786  
FXUS62 KTBW 301830  
AFDTBW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL  
230 PM EDT FRI SEP 30 2016  
   
SYNOPSIS
 
 
ALOFT - A MEANDERING LOW WAS ABOVE THE OHIO RIVER VALLEY REGION.  
SURFACE - HIGH PRESSURE SPRAWLED FROM THE SOUTHERN PLAINS TO THE  
DEEP SOUTH...A STALLED FRONTAL BOUNDARY ALONG THE SOUTHEAST U.S.  
COAST STRETCHED ACROSS NORTH FL AND SOUTHWESTWARD OUT OVER THE  
GULF...AND ATLANTIC HIGH PRESSURE RIDGED INTO SOUTH FL.  
 

 
   
SHORT TERM (REST OF TODAY-SATURDAY)
 
 
THE OHIO RIVER VALLEY LOW LIFTS UP TOWARD THE GREAT LAKES LATE IN  
THE PERIOD. THE FRONTAL BOUNDARY GRADUALLY SLIDES TO THE NORTHWEST  
WHILE SLOWLY WEAKENING...ALLOWING THE SOUTH FL SURFACE RIDGE TO MOVE  
NORTH OVER THE STATE WITH DEEPER MOISTURE SPREADING BACK ACROSS THE  
NATURE COAST AND LOW LEVEL FLOW TO BECOME NORTHEAST AND EAST.  
 
FORECAST THINKING IS THAT DEEP CYCLONIC FLOW WILL CONTINUE THIS  
AFTERNOON WITH GULF AND COASTAL SHOWERS AND STORMS PUSHING INLAND.  
THESE WIND DOWN OVERNIGHT ON LAND BUT CONTINUE ON THE GULF  
THROUGHOUT THE NIGHT. HOWEVER AS THE LOW LEVEL FLOW BECOMES  
NORTHEAST AND EAST - THE GULF CONVECTION STAYS OFFSHORE AS  
SHOWERS/STORMS FORM INLAND IN THE AFTERNOON THEN PUSH TOWARD THE  
GULF COAST LATE IN THE AFTERNOON. INITIALLY PWAT VALUES OF AROUND  
1 INCH TO 1.8 INCHES...FROM NORTH TO SOUTH...INCREASE TO 1.2  
INCHES TO AROUND 2 INCHES LATE SAT. THIS WILL SUPPORT ISOLATED TO  
SCATTERED COVERAGE WITH THE HIGHEST INLAND AND SOUTH.  
   
MID/LONG TERM (SATURDAY NIGHT - FRIDAY)
 
AN UPPER LEVEL CUTOFF  
LOW OVER THE GREAT LAKES REGION AT THE START OF THE PERIOD WILL  
CONTINUE TO WEAKEN AS IT LIFTS OUT TO THE NORTH AND NORTHEAST ACROSS  
NEW ENGLAND THROUGH MONDAY NIGHT WITH AN UPPER LEVEL TROUGH  
PERSISTING ACROSS THE EASTERN U.S AND FLORIDA, WHILE THE UPPER LEVEL  
RIDGING OVER THE ATLANTIC SHIFTS A BIT FURTHER TO THE EAST. AT THE  
SURFACE HIGH PRESSURE TO THE NORTH AND TROPICAL CYCLONE MATTHEW WELL  
TO OUR SOUTHEAST WILL SUPPORT AN EAST-NORTHEAST WIND FLOW ACROSS THE  
FORECAST AREA. AMPLE MOISTURE WITHIN THIS FLOW WILL SUPPORT  
SCATTERED TO NUMEROUS SHOWERS AND STORMS ACROSS THE REGION EACH DAY  
THROUGH TUESDAY, MAINLY DURING THE AFTERNOON AND EARLY EVENING HOUR.  
 
