NWS TBW Forecast Discussion

Sun Feb 1 10:57:32 PST 2009

AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL  
102 PM EST SUN FEB 1 2009  

.PARTLY CLOUDY SKIES FOR TONIGHT'S SUPER BOWL  

SYNOPSIS...HIGH PRESSURE IS DOMINATING OUR WEATHER TODAY  
WHEREAS   
THE FLOW ALOFT STARTING TO BREAK AWAY FROM A ZONAL PATTERN. A SERIES   
OF IMPULSES ARE NOTED MOVING ACROSS THE DEEP SOUTH/NORTHERN GULF OF   
MEXICO IN THE LATEST WATER VAPOR IMAGERY.  

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SHORT RANGE (TONIGHT-TUESDAY)  
EXPECT MOISTURE TO CONTINUE TO POOL   
UNDERNEATH THE SUBSIDENCE INVERSION AT AROUND 6000 FEET TONIGHT   
KEEPING PERIODS OF CLOUD COVER ACROSS THE REGION. THE IMPULSES ALOFT   
OVER THE GULF ARE FORECAST TO PRODUCE CYCLOGENESIS OVER THE CENTRAL   
OR NORTH CENTRAL GULF. THE CIRCULATION WILL BE SMALL SCALE...BUT   
GIVEN THE QUICK PRESSURE GRADIENT MOVING ACROSS THE STATE SHOULD   
PACK A LITTLE PUNCH MONDAY AFTERNOON AND EVENING. GIVEN THE SMALL   
NATURE OF THE SYSTEM THE WIND DIRECTION FORECAST IS DIFFICULT...AND   
WILL GO WITH A GFS/NAM/WRF BLEND.   

AS FOR RAIN CHANCES...MODEL CROSS SECTIONS ALL INDICATE QUITE A BIT   
OF MID LEVEL LIFT AND MOISTURE BEGINNING AT 12Z MONDAY...PRETTY MUCH   
AREAWIDE IN RESPONSE TO THE DEVELOPING LOW. GIVEN AN EXPECTED PATH   
ACROSS SOUTH FLORIDA DURING THE AFTERNOON...WOULD ONLY EXPECT   
SURFACE-BASED DEVELOPMENT IF ANY DOWN THERE. WILL PLACE THE BEST   
CHANCE FOR STORM DEVELOPMENT THERE...BUT GIVEN MID LEVEL INSTABILITY   
CANNOT RULE OUT AN ISOLATED STORM OR TWO FARTHER NORTH TO TAMPA BAY.  

WHAT IS CERTAIN IS THAT AS THE LOW CROSSES THE STATE IT WILL PUSH A   
COLD FRONT THROUGH...ALLOWING HIGH PRESSURE TO BUILD IN AND MAKING   
FOR A WINDY DAY TUESDAY. TEMPERATURES WILL STRUGGLE TO HIT THE UPPER   
50S ACROSS THE NATURE COAST...60 OVER THE TAMPA BAY AREA AND THE MID   
60S ACROSS SW FLORIDA.  

LONG RANGE (TUESDAY NIGHT-SUNDAY)  
A REINFORCING COLD FRONT WILL   
SWEEP SOUTHEAST THROUGH THE FORECAST AREA TUESDAY NIGHT AND EARLY   
WEDNESDAY MORNING AS SHORT WAVE ENERGY MOVES THROUGH THE BASE OF THE   
EASTERN U.S. LONG WAVE TROUGH. THIS FRONT WILL USHER IN A VERY COLD   
DRY ARCTIC AIR MASS ON A BRISK NORTHWEST TO NORTHERLY WIND FLOW WITH   
AN ADVECTIVE FREEZE LIKELY OVER THE NATURE COAST WITH NEAR FREEZING   
TEMPERATURES EXTENDING SOUTH INTO THE CENTRAL AND SOUTHERN PENINSULA   
BY EARLY WEDNESDAY MORNING. BRISK WINDS WILL LIKELY SUPPORT LOW WIND   
CHILLS WITH VALUES IN THE TEENS OVER THE NATURE COAST AND UPPER 20S   
TO ~30 ACROSS THE REMAINDER OF THE FORECAST AREA. WITH THE GFS   
SHOWING 850MB TEMPS PLUMMETING INTO THE 0 TO -5C RANGE HAVE LOWERED   
MIN TEMPS SOME FOR TUESDAY NIGHT INTO WEDNESDAY MORNING WHICH IS IN   
LINE WITH THE LATEST MEX AND 01/00Z ENSEMBLE TEMP GUIDANCE.   

