Flash Flood Warning 1, NWS Tampa Bay, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
530 AM EDT TUE JUL 2 2013

.SYNOPSIS...
09Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW A STUBBORN AND
HIGHLY AMPLIFIED UPPER LEVEL PATTERN ACROSS THE CONUS CONSISTING OF
A HUGE RIDGE OVER THE WESTERN STATES AND A DEEP DOWNSTREAM TROUGH
OVER MUCH OF THE EAST. TROUGHS ARE GENERALLY NOT SUPPOSED TO BE THIS
AMPLIFIED AND DEEP DURING THE MIDDLE OF SUMMER...AND ITS NO WONDER
WE HAVE SEEN AN EXTENDED PERIOD OF RAINY WEATHER. WE ARE IN NO WAY
DONE WITH THIS RAINY WEATHER QUITE YET...BUT THE WORST APPEARS TO BE
OVER AND THERE IS SUNLIGHT AT THE END OF THE TUNNEL (PUN INTENDED)
LATER IN THE WEEK. WV IMAGERY SHOWS A PLUME OF DEEP TROPICAL
MOISTURE STREAMING NORTHWARD ON THE EASTERN SIDE OF THE TROUGH OVER
THE FL PENINSULA. 02/00Z KTBW SOUNDING PROFILE CONFIRMS JUST HOW
MUCH MOISTURE THERE IS WITH AN ALMOST SATURATED COLUMN AND
IMPRESSIVE PW VALUE OF AROUND 2.3". A PW VALUE OF THIS LEVEL IS
AROUND THE 99TH PERCENTILE OF PAST OBSERVED VALUES FOR EARLY JULY.
OUTSIDE OF THE LARGE SCALE CYCLONIC FLOW OF THE TROUGH AIDING THE
LIFT PROCESS...A FAIRLY WELL-DEFINED SHORTWAVE FEATURE HAS BEEN
WORKING THROUGH THE SOUTH-CENTRAL/SE GULF OF MEXICO AND LIKELY
FURTHER CONTRIBUTING TO THE CONTINUOUS CONVECTIVE DEVELOPMENT ACROSS
THE EASTERN GULF. THIS FEATURE IS SHOWN BY THE GLOBAL MODELS TO
BECOME MORE STRETCHED/SHEARED OUT WITH TIME AS IT MOVES OVERHEAD
TODAY.

AT THE SURFACE...SUBTROPICAL RIDGE AXIS IS SHIFTING NORTHWARD
THROUGH THE REGION HELPING TO BRING OUR LOW LEVEL WINDS AROUND MORE
TO THE SOUTHEAST WITH TIME. REGIONAL RADARS ARE STILL ACTIVE WITH
SCT-NMRS SHOWERS RAPIDLY MOVING SOUTH TO NORTH. AS OF 5AM THE
MAJORITY OF THIS ACTIVITY IS ALONG AND WEST OF THE I-75
CORRIDOR...AND THIS IS LIKELY TO BE THE TREND FOR AT LEAST THE NEXT
SEVERAL HOURS.

&&

.SHORT TERM (TODAY THROUGH THE 4TH OF JULY)...
TODAY...
YET ANOTHER ACTIVE DAY IN TERMS OF SHOWERS AND THUNDERSTORM
ACTIVITY. THE GOOD NEWS IS THAT WE WILL BE SLOWLY STARTING TO LOSE
THE SYNOPTIC INFLUENCE FOR LIFT ASSOCIATED WITH THE STUBBORN UPPER
TROUGH TO OUR NORTHWEST. THE BAD NEWS IS THAT WE ARE STILL LEFT WITH
A VERY MOIST ATMOSPHERIC COLUMN AND NOTHING TO REALLY SUPPRESS THE
CONVECTION. SO WITH SOME LIMITED SYNOPTIC SUPPORT STILL AROUND AND
THE THE FAVORABLE COLUMN FOR CONVECTION WOULD EXPECT A HIGH COVERAGE
OF RAINFALL ONCE AGAIN. THE OVERALL TEMPORAL DURATION OF RAINFALL
TODAY IS LIKELY TO NOT BE AS HIGH AS PREVIOUS DAYS...ESPECIALLY
INLAND. FORECAST GRIDS STILL SHOW LIKELY POPS AREA-WIDE AND THE RISK
OF TRAINING STORMS AND LOCALLY HEAVY RAINFALL AMOUNTS REMAINS A
CONCERN. THE FLOOD WATCH FOR THE ENTIRE AREA WILL REMAIN IN EFFECT
DUE TO THIS CONTINUED HEAVY RAINFALL THREAT.

