358  
FXUS62 KTBW 201956  
AFDTBW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL  
256 PM EST FRI DEC 20 2024  
   
..NEW DISCUSSION, MARINE, FIRE WEATHER  
 
   
DISCUSSION  
 
ISSUED AT 255 PM EST FRI DEC 20 2024  
 
A REINFORCING COLD FRONT WILL SWEEP ACROSS THE AREA THIS EVENING  
WITH A DEEP NORTHERLY FLOW SETTING UP IN ITS WAKE AS WE HEAD INTO  
THE WEEKEND. THIS WILL FAVOR MORE NOTABLE COLD AIR ADVECTION THAN  
WHAT OCCURRED WITH THE INITIAL FRONTAL BOUNDARY YESTERDAY WITH LOWS  
DIPPING DOWN INTO THE 30S ACROSS THE NATURE COAST TONIGHT AND 40S  
FOR THE REMAINDER OF THE AREA. THE CHILLY AND DRY NORTHERLY FLOW  
WILL REMAIN IN PLACE ON SATURDAY AND DESPITE MAINLY SUNNY SKIES,  
HIGHS WILL STRUGGLE TO REACH THE 60S ACROSS THE NATURE COAST WITH  
LOW TO MID 60S FOR THE REMAINDER OF THE WEST CENTRAL AND  
SOUTHWEST FLORIDA, WHICH MEANS TEMPERATURES WILL BE AROUND 10  
DEGREES OR LESS BELOW CLIMATOLOGICAL NORMAL VALUES FOR THIS TIME  
OF THE YEAR. IT WILL ALSO BE A FEW DEGREES COLDER SATURDAY NIGHT  
COMPARED TO TONIGHT WITH LOWS POSSIBLY REACHING NEAR FREEZING  
ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA WHERE FROST  
HEADLINES MAY BE NEEDED, BUT THE REMAINDER OF THE AREA SHOULD  
MOSTLY BE IN THE LOW/MID 40S.  
 
AN EXPANSIVE AREA OF HIGH PRESSURE ACROSS THE EASTERN US WILL SLIDE  
OFF THE NORTHEAST COAST EARLY NEXT WEEK WITH THE LOW LEVEL FLOW  
VEERING TO A MORE NORTHEASTERLY DIRECTION. THIS WILL PROMOTE A  
GRADUAL WARMING TREND BEGINNING ON SUNDAY AND CONTINUING INTO LATE  
WEEK WITH TEMPERATURES RETURNING TO CLIMATOLOGICAL NORMAL VALUES BY  
MONDAY AND VALUES REACHING ABOVE NORMAL BY CHRISTMAS EVE ON TUESDAY.  
MEANWHILE, SOUTHWESTERLY FLOW ALOFT WILL BECOME ESTABLISHED ACROSS  
THE AREA BY NEXT WEEK AS A SHARP SHORTWAVE TROUGH SWINGS ACROSS THE  
LOWER MISSISSIPPI VALLEY AND BROAD MID LEVEL RIDGING SETS UP IN THE  
CARIBBEAN SEA. AS A RESULT, A MOISTENING TREND IS ALSO EXPECTED TO  
OCCUR WITH DEEP LAYER MOISTURE INCREASING INTO NEXT WEEK AS POPS  
SLIGHTLY INCREASE INTO CHRISTMAS DAY. AS THE NEW WEEK BEGINS, AN  
INVERTED SURFACE TROUGH DEVELOPS IN THE ATLANTIC WATERS OFF THE  
EAST COAST OF FLORIDA WITH SHOWERS MOSTLY OCCURRING ACROSS THE  
EAST COAST BUT MAY OCCASIONALY DRIFT WESTWARD INTO OUR INTERIOR  
AREAS AT TIMES. THIS INVERTED TROUGH MAY REMAIN SOMEWHAT  
STATIONARY FOR MUCH OF THE WEEK AS IT LINGERS IN THE SOUTHWEST  
ATLANTIC AND FURTHER UPSTREAM THE AFOREMENTIONED SHORTWAVE TROUGH  
ACROSS THE LOWER MISSISSIPPI VALLEY ON TUESDAY IS EXPECTED TO  
WEAKEN AND LIFT NORTH OF THE AREA BY WEDNESDAY WITH LITTLE TO NO  
FORCING FOR ASCENT OFFERED FOR OUR AREA SO THIS SHOULD RESULT IN MAINLY  
WEAK LOW-TOPPED SHOWER CHANCES DAILY INTO THE CHRISTMAS DAY  
HOLIDAY. BY LATE WEEK, IT APPEARS THAT UPPER LEVEL RIDGING  
DEVELOPS ACROSS THE EASTERN US DOWNSTREAM OF ANOTHER SOUTHERN  
STREAM SHORTWAVE SWINGS ACROSS THE LOWER MISSISSIPPI VALLEY. THIS  
WILL FEATURE IS EXPECTED TO SUPPORT ANOTHER FRONTAL SYSTEM THAT  
MAY INCREASE RAIN CHANCES TO THE AREA BY THE END OF THE PERIOD,  
BUT DETAILS IN THE TRACK OF THIS FEATURE REMAIN UNCERTAIN WITH  
MODELS STILL NOT IN AGREEMENT ON HOW FAR SOUTH THIS SYSTEM WILL  
TRACK. REGARDLESS, THE WARMEST DAY OF THE WEEK SHOULD OCCUR ON  
THURSDAY WITH THE UPPER LEVEL RIDGE AXIS IN PLACE BEFORE TRENDING  
CLOSER TO NORMAL VALUES BY THE END OF THE WEEK AS THE NEXT  
SHORTWAVE APPROACHES THE AREA.  
 
