FXUS62 KTBW 221830
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
130 PM EST TUE DEC 22 2009
.SHORT TERM(TONIGHT - THURSDAY)...SHORT WAVE TROUGH WILL EXIT TO THE
EAST OF THE REGION TONIGHT WITH MID LEVEL RIDGING BUILDING IN FROM THE
WEST DURING WEDNESDAY AND THURSDAY AS SURFACE RIDGING TO THE NORTH SLOWLY
SHIFTS EAST AS A VIGOROUS STORM SYSTEM MOVES FROM THE CENTRAL U.S. INTO
THE MISSISSIPPI VALLEY. VEERING LOW LEVEL FLOW INTO THE EAST ON WEDNESDAY
THEN SOUTHEAST ON THURSDAY WILL SUPPORT A SLOW INCREASE IN MOISTURE
ACROSS THE ENTIRE FORECAST AREA WITH PERHAPS A FEW SHOWERS (POPS 20
PERCENT) DEVELOPING ON THURSDAY WITHIN THE MOISTENING AIR MASS.
TEMPERATURES TONIGHT WILL NOT BE AS COLD AS THE LAST FEW WITH LOWS
FALLING INTO THE MID/UPPER 30S OVER THE NATURE COAST...LOWER/MID 40S
CENTRAL...AND UPPER 40S TO AROUND 50 FAR SOUTH. AFTER A COOL START ON
WEDNESDAY TEMPERATURES WILL MODERATE BACK TO SEASONAL NORMS...THEN CLIMB
TO ABOVE NORMAL ON THURSDAY. MAV/MET TEMPERATURES ARE FAIRLY CLOSE SO
WILL USE A BLEND. LIGHT WINDS AND CLEARING SKIES WILL ALLOW FOR SOME
PATCHY FOG TO DEVELOP IN THE NORMALLY FAVORED LOCATIONS OVER THE NATURE
COAST THE NEXT FEW NIGHTS...SO WILL INCLUDE A MENTION IN THE GRIDS/ZONES.
.LONG TERM(THURSDAY NIGHT - TUESDAY)...THE LONG TERM PERIOD WILL
START OFF WITH A STRONG WINTER STORM LIFTING NORTH THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY THURSDAY NIGHT AND FRIDAY. THE ASSOCIATED
COLD FRONT WILL BE MOVING THROUGH THE FLORIDA PANHANDLE THURSDAY
NIGHT AND THROUGH THE REMAINDER OF FLORIDA DURING CHRISTMAS DAY.
WHILE THE UPPER-LEVEL TROUGH WILL BE QUITE DEEP...MOST OF THE ENERGY
WILL RESIDE WELL TO THE NORTH...WHICH WILL KEEP THUNDERSTORM CHANCES
QUITE MINIMAL. THE COLD FRONT WILL COME TO A HALT WELL SOUTH AND
EAST OF OUR AREA...BUT WEST TO SOUTHWEST WINDS ALOFT KEEP AMPLE
CLOUD COVER ALONG WITH SOME CHANCES FOR RAIN OVER THE REGION THROUGH
THE WEEKEND.
THE 12Z RUN OF THE GFS BRINGS A NEW SHORT WAVE INTO THE NORTHEAST
FOR MONDAY AND TUESDAY...WHICH DELAYS THE CLEARING TREND PREVIOUSLY
DEPICTED FOR MONDAY. THE 00Z ECMWF SHOWS A DRY FORECAST FOR MONDAY
SO WILL NOT ADD RAIN TO MONDAYS FORECAST AT THIS TIME BUT WILL KEEP
CLOUDS IN THE FORECAST UNTIL TUESDAY.
&&
.AVIATION...VFR THROUGH WEDNESDAY WITH LIGHT NORTH TO NORTHEAST
WINDS.
&&
.MARINE...LIGHT NORTHEAST WIND FLOW TONIGHT WILL VEER INTO THE EAST
DURING WEDNESDAY AND WEDNESDAY NIGHT AS SURFACE HIGH PRESSURE TO THE
NORTH SHIFTS SLOWLY EAST AS A STORM SYSTEM MOVES THROUGH THE CENTRAL
U.S.. DURING THURSDAY THROUGH FRIDAY WINDS WILL VEER INTO THE SOUTHEAST
THEN SOUTH WITH SPEEDS AND SEAS LIKELY INCREASING INTO THE EXERCISE
CAUTION OR LOW END SMALL CRAFT RANGE AS THE PRESSURE GRADIENT TIGHTENS
BETWEEN SURFACE HIGH PRESSURE TO THE NORTHEAST AND DEEPENING LOW PRESSURE
AND AN ATTENDANT COLD FRONT MOVING THROUGH THE MISSISSIPPI VALLEY. WINDS
WILL SHIFT INTO THE NORTHWEST AND NORTH DURING THE HOLIDAY WEEKEND AS
THE COLD FRONT SWEEPS SOUTH THROUGH THE WATERS AND SURFACE HIGH PRESSURE
BUILDS IN OVER THE NORTHERN GULF IN ITS WAKE.
&&
.FIRE WEATHER...TEMPERATURE DEW POINT SPREAD TRENDS SUPPORT KEEPING
THE CURRENT RED FLAG WARNING IN EFFECT FOR THE NATURE COAST THROUGH
EARLY EVENING WITH CRITICAL RH'S DURATIONS BELOW 35 PERCENT LIKELY
TO OCCUR...WITH POCKETS OF MARGINALLY LOW RH'S EXTENDING SOUTH INTO
THE CENTRAL PENINSULA AS WELL BUT DURATIONS THERE SHOULD REMAIN BELOW
WARNING CRITERIA. INCREASING LOW LEVEL MOISTURE SHOULD KEEP HUMIDITY
VALUES ABOVE CRITICAL LEVELS THROUGH THE REMAINDER OF THE WEEK WITH
NO ADDITIONAL HEADLINES EXPECTED AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 49 73 57 77 / 0 0 5 20
FMY 50 76 58 77 / 0 5 5 20
GIF 47 73 55 76 / 0 0 5 20
SRQ 46 75 57 79 / 0 0 5 20
BKV 37 74 51 75 / 0 0 5 20
SPG 53 71 60 76 / 0 0 5 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING UNTIL 6 PM EST THIS EVENING FOR CITRUS-HERNANDO-
LEVY-PASCO-SUMTER.
GULF WATERS...NONE.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...57/MCMICHAEL
LONG TERM/AVIATION...63/JILLSON