FROM MIDWEEK ON THE FORECAST WILL ALL HINGE ON THE EXACT TRACK OF  
MATTHEW. AT THE CURRENT TIME MODEL CONSENSUS ALONG WITH THE OFFICIAL  
NHC TRACK CONTINUES TO MOVE MATTHEW NORTH THROUGH THE BAHAMAS AND  
EAST OF FLORIDA DURING WEDNESDAY AND THURSDAY. GIVEN THIS CURRENT  
TRACK THE FORECAST AREA WOULD BE ON THE DRIER SUBSIDENT SIDE OF THE  
STORM WHICH WOULD GREATLY REDUCE RAIN CHANCES WEDNESDAY THROUGH  
FRIDAY, HOWEVER SEEING THAT THINGS COULD STILL CHANGE WILL KEEP  
CLIMO POPS (20 TO 30 PERCENT RANGE) IN PLACE FOR NOW AND WAIT TO SEE  
HOW THINGS EVOLVE DURING THE NEXT SEVERAL DAYS. WARMING MID LEVEL  
TEMPERATURES ASSOCIATED WITH MATTHEW SHOULD KEEP THUNDERSTORM  
CHANCES ON THE LOW SIDE WEDNESDAY THROUGH FRIDAY WITH BREEZY, WARM  
AND MUGGY CONDITIONS WITH TROPICAL SHOWERS EXPECTED. ALL RESIDENTS  
AND VISITORS OF WEST CENTRAL AND SOUTHWEST FLORIDA SHOULD MONITOR  
THE PROGRESS OF MATTHEW THROUGH THE UPCOMING WEEKEND. FOR ADDITIONAL  
INFORMATION ON MATTHEW, SEE THE LATEST ADVISORIES BEING ISSUED BY  
THE NATIONAL HURRICANE CENTER IN MIAMI.  
 
TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD  
WITH OVERNIGHT LOWS IN THE LOWER TO MID 70S FROM NORTH TO SOUTH,  
WITH DAYTIME HIGHS IN THE MID TO UPPER 80S. OF NOTE IF DRIER AIR  
DOES IN FACT ADVECT INTO THE REGION FROM MIDWEEK ON THEN OVERNIGHT  
LOW TEMPERATURES COULD BE A FEW DEGREES COOLER THAN CURRENTLY  
FORECAST.  
 

 
   
AVIATION
 
 
30/18Z-01/18Z. PREVAILING VFR ALTHOUGH BRIEF MVFR/LCL IFR IN VCNTY  
SHRA/TSRA MOVING EAST DURING THE MID TO LATE AFTERNOON.  
WESTERLY WINDS SHIFT TO NE BY EARLY SAT...KEEPING NOCTURNAL GULF  
SHOWERS AND STORMS AWAY FROM COASTAL TERMINALS. BYD 01/18Z...INLAND  
TSRA WILL APPROACH THE TERMINALS FROM THE EAST MID TO LATE AFTERNOON.  
 

 
   
MARINE
 
 
A WEAK SURFACE HIGH PRESSURE SOUTH OF THE WATERS WILL MOVE  
NORTH DURING THE NEXT FEW DAY...WITH WESTERLY WINDS BECOMING  
NORTHEAST AND EAST. INITIALLY WINDS WILL BE LIGHT BUT INCREASE  
DURING NEXT WEEK AS THE GRADIENT TIGHTENS...IN RESPONSE TO TROPICAL  
CYCLONE MATTHEW. MARINE INTERESTS SHOULD MONITOR THE LATEST ADVISORIES  
FROM THE NATIONAL HURRICANE CENTER IN MIAMI.  
 

 
   
FIRE WEATHER
 
 
THE LIMITED DRY AIR ACROSS THE FAR NORTH THIS AFTERNOON WILL BE  
REPLACED BY DEEP MOISTURE SPREADING WEST AND NORTH. THIS MOISTURE  
CONTINUES AREA WIDE FOR THE NEXT FEW DAYS WITH NO LOW RH ISSUES.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
TPA 72 88 75 89 / 10 30 30 50  
FMY 74 90 74 90 / 10 40 30 60  
GIF 70 88 73 90 / 20 40 20 60  
SRQ 73 87 74 90 / 10 30 30 50  
BKV 67 87 70 90 / 10 30 20 50  
SPG 75 87 76 89 / 10 30 30 50  
 

 
   
TBW WATCHES/WARNINGS/ADVISORIES
 
 
FL...BEACH HAZARDS STATEMENT THROUGH MONDAY EVENING FOR COASTAL  
CHARLOTTE-COASTAL LEE-COASTAL MANATEE-COASTAL  
SARASOTA.  
 
GULF WATERS...NONE.  

 
 

 
 
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...09/RUDE  
MID TERM/LONG TERM/DECISION SUPPORT...57/MCMICHAEL  
 
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