FXUS62 KTBW 281835
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
135 PM EST SAT NOV 28 2009
...PATCHY FROST AGAIN FOR THE NATURE COAST...
.SHORT TERM (TONIGHT - MONDAY)...HIGH PRESSURE WILL SETTLE RIGHT
OVER NORTH FLORIDA TONIGHT RESULTING IN CALM WINDS. IF NOT FOR
THE CIRRUS MOVING IN FROM THE WEST...I WOULD EXPECT IT TO BE AT
LEAST AS COOL AS LAST NIGHT. AS IT IS...THERE ARE LARGE BREAKS
OCCURRING OVER THE GULF AT THIS TIME. WILL USE A BLEND OF THE
COOLER MAV AND WARMER MET WHICH STILL YIELDS SOME PATCHY FROST FOR
THE COLDEST AREAS OF THE NATURE COAST. PLACES THAT HAD FROST LAST
NIGHT WILL PROBABLY SEE FROST AGAIN TONIGHT.
THIS RIDGE OF HIGH PRESSURE WILL WEAKEN SUNDAY AND MONDAY BUT
BASICALLY REMAIN OVER NORTH OR NORTH-CENTRAL FLORIDA THROUGH THE
PERIOD. THIS WILL KEEP WINDS LIGHT AND ALLOW FOR A GRADUAL
WARMING TREND EACH DAY.
.LONG TERM (MONDAY NIGHT - SATURDAY)...AMPLIFIED PROGRESSIVE
SPLIT FLOW PATTERN TO CONTINUE DURING THE LONG TERM. A SHORT WAVE
TROUGH MOVING THROUGH THE MS/TN VALLEYS AND OFF THE MID ATLANTIC
AT THE START OF THE PERIOD WILL PUSH A COLD FRONT INTO THE
NORTHERN PENINSULA MONDAY NIGHT...THEN THE FRONT WILL STALL OUT
ACROSS THE NORTH CENTRAL PENINSULA ON TUESDAY. SLOW MOISTURE
RECOVERY AHEAD OF THIS FRONT SHOULD ONLY SUPPORT SLIGHT CHANCES
FOR SHOWERS MONDAY NIGHT MAINLY ACROSS THE NORTHERN NATURE COAST
WHERE A 20 PERCENT POP WILL BE DEPICTED WITH A SILENT 10 PERCENT
ELSEWHERE. ON TUESDAY THE STALLED FRONT ACROSS THE NORTH-CENTRAL
PENINSULA WILL CONTINUE TO BE A FOCUS FOR SCATTERED SHOWERS (POPS
30 PERCENT) OVER THE NATURE COAST WITH A SLIGHT CHANCE OF A FEW
SHOWERS (POPS 20 PERCENT) EXTENDING SOUTH INTO CENTRAL AND
SOUTHERN ZONES.
DURING TUESDAY NIGHT INTO WEDNESDAY THE STALLED FRONTAL BOUNDARY
WILL BEGIN TO LIFT BACK TO THE NORTH AS A WARM FRONT AS SURFACE
LOW PRESSURE DEVELOPS ALONG THE WESTERN END OF THE FRONT OVER THE
NORTHWEST GULF IN RESPONSE TO A VIGOROUS SHORT WAVE TROUGH
EJECTING EAST FROM TEXAS INTO THE LOWER MS VALLEY. THE GFS/ECMWF
ARE NOW IN SOMEWHAT BETTER AGREEMENT TODAY WITH THE EVOLUTION OF
THIS SYSTEM...HOWEVER THEY STILL DIFFER SLIGHTLY ON ITS TRACK...SO
WILL CONTINUE TO USE A BLEND DURING THIS TIME FRAME.
AS THE LOW LIFTS OUT TO THE NORTHEAST INCREASING MOISTURE WITHIN
A DEEP LAYERED SOUTHERLY WIND FLOW...STRONG DYNAMICS AND
INCREASING LARGE SCALE LIFT WILL LEAD TO INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS (POPS 50-60 PERCENT RANGE) ACROSS THE
FORECAST AREA WEDNESDAY THROUGH EARLY THURSDAY ALONG WITH THE
POSSIBILITY OF SOME LOCALLY HEAVY RAINFALL. IN ADDITION TO THE
RAIN STRONG MID LEVEL FORCING COMBINED WITH A LOW LEVEL 850MB JET
(IN THE 55-65 KNOT RANGE) FORECAST TO MOVE ACROSS THE NORTH-
CENTRAL PENINSULA MAY ALSO INCREASE THE POTENTIAL FOR SOME STRONG
TO SEVERE STORMS ON WEDNESDAY ESPECIALLY IN THE VICINITY OF THE
NORTHWARD MOVING WARM FRONT. THE SHOWERS AND STORMS WILL GRADUALLY
END FROM NORTH TO SOUTH ON THURSDAY AS THE FRONT EXITS TO THE
SOUTH WITH COOLER AND DRIER WEATHER EXPECTED ACROSS THE ENTIRE
FORECAST AREA THROUGH SATURDAY AS SURFACE HIGH PRESSURE BUILDS IN
FROM THE NORTH. TEMPERATURES WILL RUN ABOVE NORMAL THROUGH MID
WEEK...THEN FALL SLIGHTLY BELOW NORMAL IN THE WAKE OF THE FRONT TO
END THE WEEK AND INTO THE UPCOMING WEEKEND.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED AT ALL TERMINAL SITES
DURING THE NEXT 24 HOURS.
&&
.MARINE...GOOD BOATING CONDITIONS EXPECTED THROUGH MONDAY...THEN
EASTERLY WINDS BEGIN TO INCREASE ON TUESDAY AS LOW PRESSURE
ORGANIZES IN THE GULF. WINDS WILL LIKELY REACH SMALL CRAFT
ADVISORY LEVELS BY TUESDAY NIGHT AND MAY PEAK ABOVE 25 KNOTS ON
WEDNESDAY. NORTHWEST WINDS BEHIND A COLD FRONT WILL CONTINUE TO
GENERATE ROUGH CONDITIONS ON THURSDAY.
&&
.FIRE WEATHER...MANY AREAS BEGINNING TO FALL BELOW 35 PERCENT
RELATIVE HUMIDITY AT THIS TIME AND WILL CONTINUE THE RED FLAG
WARNING INTO THIS EVENING. HUMIDITIES ON SUNDAY WILL LIKELY
APPROACH 35 PERCENT...AND SOME AREAS MAY FALL BELOW FOR A FEW
HOURS. WE DO NOT EXPECT DURATIONS TO EXCEED 4 HOURS SO NO WATCHES
OR WARNINGS PLANNED AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 49 76 56 77 / 0 0 5 5
FMY 50 78 57 82 / 0 0 5 5
GIF 48 75 54 78 / 0 0 5 5
SRQ 47 75 53 78 / 0 0 5 5
BKV 35 75 39 76 / 0 0 5 5
SPG 54 72 59 75 / 0 0 5 5
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING UNTIL 6 PM EST THIS EVENING FOR CHARLOTTE-
CITRUS-DE SOTO-HARDEE-HERNANDO-HIGHLANDS-HILLSBOROUGH-LEE-
LEVY-MANATEE-PASCO-POLK-SARASOTA-SUMTER.
GULF WATERS...NONE.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...JILLSON
LONG TERM/AVIATION...MCMICHAEL