BY TONIGHT THE REAL EMPHASIS FOR ADDITIONAL SHOWERS WILL SHIFT TO
THE IMMEDIATE COAST AND MORE LIKELY JUST OFFSHORE AS LOW LEVEL WINDS
CONTINUE TO SHIFT AROUND MORE TO THE SOUTHEAST...AND THE SYNOPTIC
LIFT ASSOCIATED WITH THE TROUGH IS FORCED EVER FURTHER WEST INTO THE
EASTERN GULF OF MEXICO. INLAND FROM THE I-75 CORRIDOR...WE MAY SEE A
GENERALLY DRY OVERNIGHT PERIOD AFTER ANY LINGERING EVENING PURELY
INSTABILITY SHOWERS CAN DISSIPATE.

WEDNESDAY/WEDNESDAY NIGHT...A NEUTRAL UPPER LEVEL PATTERN WILL BE IN
PLACE BETWEEN THE TROUGH TO OUR WEST AND A LARGE UPPER RIDGE
STARTING TO BUILD/RETROGRADE FROM THE WESTERN ATLANTIC. DEEP LAYER
SOUTHERLY FLOW ALOFT WILL CONTINUE TO PROVIDE OUR REGION WITH
ABUNDANT COLUMN MOISTURE AND THIS FAVORABLE COLUMN SHOULD SUPPORT
NUMEROUS SHOWERS/STORMS FOR THE AFTERNOON. SO ONCE AGAIN...MUCH OF
THE AREA IS UNDER LIKELY RAIN CHANCES FOR WEDNESDAY...HOWEVER MUCH
OF THE AREA...AWAY FROM THE IMMEDIATE COAST WILL SEE THE BETTER RAIN
CHANCES DURING THE AFTERNOON...AND THE TEMPORAL EXTENT OF ANY
RAINFALL SHOULD CONTINUE TO FALL. BETTER CHANCES FOR MORE SUNNY
BREAKS AS WELL...ESPECIALLY WEDNESDAY MORNING AND WILL BEGIN TO
CREEP DAYTIME TEMPERATURES BACK UP.

4TH OF JULY...
THIS WILL BE THE FIRST DAY THIS WEEK THAT STARTS TO RESEMBLE A MORE
TYPICAL SUMMER FORECAST. THE MAIN SUPPRESSION FROM THE UPPER RIDGE
WILL STILL BE WELL TO OUR NORTHEAST. HOWEVER...OUR MID/UPPER LEVEL
FLOW WILL START TO BECOME INCREASINGLY ANTI-CYCLONIC IN NATURE AND
THIS WILL HELP TO SCOUR OUT AT LEAST SOME OF THE DEEP MOISTURE.
FORECAST FOR THE 4TH WILL FEATURE A GENERALLY QUIET MORNING WITH A
FEW SHOWERS AROUND...BUT JUST AS MUCH SUN FOLLOWED BY INCREASING
CHANCES FOR A MORE TYPICAL DISTRIBUTION OF AFTERNOON/EVENING
THUNDERSTORMS. THE BETTER SOLAR INSOLATION ALLOWS TEMPERATURES TO
PEAK BACK UP INTO THE LOWER 90S FOR MANY SPOTS. THE EVENING OF THE
4TH LOOKS TO BE A MIX OF MAN MADE AND SCATTERED MOTHER NATURE
FIREWORKS...HOWEVER OPTIMISTIC THAT WE WILL NOT BE DEALING WITH A
WASHOUT.

&&

.LONG TERM (FRIDAY THROUGH NEXT MONDAY)...
A DLM SUBTROPICAL RIDGE INITIALLY LOCATED NEAR LATITUDE 35/LONGITUDE
65-70 SLOWLY BUILDS AND SHIFTS WEST. THIS REACHES THE MID-ATLANTIC
AND SOUTHEAST COAST FOR THE WEEKEND AND CONTINUES INTO MON AS A
TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) APPROACHES FL FROM THE
BAHAMAS. THE 01/12Z ECMWF AND THE 02/00Z GFS HANDLE THIS FEATURE
SIMILARITY.

