Tornadoes in Texas, September 29, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
1156 AM CDT SAT SEP 29 2007

.UPDATE...UPPER LEVEL DIVERGENCE ASSOC W/ THE RRQ OF A 40-60 KT
H250 JET ACROSS S TX AND ADJACENT COASTAL WATERS SEEMED TO REALLY
ENHANCE TSTM ACTIVITY ALONG THE COAST AND OFFSHORE THIS MORNING.
ISOLATED RAINFALL AMOUNTS AS HIGH AS 1 TO 3 INCHES HA ALREADY
OCCURRED ACRS THE COASTAL BEND THIS MORNING. HEAVY TSTMS IN CRP
AREA HAVE SEEMED TO WORK OVER THE ATMOSPHERE AND OUTFLOWS HAVE
CREATED SFC DIVERGENCE IN THESE AREAS...LEAVING FOCUS NOW FURTHER
UP THE COAST TOWARD RKP AND PORT OCONNOR AND OFFSHORE. STILL
EXPECT ADDITIONAL TSTM DEVELOPMENT LATER TODAY OUT WEST AS THIS
AREA RECEIVES SOME SUNSHINE AND HEATING WHICH WILL INCREASE
INSTABILITY. COASTAL BEND MAY SEE ADDITIONAL DEVELOPMENT LATER AS
WELL ONCE ATMOSPHERE RELOADS AND AS ADDITIONAL STORMS OVER THE
GULF WATERS MOVE INLAND.

OVERALL CURRENT FORECAST IN GOOD SHAPE. WINDS ARE ALL OVER THE
MAP DUE TO CONVECTION IN THE AREA...BUT WONT CHASE THE OBS. POP
FORECAST GENERALLY OK...BUT DECIDED TO LOWER TO LIKELY OUT WEST AS
CATEGORICAL POPS SEEMS A BIT MUCH THERE. GIVEN RAIN AND CLOUDS IN
THE AREA...LOWERED TEMPS A BIT...ESP ACROSS THE COASTAL BEND WHERE
HIGHS MAY STRUGGLE TO REACH THE MID 80S.

WATER LEVELS HAVE COME DOWN WITH LOW TIDE AND CANCELED THE COASTAL
FOOD ADVISORY. WINDS TURNING SE IS NOT FAVORABLE FOR WATER PILING
ALONG OUR COAST...SO WATER LEVELS SHOULD NOT BE MORE ABOVE NORMAL THAN
LAST NIGHT. THAT BEING SAID...WATER WILL STILL LIKELY COVER MUCH
OF THE BEACH AT HIGH TIDE THIS EVENING...BUT DONT THINK IT WILL
REACH THE DUNES AND THEREFORE NO ADVISORY IS REQUIRED.

&&

.PREV DISCUSSION... /ISSUED 434 AM CDT SAT SEP 29 2007/

SHORT TERM (TODAY THROUGH SUNDAY)...THE INVERTED SURFACE TROUGH
AXIS LOCATED OVER THE COASTAL WATERS OF THE LOWER AND MIDDLE TEXAS
COASTS WILL SLOWLY MOVE INLAND TODAY. LOW LEVEL COASTAL CONVERGENCE
CONTINUES TO INCREASE ACCORDING TO MSAS EARLY THIS MORNING. 00Z BRO
SOUNDING SHOWED 2.3 INCHES PRECIPITABLE WATER AND LATEST GOES SOUNDER
IMAGE SHOWS THIS MOISTURE MOVING NORTHWEST INTO THE COASTAL BEND.
CONVECTION HAS STEADILY BEEN INCREASING OVER THE PAST COUPLE OF
HOURS. WATER VAPOR IMAGERY SHOWS A WEAK UPPER LEVEL SHORT WAVE
TROUGH MOVING ACROSS CENTRAL TEXAS WITH A 25H JET STREAK LOCATED
OVER THE UPPER TEXAS COAST. RIGHT ENTRANCE REGION OF THIS JET
STREAK WILL BE LOCATED OVER THE COASTAL BEND INTO EARLY THIS
AFTERNOON. GFS/NAM SHOW STRONG OMEGA FIELD OVER SOUTH TEXAS FROM
EARLY THIS MORNING INTO THE AFTERNOON HOURS. MOS GUIDANCE IS GIVING
CATEGORICAL POPS FOR MOST OF SOUTH TEXAS TODAY EXCEPT FOR THE
MID-COAST REGION AND DO NOT SEE A REASON FOR DISPUTE.

