SE TX/SW LA Discussion Thread - Heavy Rainfall Threat

[Yankeegirl]

Looks like its weakening a bit.... good news for us!

[cctxhurricanewatcher]

MESOSCALE DISCUSSION 0658
NWS STORM PREDICTION CENTER NORMAN OK
0957 PM CDT WED MAY 02 2007

AREAS AFFECTED...UPPER TX COAST AND SCNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 030257Z - 030400Z

NEW WW/S WILL LIKELY BE NEEDED SOON FOR PORTIONS OF THE UPR TX COAST
SWWD INTO PORTIONS OF SCNTRL TX.

00Z UPR AIR ANALYSIS AND NEW MODEL GUIDANCE SUGGEST THAT WEAK LARGE
SCALE HEIGHT FALLS WILL AFFECT MOST OF TX NORTH OF KLRD-KCRP
OVERNIGHT...ALONG SRN PERIPHERY OF THE UPR LOW MIGRATING ACROSS
CNTRL TX. COLD POOL HAS BEEN EXPANDING ACROSS THE I-35 CORRIDOR AND
INTO THE WRN COASTAL PLAIN FROM COLLEGE STATION SWWD TO NEAR KSAT.
DOWNSTREAM AIR MASS IS QUITE MOIST AND THE LIFT ALONG THE OUTFLOW
BOUNDARIES...ENHANCED BY THE NOCTURNAL SLY LLJ...WILL LIKELY BE
IMPETUS FOR ADDITIONAL TSTMS OVERNIGHT. H5 FLOW OF 40-45 KTS WILL
BOOST VERTICAL SHEAR TO SUPPORT SUPERCELLS... EMBEDDED WITHIN A
LARGELY LINEAR MCS. LOW-LEVEL HODOGRAPHS SHOW WEAK LOW-LEVEL
TURNING...BUT THE INHIBITION IN THE INFLOW LAYER MIGHT MITIGATE
TORNADO POTENTIAL...PARTICULARLY NORTH OF THE VICTORIA AREA.
HERE...DAMAGING WIND/HAIL WILL BE THE PRIMARY THREATS.

FARTHER S...THERE HAS BEEN A TENDENCY FOR THE STORMS TO REMAIN MORE
DISCRETE AND THE LOW-LEVEL FLOW WILL BE SOMEWHAT STRONGER. THIS
SUGGESTS THAT THE TORNADO THREAT WILL BE HIGHER ALONG THE LATITUDE
OF KCRP-KCOT.

..RACY.. 05/03/2007

Looks like I'm under the gun.

[vbhoutex]

Looks like its weakening a bit.... good news for us!

Uhh, have you looked out West along I-10? That area doesn't seem to be weakening or slowing down.

[Ptarmigan]

Looks like its weakening a bit.... good news for us!

Uhh, have you looked out West along I-10? That area doesn't seem to be weakening or slowing down.

I have a feeling these storms could slow down and stay severe and become a heavy rain event for us.

[srainhoutx]

any thoughts on a new mesoscale forming out of this cluster W of Houston Metro?

[Johnny]

This first complex just hit my house just south of Lake Conroe Dam at about 11:52 pm. I've been sitting on the front porch watching it roll in. Nothing severe but man was it nice when it first rolled through. 25 to 35 mph wind gusts, a little lightning, a little thunder and a little mist filtered in off of the wind and found me underneath the porch. I sat out there for about 10 minutes and watched the rain blow in the street light out near the road in front of my house. I've got alot of woods right next to my house and the sound of the wind cutting through the pine trees and the sound of the rain hitting my carport almost put me to sleep. It really does not get much better than this. I live for stormy nights like which help me into another tomorrow in anticipation of another soul cleanser. Ok, off to the front porch and then off into a deep sleep.

[southerngale]

Tornado



Hail



Wind

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CDT THU MAY 03 2007

VALID 031200Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NORTHERN AND CENTRAL
HIGH PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF SERN TX AND
THE LOWER MS VALLEY...

...NRN/CNTRL HIGH PLAINS...

LATE EVENING MODELS CONTINUE TO SUGGEST A FOCUSED AREA OF
SIGNIFICANT ASCENT WILL SPREAD EAST ACROSS THE NRN/CNTRL ROCKIES
INTO THE HIGH PLAINS LATER TODAY. RESULTANT TIGHT BAROCLINIC ZONE
WILL SHIFT EAST OF THE HIGHER TERRAIN BY MID AFTERNOON WHICH WILL
UNDOUBTEDLY AID DEEP CONVECTION.

