FXUS62 KTBW 111811
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
111 PM EST FRI DEC 11 2009
.SHORT TERM (TONIGHT-SUNDAY)...MID TO UPPER SW FLOW TO CONTINUE
OVER THE REGION TONIGHT THROUGH SUNDAY WHILE COOL SURFACE HIGH
PRESSURE OVER THE CAROLINAS TONIGHT MOVES INTO THE WESTERN
ATLANTIC THIS WEEKEND. STALLED FRONT OVER EXTREME SOUTHERN FL TO
SLOWLY MOVE NWARD AS WARM FRONT DURING THE DAY SATURDAY WITH
INCREASING LOW LEVEL MOISTURE AND TEMPERATURES S OF THE FRONT.
MODELS DIFFER ON EXACT TIMING OF THIS...WITH THE GFS SLIGHTLY
FASTER THAN THE NAM. THE FASTER MOVEMENT WOULD INCREASE MAX TEMPS
SATURDAY IN THE WAKE OF THE FRONT WHILE THE SLOWER MOVEMENT WOULD
KEEP MOST OF THE AREA COOLER. BUT WILL CONTINUE OVERCAST SKIES
WITH ISENTROPIC LIFT OVER THE FRONT AND CHANCES FOR LIGHT TO
MODERATE RAIN AREAWIDE WITH THE BEST CHANCES OVER NORTHERN AREAS
WITH BEST LIFT TONIGHT THROUGH SATURDAY. ON SUNDAY LOW PRESSURE
AREA ON THE FRONT OVER N FLORIDA TO PUSH EAST WITH TRAILING FRONT
DRAPED OVER THE DEEP SOUTH. SLIGHTLY DRIER MID TO UPPER CONDITIONS
FOR THE CENTRAL AND SOUTHERN AREAS AND HAVE DROPPED POPS IN THE
SLIGHT CHANCE CATEGORY WITH WARMING TEMPERATURES THERE.
.LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...BEGINS WITH AN UPPER
TROUGH OVER THE WESTERN U.S. AS RIDGING...CENTERED OVER THE
GREATER ANTILLES...EXTENDS NORTH TO THE SOUTHEASTERN STATES. AT
THE SURFACE...A LOW OVER THE PLAINS TRAILS A FRONT SOUTH OVER TX TO
NORTHERN MEXICO WHILE HIGH PRESSURE OVER THE ATLANTIC RIDGES WEST
ACROSS FL TO THE GULF. WITH TIME THE WESTERN TROUGH AND ASSOCIATED
SURFACE FEATURES SLIDE EAST AS THE RIDGE...BOTH SURFACE AND
ALOFT...OVER THE AREA EXITS. THE TIMING OF THE FRONT MOVING OVER THE
GULF AND FL IS ABOUT MID-WEEK...TUE THROUGH WED. THEN A SURFACE HIGH
DROPS SOUTHEASTWARD OUT OF THE CANADIAN PRAIRIES AS UPPER RIDGING
BUILDS NORTH OVER THE WESTERN STATES FOR THE END OF THE WEEK.
THE RIDGING EARLY IN THE WEEK WILL KEEP TEMPERATURES WARM AND
PROVIDE ENOUGH STABILITY TO PRECLUDE ANY SIGNIFICANT PRECIPITATION.
THEN THE FRONT MID-WEEK BRINGS A CHANCE TO SLIGHT CHANCE OF SHOWERS
AND ISOLATED THUNDERSTORMS...ALONG WITH SOME RATHER ROBUST WINDS -
ESPECIALLY ON THE GULF - IN ITS WAKE. THE CANADIAN HIGH SETTLES IN
OVER THE SE U.S. BY THU AND FRI...PUSHING THE FRONT DOWN ACROSS THE
STRAITS...WITH COOLER TEMPERATURES GENERALLY BELOW NORMAL AND SOME
DRIER AIR CREATING POSSIBLE FIRE WEATHER CONCERNS IN THE FAR NORTH.
&&
.AVIATION...THERE HAVE BEEN A FEW BREAKS IN THE CLOUD COVER LATE
THIS MORNING BUT EXPECT MVFR CIGS WILL RULE FOR THE NEXT 24 HOURS.
OVERRUNNING AS A FRONTAL BOUNDARY ACROSS FAR SOUTH FL BEGINS TO LIFT
NORTH TONIGHT WILL PROVIDE VCSH TONIGHT AND SAT MORNING ALONG WITH
SOME LATE NIGHT TEMPO IFR CIGS. NE WINDS VEER TO MORE EASTERLY BY
THE END OF THE PERIOD.
&&
.MARINE...4-6MB GRADIENT TO REMAIN OVER THE E GULF THIS AFTERNOON INTO
SATURDAY MORNING AND COMBINE WITH EASTERLY SURGE THIS EVENING THEN
FUNNELING OF WINDS UNDER THE OVERNIGHT INVERSION TO KEEP SMALL
CRAFT ADVISORIES IN PLACE ALL ZONES UNTIL AT LEAST 10 PM TONIGHT
THEN OFFSHORE WATERS OVERNIGHT. GRADIENT OT RELAX SATURDAY AS WARM
FRONT MOVES OVER THE E GULF WITH EASTERLY WINDS AND SEAS SUBSIDING
TO END THE WEEKEND. WEAK GRADIENT OVER THE E GULF TO START NEXT
WEEK AHEAD OF ANOTHER FRONT MID WEEK.
&&
.FIRE WEATHER...LOW LEVEL MOISTURE TO HOLD OVER THE KEEPING RHS UP
INTO NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 58 77 67 82 / 40 50 40 20
FMY 62 81 67 85 / 30 40 30 20
GIF 57 77 65 83 / 40 50 40 20
SRQ 59 78 66 82 / 40 50 30 20
BKV 55 77 63 82 / 40 60 40 30
SPG 58 76 67 80 / 40 50 40 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 AM EST SATURDAY FOR BONITA BEACH
TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR TAMPA BAY
WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM EST
SATURDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...25/DAVIS
LONG TERM/AVIATION...09/RUDE
