863  
FXUS62 KTBW 181123  
AFDTBW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL  
723 AM EDT WED JUL 18 2018  
   
AVIATION
 
 
SCATTERED SHRA/TSRA MOVING IN FROM THE GULF WITHIN A VERY  
MOIST DEEP LAYERED SOUTHWEST WIND FLOW WILL BRING BRIEF MVFR  
CIGS/VSBYS TO THE TERMINALS SITES THROUGH 00Z TONIGHT WITH  
ADDITIONAL BRIEF MVFR CONDITIONS POSSIBLE AT THE COASTAL  
TERMINALS AFTER 08Z THURSDAY MORNING AS MORE SHRA/TSRA MOVE  
ONSHORE. OUTSIDE OF THE CONVECTION VFR WILL PREVAIL DURING  
THE NEXT 24 HOURS. SOUTHWEST WINDS AROUND 5 KNOTS EARLY THIS  
MORNING WILL INCREASE TO 7 TO 10 KNOTS AFTER 15Z WITH HIGHER  
GUSTS NEAR TSRA. SOUTHWEST WINDS WILL DIMINISH TO 5 KNOTS  
OR LESS AFTER 01Z TONIGHT.  
 

 
   
PREV DISCUSSION
 
/ISSUED 419 AM EDT WED JUL 18 2018/  
 
SHORT TERM (TODAY - THURSDAY)...  
A TROUGH WILL SETTLE INTO NORTHERN FL THROUGH THE PERIOD  
WITH AN UPPER TROUGH ALSO IN PLACE PROVIDING ENHANCED UPPER  
ENERGY AS WEAK SURFACE RIDGING REMAINS ACROSS SOUTH FL.  
THIS WILL KEEP A GENERALLY SW FLOW ACROSS THE AREA THROUGH  
THE PERIOD, AND ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND  
STORMS EACH DAY, WITH THE HIGHEST CHANCES IN THE NORTH.  
STORMS ARE EXPECTED TO START OVER THE COASTAL WATERS AND  
ALONG THE COAST IN THE EARLY MORNING HOURS, THEN INCREASING  
IN COVERAGE AND SHIFTING INLAND THROUGH THE LATE MORNING AND  
AFTERNOON. HIGHS WILL BE IN THE UPPER 80S TO LOWER 90S EACH  
AFTERNOON, WITH LOWS IN THE MID 70S INLAND TO AROUND 80  
ALONG THE COAST.  
 
LONG TERM (THURSDAY NIGHT - TUESDAY)...  
STARTING OUT THE LONG TERM PERIOD, SUB-TROPICAL RIDGING FROM  
THE ATLANTIC EXTENDS WEST-SOUTHWEST OVER SOUTHERN FLORIDA  
AND INTO THE SOUTHEASTERN GULF OF MEXICO. FARTHER NORTH, THE  
FLOW IS MORE AMPLIFIED WITH RIDGING EXTENDING OVER THE  
NORTHEAST U.S. FARTHER TO THE NORTHWEST, A CLOSED UPPER LOW  
OVER MINNESOTA WITH ASSOCIATED TROUGHING EXTENDING SOUTH-  
SOUTHEAST MOVES EASTWARD THROUGH THE END OF THE WEEK. LATE  
FRIDAY INTO SATURDAY, THE RIDGE UP NORTH WILL MOVE NORTHEAST  
OVER THE CANADIAN MARITIMES AS A CLOSED UPPER LOW OVER THE  
WESTERN GREAT LAKES AND ASSOCIATED TROUGHING MOVES  
SOUTHEAST. THIS TROUGH WILL BECOME THE DOMINANT UPPER  
FEATURE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK CAUSING  
THE SUB-TROPICAL RIDGE EAST OF FLORIDA TO SHIFT FARTHER  
EASTWARD.  
 
ON THE SURFACE, HIGH PRESSURE SOUTHEAST OF BERMUDA RIDGES  
SOUTHWEST OVER THE BAHAMAS, SOUTHERN FLORIDA AND INTO THE  
SOUTHERN GULF OF MEXICO. FARTHER NORTH, AN AREA OF LOW  
PRESSURE EAST OF NOVA SCOTIA EXTENDS A FRONTAL BOUNDARY  
SOUTHWEST THROUGH THE WESTERN ATLANTIC, THROUGH GEORGIA AND  
THEN WESTWARD TO LOUISIANA. WITH THE HIGH PRESSURE NEAR  
BERMUDA CONTINUING TO RIDGE SOUTHWEST OVER SOUTH FLORIDA AND  
HIGH PRESSURE OVER NEW ENGLAND, THIS FRONT WILL STALL OUT  
OVER NORTHERN FLORIDA THROUGH THE WEEKEND. WINDS ARE  
EXPECTED TO REMAIN OUT OF THE WEST THROUGH SOUTHWEST THROUGH  
THE PERIOD, WHICH WILL ALLOW FOR ABUNDANT MOISTURE TO BE  
ADVECTED OVER THE REGION, WITH THE HIGHEST PW VALUES  
(2.0-2.4 INCHES) OVER THE NATURE COAST AND (1.25-2.0 INCHES)  
FROM TAMPA BAY SOUTHWARD. HIGHER PW VALUES COMBINED WITH  
THE PROXIMITY TO THE FRONT OVER NORTHERN FLORIDA WILL  
PRODUCE THE HIGHEST POPS (50-70 PERCENT) FARTHER NORTH ALONG  
THE NATURE COAST WITH LOWER POPS (20-50 PERCENT) EXPECTED  
FROM TAMPA BAY SOUTHWARD. TEMPERATURES WILL REMAIN WARM AND  
MUGGY WITH DAYTIME HIGHS IN THE UPPER 80S TO THE LOW 90S.  
 
MARINE...  
GENERALLY SW FLOW WILL BE IN PLACE THROUGH THE WEEK WITH  
HIGH PRESSURE TO THE SOUTH AND A TROUGH TO THE NORTH.  
SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL BE POSSIBLE  
EACH DAY, MAINLY IN THE OVERNIGHT AND MORNING HOURS. WINDS  
AND SEAS ARE EXPECTED TO REMAIN BELOW CAUTIONARY LEVELS  
THROUGH THE PERIOD.  
 
FIRE WEATHER...  
NO CONCERNS.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
TPA 89 79 89 78 / 70 50 60 50  
FMY 92 77 93 77 / 30 30 30 10  
GIF 91 76 91 76 / 60 20 60 20  
SRQ 90 80 89 79 / 60 50 60 30  
BKV 89 76 89 75 / 70 50 70 50  
SPG 88 80 88 79 / 70 60 60 40  
 

 
   
TBW WATCHES/WARNINGS/ADVISORIES
 
 
FL...NONE.  
GULF WATERS...NONE.  

 
 

 
 
AVIATION...57/MCMICHAEL  
SHORT TERM/MARINE/FIRE WEATHER...24/HUBBARD  
LONG TERM...74/WYNN  
 
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