Tornado and Flash Flooding in Texas, July 16, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
235 AM CDT MON JUL 16 2007

.DISCUSSION...THREE TO FOUR INCHES OF RAIN WERE RECEIVED IN A SHORT
PERIOD OF TIME IN NE STARR AND ALL OF BROOKS COUNTIES. THIS MCS HAS
NOW DISSIPATED. BRO REACHED 94 DEG F SUN...WITH A LOW OF 79. HRL
94/78 AND MFE 97/79...IN A SE SFC FLOW OF 15 TO 25 MPH.

THE MCS THAT ENCROACHED OUR NRN COUNTIES LAST NIGHT IS JUST A
PRECURSOR TO HVY RAINS FCST FOR LATER TDY AND TUE...POSSIBLY
EXTENDING INTO THE WEEKEND. THE MECHANICS FOR HVY RAIN PRODUCTION
ARE A COMBINATION OF A POSITIVELY TILTED UPPER LEVEL TROF EXTENDING
FROM ERN TX INTO OUR REGION...AND AN EASTERLY WAVE MVG EAST TO WEST
JUST SOUTH OF OUR REGION. THE LATEST GFS MDL...WHICH INITIALIZED
BEST WITH LAST NIGHTS MCS INTENSITY AND LOCATION...SPINS OUT A
VIGOROUS UPPER LOW AT THE BASE OF THIS COASTAL UPPER TROF BY 18Z
TDY. IF THIS SCENARIO HAPPENS...VIGOROUS PVA WILL BE AVAILABLE FOR
THE LIFTING PROCESS OF AN ATM THAT IS PROGD TO CONTAIN 2.50 INCHES
OF PWATS AND -3 SI VALUES...SKEWING TOWARD A HVY RAFL EVENT WITH
STRONG TSTM DEVELOPMENT. FM 1244 AM TDY...SPC NOTED THIS FOR
LOCATIONS IN OUR VICINITY...THOUGH BUOYANCY WILL BE LIMITED BY THE
VAST CLOUD/PCPN SHIELD...LOW-LEVEL WIND FIELDS VCNTY THE SFC LOW
WILL EXHIBIT WEAK LOW-LEVEL TURNING.  THUS...WHILE PROBABILITIES
WILL BE LOW...IT IS POSSIBLE THAT A STRONGER TSTM MAY PRODUCE A
BRIEF WEAK TORNADO. THIS ANALYSIS BY SPC WAS MAINLY FOR FL/LA
AREAS...BUT SIMILAR CONDITIONS COULD BE EXPERIENCED HERE IN DEEP S
TX...ESPECIALLY IF THE GFS UPPER LOW FORMS OVRHD THIS PM. THE MAIN
THREAT UNDER THIS SYNOPTIC SITUATION WILL BE FLOODING RAINS THIS
WEEK...AS PWATS IN THE 2.25 INCH RANGE ARE FCST NOW THRU SUN.
&&

.MARINE...BUOY020 REPORTED SE WINDS 10 TO 12 KTS AND SEAS AT 3.3
FT.  MODERATE WINDS AND SEAS WILL CONTINUE OVER THE LOWER TEXAS
COASTAL WATERS THROUGH THE MIDDLE OF THE WEEK. AN UPPER LEVEL LOW
ALONG THE DEEP SOUTH TEXAS COASTLINE WILL INCREASE THE CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF THE WEEK.  HIGH
PRESSURE WILL BUILD INTO THE AREA BY THE END OF THE WEEK CAUSING A
DRIER AND MORE STABLE AIRMASS.
&&

.AVIATION...VFR CIGS WILL PREVAIL THROUGH THE FCST WITH LIKELY
SHRA/TSRA CREATING TEMPO MVFR TO IFR CONDITIONS. WINDS WILL BE LIGHT
TO MODERATE FROM THE SOUTHEAST THROUGH TUESDAY MORNING.
&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  89  78  87  78 /  60  60  60  40
BROWNSVILLE          91  76  89  76 /  60  60  60  40
HARLINGEN            91  75  90  76 /  60  60  60  40
MCALLEN              92  75  92  75 /  60  60  60  40
RIO GRANDE CITY      95  75  93  75 /  40  40  60  40
SOUTH PADRE ISLAND   89  78  87  79 /  60  60  60  40

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR TXZ248>257.
&&

THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT:
HTTP://WWW.SRH.NOAA.GOV/BRO

SYNOPTIC/GRIDS...LEAD METEOROLOGIST PHILO 58
MESO/MARINE/AVIATION...LEAD METEOROLOGIST FLATT 65

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
500 AM CDT MON JUL 16 2007

TXZ248>257-171100-
ZAPATA-JIM HOGG-BROOKS-KENEDY-STARR-HIDALGO-INLAND WILLACY-
INLAND CAMERON-COASTAL WILLACY-COASTAL CAMERON-
500 AM CDT MON JUL 16 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS.

.DAY ONE...TODAY AND TONIGHT.

A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF THE RIO GRANDE VALLEY
THROUGH TONIGHT...AS AN UPPER LEVEL LOW PRESSURE SYSTEM DEVELOPS
OVER OUR REGION. THIS FEATURE...IN CONJUNCTION WITH COPIOUS AMOUNTS
OF MOISTURE IN THE ATMOSPHERE...WILL INDUCE THUNDERSTORM DEVELOPMENT
WITH HEAVY RAINFALL BY THIS AFTERNOON...AND THESE HEAVY RAINS WILL
LIKELY CONTINUE THOUGH THE EVENING. IF YOU ENCOUNTER WATERS OF
UNKNOWN DEPTH WHILE DRIVING...TURN AROUND...DONT DROWN.
ALSO...FACTOR IN THE LIKELIHOOD OF PONDED ROADWAYS WHILE DRIVING
AND SLOW DOWN. ALWAYS DRIVING DEFENSIVELY DURING HAZARDOUS WEATHER.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

AN UPPER LEVEL LOW WILL REMAIN ALOFT FOR TUESDAY AND WEDNESDAY
...ALONG WITH TROPICAL MOISTURE MOVING NORTH OUT OF THE BAY OF
CAMPECHE. THIS COMBINATION OF FACTORS WILL INCREASE THE THREAT OF
LOCALLY HEAVY RAINS ACROSS MOST OF DEEP SOUTH TEXAS THROUGHOUT THE
UPCOMING WEEK. ALONG WITH THE HEAVY RAIN POTENTIAL...ISOLATED STRONG
TO SEVERE THUNDERSTORMS WILL BE POSSIBLE OVER OUR REGION TUESDAY AND
WEDNESDAY...WITH A TROPICAL AIRMASS AND THE CHANCE FOR HEAVY RAINS
CONTINUING THROUGH SUNDAY. ALSO...A MODERATE RISK OF RIP CURRENTS IS
POSSIBLE EACH DAY AT LOCAL BEACHES WITH MARINE WARNING POSSIBLE AS
STRONG THUNDERSTORMS MOVE OVER OUR GULF WATERS.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION MAY BE NEEDED TODAY THROUGH
WEDNESDAY...AND POSSIBLY BEYOND THIS PERIOD.

PHILO