BUILDING HEIGHTS AND SUBSIDENCE FROM THE UPPER RIDGE WILL KEEP
THUNDERSTORMS IN THE LOW END SCATTERED RANGE AND ALLOW TEMPERATURES
TO REACH THE MID 90S IN THE AFTERNOON. A RATHER ROBUST EAST AND SW
LOW LEVEL FLOW WILL LIMIT THE WEST COAST SEA BREEZES TO THE
IMMEDIATE COASTAL AREAS WHICH WILL HAVE THE HIGHEST STORM COVERAGE.
BY MON THE SURFACE REFECTION OF THE TUTT REACHES THE STATE WITH A
RELAXING EAST OR NE FLOW...ALLOWING A MORE UNIFORM COVERAGE ACROSS
THE CWA.

&&

.AVIATION...
DEEP MOISTURE WILL CONTINUE TO FLOW NORTH WITH A BKN-OVC MID DECK.
EXPECT VCNTY SHRA WITH PERIODS OF MVFR CIGS AND -RA OVERNIGHT...THEN
BKN MVFR CIGS DURING THE DAY WITH VCNTY TSRA RESULTING IN OCNL
MVFR/LCL IFR CONDITIONS. WINDS SOUTHERLY AND GUSTY AT TIMES.

&&

.MARINE...
SOUTHERLY FLOW WILL SHIFT SOUTHEAST BY THIS EVENING AND THEN REMAIN
OUT OF THE SOUTHEAST FOR THE DURATION OF THE FORECAST PERIOD AS HIGH
PRESSURE REMAINS SITUATED TO OUR NORTH AND NORTHEAST. THE GRADIENT
LOOKS TO REMAIN TIGHT THROUGH MUCH OF THE PERIOD KEEPING WINDS
ELEVATED...HOWEVER AS WINDS SHIFT TO A MORE EASTERLY DIRECTION...THE
HIGHEST SEAS WILL ALSO BEGIN TO SHIFT OFFSHORE FOR THE SECOND HALF
OF THE WEEK.

&&

.HYDROLOGY...
A FLOOD WATCH REMAIN IN EFFECT FOR THE FORECAST AREA. HEAVY RAINFALL
OVER THE PAST SEVERAL DAYS HAS RESULTED IN A FORECAST OF SEVERAL
LOCAL RIVERS REACHING ACTION STAGE DURING THE NEXT FEW DAYS. AT THIS
TIME...NO SIGNIFICANT RIVER FLOODING IS FORECAST...HOWEVER THE
THREAT FOR ADDITIONAL HEAVY RAINFALL WILL CONTINUE INTO WEDNESDAY.
DEPENDING ON THE LOCATION AND EXTENT OF ANY ADDITIONAL HEAVY
RAINFALL...THE CURRENT FORECASTS FOR CRESTS BELOW FLOOD STAGE MAY
NEED TO BE MODIFIED. RESIDENTS ALONG AREA RIVERS AND STREAM ARE
URGED TO KEEP UP TO DATE WITH THE MOST RECENT FORECASTS AND BE
PREPARED TO TAKE ACTION SHOULD FLOOD WARNINGS BECOME NECESSARY. THE
LATEST RIVER FORECASTS CAN ALWAYS BE FOUND AT:
WATER.WEATHER.GOV/AHPS2/INDEX.PHP?WFO=TBW.

&&

.FIRE WEATHER...
DEEP TROPICAL MOISTURE....BELOW NORMAL TEMPERATURES AND HIGH DAILY
COVERAGE OF SHOWERS WILL KEEP RELATIVE HUMIDITY VALUES WELL ABOVE
CRITICAL LEVELS THROUGH THE MIDDLE OF THE WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  87  75  88  76 /  70  50  70  50
FMY  88  74  90  74 /  70  50  70  40
GIF  88  73  89  74 /  60  40  60  40
SRQ  88  75  89  75 /  70  60  70  50
BKV  86  73  89  72 /  70  50  70  40
SPG  85  77  87  77 /  70  60  70  50

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RIP CURRENT RISK THROUGH THIS EVENING FOR CHARLOTTE-
     HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.

     FLOOD WATCH THROUGH WEDNESDAY MORNING FOR CHARLOTTE-CITRUS-
     DESOTO-HARDEE-HERNANDO-HIGHLANDS-HILLSBOROUGH-LEE-
     LEVY-MANATEE-PASCO-PINELLAS-POLK-SARASOTA-SUMTER.

GULF WATERS...NONE.