MODERATE EAST-NORTHEAST FLOW OVERNIGHT ALONG WITH ASTRONOMICALLY
HIGH TIDES HAVE LED TO WATER LEVELS BEING AROUND A FOOT ABOVE THE
EXPECTED LEVELS. WITH HIGH TIDE THIS MORNING...WILL GO AHEAD AN
ISSUE A COASTAL FLOOD ADVISORY FOR THE MORNING HOURS. MARGINAL
EVENT EXPECTED AND WILL HAVE EXPIRATION TIME OF 18Z WITH LOW
TIDES OCCURRING AT PORT ARANSAS AT 11 AM AND PORT OCONNOR IN THE
EARLY AFTERNOON.

SOUTHEASTERLY LOW LEVEL FLOW WILL CONTINUE TO ADVECT MOISTURE
INTO SOUTH TEXAS REGION TONIGHT THROUGH SUNDAY. EXPECT RAIN CHANCES
WILL AGAIN FOCUS NEAR THE COAST LATE TONIGHT INTO EARLY SUNDAY
MORNING AS COASTAL CONVERGENCE ZONE SETS UP AGAIN. SCATTERED
SHOWERS/T-STORMS WILL MOVE INLAND ON SUNDAY.

AVIATION...DEEP TROPICAL MOISTURE WILL CONTINUE TO MOVE INTO
SOUTH TEXAS AREA TODAY. AREAS OF MVFR CEILINGS WILL CONTINUE TO
DEVELOP OVER THE SOUTHERN COASTAL BEND INTO THE BRUSH COUNTRY
THIS MORNING. NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
PERSIST FOR MOST OF THE DAY...LEADING TO MVFR VSBYS. IFR VSBYS
WILL OCCUR IN THE HEAVIER DOWNPOURS. EXPECT SOUTHEASTERLY LOW
LEVEL FLOW TONIGHT AND MVFR CEILINGS WILL DEVELOP OVER THE
INLAND COASTAL PLAINS AND MOVE INLAND BY DAYBREAK. SCATTERED
SHOWERS/T-STORMS WILL FORM AGAIN ALONG THE COAST AND LOW LEVEL
CONVERGENCE INCREASES.

MARINE...WINDS HAVE DIMINISHED SLIGHTLY FROM LAST NIGHT AS THE
PRESSURE GRADIENT DECREASES SOME BETWEEN THE HIGH PRESSURE RIDGE
TO THE NORTH AND THE TROUGH AXIS MOVING INTO THE LOWER AND MID
TEXAS COAST. KEPT SCEC CONDITIONS OVER THE GULF WATERS THIS
MORNING WITH WINDS EXPECTED TO LOWER TO AROUND 15 KNOTS IN THE
AFTERNOON AS THE TROUGH AXIS MOVES INLAND. NUMEROUS SHOWERS
AND THUNDERSTORMS WILL OCCUR OVER THE MARINE ZONES TODAY WITH
A SLOW DIMINISHING TREND IN THE EVENING HOURS. MORE SCATTERED
SHOWER/T-STORM ACTIVITY WILL DEVELOP OVERNIGHT/SUNDAY MORNING.

LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...PLENTIFUL
MOISTURE/INSTABILITY LINGERS SUNDAY NIGHT/MONDAY(GFS EXHIBITING IT/S
CHARACTERISTIC BIAS OF DRYING THE COLUMN TOO FAST) WITH NOCTURNAL
WIND SPEED CONVERGENCE/SEA BREEZE BOUNDARY CONTRIBUTING TO MOSTLY
CHANCE POPS. MID-LEVEL RIDGING/SYNOPTIC-SCALE SUBSIDENCE TAKES HOLD
THE REMAINDER OF THE PERIOD WITH PWATS DECREASING APPRECIABLY.
HOWEVER...BOUNDARY LAYER MOISTURE MAY STILL BE SUFFICIENT BUT MODELS
DISAGREE TEMPORALLY AS COASTAL CONVERGENCE/SEA BREEZE FRONT SERVE AS
FORCING MECHANISMS. WILL MAINTAIN CONTINUITY FROM PREVIOUS GRIDS AND
SHOW JUST SLIGHT CHANCE POPS. TEMPERATURES WILL STAY AT OR ABOVE
CLIMATOLOGICAL NORMS. WINDS WILL OCCASIONALLY REACH SCEC CRITERIA
ACROSS THE NEARSHORE/OFFSHORE WATERS THROUGH THE PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI    84  76  88  77  90  /  90  50  40  20  40
VICTORIA          84  73  89  74  90  /  70  40  40  20  30
LAREDO            90  76  93  78  93  /  70  40  40  40  40
ALICE             85  74  90  75  91  /  80  40  40  20  50
ROCKPORT          83  78  88  79  90  /  80  50  40  30  30
COTULLA           88  74  90  75  92  /  70  40  40  40  40
KINGSVILLE        84  75  89  76  91  /  90  50  40  20  40
NAVY CORPUS       84  78  87  80  89  /  90  50  40  30  30

&&

.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.

&&

MJG

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
1117 AM CDT SAT SEP 29 2007

GMZ230-235-250-255-270-275-TXZ229>234-239>247-301200-
BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS-
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT OCONNOR-
COASTAL WATERS BAFFIN BAY TO PORT ARANSAS OUT 20 NM-
COASTAL WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM-
WATERS BAFFIN BAY TO PORT ARANSAS 20 TO 60 NM-
WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL 20 TO 60 NM-
LA SALLE-MCMULLEN-LIVE OAK-BEE-GOLIAD-VICTORIA-WEBB-DUVAL-
JIM WELLS-KLEBERG-NUECES-SAN PATRICIO-ARANSAS-REFUGIO-CALHOUN-
1117 AM CDT SAT SEP 29 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH TEXAS AND THE MIDDLE
TEXAS COASTAL WATERS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

DEEP TROPICAL MOISTURE ASSOCIATED WITH A TROUGH OF LOW PRESSURE
WILL CONTINUE TO MOVE INTO THE COASTAL BEND AND BRUSH COUNTRY
THIS AFTERNOON. THIS IN COMBINATION WITH A WEAK UPPER LEVEL
DISTURBANCE WILL PRODUCE NUMEROUS TO WIDESPREAD SHOWERS AND
SCATTERED THUNDERSTORMS OVER THE SOUTH TEXAS REGION AND NEARBY
COASTAL WATERS TODAY. HEAVY RAIN WILL BE POSSIBLE WITH THE
STRONGER SHOWERS AND THUNDERSTORMS. LOCALIZED RAIN AMOUNTS COULD
BE AS HIGH AS 2 TO 3 INCHES MAINLY NEAR THE COASTAL BEND AND
COASTAL PLAINS AREAS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DECREASE IN INTENSITY AND COVERAGE TONIGHT BUT SCATTERED ACTIVITY
IS STILL EXPECTED ESPECIALLY ALONG THE COAST OVERNIGHT.

AN ISOLATED WEAK WATERSPOUT COULD ALSO OCCUR WITH ANY OF THE
SHOWERS AND THUNDERSTORMS OVER THE BAYS AND NEARSHORE WATERS
TODAY.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER THE ENTIRE
AREA SUNDAY AND MONDAY AS COPIOUS MOISTURE PERSISTS. HEAVY RAINFALL
WILL BE POSSIBLE WITH THE STRONGER THUNDERSTORMS. ONLY ISOLATED
SHOWERS AND THUNDERSTORMS ARE EXPECTED THEREAFTER AS MOISTURE
DECREASES AND HIGH PRESSURE BUILDS ALOFT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

MJG