Tornadoes and Lightning Strike in Florida, July 24, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
245 PM EDT FRI JUL 24 2009

.DISCUSSION...
THIS AFTERNOON-SATURDAY...EAST COAST SEA BREEZE HAS GOTTEN GOING
ALONG THE ENTIRE COAST EARLY THIS AFTERNOON...WITH MORE DEFINITION
AND FURTHER INLAND PENETRATION SOUTH OF THE CAPE. ISOLATED SHOWERS
HAVE DEVELOPED ALONG THE SEA BREEZE...MAINLY DOWN SOUTH AS IT
INTERACTS WITH THE LAKE OKEECHOBEE BREEZE AND IN THE VICINITY OF
DEEPER MOISTURE. WITH THE ECSB SO FAR BEING THE MORE ACTIVE OF THE
TWO...EXPECT THIS TO BE THE MAIN FOCUS FOR LIGHTNING STORMS OVER THE
REGION THROUGH THIS EVENING. A NOTABLE INCREASE IN ACTIVITY IS
EXPECTED BY EARLY EVENING AS THE SEA BREEZES COLLIDE OVER THE ST
JOHNS RIVER BASIN SOUTH TO LAKE OKEECHOBEE. FREQUENT LIGHTNING IS
EXPECTED TO BE THE MAIN CONCERN...BUT A LITTLE DRIER AIR ALOFT COULD
BRING SOME GUSTY WINDS WITH STRONGER STORMS. STORMS WILL GENERALLY
MOVE BACK TOWARDS THE COAST AND OFFSHORE IN S-SW FLOW.

LEFT OVER BOUNDARY COLLISIONS WILL LIKELY KEEP STORMS GOING THROUGH
LATE EVENING. MID/UPPER LEVEL DEBRIS CLOUDS WILL THIN OUT AFTER
MIDNIGHT...WITH A HIGHER COVERAGE CLOSER TO THE WEAK SURFACE FRONT
OVER N FLORIDA.

INCREASING MOISTURE WILL BRING A HIGHER COVERAGE OF STORMS ON
SATURDAY...ESPECIALLY DOWN SOUTH WITH THE LAKE O-ECSB INTERACTION.
MODELS HAVE PAINTED LIKELY POPS OVER THIS AREA FOR THE AFTERNOON AND
SEE NO REASON TO DISAGREE. SLIGHTLY DRIER AIR UP NORTH AND THE
POSSIBILITY OF SOME LINGERING MID-UPPER LEVEL CLOUDS IN THE VICINITY
OF THE FRONT MAY LIMIT CONVECTIVE DEVELOPMENT A LITTLE MORE IN THIS
AREA. FOCUS WILL ONCE AGAIN BE MORE TOWARDS THE COAST AS SW STEERING
FLOW CONTINUES.

WITH DEWPOINTS CONTINUING INTO THE LOW TO MID 70S...TOMORROW WILL BE
ANOTHER HOT AND HUMID DAY AS AFTERNOON TEMPERATURES REACH INTO THE
LOW 90S AT THE COAST...AND MID 90S INLAND. SOME INLAND LOCATIONS
WILL LIKELY SEE HEAT INDICES PEAKING TO 100-105F BEFORE AFTERNOON
SHOWERS AND STORMS GENERATE CLOUD COVER.

SAT NIGHT-SUN NIGHT...WEAK HIGH PRESSURE RIDGING AT THE SURFACE WILL
ALIGN ITSELF EAST-WEST ACROSS THE SOUTH-CENTRAL PENINSULA THROUGH
THIS PERIOD. RIDGING FURTHER ALOFT WILL REMAIN ACROSS SOUTH FLORIDA
GIVING US A SOUTHWEST TO NORTHEAST STEERING FLOW FOR AFTERNOON AND
EVENING CONVECTION. THIS WILL ENSURE THAT SHOWERS AND LIGHTNING
STORMS END UP ACROSS THE EASTERN PENINSULA LATE IN THE DAY.
WEST/SOUTHWEST SURFACE WINDS SUN WILL TRANSITION TO EAST/SOUTHEAST
ALONG THE COAST BEHIND THE INLAND MOVING EAST COAST SEA BREEZE. THE
SEA BREEZE WILL PROVIDE A FOCUS FOR AFTERNOON DEVELOPMENT OF
CONVECTION. MOISTURE VALUES ARE FORECAST TO BE GREATER SOUTHWARD AND
SUSPECT THAT EARLIEST STORM DEVELOPMENT WILL BE ACROSS ST. LUCIE AND
MARTIN COUNTIES WITH ACTIVITY SPREADING NORTHWARD AND INLAND THROUGH
THE DAY. WILL KEEP POP VALUES AT 50% EVERYWHERE AND ALLOW FUTURE
SHORT-TERM SHIFTS TO DETERMINE AREAS OF GREATER COVERAGE AS TIME
DRAWS NEAR.

