Moderator: S2k Moderators
jasons wrote:Another tornado warning on the way soon??
Shot at 2009-04-17
Harris County Flood Control District now on stand-by
Skywarn is now activated
Flash Flood Watch issued through Saturday PM.
Significant flash flood event unfolding across the area. Confirmed 8-10 inches since 1000am this morning over Fayette County with cars being washed off roads. Incredible rainfall rates continue to be produced and upper air pattern supports rapid back building of storms to the western end of a large training line. Radar shows near continuous development along the western end of this training line across C TX. All parameters in place favor a significant rainfall event throughout the overnight hours and into Saturday. Some very big totals will be possible along with significant flash flooding.
Additionally, HP supercells continue to spin up tornadoes. Looks like one just went through Brenham with some significant damage.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
259 PM CDT FRI APR 17 2009
.DISCUSSION...
SHOWERS AND THUNDERSTORMS FROM A LARGE AND SLOW MOVING MCS HAVE PRODUCED
A LOT OF HEAVY RAINFALL AND SOME SEVERE WEATHER ACROSS PORTIONS OF SOUTHEAST
TEXAS TODAY (SEE THE LATEST LSRHGX). SOME RAINFALL REPORTS BEING RECEIVED
ARE ACTUALLY QUITE CLOSE TO THE KHGX 88D ESTIMATED 8 TO 10 INCH BULLSEYES
BETWEEN BELLVILLE AND SCHULENBURG. BASED ON THE HEAVY RAINFALL THAT HAS
ALREADY OCCURRED AND THE POTENTIAL FOR ADDITIONAL HEAVY RAINS THIS AFTERNOON
THROUGH SATURDAY EVENING...HAVE EXTENDED THIS MORNING`S FLOOD WATCH
THROUGH 9 PM ON SATURDAY AND HAVE NOW INCLUDED ALL OF SOUTHEAST TEXAS.
VERY HIGH MOISTURE LEVELS WITH PRECIPITABLE WATER VALUES IN A 1.75 TO
2.00 INCH RANGE...GOOD SURFACE CONVERGENCE AND A VERY DIFFLUENT FLOW
ALOFT SUPPORT ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT BETWEEN
TONIGHT AND TOMORROW NIGHT. THINK THE MAIN HEAVY RAIN THREAT WILL BE
ALONG AND NORTH OF THE HIGHWAY 59 CORRIDOR. OUR HWO ISSUED THIS AFTERNOON
IS CALLING FOR ADDITIONAL RAINFALL TOTALS TO AVERAGE 2 TO 4 INCHES...AND
THIS COULD EASILY BOOST TWO DAY TOTALS (FRIDAY AND SATURDAY) UP TO 15
TO 20 INCHES BETWEEN THE BELLVILLE AND SCHULENBURG AREAS. IN ADDITION
TO THE HEAVY RAIN THREAT...THERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS
THROUGH SATURDAY EVENING AS DISTURBANCES CONTINUE TO ROTATE AROUND
THE STRONG UPPER LEVEL LOW. A COLD FRONT WILL CROSS THE AREA LATE SATURDAY
NIGHT AND WILL DRY THINGS OUT. EXPECT COOL NIGHTS AND MILD DAYS SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK WITH A DRY AIRMASS IN PLACE. A GRADUAL
WARMUP CAN BE EXPECTED DURING THE SECOND HALF OF NEXT WEEK AS A RETURN
FLOW OFF THE GULF BECOMES ESTABLISHED. AS OF NOW...ALL OF NEXT WEEK
LOOKS DRY. 42
MESOSCALE DISCUSSION 0502
NWS STORM PREDICTION CENTER NORMAN OK
0319 PM CDT FRI APR 17 2009
AREAS AFFECTED...PORTIONS S TX.
CONCERNING...SEVERE THUNDERSTORM WATCH 161...
VALID 172019Z - 172115Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 161
CONTINUES.
WW MAY NEED TO BE REPLACED BEFORE SCHEDULED 00Z EXPIRATION...TO
COVER CONDITIONAL BUT INCREASING TORNADO CONCERN AS WELL AS
POTENTIAL FOR SRN-MOST TSTMS -- NOW EVIDENT OVER PORTIONS
MCMULLEN/LIVE OAK COUNTIES -- TO MOVE MORE DEVIANTLY RIGHTWARD AND
OUT OF PRESENT WW DOMAIN TOWARD PORTIONS SAN PATRICIO COUNTY.
SFC MESOANALYSIS INDICATES OUTFLOW BOUNDARY FROM EARLIER CONVECTION
FROM ABOUT 30 NW VCT SWWD TO NEAR COT...WITH INFLECTION POINT CLOSE
TO ONGOING ACTIVITY IN MCMULLEN COUNTY. FINE LINE AND COLLOCATED
CYCLONIC SHEAR ZONE APPEAR ON VIS IMAGERY SSWWD FROM THERE ACROSS
LRD AREA...MOVING SEWD 10-15 KT. WHILE REMOVED FROM LARGEST 0-1 KM
SRH THAT HAS PERSISTED FARTHER E ALONG MARINE FRONT...TSTMS IN SRN
PORTION WW WILL MAINTAIN RELATIVELY UNIMPEDED INFLOW OF MORE BUOYANT
BOUNDARY LAYER...AMIDST SOMEWHAT FAVORABLE SHEAR. MODIFIED RAOBS
AND RUC SOUNDINGS SUGGEST SFC TEMPS LOW-MID 80S -- LIKELY FOR
ANOTHER FEW HOURS -- WITH OBSERVED DEW POINTS UPPER 60S TO LOW 70S F
-- WILL WEAKEN MLCINH TO BELOW 25 J/KG AND YIELD MLCAPE NEAR 2500
J/KG. INTERPOLATED VWP DATA AND NEAR-TERM FCST WINDS SUGGEST
EFFECTIVE SHEAR MAGNITUDES 35-45 KT...WITH 0-1 KM SRH AROUND 300
J/KG ALONG BOUNDARY AND 100-200 J/KG TO ITS S...AND BACKING SFC FLOW
NEAR COAST.
FARTHER N ACROSS ERN HILL COUNTRY AND ADJACENT BLACKLAND PRAIRIE
REGION BELOW ESCARPMENT...WIDELY SCATTERED TO SCATTERED TSTMS --
ATOP OUTFLOW POOL FROM EARLIER MCS -- WILL SUBSIST OFF ELEVATED LOW
LEVEL WAA/MOISTURE TRANSPORT REGIME. EFFECTIVE SHEAR 30-45 KT WILL
BE POSSIBLE DEPENDING ON CONVECTIVE PLUME DEPTH...HOWEVER MUCAPES
SHOULD REMAIN IN 500-1000 J/KG RANGE. MAIN CONCERN WILL BE
OCCASIONAL HAIL...BUT THREAT DOES NOT APPEAR SUFFICIENTLY
CONCENTRATED/INTENSE TO WARRANT WW.
jasons wrote:The line over Harris C0unty is bowing.....
It's also THE darkest outside I have ever seen it at 4PM in April. Ever.
