Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 192027
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
327 PM CDT SUN APR 19 2015

.DISCUSSION...
A PREFRONTAL TROUGH WAS APPROACHING THE CALDWELL AND BRYAN/COLLEGE
STATION AT 3 PM. THIS WAS COINCIDING WITH THE LEFT-FRONT QUADRANT
OF THE SUBTROPICAL JET PUSHING ACROSS THE STATE. THE TEXAS TECH
WRF...HRRR...AND NAM12 AGREE WITH A LINE OF SHOWERS AND
THUNDERSTORMS TO MOVE THROUGH AT LEAST THE NORTHERN HALF OF THE
FORECAST AREA THIS AFTERNOON AND EVENING. BREEZY WEST TO SOUTHWEST
WINDS WERE IN PLACE AHEAD OF THE FRONT...AND MODEL SOUNDING
FORECAST CAPE VALUES WERE AROUND 4600. BECAUSE OF THIS...FELT THAT
ISOLATED SEVERE STORMS WILL HAVE LARGE HAIL AND DAMAGING WINDS AS
THE MAIN THREATS. THE TIMING OF THE FRONT LOOKS TO BE ABOUT THE
SAME AS EARLIER FORECASTED AND ONLY MADE MINOR TWEAKS TO THE WIND
FORECAST. DO EXPECT THE RAIN AND THUNDERSTORM CHANCES TO MOVE OFF
THE COAST BY LATE THIS EVENING.

AFTER THE COLD FRONT MOVES THROUGH...A SURFACE HIGH WILL BUILD
INTO SE TEXAS ON MONDAY AND TUESDAY. RETURN FLOW OFF THE GULF WILL
OCCUR BY LATE TUESDAY. BOTH THE GFS AND ECMWF DEVELOP A DOWNSTREAM
RIDGE OVER TEXAS WITH AN UPPER LOW MOVING ACROSS SOUTHERN CA AND
BAJA CA INLAND TO NORTHWESTERN MEXICO AND AZ/NM BETWEEN WEDNESDAY
AND FRIDAY. BOTH MODELS SHEAR THE UPPER SYSTEM OUT AS IT MOVES
NORTHEASTWARD INTO THE SOUTHERN PLAINS ON FRIDAY AND SATURDAY WITH
THE ECMWF GENERATING A STRONGER SYSTEM AND BETTER CHANCES OF RAIN
INTO SE TEXAS AHEAD OF ANOTHER COLD FRONT THAT WILL MOVE THROUGH
LATE SATURDAY. TOOK A CONSENSUS OF THE MODELS.

40

&&

.MARINE...
A COLD FRONT WILL REACH THE UPPER TEXAS COAST LATE TONIGHT...MAY
NEED CAUTION FLAGS AFTER 4AM OR TOWARD MORNING AS OFFSHORE FLOW
INCREASES. MODERATE OFFSHORE WINDS IN THE WAKE OF THE COLD FRONT
WILL DIMINISH MONDAY AFTERNOON. ONSHORE FLOW RESUMES BY TUESDAY AS
HIGH PRESSURE MOVES OFF TO THE EAST. 47


&&

.PREV DISCUSSION... /ISSUED 1224 PM CDT SUN APR 19 2015/

AVIATION...
WILL BE WATCHING FOR A THIN BAND OF SHRA/TSRA TO INITIATE ALONG OR
JUST NORTH OF A LINE FROM CLL TO CROCKETT BETWEEN 2-3PM. HI-RES
MODELS IN PRETTY GOOD AGREEMENT WITH THIS TIMING & LOCATION. LINE
WILL THEN HEAD SE AND INTO METRO AREA TOWARD 5-7PM. MOST UNSTABLE
AIR SHOULD BE NORTH OF THE METRO AREA AND SUSPECT THE BETTER
CHANCES OF STRONG/SEVERE STORMS WILL MAINLY BE SITUATED FROM CXO
NORTHWARD. DECENT CHANCE THIS FCST LINE OF STORMS ACTUALLY BREAKS
UP BEFORE REACHING THE COAST EARLY THIS EVNG - BUT WE`LL CONTINUE
TO KEEP AN EYE ON THINGS AND AMEND AS NECESSARY. CLEARING SKIES
OVERNIGHT AS DRIER AIRMASS FILTERS IN BEHIND COLD FRONT. LAYER OF
MID/HIGH LEVEL CLOUDINESS WILL MOVE BACK IN FROM SW MID-LATE
MORNING MON. 47

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      55  74  55  79  62 /  20   0  10  10  10
HOUSTON (IAH)              61  77  57  80  64 /  30   0   0  10  10
GALVESTON (GLS)            66  77  67  78  71 /  30   0   0  10  10

&&

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

$$

DISCUSSION...40
AVIATION/MARINE...47


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