990  
FXUS62 KTBW 171827  
AFDTBW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL  
227 PM EDT TUE OCT 17 2017  
   
SHORT TERM (TONIGHT-WEDNESDAY)
 
 
A BROAD UPPER-LEVEL TROUGH CONTINUES ACROSS THE EASTERN U.S. THIS  
AFTERNOON WITH A SHORTWAVE WITHIN THIS TROUGH DROPPING SOUTHWARD  
THROUGH ALABAMA AND GEORGIA. AT THE SURFACE, THE WEAK FRONTAL  
BOUNDARY IS SLOWLY MOVING SOUTHEASTWARD ACROSS THE NORTHERN PART OF  
THE FORECAST AREA, MARKED BY LOWER DEW POINTS AND A SMALL WIND  
SHIFT. SCATTERED SHOWERS AND A FEW EMBEDDED THUNDERSTORMS CONTINUE  
TO MAKE THEIR WAY GENERALLY SOUTHWESTWARD AND THIS SHOULD CONTINUE  
THROUGH THE REST OF THE AFTERNOON AND EVENING.  
 
FOR TONIGHT, THE SHORTWAVE WILL WEAKEN AND GRADUALLY SHIFT EASTWARD  
AS THE RIDGE OVER THE SOUTHWEST U.S. SHIFTS EASTWARD AS WELL.  
SURFACE HIGH PRESSURE WILL BUILD MORE FIRMLY ALONG THE MID-ATLANTIC  
COAST, WITH AN INCREASING PRESSURE GRADIENT LEADING TO INCREASING  
NORTHEASTERLY WINDS ACROSS OUR FORECAST AREA. MOST OF THE AREA  
SHOULD BE DRY TONIGHT, BUT CANNOT RULE OUT A FEW SHOWERS MAKING  
THEIR WAY OVER THE INTERIOR ON THOSE NORTHEAST WINDS.  
 
THE RIDGE ALOFT WILL CONTINUE TO SHIFT EASTWARD OVER THE WESTERN AND  
CENTRAL GULF OF MEXICO ON WEDNESDAY WITH THE SURFACE HIGH SHIFTING  
EASTWARD A BIT BUT STILL KEEPING BREEZY NORTHEAST WINDS IN PLACE AND  
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. TEMPERATURES WILL REBOUND  
BACK INTO THE MID-80S FOR MOST AREAS WEDNESDAY AFTERNOON, WITH DEW  
POINTS IN THE UPPER 60S TO LOWER 70S. THE NATURE COAST WILL LIKELY  
BE A BIT COOLER AND DRIER STILL, WITH LOWER RAIN CHANCES.  
   
LONG TERM (WEDNESDAY NIGHT-MONDAY)
 
 
UPPER TROUGH OVER THE REGION MOVES INTO THE WESTERN ATLANTIC AS  
UPPER RIDGING BUILDS THROUGH THE GULF OF MEXICO THEN OVER THE STATE  
TO END THE WEEK AND INTO THE WEEKEND. LARGE SURFACE HIGH PRESSURE  
CENTERED OVER THE EASTERN U.S. TO GET RE-ENFORCED ALONG THE EASTERN  
SEABOARD THIS WEEKEND. THESE FEATURES TO KEEP EASTERLY LOW LEVEL  
FLOW OVER THE FORECAST AREA TO END THE WEEK AND INTO THE WEEKEND.  
LIMITED MEAN LAYER MOISTURE TO KEEP POPS IN THE 20-30 PERCENT RANGE  
WITH BEST CHANCES IN SOUTHERN AND INTERIORS ZONES. TEMPS TO REMAIN  
ON THE WARM SIDE RUNNING 2-4 DEGREES ABOVE SEASONAL AVERAGES.  
 
NEXT POSSIBLE SYSTEM FOR THE REGION AT THE END OF THE FORECAST  
PERIOD AS AN UPPER TROUGH DIGS FROM THE PLAINS INTO THE GULF REGION,  
THAT WOULD PUSH COLD FRONT INTO THE REGION MONDAY WITH INCREASING  
MOISTURE AND RAIN CHANCES.  
 

 
   
AVIATION
 
 
VFR WITH SOME OCCASIONAL MVFR CIGS CONTINUE ACROSS AREA TERMINALS  
THIS AFTERNOON. A FEW SHOWERS WILL BE POSSIBLE LATER THIS AFTERNOON  
AND EVENING, BUT THEN MOSTLY DRY CONDITIONS ARE EXPECTED OVERNIGHT.  
WINDS WILL REMAIN EASTERLY AND A BIT GUSTY THIS AFTERNOON, THEN WILL  
DECREASE SOME TONIGHT.  
 

 
   
MARINE
 
 
HIGH PRESSURE WILL BUILD INTO THE MID-ATLANTIC REGION AND REMAIN IN  
PLACE THROUGH THE REST OF THE WEEK, WITH NORTHEAST WINDS INCREASING  
TO CAUTIONARY OR ADVISORY LEVELS FOR ALL OF THE COASTAL WATERS. A  
SMALL CRAFT ADVISORY WILL BE IN EFFECT FOR THE GULF WATERS FROM  
ENGLEWOOD TO THE SUWANNEE RIVER AND INCLUDING TAMPA BAY THROUGH  
WEDNESDAY. THERE COULD BE A PERIOD OF SUB-ADVISORY WINDS DURING THE  
DAY, BUT THEY SHOULD THEN INCREASE AGAIN WEDNESDAY NIGHT, SO THE  
ADVISORY MAY NEED TO BE EXTENDED FURTHER OUT IN TIME.  
 

 
   
FIRE WEATHER
 
 
A COLD FRONT ACROSS THE NORTHERN PART OF THE PENINSULA TODAY AND  
TONIGHT WILL BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE  
REGION. HIGH PRESSURE BUILDING OVER THE MID-ATLANTIC REGION WILL  
RESULT IN NORTHEAST WINDS THROUGH THE REST OF THE WEEK, WITH DAILY  
CHANCES FOR SHOWERS. RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE  
CRITICAL LEVELS, WITH NO CONCERNS. SOME PATCHY GROUND FOG WILL BE  
POSSIBLE, BUT WIDESPREAD DENSE FOG IS NOT EXPECTED.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
TPA 71 85 71 87 / 10 10 10 20  
FMY 72 86 71 87 / 20 20 10 30  
GIF 70 83 70 85 / 10 20 10 30  
SRQ 71 85 71 85 / 10 10 10 30  
BKV 68 84 68 86 / 10 10 10 20  
SPG 71 85 72 87 / 10 10 10 20  
 

 
   
TBW WATCHES/WARNINGS/ADVISORIES
 
 
FL...NONE.  
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 AM EDT WEDNESDAY FOR COASTAL  
WATERS FROM ENGLEWOOD TO TARPON SPRINGS FL OUT 20 NM-  
COASTAL WATERS FROM TARPON SPRINGS TO SUWANNEE RIVER  
FL OUT 20 NM-TAMPA BAY WATERS-WATERS FROM ENGLEWOOD  
TO TARPON SPRINGS FL OUT 20 TO 60 NM-WATERS FROM  
TARPON SPRINGS TO SUWANNEE RIVER FL OUT 20 TO 60 NM.  
 

 
 

 
 
SHORT TERM/AVIATION/MARINE/FIRE WEATHER...05/CARLISLE  
MID TERM/LONG TERM/DECISION SUPPORT...25/DAVIS  
 
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