&&

SYNOPSIS/SHORT TERM/MARINE...MROCZKA
FIRE WX/HYDROLOGY..MROCZKA
AVIATION/LONG TERM...RUDE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
509 AM EDT TUE JUL 2 2013

FLZ039-042-043-048>052-055>057-060>062-065-GMZ830-850-853-856-870-
873-876-022115-
LEVY-CITRUS-SUMTER-HERNANDO-PASCO-PINELLAS-HILLSBOROUGH-POLK-
MANATEE-HARDEE-HIGHLANDS-SARASOTA-DESOTO-CHARLOTTE-LEE-
TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-
BONITA BEACH TO ENGLEWOOD OUT 20 NM-
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-
509 AM EDT TUE JUL 2 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WEST CENTRAL AND SOUTHWEST
FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

...THUNDERSTORM IMPACT...
NUMEROUS THUNDERSTORMS AND SHOWERS WILL CONTINUE TO STREAM
NORTHWARD ACROSS WEST CENTRAL AND SOUTHWEST FLORIDA TODAY AND
TONIGHT. THE MAIN IMPACTS WILL BE LOCALLY HEAVY RAIN...FREQUENT
CLOUD TO GROUND LIGHTNING...AND WIND GUSTS TO 40 MPH WITH THE
STRONGER STORMS.

...FLOOD IMPACT...
A FLOOD WATCH IS IN EFFECT FOR THE AREA THROUGH WEDNESDAY MORNING.
FORECASTED ADDITIONAL HEAVY RAINFALL AMOUNTS OF 3 TO 5 INCHES
WITH POSSIBLE LOCALLY HEAVIER ACCUMULATIONS CREATE A CONCERN FOR
FLOODING. SOUTH TO SOUTHWEST WINDS WILL HELP ELEVATE THE COASTAL
WATERS...BAYS...HARBORS...AND INLETS WHICH WILL MAKE DRAINAGE OF
LOWER-LYING COASTAL AREAS MORE DIFFICULT. RECENT HEAVY RAINFALL
HAS SATURATED THE SOIL IN SOME AREAS AND COULD PROVIDE AN ELEVATED
RISK OF FLOODING IF RAIN STORMS WERE TO TRAIN OVER THOSE AREAS.

...RIP CURRENT IMPACT...
LONG DURATIONS OF SOUTHWEST TO SOUTHERLY WINDS OVER THE GULF OF
MEXICO WILL CONTINUE TO RESULT IN A MODERATE RISK OF RIP CURRENTS
AT AREA BEACHES THROUGH THIS EVENING.

...RIVER FLOOD IMPACT...
THE HEAVY RAINS OVER THE PAST FEW DAYS HAVE BROUGHT THE WATER
LEVELS UP ON AREA RIVERS AND STREAMS. THE WATER LEVELS ARE
EXPECTED TO REACH ACTION STAGE ON MANY RIVERS BUT STAY BELOW
FLOOD STAGE. RESIDENTS LIVING NEAR RIVERS SHOULD STAY UP TO DATE
ON THE OBSERVED AND FORECAST LEVELS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

...THUNDERSTORM IMPACT...
A SIMILAR PATTERN IS EXPECTED WEDNESDAY WITH SCATTERED TO
NUMEROUS THUNDERSTORMS AND SHOWERS ACROSS WEST CENTRAL AND
SOUTHWEST FLORIDA WITH LOCALLY HEAVY RAIN...FREQUENT CLOUD TO
GROUND LIGHTNING...AND WIND GUSTS TO 40 MPH WITH STRONGER STORMS.
AREAL COVERAGE OF STORMS WILL DECREASE THURSDAY THROUGH MONDAY.

...FLOOD IMPACT...
THE FLOOD WATCH IS EXPECTED TO END WEDNESDAY MORNING. HOWEVER ANY
ADDITIONAL RAIN COULD CONTINUE TO CREATE SOME FLOODING PROBLEMS.

...RIVER FLOOD IMPACT...
RESIDENTS LIVING NEAR RIVERS SHOULD MONITOR THE OBSERVED AND
FORECAST LEVELS FOR THE NEXT COUPLE OF DAY AS THESE RIVERS
APPROACH OF REACH ACTION STAGE AND THEN SLOWLY DECREASE.
.
...EXCESSIVE HEAT IMPACT...
A STRONG AREA OF HIGH PRESSURE WILL MOVE INTO THE AREA LATE IN
THE WEEK AND CONTINUE FOR THE WEEKEND. THIS WILL CREATE THE
POTENTIAL FOR HIGHS IN THE MID 90S WITH HEAT INDEX VALUES OF 100
TO 105 FOR SATURDAY AND SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.

RKR