Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 281550
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1050 AM CDT TUE APR 28 2015

.UPDATE...
SURFACE AND UPPER AIR ANALYSIS THIS MORNING PLACED THE REGION
SOUTHWEST OF AN UPPER LOW /PRESENTLY CHURNING OVER THE RED RIVER/.
REGIONAL RADAR MOSAIC SHOWS A COMPLEX OF SHOWERS SLOWLY SWINGING
EAST-SOUTHEAST WITH THE UPPER LOW... AND HAVE BUMPED POPS UP OVER
THE NORTHERN COUNTIES FOR THE REMAINDER OF THE MORNING IN
RESPONSE. COULD SEE SOME EROSION OF THIS ACTIVITY AS IT MOVES
TOWARDS THE REGION /OWING TO SOME DRIER AIR EVIDENT ON AIRCRAFT
SOUNDINGS OUT OF HOUSTON THIS MORNING/... AND RAIN CHANCES WILL
END FROM WEST TO EAST THIS AFTERNOON AS THE UPPER LOW SHIFTS EAST
OF THE REGION. ADDITIONALLY... THE COMBINATION OF COLD AIR
ADVECTION BEHIND FRONT AND SOME AREAS SEEING CLOUDS
THINNING/SCATTERING AS DRIER AIR WORKS IN WILL CREATE A WIDE
VARIETY OF TEMPERATURES TODAY... AND MADE SOME ADJUSTMENTS TO
TEMPERATURES BASED ON OBSERVATIONS.

FOR THOSE INTERESTED... WE COULD REACH OR BREAK THE RECORD LOW
MAXIMUM TEMPERATURE TODAY AT COLLEGE STATION. RECORD LOW MAXIMUM
CLIMATE INFORMATION FOR APRIL 28 FOR COLLEGE STATION... HOUSTON
INTERCONTINENTAL... AND GALVESTON ARE LISTED BELOW.

SITE....                  RECORD LOW MAXIMUM...      YEAR...
COLLEGE STATION           67                         1932
HOUSTON INTERCONTINENTAL  66                         1941
GALVESTON                 69                         1941

ADDITIONAL INFORMATION IS CONTAINED WITHIN THE MARINE AND AVIATION
SECTIONS BELOW.

HUFFMAN

&&

.MARINE...

WINDS COMING UP AND GRADIENT TIGHTER TO THE WEST. AS 850 FRONT
REACHES THE COAST EARLY THIS AFTERNOON EXPECT WINDS TO RAMP UP
FURTHER AT GUSTY CAA SCENARIO TO TAKE HOLD. HAVE ADDED SCA TO
MATAGORDA BAY AND DELAYED ONSET OF SCEC FOR GALVESTON BAY. SEAS
SHOULD RESPOND BY LATE AFTERNOON REACHING 6-7 FEET WITH SUSTAINED
WINDS NEAR 20 KNOTS AND GUSTY.

45

&&

.AVIATION...

LIGHT DRIZZLE/RAIN AT CLL SHOULD EXPAND A LITTLE FURTHER EAST AS
VORT ROTATES AROUND UPPER LOW...MAY REACH UTS/CXO TERMINALS 17-22Z.
CIGS FIGHTING THE DRY AIR ALOFT BUT HAVE IN GENERAL BEEN COMING IN
LOWER SO WITH THE PASSAGE OF THE 850 FRONT AROUND NOON EXPECT CIGS
TO LOWER AND REMAIN IN THE 1000-2000FT RANGE THROUGH THE AFTERNOON.
IN ADDITION WITH STRONGER CAA WINDS SHOULD GET GUSTY THIS AFTERNOON.

SOME BREAKS IN OVC ACROSS THE HOU/SGR/GLS/LBX TERMINALS MAY BE
POSSIBLE LATE IN THE AFTERNOON AS DRIER AIR GETS TO WORK.