ON WEDNESDAY STRONG SURFACE HIGH PRESSURE WILL BUILD IN OVER THE LOWER  
MISSISSIPPI VALLEY IN THE WAKE OF THE FRONT. STRONG COLD AIR ADVECTION   
WILL LIKELY CREATE CONSIDERABLE COLD-AIR STRATO-CU OVER THE ADJACENT   
GULF WATERS WITH SOME OF THESE CLOUDS LIKELY TO AFFECT MY COASTAL ZONES  
EARLY ON WEDNESDAY BEFORE THE FLOW BECOMES MORE NORTHERLY LATE IN THE  
DAY. IT WILL BE QUITE CHILLY ON WEDNESDAY WITH HIGH TEMPS FORECAST TO  
RUN SOME 15-18 DEGREES BELOW NORMAL WITH HIGHS ONLY REACHING THE LOWER  
50S NORTH...MID 50S CENTRAL...AND UPPER 50S TO ~60 FAR SOUTH.    

THE SURFACE HIGH WILL SETTLE IN OVER THE SOUTHEASTERN STATES WEDNESDAY  
NIGHT...THEN SINK SOUTH ACROSS THE NORTHERN PENINSULA THURSDAY NIGHT  
INTO EARLY FRIDAY. CLEAR SKIES AND A LIGHT NORTHERLY DRAINAGE FLOW DOWN  
THE SPINE OF THE PENINSULA WILL SET THE STAGE FOR STRONG RADIATIONAL   
COOLING BOTH NIGHTS WITH HARD FREEZE (LOW TEMPS 20-25 DEGREES) CONDITIONS  
A GOOD BET ACROSS THE NATURE COAST...AND FREEZING TEMPERATURES POSSIBLE  
AS FAR SOUTH AS FORT MYERS...WITH DAYTIME HIGHS ON THURSDAY REMAINING  
WELL BELOW NORMAL WITH HIGHS AGAIN ONLY REACHING THE 50S NORTH INTO   
CENTRAL ZONES AND ~60 FAR SOUTH DESPITE AMPLE SUNSHINE.   

DURING FRIDAY THROUGH SUNDAY THE SURFACE HIGH WILL SHIFT EAST INTO THE  
WESTERN ATLANTIC. EASTERLY RETURN FLOW AROUND THE HIGH WILL ALLOW THE  
VERY COLD/DRY AIR MASS TO MODIFY WITH PARTLY CLOUDY SKIES EXPECTED  
EACH DAY THROUGH THE PERIOD WITH TEMPERATURES SLOWLY CLIMBING BACK TOWARD  
CLIMATIC NORMS.  

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AVIATION  
A CONTINUED SLOW INCREASE IN LOW AND MID LEVEL MOISTURE   
WILL SUPPORT INCREASING AND THICKENING CLOUDS AT ALL TERMINAL SITES   
THROUGH THE REMAINDER OF THE AFTERNOON AND OVERNIGHT TIME PERIODS   
BUT CEILING HEIGHTS AOA 4KFT WILL MAINTAIN VISUAL FLIGHT RULES   
THROUGH THE PERIOD. VFR CONDITIONS EARLY ON MONDAY WILL LOWER INTO   
THE MVFR RANGE BY MID TO LATE MORNING AND CONTINUE THROUGH THE   
AFTERNOON AS AREAS OF LIGHT RAIN...SHOWERS...AND MIST DEVELOP OVER   
THE REGION AHEAD OF AN AREA OF LOW PRESSURE MOVING EAST OVER THE   
EASTERN GULF OF MEXICO. LIGHT SOUTHEAST SURFACE WINDS IN THE 5-10   
KNOT RANGE CAN BE EXPECTED OVERNIGHT...WITH WINDS BECOMING SOUTH TO   
SOUTHWEST ~10 KNOTS ON MONDAY. WITH THE APPROACH OF THE   
AFOREMENTIONED LOW PRESSURE AREA...LOW AND MID LEVEL WINDS WILL BE   
ON THE INCREASE ON MONDAY WITH AN INCREASED RISK FOR LOW LEVEL WIND   
SHEAR FROM MID DAY ON.  