NEXT WEEK...(PREVIOUS DISCUSSION)...THE PERSISTENT TROUGH OVER THE
CENTRAL/EASTERN PART OF THE COUNTRY IS FORECAST TO LIFT/RETROGRADE
SLIGHTLY...AND ALLOW ATLANTIC RIDGE TO BUILD BACK ACROSS THE
PENINSULA. THE SURFACE RIDGE AXIS SHOULD NUDGE JUST NORTH OF THE
AREA AND RESULT IN A MORE SOUTHEAST LOW LEVEL FLOW. MOISTURE VALUES
ARE FORECAST TO REMAIN QUITE HIGH...BUT WITH RIDGE BUILDING
ALOFT...EXPECT SOME MID LEVEL WARMING. THEREFORE WILL KEEP POPS AT
40 PERCENT WHICH IS AT OR SLIGHTLY BELOW CLIMO VALUES. THERE MAY BE
A FEW NIGHTS WHERE COASTAL SECTIONS RECEIVE SOME ONSHORE MOVING
SHOWERS...BUT HAVE NOT INCLUDED THIS YET DUE TO THE PROPENSITY THIS
SEASON FOR THE MODELS TO BACK OFF OF DEPTH/STRENGTH OF ONSHORE FLOW
IN LATER RUNS.

&&

.AVIATION...SCT-BKN040-050 AREAWIDE WITH AFTERNOON CUMULUS
DEVELOPMENT. MVFR SHRA/TSRA 20Z-02Z ESPECIALLY ALONG COASTAL
ROUTES/TAF SITES. PREVAILING VFR AFTER 04Z AS DEBRIS CLOUDS THIN
OUT. PATCHY MVFR POSSIBLE THROUGHOUT THE REGION AFTER 10Z TONIGHT.

&&

.MARINE...DOMINANT LONG PERIOD 2-3 FT EASTERLY SWELL CONTINUES WITH
OVERALL SEAS RUNNING 3-4 FT. SWELL COMPONENT WILL GRADUALLY EASE
THROUGHOUT THE NEXT 24 HRS...WITH SEA HEIGHTS SUBSIDING AS WELL.
TYPICAL DIURNAL FLOW PATTERN EXPECTED WITH LIGHT S-SW WINDS
OVERNIGHT AND IN THE MORNING AND A S-SE WIND DEVELOPING NEARSHORE
WITH THE SEABREEZE IN THE AFTERNOON. SW STEERING FLOW WILL BRING AN
INCREASING THREAT FOR OFFSHORE MOVING THUNDERSTORMS OVER THE
INTRACOASTAL AND NEARSHORE WATERS BOTH TONIGHT AND TOMORROW.

SAT NIGHT-SUN NIGHT...LIGHT SW FLOW AOB 10 KTS EXPECTED SAT/SUN
NIGHT. FLOW WILL TRANSITION TO AN E/SE COMPONENT NEAR THE COAST SUN
AFTN AS THE ECSB MOVES INLAND. EXPECT THE EAST SWELL TO DIMINISH
THROUGH THE WEEKEND. BOATERS WILL NEED TO KEEP AN EYE TO THE SKY
WESTWARD LATER IN THE AFTERNOON & EVENINGS DURING THIS TIME FOR
APPROACHING SHRA/TSRA.

