Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 240902
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
402 AM CDT THU JUL 24 2014

.DISCUSSION...
THE UPPER LOW THAT WAS OVER THE LOUSIANA COAST YESTERDAY HAS
SHEARED OUT EARLY THIS MORNING...WITH THE LEFTOVER TROUGH
STRETCHING FROM EASTERN LOUSIANA TO THE MID TEXAS COAST. A
GENERAL NORTHERLY FLOW WAS IN PLACE ALOFT DUE TO THE WEAKENING
TROUGH AND AN UPPER HIGH CENTERED OVER WESTERN CO AND NM. THE
MODELS GENERALLY BUILD THE HIGH PRESSURE RIDGE OVER EASTERN TEXAS
AND NORTHERN LOUSIANA FRIDAY THROUGH SUNDAY...THEN THEN OVER SE TX
ON MONDAY AS AN UPPER TROUGH BEGINS TO DIG SOUTHWARD FROM THE
GREAT LAKES. AS THIS TROUGH PUSHES INTO THE LOWER MISSISSIPPI
VALLEY DURING THE MID WEEK PERIOD...THE HIGH WILL PUSH WESTWARD
INTO THE DESERT SOUTHWEST AND RETURN A NORTHWESTERLY FLOW OVERHEAD
THE FORECAST AREA.

THE MAIN PROBLEM FOR TODAY CONCERNS THUNDERSTORM CHANCES. THE
SHORT TERM AND HIGH RESOLUTION MODELS AGREE WITH THE BEST RAIN
CHANCES OVER THE SOUTHERN HALF OF THE FORECAST AREA. STORM MOTION
WILL AGAIN BE GENERALLY FROM THE NORTHEAST TO SOUTHWEST...WHILE
MODEL FORECAST SOUNDINGS ALSO INDICATE THE POTENTIAL FOR GUSTY
WINDS AND HEAVY DOWNPOURS IN THE STRONGER STORMS. OF NOTE...THE
NAM BUFR FORECASTS PW/S FROM 1.8 IN THE NORTHWEST TO NEAR 2 INCHES
TOWARD THE COAST...WHILE THE AFTERNOON SOUNDING FORECASTS AN
INVERTED V PROFILE BELOW 850 MB AND DCAPE VALUES OF 700 TO 1100
J/KG.

KEPT THE ISOLATED CHANCES FOR THUNDERSTORMS IN THE FORECAST FOR
FRIDAY AS THE ECWMF IN PARTICULAR KEEPS THE WEAKNESS ALOFT
OVERHEAD AND THE GFS ENSEMBLE FORECASTS SLIGHT CHANCES FOR RAIN.
HOWEVER...THE MAIN FORECAST CHALLENGE FOR FRIDAY THROUGH MONDAY
WILL BE DAYTIME HIGH TEMPERATURES. EVEN THOUGH THE RIDGE WILL
BUILD OVERHEAD...THE GUIDANCE HAS BACKED OFF A BIT ON THE VERY
WARM TEMPERATURES. GIVEN THE OVERALL SOIL MOISTURE CONTENT...
SLIGHTLY COOLER THAN EXPECTED HIGHS ARE LIKELY. HOWEVER...STILL
EXPECT HIGHS OF 96 TO 98 ACROSS THE CENTRAL AND WESTERN COUNTIES.
THE HEAT INDEX WILL ALSO BE WARMEST OVER THE FRIDAY THROUGH
MONDAY...WITH VALUES RANGING FROM 102 TO 106 EACH AFTERNOON.

WITH THE UPPER TROUGH DIGGING SOUTHWARD INTO THE LOWER MISSISSIPPI
VALLEY ON TUESDAY AND WEDNESDAY...BOTH THE GFS AND ECMWF PUSH A
SUMMERTIME COLD FRONT SOUTHWARD INTO EAST AND SOUTHEAST TEXAS.
THERE IS STILL SOME UNCERTAINTY ON HOW FAR SOUTH THE FRONT WILL
BE...BUT FOR NOW IT LOOKS LIKE BOTH DAYS WILL PROBABLY SEE A
RETURN OF THUNDERSTORM CHANCES AND SLIGHTLY COOLER DAYTIME
TEMPERATURES.

40

&&

.MARINE...
DO NOT EXPECT MUCH CHANGE IN THE FORECAST FOR THE UPPER TX COAST.
GENERALLY EXPECT SOUTH TO SOUTHWEST WINDS THROUGH THE END OF THE
WEEK AND INTO THE WEEKEND. WINDS MAY INCREASE TO MODERATE LEVELS
OVER THE WEEKEND BUT THEN DECREASE EARLY NEXT WEEK AS A FRONTAL
BOUNDARY APPROACHES EAST TX. LIGHT TO MODERATE WINDS WILL SUPPORT
MAINLY LOW SEAS FOR THE NEXT SEVERAL DAYS. NO MARINE HAZARDS ARE
EXPECTED AT THIS TIME.

39

.AVIATION...
OUTFLOW FROM A SQUALL LINE THAT PUSHED INTO THE AREA LATE LAST
NIGHT MAY SUPPORT A FEW SHOWERS THAT COULD AFFECT KCLL THIS
MORNING. OTHERWISE REST OF THE TERMINALS SHOULD BE DRY. CONVECTIVE
FORECAST WILL BE THE MAIN ISSUE AGAIN. LIKE THE AFTERNOON TIMING
FOR CONVECTION AGAIN AS SHOULD NEED DAYTIME HEATING TO INITIATE
CONVECTION. AREA WILL AGAIN REMAIN BETWEEN AN UPPER LOW OVER S LA
AND UPPER RIDGE OVER THE ROCKIES. HARD TO TELL IF THERE WILL BE
ANOTHER DISTURBANCE TO RATE THROUGH THE AREA AROUND THE RIDGE TO
SUPPORT TSRA. COULD SEE MORE TSRA COVERAGE IF UPPER LEVEL SUPPORT
BECOMES MORE FAVORABLE. CIGS SHOULD MAINLY BE VFR EXCEPT FOR
AROUND TSRA. THINK THERE WILL BE TOO MUCH CLOUD COVER FOR ANY FOG
THIS MORNING.

39

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      97  75  98  76  98 /  20  20  10  10  10
HOUSTON (IAH)              96  76  96  76  96 /  40  20  20  10  10
GALVESTON (GLS)            91  79  91  80  91 /  40  10  20  10  10

&&

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

$$

DISCUSSION...40
AVIATION/MARINE...39



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