Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KHGX 310444
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1144 PM CDT SUN AUG 30 2015

.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION SECTION.

&&

.AVIATION...
OVERALL TAFS LOOK ON TRACK FROM 00Z PACKAGE. MAIN CHANGE WAS TO
DELAY THE ONSET OF VCSH ACROSS HOUSTON TERMINALS AND THE COAST.
LATEST HRRR/NAM SHOW SHRA DEVELOPING ABOUT 2-3 HRS LATER THAN
PREVIOUS PROGS. OVERALL EXPECT WIDESPREAD CIRRUS WITH A STRATOCU
DECK FOR MUCH OF THE DAY. WINDS WILL PICK UP TO AROUND 8-10KTS
FROM THE SE DURING THE AFTERNOON.

39

&&

.PREV DISCUSSION... /ISSUED /

DISCUSSION...
A WEAK HIGH PRESSURE RIDGE WAS OVER SE TEXAS EARLY THIS EVENING. A
SMALL CAP WAS EVIDENT ON THE EVENING SOUNDINGS NEAR THE COAST...
KCRP AND KLCH...WHICH WAS ALSO REFLECTED IN THE NAM BUFR FORECAST
SOUNDINGS FOR THE COASTAL FORECAST POINTS. THE CAP ERODES DURING
THE NIGHT. A WEAK SHORTWAVE TROUGH EVIDENT IN THE FLOW OVER FAR
NORTHEASTERN MEXICO AND FAR SOUTH TEXAS SHOULD BE MOVING UP THE
COASTAL AREAS LATER TONIGHT. LIKE THE LATEST RAP13 WHICH BRINGS
CHANCES FOR RAIN INTO THE COASTAL AREAS OVERNIGHT TONIGHT.

MADE A FEW TWEAKS TO THE TEMPERATURE AND HUMIDITY FORECASTS.
OTHERWISE NO CHANGES TO THE REMAINDER OF THE FORECAST.

40

PREV DISCUSSION... /ISSUED 628 PM CDT AUG 30 2015/

DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.

AVIATION...
WATER VAPOR IMAGERY SHOWS UPPER LOW OVER C TX WHICH HAS KEPT
HIGH/MID LEVEL CEILINGS IN PLACE OVER MUCH OF SE TX. TSRA NEAR
KAUS SHOULD STAY WEST OF KCLL TONIGHT AND LIKELY DISSIPATE. EXPECT
MAINLY HIGH CLOUDS WITH CALM WINDS OVERNIGHT. HIGH CLOUDS SHOULD
LIMIT ANY FOG DEVELOPMENT. GFS/NAM/HRRR ALL HINT AT SHRA
DEVELOPING ALONG THE COAST AND SPREADING INLAND THROUGH THE DAY.
ADDED VCSH TO TAFS FOR KIAH SOUTHWARD. EXPECT VFR CIGS WITH MAYBE
SOME LOW SCT STRATOCU THROUGH THE DAY.

39

PREV DISCUSSION... /ISSUED 319 PM CDT SUN AUG 30/

DISCUSSION...
SEVERAL FEATURES OF NOTE WERE OBSERVED ON WATER VAPOR IMAGERY
THIS AFTERNOON OVER THE SOUTHERN CONUS... WITH A FEW EXPECTED TO
PROVIDE SENSIBLE WEATHER CHANGES FOR THE REGION DURING THE WORK
WEEK. SHORTWAVE TROUGHS WERE CENTERED OVER SOUTHWEST TEXAS AND
WESTERN ARKANSAS WITH AN ELONGATED MID/UPPER LEVEL TROUGH
STRETCHING FROM CENTRAL TEXAS INTO THE GREAT LAKES. FARTHER
EAST... AN UPPER LOW OVER GEORGIA/ALABAMA WAS CHURNING TOWARDS THE
SOUTH ATLANTIC STATES. SCATTERED TO BROKEN SKIES HAD KEPT
AFTERNOON TEMPERATURES IN THE UPPER 80S TO LOW 90S WITH A BROAD
SURFACE HIGH PROMOTING LIGHT AND VARIABLE WINDS. AREA RADARS
CONTINUED TO SHOW SOME LIGHT RETURNS OVER PARTS OF MADISON AND
LEON COUNTIES... WITH LITTLE OBSERVATIONAL INDICATION THIS
ACTIVITY WAS REACHING THE GROUND.