45

&&

.PREV DISCUSSION... /ISSUED 355 AM CDT TUE APR 28 2015/

DISCUSSION...
THE LARGE UPPER-MID LEVEL LOW IS BECOMING SLIGHTLY SHEARED AS IT
ROTATES PARALLEL TO THE RED RIVER VALLEY AND IS PROGGED BY THE
NWP GLOBAL MODEL ENSEMBLE TO BE OVER THE ARKLATEX BY SUNSET
TONIGHT. AN UNSEASONABLY COLD AND DRY AIR MASS (AROUND 2 STD DEV
I.R.T. MID-LEVEL COOLING) IS DESCENDING UPON THIS UPPER LOW`S
WESTERN FLANK...WITH THE SOUTHERN EXTENT OF THE AIR MASS THE COLD
FRONT THAT WILL BE ADVANCING SOUTH TO THE COAST OVER THE NEXT FEW
HOURS...THE BOUNDARY TO BE WELL OFFSHORE BY LATE MORNING. THE
GENERAL SYNOPTIC SOUTHERN PLAINS FLOW PATTERN WILL BECOME MORE
NORTH AND WEST AS TEXAS FALLS BETWEEN RETREATING EASTERN TROUGHING
AND AMPLIFYING WESTERN CONUS RIDGING. THIS DRY AND STABLE PATTERN
WILL PERSIST FOR THE REMAINDER OF THE WEEK.

LINGERING CLOUD COVER UNDER THE POST-FRONTAL INVERSION...IN
TANDEM WITH COLD AIR ADVECTION...WILL REGULATE TODAY`S WARMTH TO
ONLY THE UPPER 60S TO NEAR 70F. COMBINE THIS LATE SEASON CAA WITH
A NEAR 15 MB OFFSHORE PRESSURE GRADIENT CREATED BY A DESCENDING
1025 MB CENTRAL PLAINS HIGH AND THE GENERATION OF A FRESH NEAR 15
KT SUSTAINED NORTH WIND WILL BE THE RESULT. AS EVIDENCED BY UPPER
40 DEW POINT AIR SPILLING INTO THE STATE THIS MORNING...THE ONCE
OVERLY-SATURATED RESIDENT AIR MASS WILL TRANSITION TO A MUCH DRIER
ONE THROUGH THE DAY...BEST REALIZED BY THIS TIME TOMORROW MORNING
AS MINIMUM TEMPERATURES FALL INTO THE MEAN LOWER 50S (OR ABOUT 10
DEGREES BELOW NORMAL LATE APRIL STANDARDS). A DRY REINFORCING
FRONTAL PASSAGE WEDNESDAY AS WESTERN HIGH PRESSURE BUILDS IN AND
FORTIFIES THE TAUNT OFFSHORE GRADIENT...WITH MORE MID-WEEK SUN TO
WARM WEDNESDAY PM INTO THE LOWER TO MIDDLE 70S. HIGH PRESSURE AT
THE SURFACE AND UPPER SOUTHWESTERN U.S.-BASED RIDGING THROUGH THE
END OF THE WEEK WILL GUARANTEE SUBSEQUENT DAY WARMING BACK INTO
THE LOWER 80S BY THE WEEKEND WITH CONTINUED LOW TO NIL POPS. LATE
WEEK EASTERN TEXAS HIGH PRESSURE TRANSITIONING EAST WILL ALLOW
RETURN FLOW TO RE-DEVELOP BY FRIDAY AFTERNOON. THE REGION WILL
STILL BE THE GRIP OF UPPER RIDGING NEXT WEEKEND. THIS EQUATES TO
NEAR NORMAL EARLY MAY CONDITIONS....MANAGEABLE HUMIDITIES AND ONLY
SLIGHT RAIN CHANCES PER WEAK DISTURBANCE PASSAGES AS UPPER-MID
RIDGING BEGINS TO BREAK DOWN ABOUT A WEEK FROM NOW. 31

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      66  50  72  52  77 /  30  10   0   0   0
HOUSTON (IAH)              71  50  74  53  79 /  20  10   0   0   0
GALVESTON (GLS)            72  57  71  62  75 /  20  10   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT WEDNESDAY FOR THE FOLLOWING
     ZONES: MATAGORDA BAY...WATERS FROM FREEPORT TO THE
     MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
     FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
     FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
     ISLAND TO FREEPORT OUT 20 NM.

     SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH WEDNESDAY MORNING
     FOR THE FOLLOWING ZONES: GALVESTON BAY.

&&

$$

DISCUSSION...14
MARINE/AVIATION...45



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