Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 191714
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1214 PM CDT FRI SEP 19 2014

.DISCUSSION...
SEE 18Z AVIATION DISCUSSION.

&&

.AVIATION...
INTENSE CONVECTION OVER HARRIS COUNTY WILL PROBABLY STABILIZE
THINGS OVER THE HOUSTON TERMINALS THIS AFTN WITH CONVECTION
REDEVELOPING ON THE PERIPHERY OF THIS MORNINGS RAINFALL. HAVE
REMOVED TSRA FROM KHOU/KIAH/KSGR BUT WILL KEEP VCTS FOR OTHER
AIRPORTS. FCST SOUNDINGS REALLY DRY THINGS OUT OVERNIGHT AND HINT
AT CLEARING SKIES AFTER 06Z. FEEL RESIDUAL MSTR WILL ALLOW FOR
PATCHY FOG AND PERHAPS SOME MVFR/POTENTIALLY LIFR CIGS TOWARD
SUNRISE. DRIER WEATHER IS EXPECTED ON SATURDAY WITH LIGHT E-SE
WINDS. 43

&&

.PREV DISCUSSION... /ISSUED 1125 AM CDT FRI SEP 19 2014/

..FLOOD WATCH IS NOW IN EFFECT UNTIL 7 PM CDT THIS EVENING FOR
THE SOUTHERN TWO THIRDS OF THE COUNTY WARNING AREA...

UPDATE...
DAY THREE OF THE RAIN EVENT IS APPEARING TO BE MUCH MORE TAME
THAN THE PREVIOUS TWO. THE SOUTHERN THIRD OF THE FORECAST AREA IS
CERTAINLY NOT OUT OF THE WOODS YET CONCERNING THE REGENERATION OF
AFTERNOON CONVECTION THAT COULD LEAD TO LOCALIZED FLOODING BUT...
OVERALL...IT DOES APPEAR THE HEAVY RAIN-LEADING-TO-WIDESPREAD-FLOODING
THREAT IS DIMINISHING. THUS...HAVE PARED BACK THE CURRENT FLOOD
WATCH TO COVER THOSE COUNTIES THAT HAVE RECEIVED THE HIGHEST RAINFALL
OVER THE PAST 24 HOURS AND HAVE SHORTENED IT`S IN EFFECT DURATION.

ALL OF THE MET ELEMENTS ARE STILL THERE FOR THE AFTERNOON REGENERATION
OF LIGHT TO MODERATE RAIN...ESPECIALLY POINTS WEST AND SOUTH OF THE
CITY OF HOUSTON. A MOISTURE AXIS CENTERED OVER THE TEXAS COASTLINE
WITH A COUPLE OF AREAS OF LOW-MID LEVEL CONVERGENCE...ALONG WITH
BETTER UPPER LEVEL DIFFULENCE THAN YESTERDAY. OF COURSE...THE
MOISTURE VALUES ARE STILL HIGH BUT MORE CENTERED FROM GALVESTON
COUNTY AND POINTS OFFSHORE. THE ONE FEATURE THAT MAY NOT BE A FACTOR
TODAY (AS IN PREVIOUS DAYS) WILL BE A STRONG ENOUGH UPSTREAM
SHORTWAVE DISTURBANCE TO AID IN TRIGGERING LIFT. AS IS THE CASE WITH
TROPICAL AIR MASSES...THEY DO NOT AS MUCH WARMING/LIFT IN GENERATING
PRECIPITATION SO PLEASE REFERENCE THE SECOND SENTENCE. THERE IS AN
INTRUSION OF DRIER NORTHEASTERLY AIR THAT WILL SIGNIFICANTLY THWART
THE REDEVELOPMENT OF EASTERN REGION PRECIPITATION...IT APPEARS THAT
ANY REDEVELOPMENT WILL GENERALLY BE ALONG AND SOUTH OF THE I-10
CORRIDOR FROM TODAY INTO THE WEEKEND. THE FFA PRODUCT GOES FURTHER
INTO THE QPF...TIMING... AND LOCATION OF NEAR TERM RAINFALL. 31

