Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 271111
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
611 AM CDT WED MAY 27 2015

.DISCUSSION...
SEE 12Z AVIATION DISCUSSION.

&&

.AVIATION...
SHORT TERM GUIDANCE HAS BEEN PITIFUL OVERNIGHT AND CONFIDENCE
REGARDING CONVECTIVE TRENDS IS LOW. COLD POOL SHOULD CONTINUE
TO PUSH THE OUTFLOW BOUNDARY AND ASSOCIATED CONVECTION TO THE
COAST. WILL CARRY TSRA FOR HOUSTON TERMINALS SOUTHWARD WITH SOME
LIGHT RAIN OVER THE NORTHERN TAF SITES. MVFR CONDS EXPECTED
OVERNIGHT. 43

&&

.PREV DISCUSSION... /ISSUED 503 AM CDT WED MAY 27 2015/

DISCUSSION...
CHALLENGING START TO THE MORNING UNDERWAY FOR SOUTHEAST TEXAS AS
A THUNDERSTORM COMPLEX THAT DEVELOPED OVER NORTHWEST TEXAS
YESTERDAY EVENING HAS TRACKED INTO NORTHERN PORTIONS OF THE
FORECAST AREA EARLY THIS MORNING. THIS HAS BEEN HANDLED POORLY BY
SHORT-TERM GUIDANCE... AND THIS INSTILLS A CONSIDERABLE AMOUNT OF
UNCERTAINTY FOR TODAY/S FORECAST. TRENDS IN OBSERVATIONAL DATA
HAVE SERVED AS THE BASIS FOR THE EVOLUTION OF THIS COMPLEX THIS
MORNING AND ANTICIPATE THE LINE TO CONTINUE PUSHING TOWARDS THE
SOUTH/SOUTHEAST BEHIND AN OUTFLOW BOUNDARY STRETCHING FROM NEAR LA
GRANGE EASTWARD TOWARDS CLEVELAND. VAD WIND PROFILERS AT CORPUS
CHRISTI AND DICKINSON SHOW A 25 KNOT LOW LEVEL JET RIDING OUT THIS
OUTFLOW BOUNDARY... SUPPLYING ADDITIONAL/MOISTURE AND INSTABILITY
INTO THIS SYSTEM. INFRARED SATELLITE IMAGERY AS OF 415 AM CDT
SHOWED CLOUD TOPS HAVE COOLED TO NEAR -70 DEG... AND THIS IS AN
OMINOUS SIGN FOR THE INTENSITY OF THIS LINE AS IT APPROACHES THE
HOUSTON METRO AS RAIN RATES HAVE INCREASED TO NEAR 2.5 TO 3 INCHES
AN HOUR OF PARTS OF SAN JACINTO AND GRIMES COUNTIES.

EXTRAPOLATION SHOWS THIS LINE REACHING INSIDE THE WESTERN 610
LOOP AND POINTS SOUTHWEST... SOME OF THE AREAS THAT SAW THE
HIGHEST RAIN TOTALS YESTERDAY /8 TO 11 INCHES/... BY 6 AM CDT.
BECAUSE OF THE ANTICIPATED APPROACH OF THIS LINE INTO THE HOUSTON
METRO... HAVE OPTED TO ISSUE A FLASH FLOOD WATCH FOR
MONTGOMERY...HARRIS... AND FORT BEND COUNTIES. LOCALIZED FLOODING
ISSUES WILL DEFINITELY BE POSSIBLE OUTSIDE OF THIS AREA AS WELL.
UNCERTAIN ON WHETHER OR NOT THIS LINE WILL ACTUALLY REACH THE
UPPER TEXAS COAST... PER THE CAP CITED IN WPC/S MESOSCALE
DISCUSSION... BUT WITH SPC MESOANALYSIS SHOWING THE SYSTEM STILL
MAINTAINING ITSELF WITHIN THIS MORE STABLE MID-LEVEL AIR... HAVE
INCREASED POPS ALONG THE COAST FOR THIS MORNING. AS FAR AS THE
EVOLUTION OF THIS AFTERNOON IS CONCERNED... THINK STABILIZATION/
SUBSIDENCE IN THE WAKE OF THIS SYSTEM WILL PROVIDE A LULL IN
ACTIVITY LATE MORNING TO EARLY AFTERNOON BUT COULD SEE ADDITIONAL
ISOLATED TO SCATTERED STORMS DEVELOP ALONG REMNANT BOUNDARIES AS
AFTERNOON TEMPERATURES CLIMB INTO THE MID TO UPPER 80S AND HAVE
KEPT POPS IN THE 20 TO 40 RANGE.

