Flash Flood Warning 18, NWS Brownsville, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
637 PM CDT SAT SEP 27 2014

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...RELATIVELY HEAVY SHOWERS ARE EXPECTED TO CONTINUE IN
CAMERON AND WILLACY COUNTIES FOR ANOTHER COUPLE OF HOURS ROTATING
AROUND A WEAK LOW PRESSURE AREA. WEST OF THERE RAINFALL SHOULD
PRETTY MUCH HAVE ENDED FOR THE NIGHT. COASTAL TROUGHING SHOULD
WEAKEN AS UPPER LEVEL LOW PRESSURE MOVES NORTHEAST OUT OF THE AREA
AND EXPECT A TRANSITION TOWARDS CLEARER WEATHER AND VFR CIG/VISBY
OVERNIGHT TONIGHT. WILL BE MONITORING FOR GROUND FOG IN THE EARLY
MORNING HOURS BUT PROBABILITY TOO LOW FOR TAF MENTION. BETTER
WEATHER AND VFR/CIG VISBY FORECAST ACROSS THE AREA SUNDAY WITH
VERY LOW RAIN CHANCES. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 603 PM CDT SAT SEP 27 2014/

DISCUSSION...LARGE UPPER LEVEL SHORTWAVE TROUGH THAT SHOULD MARK
A CHANGE TO STRONG SUBSIDENCE AND MID LEVEL DRYING IS MOVING INTO
THE CWA. THIS TROUGH IS ALSO HELPING CONTINUE COASTAL TROUGHING
THAT IS RESULTING IN ROUGH EASTERLY SWELL AND COASTAL FLOODING.

THE AREAS WHERE PRECIP HAS ALREADY ENDED APPEAR TO BE DONE FOR THE
NIGHT...BUT WILL BE MONITORING CAMERON/WILLACY/KENEDY WITH AMPLE
MOISTURE AND RESIDUAL LIFT. WATER VAPOR TRENDS SEEM TO SHOW THE
WAVE HAS STOPPED DIGGING AS VIGOROUSLY AND IT MAY TAKE ANOTHER
COUPLE OF HOURS TO SEE THE SPIGOT CUT OFF IN THE EAST...WHERE
2.1/2.2 PWATS AND ONGOING CONVECTION WILL STILL POSE A FLOOD CONCERN.

TIDAL GAUGES ARE A LITTLE HIGHER THAN ANTICIPATED AND WEBCAMS FROM
SOUTH PADRE ISLAND SHOW THE WATER LEVELS UP TO THE DUNE LINE. HIGH
TIDE IS STILL ABOUT 90 MINUTES AWAY WITH EASTERLY SWELL CONTINUING
SO REPLACED THE COASTAL FLOOD STATEMENT WITH A COASTAL FLOOD
ADVISORY FOR WATER INTO THE DUNE LINES THROUGH THIS HIGH TIDE
CYCLE. /68-JGG/

PREV DISCUSSION... /ISSUED 405 PM CDT SAT SEP 27 2014/

SHORT TERM /NOW THROUGH SUNDAY NIGHT/...WIDESPREAD RAIN EVENT FRO
THE PAST FEW DAYS WILL BEGIN TO WIND DOWN DURING THE NEXT 36 HOURS
AS DRY AIR CAPS OFF THE ATMOSPHERE. UNTIL THEN...SHOWERS AND A FEW
THUNDERSTORMS WILL CONTINUE TO PRODUCE VERY HEAVY RAINFALL IN PLACES
INTO TOMORROW MORNING.

TONIGHT...THE H5 LOW CURRENTLY CENTERED JUST NORTH OF DRT IS MOVING
NE...BEING DRAWN NORTHWARD BY THE RETREATING TROUGH AND PUSHED OUT
BY LARGER TROUGH ACROSS THE WEST COAST. SIGNIFICANTLY DRIER AIR IS
NOTED TO THE NW APPROACHING THE REGION. UNTIL WINDS ALOFT TURN FROM
THE SW TO THE NW...RAIN WILL CONTINUE TO AFFECT THE REGION AS MOIST
SW FLOW INTERACTS WITH WEAK COASTAL TROUGH.

