FXUS62 KTBW 220803
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
303 AM EST TUE DEC 22 2009
.SHORT TERM (TODAY-THURSDAY)...CIRRUS CLOUDS AGAIN HAMPERING
RADIATIONAL COOLING AND EXPECTED LOW TEMPERATURES THIS MORNING.
CURRENT OBSERVATIONS SHOWING TEMPERATURES AND DEW POINTS IN THE
MID TO UPPER 30S OVER THE NATURE COAST WITH CONSTANT BUT THINNING
CIRRUS OVER THE NE GULF. EVEN IF TEMPERATURES FALL TO NEAR FREEZING
BEFORE SUNRISE NEEDED DURATIONS WILL NOT BE MET FOR FREEZE WARNING
AND WILL CANCEL SHORTLY.
SHORTWAVE OVER THE CENTRAL GULF TO MOVE INTO THE SE GULF TODAY
WITH CIRRUS SHIELD PUSHING SE THROUGH THE DAY. SURFACE HIGH
PRESSURE OVER THE DEEP SOUTH TO MOVE OVER THE CAROLINAS VEERING
LOW LEVEL FLOW NEWARD. WITH MOSTLY SUNNY SKIES FOR MUCH OF THE
AREA AND MODERATING LOW LEVELS...TEMPERATURES BEGIN TO RISE BUT
REMAIN ABOUT 5 DEGREES BELOW NORMAL TODAY AND TONIGHT.
ON WEDNESDAY BRIEF MINI RIDGING ALOFT AHEAD OF UPPER LOW AND
TROUGH OVER THE SOUTHERN PLAINS WHILE LOW LEVEL EASTERLY FLOW
INCREASES BETWEEN MID ATLANTIC RIDGING AND DEVELOPING SOUTHERN
PLAINS STORM SYSTEM FURTHER WARMING AND MOISTENING THE AIRMASS OVER
THE STATE. DAYTIME TEMPERATURES WARM TO NEAR NORMAL LEVELS
WEDNESDAY.
ADVANCING SHORTWAVE AND VORTICITY MAX AHEAD OF CENTRAL U.S. LOW TO
PUSH A COLD FRONT INTO THE CENTRAL GULF LATE THURSDAY. CWA TO BE
IN WARM SECTOR OF SYSTEM WITH TEMPERATURES WARMING 5 TO 10 DEGREES
ABOVE NORMAL. MODELS HAVE SLIGHTLY SLOWED THE FORWARD PROGRESS OF
THE SYSTEM SO RAIN CHANCES WILL BE AROUND 20 PERCENT OVER LAND AREAS
THURSDAY AND 30 PERCENT OF THE E GULF WATERS.
.LONG TERM (THURSDAY NIGHT THROUGH MONDAY)...A COLD FRONT ASSOCIATED
WITH A NEARLY STACKED LOW PRESSURE SYSTEM MOVING NNE THROUGH THE
MIDWEST WILL MOVE THROUGH OUR REGION CHRISTMAS DAY. SOUTHERLY FLOW
AHEAD OF THE FRONT WILL PROVIDE PLENTY OF MOISTURE TO SUPPORT A
CHANCE FOR SOME RAIN SHOWERS ALONG THE FRONT. A BETTER CHANCE OF
SHOWERS WILL OCCUR EARLIER IN THE MORNING ALONG THE WARM FRONT
LIFTING NORTH. MAINTAINED A N-S POP GRADIENT ON SUN NIGHT AND FRIDAY
MORNING FAVORING AREAS NORTH OF HILLSBOROUGH AND POLK CO. NOT
EXPECTING MUCH IF ANYTHING IN THE WAY OF THUNDERSTORMS WITH THIS
SYSTEM. THE UPPER LEVEL TROUGH AXIS WILL BE WELL TO THE NW OF THE
PENINSULA PROVIDING MINIMAL UPPER LEVEL SUPPORT.
FOR THE REST OF THE LONG TERM...THE COLD FRONT MOVES SOUTH OF THE
AREA AS HIGH PRESSURE BUILDS IN FROM THE NW. COOLER AND DRIER AIR AT
THE SURFACE WILL FILTER THROUGH THE PENINSULA. GFS IS INDICATING
SOME OVERRUNNING MOISTURE IN THE MID AND UPPER LEVELS AS THE TROUGH
AXIS MOVES EASTWARD. GFS DOES SHOW POPS IN THE 40 RANGE ON SAT NIGHT
AND SUN MORNING BUT THAT MAY BE TOO HIGH CONSIDERING A PUSH OF DRIER
AIR IN THE LOW TO MID LEVELS. MAINTAINED A ONLY A SLIGHT CHANCE OF
SHOWERS THROUGH SUN NIGHT BUT BUMPED UP CLOUD COVER ACROSS THE
REGION. BY MONDAY...SURFACE HIGH PRESSURE GETS FORCED EASTWARD NORTH
OF THE PENINSULA. ENOUGH DRY AIR AND SUBSIDENCE WILL DECREASE COVER
AND LOWER RAINFALL CHANCES BEFORE THE NEXT WEATHER SYSTEMS DEVELOPS
IN THE WESTERN GULF.
$$
AVIATION...PATCHY FOG MAY DEVELOP FOR AREAS NORTH AND INLAND OF SRQ
BUT NOT EXPECTING VSBYS TO DROP TO IFR CONDITIONS. OTHERWISE...VFR
CONDITIONS EXPECTED THROUGH TODAY.
&&
.MARINE...WEAK HIGH PRESSURE TO REMAIN NORTH OVER THE IMMEDIATE
AREA WITH EASTERLY FLOW SETTING UP TODAY AND TONIGHT. GRADIENT TO
TIGHTEN OVER THE E GULF WEDNESDAY BETWEEN THE CAROLINAS HIGH PRESSURE
AREA AND A DEVELOPING STORM SYSTEM TO THE WEST. COLD FRONT TO MOVE
THROUGH THE CENTRAL GULF LATE THURSDAY THEN E GULF FRIDAY. HIGH PRESSURE
TO BUILD INTO THE REGION BEHIND THE FRONT OVER THE WEEKEND.
&&
.FIRE WEATHER...DRIEST AIR TO HOLD OVER NORTHERN ZONES TODAY WITH
LONG DURATIONS OF CRITICALLY LOW RH THIS AFTERNOON AND HAVE RAISED
RED FLAG WARNING FROM PASCO COUNTY NWARD THROUGH LEVY COUNTY. CENTRAL
AREA TO SEE 1-3 HOURS OF LOW RHS. LOW LEVEL MOISTURE INCREASES TUESDAY
THROUGH THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 67 49 75 58 / 0 0 0 5
FMY 71 52 78 58 / 5 0 5 10
GIF 67 48 74 56 / 0 0 0 5
SRQ 68 49 75 58 / 0 0 0 5
BKV 67 38 73 52 / 0 0 0 5
SPG 65 53 71 60 / 0 0 0 5
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
CITRUS-HERNANDO-LEVY-PASCO-SUMTER.
GULF WATERS...NONE.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...25/DAVIS
LONG TERM/AVIATION...20/BARRON
