SE TX / SW LA - Heavy rains this week-Tues. and Fri???

[Extremeweatherguy]

radar rainfall estimates of 2-3" for much of northern Harris county this evening, and I wouldn't be surprised to see a few 4" totals before this batch of rain moves out.

Any additional precipitation areas overnight or tomorrow could lead to a big flooding concern. Let's hope we don't seen anything too heavy...

[Extremeweatherguy]

Here is a short video of some of the storm footage I shot tonight. It is nothing too exciting.. just a lot of lightning, heavy rain, a few gusts of wind and some minor flooding:

[youtube]http://www.youtube.com/watch?v=YcM-37Sojc4[/youtube]

[Extremeweatherguy]

SPC seems to think we will have another round of severe weather this afternoon...

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1250 AM CDT WED MAR 14 2007

VALID 141200Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PART OF THE NWRN TO
CENTRAL GULF COAST REGIONS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MIDWEST AND OH
VALLEY REGIONS...

...PART OF THE NWRN TO CENTRAL GULF COAST REGIONS...
CLOSED MID/UPPER LEVEL LOW IS EXPECTED TO BE OVER CENTRAL TX EARLY
THIS MORNING AND SHOULD SLOWLY EVOLVE INTO AN OPEN WAVE AS IT MOVES
ESEWD REACHING THE LA COAST/NWRN GULF REGION BY 12Z THURSDAY.

A CLUSTER OF TSTMS IS EXPECTED TO BE ONGOING AT 12Z TODAY ACROSS
PARTS OF THE UPPER TX COAST/NWRN GULF INTO SWRN LA...WITH THE
ATTENDANT OUTFLOW BOUNDARY FROM THIS ACTIVITY EXTENDING SWWD INTO S
TX. CLOUDINESS SPREADING EWD ACROSS THE LOWER MS VALLEY WITH THE
MORNING TSTM ACTIVITY WILL LIKELY LIMIT SURFACE HEATING. DESPITE
MODEST LAPSE RATES/LIMITED SURFACE HEATING...MOIST AIR MASS AND
COOLING MID LEVEL TEMPERATURES WITH APPROACH OF UPPER LOW ARE
EXPECTED TO PROMOTE ADDITIONAL TSTMS FROM THE NWRN GULF INTO THE
LOWER MS VALLEY. ALTHOUGH INSTABILITY WILL BE GREATER OFFSHORE...
FORECAST SOUNDINGS SHOW LARGE HODOGRAPH CURVATURE ACROSS SRN LA INTO
SWRN MS WHICH SHOULD PROMOTE AN INCREASED TORNADO POTENTIAL.

FARTHER WEST ACROSS PARTS OF THE MIDDLE AND UPPER TX COAST
REGION...MODELS SUGGEST TSTMS SHOULD DEVELOP MAINLY NORTH OF THE
OUTFLOW BOUNDARY AND INITIALLY ATOP A STABLE BOUNDARY LAYER. SOME
SURFACE HEATING TODAY MAY SUPPORT SURFACE BASED TSTMS AS AIR MASS
BECOMES MODERATELY UNSTABLE. EFFECTIVE BULK SHEAR OF 40-50 KT
SUGGESTS POTENTIAL FOR SUPERCELLS...WITH LARGE HAIL AND DAMAGING
WINDS THE PRIMARY THREATS AS COLD MID LEVEL TEMPERATURES/STEEP LAPSE
RATES WITH THE CLOSED LOW SPREAD ACROSS THIS REGION. SEVERE THREAT
ACROSS THIS PART OF TX SHOULD DIMINISH BY EARLY EVENING AS ACTIVITY
MOVES OFFSHORE INTO THE NWRN GULF.

[HouTXmetro]

Looks like the storms to our SW might make it to Metro Houston

[ncupsscweather]

Hay Extremeweatherguy thanks for the Video footage of the Storms that moved through Texas. Would have loved to seen some of them up here in North Carolina.

[Extremeweatherguy]

The SPC has taken Houston out of today's slight risk zone (we are now on the NE edge of it), but I think it may wind up being placed back over us later today. Why? Well, if the peeks of sun I am seeing outside continue into this afternoon, then I believe we could destabalize enough to have another severe event today. Large hail is the main threat according to the SPC.