SUNDAY...WITH THE H5 LOW AXIS TO THE EAST...NW WINDS WILL QUICKLY
INTRODUCE DRIER AIR AT MIDLEVELS. THIS WILL SLOWLY BRING TO AN END
THE SHOWER ACTIVITY AREAWIDE...WITH WESTERN AREA DURING THE EARLY
AFTERNOON AND COASTAL COUNTIES LATE IN THE AFTERNOON. SHOWERS WILL
BE MUCH MORE ISOLATED...AND WITH DRIER AIR INGESTING INTO THE
MIDLEVELS OF ANY SHOWERS...SHOWERS WILL HAVE A HARDER TIME PRODUCING
HEAVY RAINFALL. HIGH TEMPERATURES WILL CLIMB A FEW MORE DEGREES THAN
THE PAST SEVERAL DAYS...BUT WILL STILL REMAIN BELOW 90 DEGREES.

SUNDAY NIGHT...WITH THE LOSS OF DAYTIME HEATING AND FULLER
INTRODUCTION OF DRY AIR...WILL BE VERY TOUGH TO HAVE ANY SHOWERS
OVERNIGHT. THE BEST CHANCES WOULD BE ALONG THE IMMEDIATE COAST WITH
STREAMER SHOWERS MOVING ASHORE LATE.

LONG TERM /MONDAY THROUGH SATURDAY/...A SERIES OF 500 MB TROUGHS
WILL SWING ACROSS THE WESTERN AND CENTRAL PORTIONS OF THE LOWER
48 STATES OVER NEXT WEEK. THIS APPROACH AND PASSAGE OF THESE
FEATURES WILL ALLOW FOR DRIER AIR TO FILTER INTO THE REGION IN THE
MIDDLE AND UPPER PORTIONS OF THE ATMS. THIS WILL HOLD DOWN THE
PCPN CHCS EARLY NEXT WEEK. HOWEVER SOME DEEPER LAYER TROPICAL
MOISTURE WILL START TO ADVECT BACK UP TO THE NORTH FROM CENTRAL
MEXICO AND THE SOUTHWESTERN GULF OF MEXICO FRIDAY AND SATURDAY.
ALSO A COLD FRONT MOVING SOUTH OUT OF CENTRAL TX WILL START TO
PUSH INTO DEEP SOUTH TX FRIDAY NIGHT INTO SATURDAY WHICH WILL
LIKELY INCREASE THE SURFACE CONVERGENCE ALLOWING FOR SOME BETTER
CONV POTENTIAL.

THE LONGER RANGE MODELS ARE IN PRETTY GOOD AGREEMENT IN THE
OVERALL SYNOPTIC PATTERN ON THROUGH DAY 7. THE BIGGEST DIFFERENCE
IS THAT THE ECMWF MAINTAINS A LITTLE WETTER PATTERN THROUGH NEXT
SATURDAY VERSUS THE GFS. FOR OVERALL TEMP TRENDS BOTH THE MODELS
ARE IN GENERALLY GOOD AGREEMENT DURING THE OUTLOOK PERIOD. SO WILL
GO WITH A ROUGH 50/50 MODEL BLEND OF THE GFS AND ECMWF FOR BOTH
TEMPS AND POPS.

OVERALL CONFIDENCE IN THE LONGER RANGE FORECAST WORDING IS PRETTY
GOOD DUE TO GOOD AGREEMENT BETWEEN THE GFS AND THE ECMWF. ALSO RUN
TO RUN CONSISTENCY WITH THE GFS MEX MOS TEMPS AND POPS IS PRETTY
STABLE.

MARINE...NOW THROUGH SUNDAY NIGHT...AGITATED CONDITIONS WILL RELAX
AS THE COASTAL TROUGH COLLAPSES DURING THE DAY SUNDAY. SEAS WILL
BEGIN AROUND 6 FEET...BEING CHURNED BY LOCAL THUNDERSTORM
ACTIVITY...BEFORE RELAXING TO 2 TO 3 FEET BY SUNDAY EVENING. WINDS
OF 15 TO 20 KNOTS TONIGHT WILL RELAX TO AROUND 10 KNOTS BY SUNDAY
AFTERNOON...WITH IMPROVED MARINE ACTIVITY CONDITIONS.