IT APPEARS A NARROW AXIS OF INSTABILITY WILL DEVELOP FROM ERN
CO...NWD INTO ERN MT BY EARLY-MID AFTERNOON...THOUGH SBCAPE VALUES
SHOULD GENERALLY REMAIN BELOW 1000 J/KG AS SFC DEW POINTS HOLD IN
THE 40S. THIS SHOULD PROVE MORE THAN ADEQUATE FOR ROBUST
THUNDERSTORM DEVELOPMENT BETWEEN 18-21Z FROM NERN CO TO THE CANADIAN
BORDER OF NERN MT. FORECAST SOUNDINGS DEPICT MORE THAN ADEQUATE
SHEAR FOR SUPERCELLS...ALTHOUGH STRONG FORCING MAY VERY WELL ASSIST
STORM MERGERS AND POTENTIAL LINEAR EVOLUTION. SUPERCELLS MAY REMAIN
MORE DISCRETE ACROSS THE SRN HALF OF THE SLIGHT RISK FROM SERN
WY/NEB INTO NERN CO...POSSIBLY RESULTING IN AN ENHANCED RISK FOR
ISOLATED TORNADOES WHERE LOW LEVEL FLOW WILL REMAIN DECIDEDLY ELY IN
THE LOWEST 1KM. FRONTAL ZONE SHOULD REMAIN ACTIVE AS IT MOVES EAST
DURING THE EVENING HOURS BEFORE GRADUALLY LOSING INTENSITY AS MORE
HOSTILE AIRMASS IS ENCOUNTERED OVER THE CNTRL/NRN PLAINS.

...LOWER MS VALLEY/TX...

HEIGHT FALLS INTO THE SRN ROCKIES WILL SOON KICK WEST TX UPPER
TROUGH TOWARD THE LOWER MS VALLEY REGION. THIS FEATURE WAS PARTLY
RESPONSIBLE FOR LONG-LIVED MCS THAT RACED EAST ACROSS MOST OF THE
STATE OF TX DURING THE DAY WED. LEADING EDGE OF THIS ACTIVITY WILL
GRADUALLY WEAKEN AS IT OUTRUNS LARGE SCALE SUPPORT WELL UPSTREAM.
ALTHOUGH THUNDERSTORMS SHOULD BE ONGOING NEAR THE SABINE RIVER AT
12Z...RENEWED DEVELOPMENT IS LIKELY BY MID DAY ACROSS PORTIONS OF LA
AS BOUNDARY LAYER HEATS AHEAD OF CONVECTIVE OUTFLOW. DAMAGING
WINDS AND LARGE HAIL WILL LIKELY ACCOMPANY UPWARD EVOLVING
CONVECTION AS UPDRAFTS INTENSIFY DURING THE HEAT OF THE DAY.

UPSTREAM...CONFIDENCE IN WIDESPREAD REDEVELOPMENT IN THE WAKE OF THE
UPPER TROUGH AXIS ACROSS TX IS NOT THAT GREAT. LOW LEVEL
CONVERGENCE CERTAINLY WEAKENS ALONG THE I-35 CORRIDOR AS DOWNSTREAM
LLJ SHIFTS INTO THE MS DELTA REGION...AND UPSTREAM LLJ INTENSIFIES
OVER THE HIGH PLAINS. ULTIMATELY...ANY THUNDERSTORMS THAT EVOLVE
ACROSS THE ERN HALF OF TX WILL BE DRIVEN BY DAYTIME HEATING BENEATH
THE UPPER TROUGH WHERE MARGINAL INHIBITION AND MOIST PROFILES WILL
EXIST. DEEP LAYER SHEAR WOULD SUPPORT SUPERCELLS IF CONVECTION CAN
INDEED DEVELOP.

..DARROW/TAYLOR.. 05/03/2007

http://www.spc.noaa.gov/products/outlook/day1otlk.html

[vbhoutex]

Well, I slept right through the storms as they came through. We had 0.95" of rain from them. Still to dark to see if we had any llimbs down from winds.

[Extremeweatherguy]

According to the NWS, we could be looking at yet another round of storms this afternoon...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
428 AM CDT THU MAY 3 2007

