Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 050503
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1203 AM CDT SAT SEP 5 2015

.DISCUSSION...
UPDATED AVIATION SECTION.

&&

.AVIATION...
LATEST SATELLITE IMAGERY SHOWING CLEAR SKY ACROSS THE AREA WITH NO
SIGN OF ANY SHOWERS ACROSS THE AREA. QUESTION FOR THE OVERNIGHT IS
WHETHER THERE WILL BE ANY FOG OR STRATUS DEVELOPMENT AND FOR
SATURDAY WHAT KIND OF COVERAGE WELL SEE FROM SHOWERS. LATEST RUNS
OF RADPID REFRESH AND HIGH RES RAPID REFRESH ARE A LITTLE WETTER
THAN AVBL MODELS. MODEL SOUNDINGS SHOW SOME SUBTLE DIFFERENCES
WITH MAYBE A TAD LESS CAPE SATURDAY. BOTTOM LINE THINK WE WILL SEE
DEVELOPMENT AGAIN SATURDAY...MUCH AS TODAY...BUT WITH SLIGHTLY
LESS COVERAGE. HAVE WRITTEN TAFS WITH VCSH FOR MOST LIKELY
WINDOWS. MAY NEED TO HIT HARDER IF RADAR TRENDS SHOW CELL
DEVELOPMENT OVERNIGHT. ALSO...ONLY MENTION OF FOG ARE THE MORE
FAVORED LOCATIONS...CXO AND LBX...AS OCCURRED LAST NIGHT. HAVE
ALSO INCLUDED SOME SCATTERED STRATUS INLAND SITES. 46

&&

.PREV DISCUSSION... /ISSUED /

DISCUSSION...
ALL OF TODAY`S SHOWERS AND THUNDERSTORMS ARE GONE. HAVE UPDATED THE
FORECAST PACKAGE THIS EVENING WITH JUST SOME VERY MINOR FIRST PERIOD
ADJUSTMENTS. THE REST OF THE FORECAST LOOKS GOOD.  42

PREV DISCUSSION...

DISCUSSION...
UPDATED AVIATION DISCUSSION.

AVIATION...
SHOWERS HAVE DIMINISHED RAPIDLY OVER THE AREA OVER THE PAST HOUR.
AS CLOUDS ALSO DIMINISH EXPECT SKC TO SCT040 FOR MOST OF THE NIGHT
FROM HERE ON OUT. THERE IS THE POSSIBILITY OF AT LEAST SCATTERED
STRATUS AND PATCHY FOG MAINLY INLAND LOCATIONS. HAVE KEPT FOG
MENTION AT THE USUAL LOCATIONS...LBX AND CXO. TOMORROW THINK WILL
ONCE AGAIN HAVE SHOWER DEVELOPMENT FIRST AT THE COAST IN THE
MORNING...THEN FARTHER INLAND DURING THE AFTERNOON. NOT SURE ABOUT
COVERAGE THOUGH AS NAM SOUNDINGS SHOW SOMEWHAT LESS INSTABILITY.
HOWEVER AS POINTED OUT BY PREVIOUS DISCUSSION PRECIPITABLE WATERS
QUITE HIGH ESPECIALLY IN NAM12. WILL KEEP MENTION OF VCSH MOST
SPOTS TO ACCOUNT FOR THE DEVELOPMENT BUT WITH POSSIBLY MORE
LIMITED COVERAGE.

PREV DISCUSSION...

DISCUSSION...
SCATTERED SHOWERS CONTINUE TO DEVELOP AND MOVE OVER SE TX.
PW VALUES REMAIN AROUND 2.00 INCHES AND ALTHOUGH RAINFALL TOTALS
TODAY HAVE BEEN LIGHT...COVERAGE HAS BEEN RATHER EXTENSIVE. THE
NAM12 INITIALIZED BEST AND VERIFIED THE BEST TODAY WITH IT`S
LIKELY POPS. THE NAM12 IS AGAIN THE MOST AGGRESSIVE WITH MOISTURE
ON SATURDAY WITH PW VALUES NEAR 2.00 INCHES. FCST SOUNDINGS SHOW A
SATURATED LAYER BETWEEN 900-800 MB WITH DRY AIR ABOVE 700 MB.
MOISTURE LEVELS AGAIN LOOK SUFFICIENT FOR 30/40 PERCENT COVERAGE.
UPPER LEVEL RIDGING TRIES TO BUILD INTO SE TX SAT/SUN BUT IT LOOKS
LIKE THE RIDGE NEVER QUITE GETS HERE AND IS DISPLACED TO THE W-NW
OF SE TX. AN UPPER LEVEL LOW OVER THE NORTHERN GULF COAST WILL
ALSO SLOWLY DRIFT WEST. PW VALUES ON SUNDAY DROP A BIT BUT ARE
STILL BETWEEN 1.80 AND 2.00 WHICH IS MORE THAN ENOUGH TO GENERATE
SCATTERED SHOWERS. CONVECTIVE TEMPS ON SUNDAY ARE HIGHER SO IN
THEORY...COVERAGE SHOULD BE A BIT LESS. WILL MAINTAIN 20/30 POPS
FOR NOW. IF GOING TO THE BEACH OVER THE WEEKEND...SLIGHTLY WARMER
TEMPS COUPLED WITH HIGHER HUMIDITY WILL YIELD HEAT INDEX VALUES
BETWEEN 102 AND 106 DEGREES. ITS NOT ADVISORY CRITERIA BUT STILL
PLENTY OPPRESSIVE FOR THIS TIME OF YEAR.