MONDAY THROUGH THURSDAY...A FAIRLY WEAK PGF WILL PREVAIL ACROSS
THE LOWER TX BAY AND GULF WATERS ON MON AND TUES WHICH WILL
MAINTAIN FAIRLY LOW WINDS AND SEAS. HOWEVER A SURFACE LOW
DEVELOPING OVER THE TX/OK PANHANDLE REGION WILL INCREASE THE
SURFACE WINDS FROM THE S-SE FOR WED AND THURS. THIS WILL BUILD UP
THE WINDS AND SEAS A BIT MORE TOWARDS THE END OF NEXT WEEK. BUT
NOT SCA CONDITIONS EXPECTED AT THIS TIME.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...COASTAL FLOOD ADVISORY UNTIL 3 AM CDT SUNDAY FOR TXZ251-256-257.

GM...NONE.
&&

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/59

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
351 PM CDT SAT SEP 27 2014

TXZ248>257-282100-
ZAPATA-JIM HOGG-BROOKS-KENEDY-STARR-HIDALGO-INLAND WILLACY-
INLAND CAMERON-COASTAL WILLACY-COASTAL CAMERON-
351 PM CDT SAT SEP 27 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

WIDESPREAD HEAVY RAINFALL MAY LEAD TO FLASH FLOODING THROUGH THIS
EVENING...MAINLY IN HIDALGO...WILLACY...STARR AND CAMERON COUNTIES.

THERE IS A MODERATE RISK OF RIP CURRENTS AT AREA BEACHES.

MINOR COASTAL FLOODING IS POSSIBLE AT AREA BEACHES DUE TO HIGHER
THAN NORMAL TIDES AND ROUGH EASTERLY SWELLS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

AN ELEVATED RISK OF RIP CURRENTS IS LIKELY AT LOCAL BEACHES ON SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ASKED TO REMAIN ALERT FOR SIGNIFICANT WEATHER AND
REPORT ANY FLOODING OBSERVED IN STARR...CAMERON...WILLACY AND CAMERON
COUNTIES.

GMZ130-132-135-150-155-170-175-282100-
LAGUNA MADRE FROM THE PORT OF BROWNSVILLE TO THE ARROYO COLORADO-
LAGUNA MADRE FROM THE ARROYO COLORADO TO 5 NM NORTH OF PORT
MANSFIELD TX-
LAGUNA MADRE FROM 5 NM NORTH OF PORT MANSFIELD TO BAFFIN BAY TX-
COASTAL WATERS FROM PORT MANSFIELD TO THE RIO GRANDE OUT 20 NM-
COASTAL WATERS FROM BAFFIN BAY TO PORT MANSFIELD OUT 20 NM-
WATERS FROM PORT MANSFIELD TO THE RIO GRANDE EXTENDING FROM 20 TO
60 NM-
WATERS FROM BAFFIN BAY TO PORT MANSFIELD EXTENDING FROM 20 TO
60 NM-
351 PM CDT SAT SEP 27 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE GULF OF MEXICO AND THE
LAGUNA MADRE.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE TONIGHT...SOME MAY
PRODUCE STRONG AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

JGG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
421 PM CDT SAT SEP 27 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0400 PM     FLASH FLOOD      MCALLEN                 26.22N  98.24W
09/27/2014                   HIDALGO            TX   BROADCAST MEDIA

            EXTENSIVE STREET FLOODING IN MCALLEN. SOCIAL MEDIA POST
            FROM KRGV. WATER NEAR TOP OF TIRE WELLS SEEN ON SOME
            VEHICLES.

&&

EVENT NUMBER BRO1400073

TS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
433 PM CDT SAT SEP 27 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1030 AM     HEAVY RAIN       SOUTH PADRE ISLAND      26.08N  97.18W
09/27/2014  E4.00 INCH       CAMERON            TX   NWS EMPLOYEE

            REPORT OF STREET FLOODING IN SOUTH PADRE ISLAND RELAYED
            BY OFF DUTY NWS PERSONNEL VIA FACEBOOK.

&&

EVENT NUMBER BRO1400074

TS