MON-WED...SOUTHEAST FLOW AT 5-10 KNOTS IS FORECAST AS THE SURFACE
RIDGE AXIS NUDGES JUST TO THE NORTH OF THE AREA. PLENTY OF MOISTURE
WILL KEEP A CHANCE OF SHOWERS/STORMS...THOUGH WEAKENING STEERING
FLOW SHOULD KEEP THE AFTERNOON STORMS FROM MOVING BACK ACROSS THE
COAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  72  91  73  90 /  30  40  20  50
MCO  75  93  74  93 /  20  50  20  50
MLB  73  90  72  89 /  30  60  30  50
VRB  73  90  72  91 /  30  60  30  50

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&

SHORT TERM/AVIATION...MOSES
LONG TERM....SEDLOCK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MELBOURNE FL
433 AM EDT FRI JUL 24 2009

AMZ550-552-555-570-572-575-FLZ041-044>047-053-054-058-059-064-141-
144-147-242000-
COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE
OUT 20 NM-
COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN
INLET OUT 20 NM-
COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO
60 NM OFFSHORE-
WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO
60 NM OFFSHORE-
WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-
INLAND VOLUSIA-NORTHERN LAKE-ORANGE-SEMINOLE-SOUTHERN BREVARD-
OSCEOLA-INDIAN RIVER-OKEECHOBEE-ST. LUCIE-MARTIN-COASTAL VOLUSIA-
SOUTHERN LAKE-NORTHERN BREVARD-
433 AM EDT FRI JUL 24 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

...THUNDERSTORM IMPACT...
ISOLATED SHOWERS AND LIGHTNING STORMS ARE EXPECTED TO FORM ALONG
THE SEA BREEZE AS IT PUSHES ACROSS THE COASTAL AREAS AND WEST OF
INTERSTATE 95 THIS AFTERNOON. THE PREVAILING SOUTHWESTERLY WIND
FLOW...STRONGER WEST COAST SEA BREEZE...WILL KEEP THE EAST COAST
SEA BREEZE FROM PENETRATING VERY FAR INLAND. THE TWO SEA BREEZES
ARE EXPECTED TO COLLIDE ALONG THE COAST WEST OF INTERSTATE 95 LATE
AFTERNOON. STORMS WILL THEN MOVE SLOWLY BACK TOWARD THE ATLANTIC.

AS WITH SEA BREEZE INTERACTION STORMS...SOME OF THE STORMS MAY
PRODUCE FREQUENT TO EXCESSIVE LIGHTNING STRIKES...WIND GUSTS OF
40 TO 50 MPH AND LOCALLY HEAVY RAIN ASSOCIATED WITH SLOWER MOVING
STORMS. AS STRONGER STORMS APPROACH THE COAST THERE MAY BE ENOUGH
WIND SHEAR TO PRODUCE WEAK ROTATION IN THE LOWER PORTIONS OF THE
CLOUD FOR FUNNEL CLOUDS TO FORM..

BOATERS ON INLAND LAKES AND RIVERS SHOULD KEEP AN EYE TO THE
SKIES FOR APPROACHING WEATHER IN THE AFTERNOON AND EARLY EVENING
AND HEAD BACK TO SHORE IF STORMS ARE MOVING IN YOUR DIRECTION.

...RIP CURRENT IMPACT...
OCEAN CONDITIONS WILL PRODUCE A MODERATE THREAT FOR RIP CURRENTS AT
THE BEACHES OF EAST CENTRAL FLORIDA TODAY. NEVER SWIM ALONE AND ALWAYS
SWIM WITHIN SIGHT OF A LIFEGUARD.

...MARINE THUNDERSTORM GUST IMPACT...
BOATERS ON THE INTRACOASTAL WATERWAY AND NEARSHORE ATLANTIC WATERS
SHOULD KEEP AN EYE TO THE WEST FOR AFTERNOON AND EVENING STORMS
MOVING OFF THE MAINLAND AND SEEK SAFE HARBOR WELL IN ADVANCE OF
THE STORMS IMPACTING YOU. SOME OF THE STORMS WILL BE CAPABLE OF
PRODUCING GUSTY WINDS...LOCALLY ROUGH SEAS...FREQUENT CLOUD TO
WATER LIGHTNING STRIKES AND POSSIBLY FUNNEL CLOUDS AS THEY COME
OFF THE MAINLAND.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
A WEST TO EAST WIND PATTERN WILL FAVOR THE EAST SIDE OF THE
PENINSULA FOR AFTERNOON AND EVENING LIGHTNING STORMS SATURDAY
THROUGH MONDAY. THE WIND PATTERN SHIFTING TO AN EAST TO WEST
DIRECTION WEDNESDAY AND THURSDAY WILL TEND TO PUSH STORMS AWAY
FROM THE ATLANTIC SIDE OF THE PENINSULA.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE REQUESTED TO MONITOR THE WEATHER OVER THE SPACE AND
TREASURE COASTS AND SELF ACTIVATE IF NEEDED.

WIMMER