Here is their latest Day 1 update...

http://www.spc.noaa.gov/products/outloo ... k_1300.gif

...MIDDLE TX COAST AND S CENTRAL TX TODAY...
THE OVERNIGHT MCS HAS NOW MOVED WELL OFFSHORE INTO THE NW
GULF...LEAVING A DIFFUSE OUTFLOW BOUNDARY ACROSS S TX. CONVECTIVE
DEVELOPMENT THIS MORNING SHOULD BE ELEVATED AND CONFINED TO A NW-SE
BAND WELL N OF THE RESIDUAL OUTFLOW BOUNDARY. BY ABOUT MIDDAY...THE
INITIAL ELEVATED CONVECTION COULD BECOME SURFACE BASED AS THE
LOW-LEVELS DESTABILIZE AND ANOTHER EMBEDDED SPEED MAX TRANSLATES
ESEWD FROM CENTRAL TX. STEEP MID LEVEL LAPSE RATES AND 65-70 F
BOUNDARY LAYER DEWPOINTS REMAIN INTACT OVER S TX THIS MORNING...AND
STRONG INSTABILITY WILL BE POSSIBLE OVER THIS AREA DURING THE
AFTERNOON. SUPERCELLS WITH LARGE HAIL WILL BE THE PRIMARY SEVERE
THREAT...THOUGH DAMAGING WINDS AND AN ISOLATED TORNADO MAY ALSO
OCCUR WITH ANY SURFACE-BASED STORMS GIVEN THE MAGNITUDE OF THE
INSTABILITY AND FAVORABLE VERTICAL SHEAR PROFILES.

Next SPC update expected around 11:30am.

[jeff]

Area was rocked again overnight with severe storms and heavy rainfall.



Strong mesocyclone with good low level rotation passed over my area between 945pm and 1000pm with 50-60mph winds. Never before have I seen a 180 degree wind shift over a 15 minute duration until last night. Strong (45-55mph) WSW wind onset around 945pm with leading edge of bowing supercell…with wind shifting gradually to the NW and then N and NE by 1000pm. Strongest winds came between 955pm and 1000pm (est 55-60mph) from impressive rear flanking downdraft on back side of rotation couplet noted in radar over KIAH at the time. Tornado warning issued at 1004pm for N Harris Co was very well justified as broad rotation was clearly evident by the wind shift…would expect a brief tornado was very possible NE of my area (near Humble) if the circulation was able to tighten.



Discussion:



Double MCS/bow echo event has crossed SE TX overnight. Current very impressive bow echo clearing the coastal waters with radar velocities of 60-70mph along the leading edge. Wake/meso low is located over Liberty/Chambers County moving ENE and should clear the area by 800am. Widespread 1-2 inches of rainfall has fallen with heavier rates out west leading to moderate to major river flooding…see hydro section below.



Upper trough responsible for active weather is on the move and located over NC TX this morning. Air mass has been worked over, however models show refiring of thunderstorms by mid morning atop stable surface layer and elevated moisture surges back northward. Air mass is still fairly unstable given location of upper low cold pocket with very steep lapse rates over the area. Expect convection to begin to fire in the next 3-4 hours and then become increasingly surface based as heating commences. Lack of good low level inflow and weaker dynamics should preclude a tornado threat, however freezing levels crash below 10,000 ft as the cold pocket crosses the area. Low freezing levels supports a large hail threat with any storms…and they may be very efficient at producing lots of small hail.



Last batch of weather should clear the area by late afternoon with clear skies and warm humid weather on tap for Thursday ahead of a cold front Friday. Models now show enough moisture and instability ahead of the front to produce and chance of thunderstorms.



Hydro:



Detailed hydro information will be out later this morning after RFC runs overnight rainfall into river guidance products.



Moderate to major flooding is ongoing or forecast form many C TX rivers and coastal bend rivers.



Expect flooding to develop along the San Bernard River, Lavaca/Navidad River, Navasota River, rise to bankfull on the Brazos River.

[jasons2k]

EWG I agree, I think we have a decent shot of being included again.

[jasons2k]

already hail showing-up in the storms to our SW:

[Extremeweatherguy]

those storms are developing pretty rapidly down there too. We will have to see if they can begin to fire further north now...especially toward lunch-time.

[Extremeweatherguy]

[web]http://www.weatherunderground.com/radar/radblast.asp?ID=HGX&lat=0&lon=0&label=you&type=N0R&zoommode=pan&map.x=400&map.y=240&centerx=400&centery=240&prevzoom=zoom&num=6&delay=15&scale=1&noclutter=0&showstorms=0&showlabels=1&rainsnow=0&lightning=1[/web]

[Extremeweatherguy]

WOW!

4 counties now under severe warnings! And the hail down there is up to GOLF BALL size..

