES RESIDE...
THUNDERSTORMS COULD REDEVELOP OVER THE AREA IN THE AFTERNOON.
RAINFALL TOTALS ON THURSDAY WILL AVERAGE 1 TO 2 INCHES IN THE
MORNING WITH ANOTHER INCH POSSIBLE IN THE AFTERNOON. ISOLATED
TOTALS WILL EXCEED 5 INCHES IN A FEW PLACES.

.SPOTTER INFORMATION STATEMENT...

EMERGENCY MANAGEMENT AND SPOTTER ACTIVATION MAY BE REQUIRED LATER
TONIGHT INTO EARLY THURSDAY.

[JenBayles]

Anyone looking at the line around Waco? Does it appear to be diving more SE towards Houston now? The other line west of I-35 is really barrelling due East. What happens when they collide?

[Extremeweatherguy]

if these bows hold together or strengthen, then we will be in for one wicked night!

[Stratosphere747]

Look for the line towards the San Antonio/Austin area to be our main concern....

[KatDaddy]

WOW! Look at that cell in Uvalde County Sw of San Antonio and across the border in MX

http://radar.weather.gov/ridge/radar.ph ... 11&loop=no

[jeff]

Very destructive derecho "long lived wind event" plowing through N TX. Many reports of winds at or above 90-100mph producing widespread wind damage. Confirmed sustained wind of 68mph at Plano TX and estimate 95-105mph at Terrell, TX. Very impressive bow echo punching ENE through the entire area extending from Rockwall to near Waco moving ENE at 45mph.

Secondary MCS/bow echo is developing from Near Georgetown, TX to WSW of Austin then SW to near Del Rio. Already seeing significant bowing of the line from W of Georgetown to WSW of Austin and similar very high end winds appear likely with this line as it moves ESE into SE TX.

Damaging winds of 60-80mph will be possible producing widespread wind damage. A few gust may exceed 90mph in the strongest cells and near the apex of bowing segments.

Storms will be moving from WNW to ESE so west facing walls will take the brunt of the wind and tree fall will be toward the E or ESE.

[KatDaddy]

Thanks Jeff. A serious event unfolding tonight across Texas. Sort of reminds me of the 1983 May severe weather event.

[jeff]

Concern growing over flash flood threat N of I-10 and mianly N of HWY 105 where first outflow from N TX bow is stalling out awaiting C TX bow. Very HP cells will train along this line with hourly rates of 2-3 inches.

Tornado threat will be enhanced from N of Austin to UTS as incoming severe MCS/bow intersects backed low level winds near boundary. Expecting a few 80+mph reports over Brazos, Grimes, Walker counties with next bow. Rest of SE TX may have to await potential 3rd MCS forming W of KSAT with roar E along I-10 late overnight. Threat of excessive rains and flash flooding will reside where southern end outflows stall out.

[JenBayles]

That is an incredible radar shot out of DFW. I honestly don't think I've ever seen that before. Can someone freeze-frame that shot for future reference?

[JenBayles]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
807 PM CDT WED MAY 2 2007

.DISCUSSION...
STRONG MCS EVOLVING OVER CENTRAL TX AND BEARING DOWN ON THE CWA.
BASED ON CURRENT MOVEMENT STORMS WILL BEGIN MOVING INTO THE CWA
BETWEEN 9 AND 11 PM. DAMAGING WINDS WILL BE THE MAIN THREAT GIVEN
THE FAST MOVEMENT AND BOW STRUCTURES SEEN WITHIN THE MCS. LARGE
HAIL AND ISOLATED TORNADOES ALSO POSSIBLE. SPC HAS ISSUED TORNADO
WATCH #214 FOR THE NW THIRD OF THE CWA UNTIL 08Z. HAVE BOOSTED UP
POPS AND HAVE MENTION OF SEVERE/HEAVY RAIN FOR ENTIRE CWA TONIGHT.
WILL KEEP AN EYE ON TRENDS AND MAY INCREASE POPS SOME MORE OVER SE
ZONES IF MCS PROGRESSES. HAVE HELD OFF ON ISSUING A FLOOD WATCH
FOR THE TIME BEING GIVEN THE FAST MOVEMENT OF THE STORMS.

[JenBayles]

Outflow beginning to show up on the old Standard Version radar: http://radar.weather.gov/ridge/radar_li ... R&loop=yes

Will we see development along that line as it hauls SE?

[KatDaddy]

Mini Bow developing E of Uvalde.

[jasons2k]

Look at the radar out of KGRK (central Texas) - it'as amazing. As the outflow plows east, stroms quickly explode along the outlfow line as it passes.

[Extremeweatherguy]

wow, the met on Fox26 must be on crazy pills or something! He seems to think the activity out in central TX will divert around Houston tonight and that we will be spared (simply because we are not currently under a tornado watch). It is moments like this that you can easily distinguish between a true met and someone who just plays one on TV. lol.

[jasons2k]

That is an incredible radar shot out of DFW. I honestly don't think I've ever seen that before. Can someone freeze-frame that shot for future reference?

Check out the N. TX Derecho thread - I just posted some

[jasons2k]

wow, the met on Fox26 must be on crazy pills or something! He seems to think the activity out in central TX will divert around Houston tonight and that we will be spared (simply because we are not currently under a tornado watch). It is moments like this that you can easily distinguish between a true met and someone who just plays one on TV. lol.

No kidding - all one has to do is study the loop from Central Texas to see what's going to happen...that outflow is quite impressive and headed straight this way

[jasons2k]

Here is a radar shot with the outflows outlined (in red) and arrows showing the direction they are headed:

[Extremeweatherguy]

Here is a radar shot with the outflows outlined (in red) and arrows showing the direction they are headed:

I don't like the look of that. We will probably see major storm development along the outflows as they plow SE.

[Extremeweatherguy]

[web]http://www.weatherunderground.com/radar/radblast.asp?zoommode=zoom&num=6&delay=15&rbscale=0.46630434782608693&scale=0.780&noclutter=0&ID=GRK&type=N0R&lat=0&lon=0&label=you&showstorms=0&map.x=473.5&map.y=256.5&centerx=357&centery=200&lightning=0&showlabels=1&rainsnow=0[/web]

storms starting to fire along the gust front!