Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 022002
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
402 PM EDT SUN AUG 2 2015

.SHORT TERM (TONIGHT - MONDAY)...
A WELL DEFINED LOW PRESSURE SYSTEM HAS DEVELOPED OVER APALACHEE
BAY THE EXTREME NORTHEAST PORTION OF THE GULF. THE PRESSURE
GRADIENT BETWEEN THIS LOW AND THE ATLANTIC RIDGE TO THE SOUTHEAST
HAS TIGHTENED SIGNIFICANTLY...RESULTING IN STRONGER WINDS OVER THE
REGION. IN FACT...WE HAVE ABOUT A 40 KNOT JET BETWEEN 925 AND 850
MBS THAT SHOWS UP WELL ON OUR RADAR. EVEN VERY SHALLOW SHOWER
ACTIVITY IS BRINGING DOWN 40 MPH WINDS. DEEPER SHOWERS HAVE BEEN
PRODUCING WIND GUSTS TO 45 MPH. HI-RES MODEL BLENDS DO SHOW THIS
FEATURE WEAKENING OVERNIGHT...BUT THIS IS NOT A GUARANTEE. THE
CURRENT FORECAST WILL ASSUME THIS TO BE THE CASE...HOWEVER.

THERE IS A FAIRLY GOOD CHANCE THE INCREASED LOW-LEVEL CONVERGENCE
SOUTH OF THE LOW CENTER WILL GENERATE MORE SHOWERS AND STORMS OVER
THE GULF TONIGHT. THESE WILL MOVE ONSHORE...BRINGING ADDITION
HEAVY RAIN. THE BEST CHANCE SHOULD SHIFT TO THE NORTH OF THE
TAMPA BAY AREA...BUT EVEN THE BAY AREA WILL LIKELY SEE SHOWERS
WITH HEAVY RAIN.

ANY REMAINING LOW-LEVEL JET SHOULD BE PULLING AWAY AS THE
APALACHEE BAY LOW CENTER MOVES NORTHEAST ACROSS NORTH FLORIDA AND
TOWARD THE ATLANTIC COAST MONDAY. LOW-LEVEL CONVERGENCE WILL BE
WEAKENING THROUGH THE DAY...BUT WE WILL HAVE A FAIRLY LONG FETCH
OF DEEP MOISTURE CONTINUING TO MOVE EASTWARD ACROSS THE NORTHERN
GULF. THE ATLANTIC RIDGE WILL FINALLY BE LIFTING NORTHWARD INTO
SOUTH FLORIDA...BUT THAT COULD ACTUALLY INCREASE THE CONVERGENCE
OVER THE INTERIOR PENINSULA DURING THE AFTERNOON HOURS. WITH A
LITTLE MORE SUNSHINE EXPECTED...IT SEEMS LIKELY WE WILL SEE
SHOWERS AND THUNDERSTORMS LIGHTING UP EAST OF I-75. THE WEAK
FRONTAL BOUNDARY ASSOCIATED WITH THE LOW MOVING OUT TOWARD THE
ATLANTIC MAY ALSO HELP TO FOCUS ACTIVITY OVER OUR NORTHERN ZONES.

.LONG TERM (TUESDAY THROUGH NEXT SUNDAY)...
THE SYNOPTIC PATTERN ON TUESDAY CONTINUES TO SHIFT AWAY FROM THE
UNUSUALLY WET AND ATYPICAL LATE SUMMER CONDITIONS TO ONE MORE
EXPECTED FOR EARLY AUGUST. THE TROUGH/FRONT THAT HAS LINGERED OVER
THE NORTHEAST GULF/NORTHERN FLORIDA FOR DAYS WILL HAVE SHIFTED
NORTH INTO AL/GA/CAROLINAS...ALLOWING THE SUBTROPICAL RIDGE AXIS
TO MIGRATE NORTHWARD. THIS RIDGE AXIS WILL ALIGN ITSELF ACROSS THE
CENTRAL FL PENINSULA AND EASTERN GULF OF MEXICO...WITH LITTLE IN
THE WAY OF ANY LINGERING UPPER LEVEL SUPPORT. ALL THIS SHOULD
CONTINUE THE TRANSITION BACK TO A PATTERN DOMINATED BY DIURNAL
SEA-BREEZE CONVECTION. HOWEVER...KEEP IN MIND THAT MUCH OF OUR
AREA IS EXPERIENCING VERY SATURATED SOILS AT THIS POINT. THE ADDED
EVAPORATIVE POTENTIAL COULD VERY WELL RESULT IN AN ACTIVE
CONVECTIVE DAY...WITH HEAVY RAIN POTENTIAL. THIS WILL ESPECIALLY
BE TRUE LATE IN THE DAY AND INLAND FROM THE I-75 CORRIDOR. ITS A
GENERAL RULE...RAIN PROMOTES RAIN...AND DROUGHT PROMOTES DROUGHT.
WE ARE OBVIOUSLY IN THE RAIN PROMOTES RAIN REGIME GOING TO TAKE A
WHILE AND A LOT OF SUN TO START TO RETURN OUR SOIL MOISTURES TO
MORE NORMAL LEVELS.