&&

PREV DISCUSSION... /ISSUED 452 AM CDT FRI SEP 19 2014/

DISCUSSION...
SHOWERS AND A FEW THUNDERSTORMS DEVELOPED QUICKLY AROUND 330 AM
AND HAVE CONTINUED TO EXPAND AND INTENSIFY. STORMS ARE LINING UP
FROM AROUND COLLEGE STATION ACROSS MONTGOMERY COUNTY AND ANOTHER
LINE ACROSS BRENHAM TO SW HARRIS TO GALVESTON. THESE STORMS APPEAR
TO BE FOCUSING ALONG THE 850-700 TROUGH AXIS AND MOISTURE IS IN
ABUNDANCE WITH GPS DATA SHOWING 2.4" PW AT HOUSTON AND MODEL
SOUNDING ARE PROGGING VERY FAVORABLE CONDITIONS FOR HEAVY RAINFALL
ACROSS THE AREA TODAY. HAVE EXPANDED THE FLOOD WATCH AND EXTENDED
IT TO 10 PM THOUGH BY 7 PM AM EXPECTING STORMS TO BE WEAKENING.
OF NOTE THE TEXAS TECH WRF ENSEMBLE PAINTS A VERY WET PATTERN FOR
MUCH OF THE AREA FROM COLLEGE STATION TO HUNTSVILLE AND AROUND THE
HOUSTON METRO AREA. DO HAVE SOME CONCERNS THAT BREAKS IN THE
CLOUDS TODAY COULD DRIVE UP TEMPERATURE AND DRAMATICALLY INCREASE
THE INSTABILITY. BASED ON YESTERDAYS MINIMAL DIURANAL TEMPERATURE
RANGES HAVE LOWERED TEMPERATURES TODAY AND THEY MAY NEED FURTHER
SHRINKING.

AS RIDGING SETTLES INTO LOWER MS VALLEY SATURDAY DRIER AIR FIRST
IN THE MID LEVELS AND EVENTUALLY THE LOWER LEVELS SPREADS INTO THE
AREA FROM THE EAST AND RAIN CHANCES SHIFT SOUTHWESTWARD AND FALL
OFF DRAMATICALLY FROM TODAYS NUMBERS. A SHOT OF DRIER AIR PUSHES
IN WITH THE NEXT FRONT AND BY MIDWEEK VERY PLEASANT WEATHER SHOULD
BE ON TAP. 45

MARINE...
ONSHORE WINDS WILL REMAIN RELATIVELY LIGHT OVER THE WATERS TODAY
THANKS TO A WEAK PRESSURE GRADIENT. WINDS WILL BEGIN TO BACK SUNDAY
AND TURN EASTERLY AS THE NEXT WEAK COLD FONT APPROACHES. WEEKEND
MARINERS CAN EXPECT SLIGHTLY ELEVATED SEA HEIGHTS DUE TO THE
PROLONGED EASTERLY FETCH. A SECONDARY SURGE OF UPPER LEVEL ENERGY
WILL PUSH THE COLD FRONT SLIGHTLY FURTHER SOUTH ON MONDAY BUT IT
WILL STILL NOT MAKE IT. EAST WINDS WILL PERSIST THROUGH NEXT WEEKEND
AND GRADUALLY STRENGTHEN TOWARD THE END OF THE WEEK AS THE PRESSURE
GRADIENT TIGHTENS. A PERSISTENT EASTERLY FETCH WILL ALLOW TIDE
LEVELS TO SLOWLY INCREASE THROUGH THE WEEK. 23

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      84  72  88  73  89 /  70  20  30  10  20
HOUSTON (IAH)              85  72  87  74  89 /  90  20  30  10  30
GALVESTON (GLS)            85  78  85  78  85 /  90  30  30  30  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES:
     AUSTIN...BRAZORIA...CHAMBERS...COLORADO...FORT BEND...
     GALVESTON...HARRIS...JACKSON...LIBERTY...MATAGORDA...
     MONTGOMERY...WALLER...WHARTON.

GM...NONE.
&&

$$

DISCUSSION...31
AVIATION/MARINE...43



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