Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 010057
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
857 PM EDT FRI JUL 31 2015

.UPDATE (OVERNIGHT AND SATURDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED NORTHERN
STREAM FLOW CONSISTING OF LONGWAVE RIDGING OVER THE PACIFIC
NORTHWEST/WESTERN CANADA AND DOWNSTREAM TROUGHING INTO THE GREAT
LAKES AND NORTHEASTERN STATES. FOLLOWING THE WESTERN RIDGE
SOUTHWARD WE FIND A RIDGE CENTER OVER THE SOUTHWESTERN
STATES/SOUTHERN PLAINS. THIS CIRCULATION OF THIS RIDGE DOES NOT
QUITE REACH OVER TO OUR REGION...AND LEAVES THE FLORIDA PENINSULA
UNDER A MORE ILL-DEFINED MID-LEVEL FLOW REGIME BETWEEN THIS RIDGE
AND ANOTHER LONGWAVE UPPER RIDGE TO THE EAST OF THE BAHAMAS.

WV IMAGERY CONTINUES TO SHOW OUR REGION UNDER ABUNDANT MID/UPPER
LEVEL MOISTURE WHICH IS CONTRIBUTING TO THE EFFICIENT
CONVECTIVE/RAIN PROCESSES. THE 01/00Z SOUNDING IS MOIST THROUGH
THE EXTENT OF THE TROP WITH A PW VALUE NEAR 2" THIS EVENING.
WINDS JUST ABOVE THE SURFACE ARE RATHER BREEZY OFF THE SOUNDING...
AROUND 25-30KTS...AND THIS EXPLAINS THE GUSTY CONDITIONS WE HAVE
SEEN WITH MANY OF THE MORE ORDINARY LOOKING SHOWERS ON RADAR THIS
PAST AFTERNOON/EARLY EVENING.

REST OF THE OVERNIGHT WILL SEE A SCATTERING OF GUSTY
SHOWERS...MAINLY TO THE NORTH OF CHARLOTTE COUNTY...WITH AN
OVERALL DIMINISHMENT IN COVERAGE AS WE HEAD FURTHER INTO THE
EVENING HOURS. ONLY EXCEPTION WILL BE OVER THE NATURE
COAST...MAINLY NORTH OF BROOKSVILLE WHERE THE CLOSER PROXIMITY TO
THE SURFACE TROUGH SHOULD SUPPORT BETTER CHANCES OF CONTINUED
ON AND OFF SHOWERS THROUGH THE OVERNIGHT. WHILE RAIN CHANCES DROP
BELOW THE LIKELY RANGE FOR MOST OF THE AREA WITHIN THE NEXT FEW
HOURS...WILL KEEP 60-70% POPS UP TOWARD CITRUS...AND ESPECIALLY
LEVY THROUGH THE OVERNIGHT.

ALL INDICATIONS FOR SATURDAY ARE THAT THE MOST WIDESPREAD SHOWER
ACTIVITY AND THE POTENTIAL FOR DECENT RAINFALL TOTALS WILL BE
NORTH OF THE I-4 CORRIDOR...AND EVEN NORTH OF A LINE FROM
BROOKSVILLE TO SUMTERVILLE. THIS PATTERN OF SIGNIFICANT RAINFALL
POTENTIAL OVER OUR FAR NORTHERN ZONES ACTUALLY MAY BE THE PATTERN
THROUGH THE UPCOMING WEEKEND. GIVEN THE SOIL MOISTURE AND COLUMN
MOISTURE...WILL STILL BE LOOKING FOR SCT SHOWERS/STORMS FURTHER
SOUTH...BUT APPEARS AS THROUGH THE FURTHER SOUTH ONE TRAVELS...THE
MORE OF A TYPICAL SUMMER PATTERN WILL PRESENT ITSELF COMPARED TO
THE WIDESPREAD SHOWERS/CLOUDS MANY OF US HAVE CONTENDED WITH FOR
MANY DAYS NOW.

