Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 241725
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1225 PM CDT THU JUL 24 2014

.AVIATION...
MOIST AND UNSTABLE AIRMASS ACROSS THE AREA IN COMBINATION WITH DAYTIME
HEATING AND SURFACE BOUNDARIES SHOULD ALLOW FOR ADDITIONAL SHRA/TSRA
DEVELOPMENT THIS AFTERNOON. WILL CARRY VCTS FOR MOST OF THE 18Z TAFS
SOUTH OF IAH. EXPECT DECREASING COVERAGE THIS EVENING WITH THE LOSS
OF HEATING. WITH UPPER LEVEL RIDGING TRYING TO BUILD INTO THE AREA
FROM THE NORTHWEST TOMORROW...THE AREA SHOULD SEE LESS SHRA/TSRA
COVERAGE. FOR NOW...WILL JUST CARRY VCSH NEAR THE COAST TOWARD SUNRISE.
IF THE RIDGE DOESN`T GET STRONG ENOUGH...WE MIGHT END UP NEEDING TO
CARRY SOME VCSH OR VCTS FURTHER INLAND.  42
&&

.PREV DISCUSSION... /ISSUED 1040 AM CDT THU JUL 24 2014/

UPDATE...
SLOW-MOVING SHOWERS AND LIGHT RAIN AFFECTING THE WESTERN FORECAST
AREA THIS MORNING...PUTTING DOWN BETWEEN 1.5 TO 2.5 INCHES LOCALLY
OVER PARTS OF COLORADO...AUSTIN AND WALLER COUNTIES. ALTHOUGH
THERE WILL BE ISOLATED INLAND THUNDER...THE MAJORITY OF THE STORM
CLUSTERS ARE OFFSHORE...LOCATED APPROXIMATELY 20 NM AND BEYOND OFF
GALVESTON ISLAND. THE NOTED UPPER HEIGHT WEAKNESS CURRENT LAYING
OVER THE WESTERN GULF COAST...WITH THE 5H RIDGE CENTERED OVER NEW
MEXICO...WILL BE THE PATTERN OVER THE NEXT 24 TO 48 HOURS. AMPLE
COLUMN MOISTURE AND UNSTABLE PROFILES SUGGEST THAT CHANCE POPS
WILL LINGER ON THROUGH THE DAY...POSSIBLE RETURN AGAIN FRIDAY. NO
DISCERNIBLE SHORTWAVE DISTURBANCE ROUNDING THE EASTERN PERIPHERY
OF THE UPPER RIDGE...NOR ANY NEAR TERM FORESEEABLE UPSTREAM OUTFLOW
BOUNDARY AS A TRIGGER (AS WAS CASE THIS MORNING)...WILL KEEP OVERNIGHT
INTO EARLY FRIDAY RAIN CHANCES ON THE SLIGHT SIDE. EARLY DAY SUN
UP NORTH MAY COUNTER RECENTLY WETTENED GROUND IN PRODUCING MAXIMUM
TEMPERATURES IN THE MEAN MIDDLE 90S. 31

PREV DISCUSSION... /ISSUED 402 AM CDT THU JUL 24 2014/

DISCUSSION...
THE UPPER LOW THAT WAS OVER THE LOUISIANA COAST YESTERDAY HAS
SHEARED OUT EARLY THIS MORNING...WITH THE LEFTOVER TROUGH
STRETCHING FROM EASTERN LOUISIANA 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 LOUISIANA 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.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      97  75  98  76  98 /  30  20  10  10  10
HOUSTON (IAH)              96  76  96  76  96 /  50  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...31
AVIATION/MARINE...42


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