967 
FXUS64 KHGX 291004
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
404 AM CST SUN NOV 29 2015

.DISCUSSION...
A COLD FRONT HAS PUSHED THROUGH SE TEXAS AND INTO THE GULF WHERE
IT CONTINUES TO MAKE SLOW PROGRESS SOUTH. TEMPERATURES HAVE
DROPPED INTO THE 40S/50S ACROSS MUCH OF SE TEXAS. LOOKING AT 00Z
CRP SOUNDING AND KHGX VAD WIND PROFILE...COLD AIRMASS IS ONLY 1000
TO 2000 FEET DEEP. SOUTHERLY WINDS PREVAIL ABOVE 2000FT WHICH
CONTINUE TO ADVECT GULF MOISTURE OVER TOP THE COLDER AIRMASS. THIS
HAS ALLOWED FOR LOW CLOUD DECKS AND EVEN PATCHY FOG AT TIMES WITH
DRIZZLE.

WATER VAPOR IMAGERY SHOWS MAIN UPPER LOW OVER UTAH WITH SW FLOW
ALOFT OVER MUCH OF TEXAS. WATER VAPOR IAMGERY ALSO SHOWS A WEAK
SHORT WAVE TROUGH OVER N CENTRAL MEXICO WHICH SHOULD REACH S TEXAS
THIS MORNING. THIS WAVE MAY INCREASE SHOWER ACTIVITY OVER THE AREA
TODAY BUT MESOSCALE MODELS ARE NOT RESOLVING THIS FEATURE WELL.
ALSO OF NOTE IS 850MB FRONT STRETCHING FROM W TX NW TOWARDS C
OKLAHOMA. THIS HAS BEEN THE FOCUS FOR WIDE SPREAD RAIN ACROSS MUCH
OF W TX INTO THE RED RIVER. OVERALL EXPECTATION FOR TODAY IS FOR
THE SHORTWAVE TROUGH TO HELP INCREASE SHOWER ACTIVITY AND FOR THE
ACTIVITY OVER W TX TO MOVE EAST ACROSS MUCH OF N TEXAS. RAIN
CHANCES ARE HIGHER NORTH TO SOUTH ACROSS SE TEXAS FORECAST AREA.
THIS IS MAINLY DUE TO FORCING FROM JET STREAK OVER THE S ROCKIES
MOVING INTO TEXAS AS MAIN UPPER LOW MOVES TOWARDS THE C PLAINS
SUNDAY INTO MONDAY.

PERSISTENT S/SW 850MB FLOW WILL CONTINUE TO KEEP CLOUD COVER AND
RAIN/DRIZZLE OVER THE AREA THROUGH THE MIDDLE OF THE WEEK. RAIN
CHANCE MAY BE SLIGHTLY HIGHER ON TUESDAY AS 850MB FRONT BECOMES
STALLED OVER NORTHERN PORTIONS OF THE AREA FROM COLLEGE STATION TO
CROCKETT. GFS SHOWS INCREASED FRONTOGENESIS AT THE 850-700MB LAYER
DURING THIS TIME AND 295K ISENTROPIC SURFACE HAS INCREASED
CONVERGENCE WITHIN THE FRONTAL ZONE. FORCING LOOKS SUPPORTIVE OF
AT LEAST SOME RAIN BANDS ALONG THE BOUNDARY ON TUESDAY. HIGH
PRESSURE OVER THE N ROCKIES BEGINS TO BUILD INTO THE PLAINS WED
NIGHT INTO TUE. THIS SHOULD PUSH THE FRONT OFF THE COAST ENDING
RAIN CHANCES LATE WEDNESDAY. COLD ADVECTION ON WEDNESDAY WITH
CLOUD COVER AND RAIN SHOULD KEEP MAX TEMPS IN THE 50S AS CLOUD
COVER MAY BE SLOW TO ERODE. STRONGER SUBSIDENCE SHOULD NOT ARRIVE
UNTIL LATE WEDNESDAY.

HIGH PRESSURE SHOULD CONTINUE TO BUILD THROUGH THE PLAINS WITH
COLD ADVECTION PERSISTING UNTIL FRIDAY. HIGH TEMPS THURSDAY AND
FRIDAY WILL BE HARD PRESSED TO REACH 60F. RETURN FLOW MAY NOT SET
UP UNTIL LATE SATURDAY INTO SUNDAY AS A STRONG UPPER LOW DEVELOPS
OVER THE S ROCKIES INTO W TX. BOTH THE GFS AND ECMWF HAVE SOME
CONSISTENCY WITH THIS FEATURE. WILL ALSO ADD 20 POPS FOR THE
FORECAST FOR NEXT WEEKEND AS UPPER LOW MAY PROVIDE ENOUGH LIFT TO
SQUEEZE OUT SOME RAIN SHOWERS. GIVEN THE PROLONGED COLD ADVECTION
PRIOR TO THE MOISTURE RETURN...THERE MAY NOT BE ENOUGH MOISTURE TO
SUPPORT WIDE SPREAD RAIN CHANCES. STILL IT IS HARD TO IGNORE SUCH
A STRONG SYSTEM AND THINK SLIGHT RAIN CHANCES DESERVE MENTION IN
THE EXTENDED FORECAST.

39

&&

.MARINE...
MODERATE OFFSHORE WINDS CONTINUE EARLY THIS AM. EXPECT WINDS TO
GRADUALLY DIMINISH TODAY. WILL LET THE CAUTION STATEMENT GO FOR
THE OFFSHORE WATERS AS I EXPECT WINDS/SEAS TO SUBSIDE. SOME
DIFFERENCES BETWEEN THE MODELS WITH MONDAY'S MARINE WINDS. THE GFS
IS AN OUTLIER WITH ONSHORE WINDS AS OTHER MODELS KEEP WINDS
OFFSHORE ALONG THE COAST UNTIL THE NEXT FRONT MAKES IT INTO THE
REGION ON TUE. THERE IS SOME UNCERTAINTY REGARDING WIND DIRECTIONS
MON THRU EARLY TUE...ESPECIALLY IN THE 20-60NM MARINE ZONES.
OFFSHORE FLOW WILL INCREASE ON TUE NIGHT AND ON WED BEHIND THE
NEXT COLD FRONT WHICH WILL REQUIRE ADVSY FLAGS FOR THE OFFSHORE
WATERS. 33

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      49  47  54  48  58 /  80  40  30  40  40 
HOUSTON (IAH)              56  52  61  53  61 /  50  40  30  30  30 
GALVESTON (GLS)            60  59  65  59  64 /  40  30  40  30  30 

&&

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

$$

DISCUSSION...39
AVIATION/MARINE...33