FOR TONIGHT... AN ISOLATED SHOWER OR TWO WILL REMAIN POSSIBLE
THIS EVENING GENERALLY ALONG AND NORTH OF A BRENHAM TO GROVETON
LINE AS THE SHORTWAVE OVER SOUTHWEST TEXAS DIVES FARTHER SOUTH.
THIS FEATURE WILL PHASE WITH THE MID/UPPER LEVEL TROUGH
TONIGHT... EXTENDING THE RIDGE FROM THE GREAT LAKES SOUTHWEST TO
THE RIO GRANDE. AIRCRAFT SOUNDINGS OUT OF HOUSTON HAVE SHOWN THE
DRY LAYER OF AIR OBSERVED THIS MORNING /APPROXIMATELY 8KFT DEEP/
REMAINED IN PLACE THIS AFTERNOON AND DESPITE THE LIFT PROVIDED
FROM THE NEARBY TROUGH AND SHORTWAVE... DRY LOW TO MID-LEVEL AIR
WILL PRECLUDE A RAIN MENTION OUTSIDE OF THE NORTHERN ZONES. HIGH
RESOLUTION GUIDANCE ALSO PLACES THE BEST CHANCES /ALBEIT LOW ONES/
OVER THE NORTHERN ZONES WITH MOSTLY DRY CONDITIONS CONTINUING
OVERNIGHT. IN ADDITION TO A MOSTLY DRY NIGHT... EXPECT LOW
TEMPERATURES TO FALL INTO THE 70S TO NEAR 80 AGAIN. HOUSTON
INTERCONTINENTAL... ANAHUAC... CLEVELAND... AND CROCKETT ALL
REPORTED LOWS IN THE MID TO UPPER 60S THIS MORNING AND WE MAY BE
ABLE TO SQUEEZE OUT ONE MORE MORNING TOMORROW WITH A FEW SPOTS
SEEING THESE TEMPERATURES. SOME PATCHY FOG WILL ALSO BE POSSIBLE
MAINLY WEST AND SOUTHWEST OF THE HOUSTON METRO.

BETTER MOISTURE ARRIVES ON MONDAY AS PRECIPITABLE WATER VALUES
CLIMB INTO THE 1.6 TO 1.8 INCH RANGE /NEAR NORMAL FOR THIS TIME OF
YEAR/... AND RAIN CHANCES WILL INCREASE ACCORDINGLY AS THIS HAPPENS.
EXPECT ISOLATED STREAMER SHOWERS OVER THE COASTAL WATERS/ALONG THE
COAST MONDAY MORNING... WITH ISOLATED SHOWERS AND THUNDERSTORMS
POSSIBLE LATE MORNING INTO THE EARLY EVENING HOURS AS A SEA
BREEZE PUSHES INLAND TOMORROW AFTERNOON. PARTLY TO MOSTLY CLOUDY
SKIES WILL HELP KEEP TEMPERATURES SIMILAR TO TODAY ACROSS MUCH OF
THE REGION... WITH AFTERNOON HIGHS TOPPING OUT IN THE UPPER 80S TO
MID 90S.

THE UPPER TROUGH AXIS SHIFTS FARTHER EAST OVER THE REGION ON
TUESDAY /ROUGHLY ALONG THE HIGHWAY 59 CORRIDOR/ AND CARRYING THE
HIGHEST RAIN CHANCES FOR THIS FORECAST /30 TO 40 POPS/ DURING
THIS TIME. SCATTERED THUNDERSTORMS WILL REMAIN POSSIBLE ACROSS THE
REGION HEADING INTO WEDNESDAY AS THE UPPER TROUGH REMAINS OVERHEAD.
BY THURSDAY... THE SOUTHERN END OF THE TROUGH CUTS OFF OVER THE
REGION. EVOLUTION OF THIS CUTOFF LOW BECOMES INCREASINGLY MURKY
FOR THE LATE WEEK PERIOD AND THIS WILL PLAY A BIG ROLE IN
TEMPERATURES AND RAIN CHANCES DURING THIS TIME.

MEDIUM RANGE GUIDANCE SHIFTS THE CUTOFF UPPER LOW EASTWARD TOWARDS
LOUISIANA BUT DISAGREES ON HOW IF THAT EASTWARD MOVEMENT CONTINUES
INTO THE WEEKEND. THE 12Z ECMWF AND CANADIAN BOTH BRING IT OVER
THE SOUTHEASTERN CONUS BY THE END OF THE WEEK... SHEARING IT OUT
OVER THE WEEKEND. THE 12Z DETERMINISTIC GFS BRINGS IT OVER THE
NORTHWEST GULF OF MEXICO OVER THE UPCOMING WEEKEND. THE
TRANSLATION FOR ALL OF THIS IS THAT IF THE UPPER LOW MAINTAINS A
PRESENCE NEAR THE REGION... RAIN CHANCES WILL PERSIST INTO LABOR
DAY WEEKEND AND CONTINUING 20 TO 30 POPS THROUGH THE WEEKEND DUE
TO THIS UNCERTAINTY. OTHERWISE... KEPT TEMPERATURES NEAR
CLIMATOLOGICAL NORMALS /UPPER 80S ALONG THE COAST TO LOW 90S
INLAND/.

HUFFMAN

MARINE...
LITTLE CHANGE WAS MADE TO THE FORECAST AS HIGH PRESSURE TO THE
EAST MAINTAINS LIGHT (TO OCCASIONALLY MODERATE) SOUTH TO SOUTHEAST
WINDS ACROSS THE WATERS THROUGHOUT THE UPCOMING WEEK. A BROAD UPPER
LEVEL DISTURBANCE DEVELOPING OVER THE REGION WILL SUPPORT PERIODS
OF SHOWERS AND THUNDERSTORMS...AND EXPECT HIGHER WINDS AND SEAS IN
AND NEAR THIS ACTIVITY.  42

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      72  92  73  92  73 /  10  10  10  40  10
HOUSTON (IAH)              72  91  74  89  73 /  10  20  20  40  10
GALVESTON (GLS)            79  88  78  86  79 /  20  20  40  40  20

&&

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

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.