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MARINE  
WILL SEE SOME RAINS BEGINNING LATE TONIGHT ACROSS OUR  
WATERS AND BECOMING MORE WIDESPREAD DURING THE DAY MONDAY. LOW  
PRESSURE DEVELOPING OVER THE GULF WILL BRING SOME WINDS TO THE  
WATERS...BUT EXACT LOCATION OF WIND MAX IS DIFFICULT TO PINPOINT.  
EXERCISE CAUTION OR ADVISORY CONDITIONS ARE POSSIBLE WITH THE  
RAINS MONDAY AND ARE LIKELY MONDAY NIGHT AND TUESDAY.  

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FIRE WEATHER  
AS THE DRIEST AIR PUSHES IN BEHIND THE COLD  
FRONT...WILL HAVE RED FLAG CONDITIONS OVER THE NORTHERN THREE  
COUNTIES TUESDAY AFTERNOON. MAY GET THOSE FARTHER SOUTH AS  
WELL...BUT FOR NOW HAVE ENOUGH CONFIDENCE TO GO WITH A WATCH UP  
THERE.   

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PRELIMINARY POINT TEMPS/POPS  

TPA  52  64  51  60 /  10  80  40  10   
FMY  53  71  56  64 /  10  70  50  20   
GIF  51  63  51  60 /  10  80  40  10   
SRQ  51  65  53  61 /  10  80  40  10   
BKV  44  62  44  57 /  10  80  40  10   
SPG  54  63  52  59 /  10  80  40  10   

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TBW WATCHES/WARNINGS/ADVISORIES  

FL...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR CITRUS-LEVY-SUMTER.  

GULF WATERS...NONE.  

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SHORT TERM/MARINE/FIRE WEATHER...55/SHARP  
LONG TERM/AVIATION...57/MCMICHAEL  

CLICK HERE TO GO TO PREVIOUS BULLETINS.----- Original Message ----- From: "Thomas F. Giella KN4LF" <kn4lf at tampabay.rr.com>To: <kn4lf at tampabay.rr.com>Sent: Sunday, February 01, 2009 6:30 AMSubject: Another Big Freeze On The Way?!> Guys & Gals,> > It looks like we are still on track for some strong storms during the > Monday-Tuesday 02/02-03/2009 period. It appears that the surface > extratropical (cold) low will cross the peninsula and given that and other > strong atmospheric dynamics some isolated severe weather is possible.> > During the Wednesday-Friday 02/04-06/2009 period another significant freeze > event is probable with the coldest day being the 5th.. Minimum temperatures > could drop as low if not lower than the last freeze that occurred between > 01/20-24/2009. In inland rural areas the subfreezing line will extend as far > south as Immokalee in the Everglades.> > As before there is also a slim chance for ocean effect snow showers along > the west coast of the central peninsula, with better chances over NE Florida > on early Wednesday morning the 18th.> > We should then see a mild to warm period between approximately 02/07-14/2009 > followed more cold weather.> > Take Care,> Thomas F. Giella, KN4LF> Lakeland, FL, USA> kn4lf at arrl.net> > CWOP #AR692/KN4LF> CoCoRaHs #FL-PK-18> NWS Skywarn #POL-10A> > Lakeland, FL Daily Climatological Weather Data Archive: > http://www.kn4lf.com/kn4lf22.htm> Harmful Man Induced Climate Change (Global Warming) Refuted: > http://www.kn4lf.com/globalwarminglie.htm> > ----- Original Message ----- > From: "Thomas F. Giella KN4LF" <kn4lf at tampabay.rr.com>> To: <kn4lf at tampabay.rr.com>> Sent: Thursday, January 29, 2009 10:18 PM> Subject: Another Big Freeze For Florida?> > >> Guys and Gals,>>>> Taking a look at the 1200 UTC run of the GFSX forecast model, if it >> verifies>> the weather could get pretty rough in Florida on February 3-4, 2009.>>>> It looks like the surface low may undergo bombogenesis after crossing the>> state. It kind of reminds me of the March 1993 superstorm misnamed as>> the "no named" hurricane by the media.>>>> So the bottom line is that if the model verifies Florida could see a >> severe>> weather outbreak followed by another significant freeze event.>>>> 73 & GUD DX,>> Thomas F. Giella, KN4LF>> Lakeland, FL, USA>> kn4lf at arrl.net>>>> KN4LF Amateur & SWL Radio Autobiography: http://www.kn4lf.com
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