 
   
AVIATION  
 
(18Z TAFS)  
ISSUED AT 1224 PM EST FRI DEC 20 2024  
 
OCCASIONAL MVFR CIGS COULD OCCUR FOR THE FIRST HOUR OR TWO OF THE  
TAF PERIOD DUE TO PATCHY LOW STRATUS BUT THE LOW STRATUS WILL  
CONTINUE TO ERODE AS DRIER AIR CONTINUES TO FILTER IN. AFTER THE  
LAST OF THE LOW STRATUS ERODES, VFR CONDITIONS ARE THEN EXPECTED  
AREA-WIDE THROUGH THE REMAINDER OF THE PERIOD WITH NORTHERLY WINDS  
AROUND 5 KTS TONIGHT AND 5-10 KTS ON SATURDAY.  
 
 
   
MARINE  
 
ISSUED AT 255 PM EST FRI DEC 20 2024  
 
DRIER AND COOLER AIR WILL CONTINUE TO FILTER INTO THE AREA WITH  
NORTHERLY WINDS INCREASING THROUGH THE END OF THE WEEK AND TO  
START THE WEEKEND. ANOTHER SECONDARY COLD FRONT MOVES THROUGH THE  
GULF WATERS TONIGHT WITH WINDS REACHING CAUTIONARY LEVELS LATER  
TODAY INTO SATURDAY MORNING AND SEAS REACHING 3-4 FEET. WINDS THEN  
BECOME NORTHEASTERLY BY LATE WEEKEND INTO NEXT WEEK WITH SEAS  
SUBSIDING SLIGHTLY AS HIGH PRESSURE TO THE NORTH REMAINS IN  
CONTROL, THOUGH SEAS STILL REMAIN AROUND 1-3 FEET INTO EARLY NEXT  
WEEK.  
 
 
   
FIRE WEATHER  
 
ISSUED AT 255 PM EST FRI DEC 20 2024  
 
A SECONDARY COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT AND  
BRING A REINFORCING SHOT OF COOLER AND DRIER AIR INTO THE WEEKEND  
WITH MINIMUM RH VALUES DROPPING TO NEAR CRITICAL LEVELS ON  
SATURDAY. DRY NORTHERLY WINDS WILL ALSO BE IN PLACE TOMORROW BUT  
WIND SPEEDS SHOULD REMAIN BELOW CRITICAL LEVELS SO RED FLAG  
CONDITIONS ARE NOT EXPECTED AT THIS TIME. WINDS SHIFT TO MORE  
NORTHEASTERLY BY SUNDAY AND EASTERLY BY NEXT WEEK WITH HIGHER  
HUMIDITY VALUES EXPECTED AS DEEPER MOISTURE MOVES INTO THE AREA.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
TPA 71 46 61 44 / 0 0 0 0  
FMY 77 49 66 45 / 0 0 0 0  
GIF 76 46 63 44 / 0 0 0 0  
SRQ 73 49 62 45 / 0 0 0 0  
BKV 70 38 60 35 / 0 0 0 0  
SPG 69 51 60 48 / 0 0 0 0  
 
 
   
TBW WATCHES/WARNINGS/ADVISORIES  
 
FL...NONE.  
GULF WATERS...NONE.  
 
 
 
 
 
DISCUSSION/AVIATION/MARINE/FIRE WEATHER...GIARRATANA  
DECISION SUPPORT...ADAVIS  
UPPER AIR/CLIMATE...ADAVIS  
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