.DISCUSSION...
QUITE A COMPLEX OF STORMS DEVELOPING OVER SE TX THIS MORNING AS WE
ARE SEEING SOME DECENT RAINFALL AMOUNTS SO FAR THIS SHIFT. PER OBS
THERE DOES NOT SEEM TO BE A WHOLE LOT OF DRYING IN THE WAKE OF THE
STORMS. THIS ALONG WITH THE FACT(S) THAT THE UPPER LOW IS STILL TO
THE WEST...ANOTHER S/W APPEARS TO BE ROUNDING THE BASE AND HEADING
TOWARD US AND THE UPPER LEVELS REMAIN VERY DIFFLUENT WILL KEEP POP
VALUES HIGH FOR TODAY. REDEVELOPMENT A GOOD POSSIBILITY DURING THE
AFTN. IN ADDITION SEVERE WX CANNOT BE TOTALLY RULED OUT AS THE IN-
COMING COLDER AIR ALOFT ENHANCES THE HAIL/WIND THREAT. UPPER RIDGE
BUILDING IN TONIGHT AND HOLDING THROUGH THE WEEKEND AS WARM/MUGGY/
SUMMERY WX PREVAILS. EXTENDED FCST TO HIGHLIGHT A SLIGHT CHANGE...
MOST NOTABLY THE INCLUSION OF LOWISH POPS AS THE UPPER TROF TO THE
OUT WEST LOOKS TO SET UP A BIT FURTHER EAST THAN THE PREVIOUS RUNS
HAVE INDICATED. 41

[JenBayles]

I woke up around 2:00 a.m. to lots of electrical activity, wind and rain. Since I was too comfy in my little bed, I didn't bother to get up to observe, but it seemed to come and go in several waves. Judging by the pool level, we got over an inch under the BC Dome.

[jasons2k]

When I went to bed last night (about 11PM) I was pretty confident the severe threat was winding down and that appears to be the case. No LSR from the NWS overnight/this AM. I got .32" of rain and not a single leaf or branch was in the yard this AM. Lots of bark but no bite...

[southerngale]

I woke up to thunderstorms, about 4something I believe. I heard some thunder, but don't think there was much wind. Just plain ol thunderstorms, but that's good. Nobody wants to be woke up by severe weather.

Regarding today... from NWS LCH early morning:

NATIONAL WEATHER SERVICE LAKE CHARLES LA
438 AM CDT THU MAY 3 2007

<snippet>

MCS OVER SOUTHEAST TEXAS WILL GRADUALLY WEAKEN DURING THE
REMAINDER OF THE MORNING. HOWEVER...DURING THE AFTERNOON EXPECT
RE-DEVELOPMENT ALONG THE LEFT OVER BOUNDARY WITH DAYTIME HEATING.
MEANWHILE...UPPER LOW WILL OPEN UP INTO A WAVE AND MOVE EAST
ACROSS THE FORECAST TONIGHT. THESE TWO FACTORS WILL LEAD TO HIGH
POPS ACROSS THE FORECAST AREA THROUGH TONIGHT...WITH A GRADUAL
DECREASE IN POPS ON FRIDAY AS SYSTEM MOVES OFF TO THE EAST.

GOOD SOUTHERLY FLOW AHEAD OF THE SYSTEM WILL CONTINUE TO INCREASE
MOISTURE VALUES. THE 06Z SPECIAL UPPER AIR SOUNDING FROM KLCH
SHOWED PWAT VALUE UP TO NEAR 1.4 INCHES WHICH IS ABOUT 125 PERCENT
OF NORM. MEANWHILE...LAPS ANALYSIS SHOWS PWAT VALUES OVER
SOUTHEAST TEXAS INCREASING TO ABOUT 1.75 INCHES WHICH IS TWICE THE
STANDARD DEVIATION FOR THE MONTH OF MAY. ALSO...GOOD UPPER LEVEL
DIVERGENCE SHOULD CONTINUE TODAY INTO TONIGHT AS AREA WILL BE NEAR
THE LEFT EXIT REGION OF JET MOVING AROUND THE UPPER LOW.
THEREFORE...THERE WILL BE A CHANCE FOR SOME HIGH RAINFALL RATES
AND LOCALLY HEAVY RAINFALL. ONCE AGAIN FLASH FLOOD GUIDANCE
NUMBERS ARE RATHER HIGH SO WILL NOT ISSUE A FLOOD WATCH AT THIS
POINT BUT WILL KEEP A CLOSE EYE ON THINGS.


SPC has us in a Slight Risk for severe weather again this afternoon. I'll take a guess that it's a little more bark, but no bite.

[JenBayles]

Looks like a few storms are starting to pop along I-35 around Waco.

[jasons2k]

Latest from Jeff:

Watching trends closely early this afternoon.

Weather watch may be issued shortly for parts of the area given visible sat trends of towering cumulus and radar showing storms firing over Wharton County.

Numerous low level boundaries are in place and with surface heating ongoing in a very moist air mass it is only a matter of time before local capping is breached. Strong shortwave noted over TX panhandle will pivot around the upper low over N TX and into this very moist and unstable air mass by mid afternoon. Expecting rapid development along existing boundaries locally and deep surface based development over C TX where strong heating is ongoing.