FOR TONIGHT AND TOMORROW... SHOULD SEE ANY SHOWERS AND
THUNDERSTORMS THAT DEVELOP THIS AFTERNOON DIMINISH WITH LOSS OF
DAYTIME HEATING. ANOTHER ROUND OF DIURNALLY DRIVEN ACTIVITY WILL
BE POSSIBLE AGAIN ON THURSDAY... WITH TEMPERATURES NEAR SEASONAL
NORMALS. ANOTHER THUNDERSTORM COMPLEX COULD APPROACH THE REGION
LATE THURSDAY INTO FRIDAY AHEAD OF AN UPPER TROUGH SWINGS ACROSS
THE REGION LATE WEEK. AS IT PASSES... IT WILL SEND A COLD FRONT
TOWARDS THE REGION ON SUNDAY WITH ADDITIONAL SHOWERS AND
THUNDERSTORMS POSSIBLE ALONG IT.

HUFFMAN

MARINE...
A MODERATE ONSHORE FLOW WILL GRADUALLY DIMINISH THIS MORNING AS THE
GRADIENT WEAKENS BUT SEAS WILL BE SLOW TO FALL AS LONG PERIOD SWELLS
PROPAGATE INTO THE COASTAL WATERS. WILL MAINTAIN A SCEC FOR ELEVATED
SEAS THROUGH THE MORNING. STILL SOME THREAT FOR RIP TIDES AS THE
ONSHORE FLOW PERSISTS AND ELEVATED SWELLS HEAD TOWARD THE SHORE.
TIDES WILL REMAIN ELEVATED DUE TO THE SWELLS AND DISCHARGE OF FLOOD
WATERS INTO GALVESTON BAY. LOOKING AHEAD...A GENERALLY LIGHT TO
OCCASIONALLY ONSHORE FLOW IS EXPECTED THROUGH THE WEEKEND.

CLIMATE... PERIODS OF HEAVY RAIN HAVE PLAGUED SE TX SINCE APRIL.
THE RAIN AND ASSOCIATED CLOUDS/WET GROUND HAS LIMITED HEATING. NONE
OF THE FIRST ORDER CLIMATE SITES HAVE RECORDED A 90 DEGREE DAY SO
FAR THIS YEAR. THE AVERAGE FIRST DATE FOR THE TEMPERATURE TO REACH
90 DEGREES IS ON MAY 7TH IN HOUSTON AND MAY 5TH IN COLLEGE STATION.
THE LATEST TIME IN THE YEAR TO REACH 90 DEGREES WAS JUNE 15TH 1897
FOR HOUSTON AND JUNE 12TH 1976 FOR COLLEGE STATION. RAINFALL IN
HOUSTON FOR MAY HAS TALLIED 12.18 INCHES WHICH IS THE 7TH WETTEST
MAY ON RECORD. SUGAR LAND ASOS (KSGR) HAS MEASURED 17.79 INCHES OF
RAIN DURING MAY AND THIS IS THE WETTEST MAY ON RECORD. THE SUGAR
LAND CO-OP SITE HAS MEASURED 15.66 INCHES OF RAIN AND THIS IS ALSO
THE WETTEST MAY ON RECORD. LASTLY...HUNTSVILLE CO-OP HAS MEASURED
12.99 INCHES OF RAIN IN MAY WHICH IS THE 4TH WETTEST MAY ON RECORD
WHILE THE HUNTSVILLE ASOS (KUTS) HAS MEASURED 13.77 INCHES WHICH IS
THE WETTEST MAY ON RECORD.

IT IS THE WETTEST MARCH 1ST THROUGH MAY 26TH IN CITY OF HOUSTON
HISTORY WITH 24.62 INCHES OF RAIN OVER THE LAST 86 DAYS. FWIW...THE
CITY OF HOUSTON HAS MEASURED 28.45 INCHES OF RAIN SINCE JAN 1ST AND
THIS IS THE 5TH WETTEST START TO A YEAR IN RECORDED HISTORY. THE
WETTEST YEAR WAS 30.18 INCHES IN 1922. 43

MAR 1 - MAY 26

24.62 - 2015
23.85 - 1922
21.39 - 1993
21.08 - 1997
19.11 - 1970

JAN 1 - MAY 26

1922  30.18
1993  29.85
1997  29.69
1991  29.06
2015 28.45

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      89  72  86  73  85 /  50  30  40  30  40
HOUSTON (IAH)              86  73  85  74  85 /  50  20  40  20  40
GALVESTON (GLS)            85  77  84  78  84 /  50  10  30  20  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL NOON CDT TODAY FOR THE FOLLOWING ZONES:
     FORT BEND...HARRIS...MONTGOMERY.

GM...SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR THE
     FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
     CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
     FREEPORT 20 TO 60 NM.

&&

$$

DISCUSSION...14
AVIATION/MARINE...43


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