FXUS64 KHGX 081117
AFDHGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
517 AM CST TUE DEC 8 2009
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW.
&&
.AVIATION...
COMPLICATED AND MESSY TAFS. FORECAST SOUNDINGS SHOW LOW CIGS
REMAINING IN PLACE THROUGH AT LEAST 18Z AND PROBABLY INTO THE
EARLY AFTERNOON. THERE SHOULD BE A BREAK DURING THE AFTERNOON
WITH CIGS CRASHING AGAIN TONIGHT AHEAD OF ANOTHER FRONT. 43
.PREV DISCUSSION... /ISSUED 508 AM CST TUE DEC 8 2009/
UPDATE...
UPDATE FOR DENSE FOG.
DISCUSSION...
UPDATED THE FORECAST FOR THE DENSE FOG ADVISORY. AREAS OF FOG AND
SOME DENSE WILL BE POSSIBLE THROUGH THE LATE MORNING HOURS. SW
WINDS SHOULD DEVELOP WHICH WILL HELP ERODE THE FOG.
39
PREV DISCUSSION... /ISSUED 354 AM CST TUE DEC 8 2009/
DISCUSSION...
OVERALL A RATHER PROGRESSIVE PATTERN IS EXPECTED THROUGH THE
WEEKEND. FOR NOW...ISENTROPIC UPGLIDE IS IN PLACE OVER SE TX
LEADING TO LIGHT RAIN/DRIZZLE AND FOG. A WARM FRONT IS EXPECTED
TO PUSH INLAND TODAY WHICH WILL PRESENT A CHALLENGE FOR THE MAX
TEMP FORECAST. WARM FRONT MAY PUSH INLAND SOME...MORE SO THAN
WHAT THE NAM THINGS BUT NOT AS MUCH AS WHAT THE GFS THINKS. FOR
NOW WILL SPLIT THE DIFFERENCE BETWEEN THE TWO MODEL TEMP
FORECASTS AS COASTAL AREAS SHOULD WARM UP SOME AS THE WARM FRONT
MOVES INLAND BUT THE COLDER AIRMASS OVER C TX WILL PREVENT IT
MOVING TOO FAR NORTH. SW BOUNDARY LAYER FLOW MAY HELP AREAS
AROUND THE COASTAL BEND TO HAVE THINNING CLOUD COVER SO MAX TEMPS
IN THE LOW 70S IS POSSIBLE. OTHERWISE MUCH OF SE TX WILL BE COOL
AND DAMP AT LEAST FOR ONE MORE DAY.
UPPER LEVEL MAP ANALYSIS AT 00Z SHOWS A STRONG JET STREAK COMING
OUT OF THE S ROCKIES TODAY WHICH WILL CAUSE A DEEPENING AREA OF
LOW PRESSURE OVER THE PLAINS. WINDS SHOULD VEER TO THE SW LATER
THIS AFTERNOON AND SHIFT ANY RAIN CHANCES OFF TO THE EAST. RAIN
CHANCES AFTER 00Z WED WILL BE MINIMAL AT BEST AND A STRONG COLD
FRONT SHOULD PUSH OFF THE COAST BY WED MORNING. COLD ADVECTION ON
WED SHOULD HOLD TEMPS IN THE 50S TO MAYBE LOW 60S ALONG THE
COAST. HIGH PRESSURE THEN BUILDS OVER THE PLAINS WED NIGHT INTO
THU MORNING SETTING THE STAGE FOR A COLD THU MORNING. FREEZING
TEMPERATURES WILL BE EXPECTED MAINLY ACROSS RURAL AREAS OUTSIDE
THE HOUSTON METRO AREA. ALL OF SE TX CAN EXPECT TEMPS IN THE 30S
EXCEPT FOR MAYBE THE IMMEDIATE COAST.
THE NEXT CHANCE OF RAIN LOOKS TO BE ON TRACK FOR FRIDAY.
WEDNESDAY'S FRONT WILL REMAIN STALLED OUT OVER THE GULF. ANOTHER
WARM ADVECTION PATTERN WITH ISENTROPIC LIFT SETS UP THU NIGHT
INTO FRI AS DIVERGENCE FROM THE RIGHT REAR ENTRANCE REGION OF A
STRONG JET STREAM OVER TX BEGINS TO MOVE OVER THE REGION. ANOTHER
COASTAL LOW WILL DEVELOP AS A RESULT WITH THE BEST CHANCE OF
SHOWERS/ISO THUNDERSTORMS ALONG THE COAST. POPS WERE INCREASED TO
50/60 PERCENT FOR FRIDAY. THE OTHER CONCERN WILL BE COASTAL
FLOODING AS STRONG EAST WINDS WILL DEVELOP THU INTO FRI. THIS
SYSTEM SHOULD MOVE EAST AND CLEAR THE AREA FRI NIGHT INTO SAT.
DRIER CONDITIONS ARE EXPECTED SUN BUT MAY BE SHORT LIVED. THE GFS
SEEMS TO SUGGEST YET ANOTHER SHORTWAVE TROUGH COMING INTO THE
REGION FOR THE EXTENDED FORECAST. THE GFS AND ECMWF DIFFER QUITE
A BIT IN THE TIMING OF THE SHORTWAVE SO THE DETAILS ARE RATHER
SKETCHY. WILL KEEP 20 POPS FOR MON BUT IF THE SHORTWAVE IS SLOWER
LIKE THE ECMWF...POPS WILL NEED TO BE ADJUSTED AGAIN.
39
&&
.MARINE...
A WEAK FRONT STRADDLING THE COAST WILL MOVE INLAND TODAY WITH STRONG
SOUTH TO SOUTHWEST WINDS DEVELOPING. FOG AHEAD OF THE FRONT WILL
LINGER THROUGH MID MORNING BEFORE FINALLY DISSIPATING. SCEC
CONDITIONS WILL DEVELOP THIS MORNING AND PERSIST THROUGH 03Z
TONIGHT. ANOTHER COLD FRONT THEN PUSHES OFF THE COAST LATE TUESDAY
NIGHT. SCA CONDITIONS LOOK TO DEVELOP ONCE AGAIN BY WEDNESDAY
AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE MID-MISSISSIPPI VALLEY
ON THURSDAY AND LOW PRESSURE WILL DEVELOP ALONG THE LOWER COAST. A
TIGHT EASTERLY GRADIENT WILL DEVELOP BETWEEN THESE FEATURES. A LONG
EASTERLY FETCH OF MODERATE TO STRONG WINDS WILL LIKELY GENERATE
ABOVE NORMAL TIDES THURSDAY AND FRIDAY. COASTAL FLOODING COULD AGAIN
BE POSSIBLE LATE THURSDAY AND EARLY FRIDAY. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 61 43 55 31 55 / 40 10 0 0 0
HOUSTON (IAH) 67 48 60 34 57 / 50 10 0 0 0
GALVESTON (GLS) 68 52 61 44 57 / 50 10 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...
CHAMBERS...COLORADO...FORT BEND...GALVESTON...GRIMES...
HARRIS...HOUSTON...JACKSON...LIBERTY...MADISON...
MATAGORDA...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
WALKER...WALLER...WASHINGTON...WHARTON.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH THIS EVENING FOR THE
FOLLOWING ZONES: 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.
&&
$$
DISCUSSION...39