THAT BEING SAID...WILL NEED TO KEEP A CLOSE MONITORING ON GUIDANCE
TRENDS FOR THE RAINFALL POTENTIAL OVER OUR FAR NORTHERN
ZONES...CITRUS/LEVY ESPECIALLY. FLOOD WATCHES ARE CURRENTLY IN
EFFECT FOR SATURDAY/SATURDAY NIGHT DOWN THROUGH DIXIE COUNTY TO
THE SUWANNEE RIVER. THE POTENTIAL EXISTS THAT THESE WATCHES WILL
NEED TO BE EXTENDED SOUTH OF THE RIVER INTO LEVY COUNTY
EVENTUALLY. SINCE THERE IS STILL SOME DISAGREEMENT CONCERNING THE
CORRIDOR OF HEAVIEST RAINFALL THE NEXT 72 HOURS...WITH SOME
RELIABLE GUIDANCE MEMBERS KEEPING THE MOST SIGNIFICANT TOTALS
NORTH OF LEVY COUNTY...WILL HOLD OFF ON ANY FLOOD WATCHES AT THIS
TIME. THE OVERNIGHT SHIFT CAN EVALUATE THE NEXT SET OF GUIDANCE
AND MAKE A MORE INFORMED DECISION ON ANY HAZARDS THAT MAY PRESENT
THEMSELVES BY THE END OF THE WEEKEND.

&&

.AVIATION...
A SCATTERING OF SHOWERS WILL CONTINUE TO IMPACT THE TERMINALS
NORTH OF KPGD THIS EVENING...ALTHOUGH THE POTENTIAL FOR HEAVY RAIN
AND GUSTY WINDS IS DIMINISHING. GENERAL VFR CONDITIONS ARE
EXPECTED...ALTHOUGH BRIEF MVFR CIGS/VIS ARE POSSIBLE WITH ANY OF
THE SHOWERS THROUGH 06Z. VFR CONDITIONS WILL BE AROUND THE REGION
ON SATURDAY AWAY FROM SCT SHOWERS. THE BEST CHANCES FOR THE SHOWERS
WILL BE NORTH OF KSRQ...ALTHOUGH THE MOST WIDESPREAD RAINFALL
POTENTIAL APPEARS IT WILL REMAIN NORTH OF THE I-4 CORRIDOR.

&&

.MARINE...
THE FORECAST WATERS WILL REMAIN BETWEEN A TROUGH OF LOW PRESSURE
NEAR THE FLORIDA PANHANDLE AND THE SUBTROPICAL RIDGE AXIS DOWN
TOWARD THE FLORIDA STRAITS THROUGH AT LEAST THE WEEKEND. THE
GRADIENT BETWEEN THESE FEATURES WILL PROVIDE A GENERAL SOUTHWEST
FLOW ACROSS THE EASTERN GULF OF MEXICO. THE GRADIENT WILL BE
STRONGEST OVER THE NORTHEAST GULF AND PROVIDE PERIODS OF
CAUTIONARY LEVEL WINDS OVERNIGHT...MAINLY TO THE NORTH OF TARPON
SPRINGS...AND MAINLY NORTH OF ENGLEWOOD DURING THE DAYLIGHT HOURS
OF SATURDAY. ALTHOUGH SCATTERED SHOWERS AND STORMS WILL BE
POSSIBLE IN ANY OF THE MARINE ZONES...THE MOST WIDESPREAD AND
HEAVY RAINFALL POTENTIAL LOOKS TO EXIST TO THE NORTH OF TARPON
SPRINGS THROUGH THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  77  87  78  88 /  60  50  40  50
FMY  77  92  77  91 /  30  30  20  50
GIF  75  88  75  89 /  70  50  20  70
SRQ  77  88  77  89 /  80  50  30  40
BKV  75  87  74  88 /  60  60  40  60
SPG  78  87  78  88 /  60  50  40  50

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK UNTIL 8 AM EDT SATURDAY FOR COASTAL
     CHARLOTTE-COASTAL HILLSBOROUGH-COASTAL LEE-COASTAL
     MANATEE-COASTAL SARASOTA-PINELLAS.

GULF WATERS...NONE.

&&

$$

UPDATE/AVIATION/MARINE...MROCZKA
DECISION SUPPORT...RUDE
UPPER AIR...PAXTON/GUSACK


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