Cold mid level pocket associated with upper low will produce a large hail threat. Isolated tornadoes will be possible with convective onset of supercells initially then potential for linear lines and segments toward early evening.

Very heavy rains will also be possible.

[PTrackerLA]

It will be interesting to see what kind of redevelopment we will see later this evening. The sun is now out heating everything up but radars are quiet except for a few storms south of Houston. Only received about .25" with the rain that moved through earlier so some more would be nice! Flood watches are up just to my east for 3-6" of rain possible but I just don't see this happening at this time.

[Extremeweatherguy]

ESOSCALE DISCUSSION 0665
NWS STORM PREDICTION CENTER NORMAN OK
0219 PM CDT THU MAY 03 2007

AREAS AFFECTED...SOUTHEAST TEXAS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 031919Z - 032045Z

TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT AND THE
POSSIBILITY OF A WW.

LATEST RUC GUIDANCE SUGGESTS THAT BROAD LOWER/MID-TROPOSPHERIC
THERMAL RIDGE IS FLATTENING IN RESPONSE TO EASTWARD PROGRESSION OF
WEAKENING SOUTHERN BRANCH TROUGH. AND...INSOLATION CONTINUES TO
MODIFY BOUNDARY ACROSS MUCH OF SOUTHEAST TEXAS...PREVIOUSLY
STABILIZED BY CONVECTIVE OUTFLOW. LOW-LEVEL FOCUS FOR CONVECTIVE
DEVELOPMENT IS A BIT UNCERTAIN...BUT INITIATION OF STORMS IS ONGOING
NEAR WHAT APPEARS TO INTERSECTION OF WEAKENING/RETREATING CONVECTIVE
BOUNDARIES TO THE SOUTH/SOUTHWEST OF HOUSTON. WITH INHIBITION
WEAKENING FOR BOUNDARY LAYER PARCELS WITH CAPE ON THE ORDER OF
1000-2000 J/KG...CONVECTION LIKELY WILL INTENSIFY...WITH ADDITIONAL
STORMS PROBABLE THROUGH 20-21Z ACROSS THE UPPER TEXAS COASTAL PLAIN.
DEEP LAYER SHEAR PROFILES ARE ALREADY SUPPORTIVE OF SUPERCELLS...AND
THIS WILL INCREASE FURTHER AS CORE OF 40+ KT 500 MB JET STREAK
OVERSPREADS REGION DURING THE LATE AFTERNOON. THOUGH MODELS SUGGEST
A TENDENCY FOR WEAKENING OF 30 KT SOUTHERLY 850 FLOW...SOUTHEASTERLY
SURFACE WINDS WILL STILL CONTRIBUTE TO SIZABLE LOW-LEVEL HODOGRAPHS.
AND...POTENTIAL FOR TORNADOES WILL EXIST...IN ADDITION TO RISK FOR
LARGE HAIL/DAMAGING WINDS.

..KERR.. 05/03/2007

[Stratosphere747]

SE Texas into La, are now under a tornado watch till 11 tonight. Looks tranquil right now, but things should begin to ramp up soon.


Tornado Watch

TORNADO WATCH OUTLINE UPDATE FOR WT 219
NWS STORM PREDICTION CENTER NORMAN OK
305 PM CDT THU MAY 3 2007

TORNADO WATCH 219 IS IN EFFECT UNTIL 1100 PM CDT FOR THE
FOLLOWING LOCATIONS

TXC005-015-039-041-051-071-089-157-167-185-199-201-225-241-245-
291-313-339-347-351-361-373-403-405-407-419-455-457-471-473-477-
481-040400-
/O.NEW.KWNS.TO.A.0219.070503T2005Z-070504T0400Z/

TX
. TEXAS COUNTIES INCLUDED ARE

ANGELINA AUSTIN BRAZORIA
BRAZOS BURLESON CHAMBERS
COLORADO FORT BEND GALVESTON
GRIMES HARDIN HARRIS
HOUSTON JASPER JEFFERSON
LIBERTY MADISON MONTGOMERY
NACOGDOCHES NEWTON ORANGE
POLK SABINE SAN AUGUSTINE
SAN JACINTO SHELBY TRINITY
TYLER WALKER WALLER
WASHINGTON WHARTON

[Yankeegirl]

I was just thinking how quiet it looked outside... and now a tornado watch? Things better get poppin now before it gets too late!!!

[Johnny]

Looks like I could have a chase later this afternoon fairly close to the house!

[Yankeegirl]

I just left the computer for a few minutes and when i came back the radar has lit all up!!! Its amazing what a few minutes can do!!!