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
940 AM CDT WED MAR 14 2007

TXC175-469-141530-
/O.CON.KCRP.SV.W.0020.000000T0000Z-070314T1530Z/
GOLIAD-VICTORIA-
940 AM CDT WED MAR 14 2007

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 AM CDT
FOR NORTHEASTERN GOLIAD AND NORTHERN VICTORIA COUNTIES...

AT 936 AM CDT...THE PUBLIC REPORTED A SEVERE THUNDERSTORM PRODUCING
LARGE DAMAGING HAIL UP TO GOLF BALL SIZE. THIS STORM WAS LOCATED
NEAR MISSION VALLEY...OR ABOUT 7 MILES WEST OF VICTORIA...MOVING
EAST AT 20 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
VICTORIA BY 950 AM CDT
TELFERNER BY 1020 AM CDT
INEZ BY 1030 AM CDT

[web]http://www.srh.noaa.gov/hgx/[/web]

[Extremeweatherguy]

HAIL THREAT IS INCREASING AS ELEVATED STORMS DEVELOP ACROSS THIS
REGION. NEW WW MAY BE NEEDED.

MORNING CRP SOUNDING INDICATED VERY STEEP LAPSE RATES ABOVE A
LOW-LEVEL CAPPING INVERSION NEAR 800 MB...YIELDING SUBSTANTIAL /NEAR
2000 J/KG/ ELEVATED CAPE. SHEAR THROUGH THE CLOUD-BEARING LAYER IS
SUFFICIENT FOR ORGANIZED/ROTATING STORMS...WHICH COMBINED WITH THE
THERMODYNAMICALLY-DRIVEN POTENTIAL FOR STRONG UPDRAFTS SUPPORTS THE
LIKELIHOOD FOR LARGE HAIL.

WITH TIME...WARMER AIR IN THE CAPPING LAYER -- EVIDENT IN MORNING
RAOBS FROM DRT INTO NRN MEXICO -- SHOULD ADVECT EWD TOWARD THE
DISCUSSION AREA...LIMITING THE WWD EXTENT OF CONVECTIVE THREAT.
HOWEVER...WITH SMALL-SCALE CIRCULATION CENTER /NOW INVOF AUSTIN TX
PER LATEST WV IMAGERY/ MOVING EWD ACROSS THIS REGION...EXPECT STORMS
TO PERSIST OVER THE TX COASTAL PLAIN FOR SEVERAL HOURS.

LOW CLOUDS WILL CONTINUE TO INHIBIT DAYTIME HEATING FOR THE NEXT
COUPLE OF HOURS AT LEAST...THUS LIMITING THE POTENTIAL FOR
SURFACE-BASED STORMS. HOWEVER...SHOULD SUFFICIENT HEATING COMMENCE
LATER THIS MORNING/EARLY AFTERNOON...SURFACE-BASED STORM POTENTIAL
WOULD INCREASE. GIVEN PRESENCE OF RETREATING SURFACE
OUTFLOW...LOW-LEVEL SHEAR MAY BE SUFFICIENT -- PARTICULARLY NEAR
THIS BOUNDARY -- TO SUPPORT A TORNADO THREAT ACROSS A PORTION OF THE
MIDDLE TX COASTAL REGION. HOWEVER...THIS REMAINS A CONDITIONAL
THREAT ATTM...WITH LARGE HAIL LIKELY TO REMAIN THE PRIMARY
SHORT-TERM SEVERE WEATHER CONCERN.

[Extremeweatherguy]

we are now under a severe T-storm watch until 7pm!

[jasons2k]

[weatherrabbit_tx]

see some cells around Bryan/College Station area and the La Grange area moving our way, now if stay together and grow is the question?

[Ptarmigan]

It was stormy last night and early this morning. I heard thunder arond 4:00 AM and it woke me up. I like hearing thunder, but I hate it when it wakes me up.

[Johnny]

I've been down in Galveston (Jamaica Beach) with my family since Friday. Monday morning we got rocked by a squall line pushing 60 mph winds. The patio furniture went flying through the air and straight into the canal!lol

Last night it stormed all night long. I drove in this morning and my wife and son are still at the beach house. They can't leave because they are getting pounded big time!

Spring time in Texas...gotta love it!

[JenBayles]

Johnny - I just looked at your location. Love it!!! :-D

I see the storm watch is up until 7:00 p.m. but it appears this line will be the last for us if the radar is any indication. Anyone think the atmosphere will remain unstable enough after this line goes thru for redevelopment late afternoon/ early evening?

[jasons2k]

http://www.spc.noaa.gov/products/md/md0284.html