THIS GENERAL MORE TYPICAL PATTERN OF SCT DIURNAL CONVECTION AND NEAR
NORMAL TEMPERATURES IS FORECAST TO HOLD BY THE GLOBAL ENSEMBLES
THROUGH THE WORK WEEK. HEADING INTO NEXT WEEKEND...GFS/ECMWF BOTH DO
SHOW A GENERAL AMPLIFICATION OF THE PATTERN BACK INTO TROUGHING OVER
THE SOUTHEAST CONUS. DEPENDING ON THE AXIS/AMPLITUDE OF THIS
EVENTUAL TROUGH...WE MAY SEE ANOTHER FRONTAL BOUNDARY DIP TOWARD THE
I-10 CORRIDOR SATURDAY OR SUNDAY WITH A MORE FOCUSED AREA OF SHOWER
POTENTIAL FOR OUR NORTHERN NATURE COAST ZONES (LEVY/CITRUS).
HOWEVER...THIS IS A WAYS OUT AND PLENTY OF TIME TO WATCH THE
ENSEMBLES EVOLVE. FOR THE CENTRAL AND SOUTHERN ZONES...NEXT WEEKEND
STILL LOOKS RATHER NORMAL WITH SCT AFTERNOON/EVENING STORMS AND
DAYTIME TEMPS WITHIN A COUPLE DEGREES EITHER SIDE OF 90.

&&

.AVIATION...
NOT MUCH CHANGE FROM THE LAST SEVERAL DAYS. WINDS WILL BE ON THE
GUSTY SIDE THIS EVENING BUT SHOULD DIMINISH AGAIN OVERNIGHT. STILL
THE POSSIBILITY OF MVFR/IFR CIG/VIS IN HEAVIER SHOWERS...BUT THEY
WILL MOVE QUICKLY AND FORECASTING THE TIMING OF THESE EVENTS IS
NEXT TO IMPOSSIBLE.

&&

.MARINE...
HAVE ISSUED SMALL CRAFT ADVISORIES BETWEEN ENGLEWOOD AND SUWANNEE
RIVER INCLUDING TAMPA BAY. AS MENTIONED IN THE SHORT-TERM
DISCUSSION ABOVE...LOW PRESSURE THAT DEVELOPED IN APALACHEE BAY
HAS RESULTED IN SUSTAINED 20 TO 25 KNOT SOUTHWESTERLY WINDS WITH
GUSTS TO GALE FORCE. ANY SHOWER...EVEN WEAK SHOWERS...WILL EASILY
BRING DOWN 35 KNOTS OF WIND. WE EXPECT THE LOW TO GRADUALLY MOVE
NORTHEAST ACROSS NORTH FLORIDA TONIGHT AND REACH THE ATLANTIC ON
MONDAY. THIS SHOULD ALLOW THE WINDS TO SUBSIDE BELOW ADVISORY
LEVELS LATER TONIGHT OR EARLY MONDAY MORNING.

THE ATLANTIC RIDGE WILL BEGIN TO MOVE NORTHWARD OVER THE STATE
MONDAY NIGHT AND FINALLY BRING A RETURN TO MORE TYPICAL SUMMER
CONDITIONS FOR THE REST OF THE WEEK.

&&

.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS. RECENT HEAVY RAINS HAVE LEFT THE GROUND
SATURATED OVER MOST OF THE AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  76  86  78  90 /  70  80  40  50
FMY  77  90  76  92 /  30  40  30  50
GIF  74  87  74  92 /  50  70  40  50
SRQ  77  87  77  88 /  60  60  40  30
BKV  75  86  74  90 /  80  90  50  50
SPG  77  86  79  89 /  70  80  40  40

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR COASTAL CITRUS-
     COASTAL HERNANDO-COASTAL HILLSBOROUGH-COASTAL LEVY-
     COASTAL PASCO-INLAND CITRUS-INLAND HERNANDO-INLAND
     HILLSBOROUGH-INLAND LEVY-INLAND PASCO-PINELLAS.

     HIGH RIP CURRENT RISK UNTIL 4 PM EDT MONDAY AFTERNOON
     FOR COASTAL CHARLOTTE-COASTAL HILLSBOROUGH-COASTAL LEE-
     COASTAL MANATEE-COASTAL SARASOTA-PINELLAS.

GULF WATERS...SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY
     MORNING 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...JILLSON
LONG TERM...MROCZKA
DECISION SUPPORT...NOAH/MROCZKA


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