THINGS ARE A BIT MORE INTERESTING ON LABOR DAY. THE UPPER LOW
OVER THE NORTHERN GULF SHIFTS FURTHER WEST AND THE UPPER RIDGE
OVER NORTH TEXAS BECOMES STRETCHED FROM NE TO SW. THE UPPER FLOW
OVER SE TX WILL BECOME NE AND THIS WILL ALLOW A DISTURBANCE
ROTATING AROUND THE UPPER LOW TO APPROACH SE TX IN THE AFTN. PW
VALUES WILL ONCE AGAIN EXCEED 2.00 INCHES IN THE AFTN WITH FCST
SOUNDINGS SHOWING A SATURATED LAYER BETWEEN 850-700 MB. THE
DISTURBANCE COUPLED WITH HIGHER MOISTURE AND DAYTIME HEATING
SHOULD AGAIN ALLOW FOR SCATTERED SHRA/TSRA. JET DYNAMICS NOT THE
BEST ON MONDAY AS SE TX LOOKS LIKE IT`LL LIE IN THE SUBSIDENT
REGION OF THE JET.

PW VALUES LOWER TUES/WED AND RAIN CHANCES ARE EXPECTED TO DROP.
TEMPS WILL BE NEAR OR JUST SLIGHTLY WARMER THAN NORMAL. THE
RAINY WEATHER RETURNS AGAIN AS EARLY AS THURSDAY AS A S/WV MOVES
INTO THE REGION. THE ECMWF IS MORE AGGRESSIVE WITH UPPER LEVEL
ENERGY AND MOISTURE. THE GFS IS ABOUT A DAY SLOWER BUT BOTH MODELS
EVENTUALLY CARVE OUT A FAIRLY DEEP LONG WAVE TROUGH WITH THE BASE
OF THE TROUGH OVER SOUTH TEXAS. THERE ARE SOME TIMING DIFFERENCES
WITH THE ECMWF HOLDING THE BASE OF THE TROUGH OVER TEXAS AND
LEADING TO SOME SIGNIFICANT RAINFALL POTENTIAL WHILE THE GFS IS A
BIT MORE PROGRESSIVE AND ITS TROUGH IS NOT AS SHARPLY DEFINED.
EITHER WAY...IT LOOKS LIKE FRI-SAT OF NEXT WEEK WILL BE WET WITH
SOME POTENTIAL FOR HEAVY RAINFALL AMOUNTS. 43

MARINE...
THE GENERAL WEATHER PATTERN OVER THE HOLIDAY WEEKEND WILL BE FAIRLY
BENIGN AS EASTERN HIGH PRESSURE SLOWLY EXPANDS WESTWARD AND
INFLUENCES LOCAL MARITIME CONDITIONS. SCATTERED EARLY DAY
SHOWERS WILL STILL OCCUR WITH ISOLATED STRONGER CELLS LOWERING
VISIBILITIES WITHIN HEAVY RAIN...A VERY SLIGHT CHANCE OF A STORM
THROUGH LABOR DAY. AVERAGE WINDS WILL BE LIGHT ONSHORE OVER NEAR 2
FOOT SEAS. A WEAK DISTURBANCE MOVING OUT OF LOUISIANA LABOR DAY MAY
INCREASE EARLY WEEK PRECIPITATION CHANCES. 31

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      76  95  75  96  75 /  10  20  10  20  10
HOUSTON (IAH)              76  93  76  95  77 /  30  40  10  30  10
GALVESTON (GLS)            81  90  81  90  81 /  20  30  20  30  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

DISCUSSION...99
AVIATION/MARINE...99


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