Funnel Cloud in Florida, August 4, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
914 AM EDT TUE AUG 4 2015

.UPDATE...
NO CHANGES TO CURRENT THINKING WITH THE 12Z MFL SOUNDING
CONFIRMING A DEEPER SOUTH-SOUTHEAST FLOW HAS DEVELOPED ACROSS
SOUTH FLORIDA. MOISTURE HAS ALSO INCREASED A TAD WITH THE PWAT
BACK UP TO JUST UNDER 2" BUT MID LEVEL LAPSE RATES CONTINUE TO BE
MEAGER AT LESS THAN 6C/KM. STRONG DIURNAL HEATING WILL OVERCOME
SOME OF THE WEAK INSTABILITY BUT MOST STORMS WILL BE CONCENTRATED
OVER THE INTERIOR BUT COULD AFFECT THE EAST COAST SUBURBS UPON
INITIALIZATION.

KOB

&&

.PREV DISCUSSION... /ISSUED 739 AM EDT TUE AUG 4 2015/

AVIATION...
NO CHANGES TO PREVIOUS THINKING WITH MOSTLY VFR CONDITIONS AND A
LITTLE MORE OF A SOUTHEAST PUSH TO THE CONVECTION TODAY. THERE
COULD BE A FEW SHOWERS BEFORE MOVING INLAND AND THUS A SMALL
THREAT FOR TSRA AT KTMB. WIND WILL BE L/V THIS MORNING BECMG E 7-8
KT ALONG THE EAST COAST AND SW AT KAPF.

KOB

PREV DISCUSSION... /ISSUED 241 AM EDT TUE AUG 4 2015/

DISCUSSION...
UPPER TROUGH OVER THE EASTERN CONUS WILL LIFT NORTHEAST
TODAY...AND THE SUBTROPICAL RIDGE OVER THE WESTERN ATLANTIC WILL
PUSH INTO THE FLORIDA PENINSULA. SURFACE LOW PRESSURE OVER COASTAL
GEORGIA/SOUTH CAROLINA WILL MOVE QUICKLY NORTHEASTWARD TODAY...AND
THE SURFACE RIDGE AXIS WILL SLIDE NORTHWARD INTO CENTRAL FLORIDA.
THIS WILL ALLOW DEEP EAST TO SOUTHEAST FLOW TO RETURN TO THE
REGION.

HIRES AND GLOBAL MODELS SHOW THAT SHOWERS AND POSSIBLY A FEW
STORMS MAY DEVELOP THIS MORNING ALONG THE EAST COAST AND MOVE
INLAND. THE EAST COAST SEA BREEZE WILL DEVELOP BY MID/LATE
MORNING...WITH CONVECTION THEN DEVELOPING ACROSS THE INTERIOR AND
MAINLY INLAND OF THE METRO AREAS IN THE EARLY/MID AFTERNOON. LAPSE
RATES WILL STEEPEN SLIGHTLY THIS AFTERNOON AS DRIER AIR IN THE
700-500MB LAYER MOVES INTO THE REGION...WITH THE FREEZING LEVEL
FORECAST TO RISE ABOVE 15.5KFT. SO CANNOT RULE A FEW STRONG WIND
GUSTS...MAINLY ACROSS THE EVERGLADES.

A LARGE AREA OF SAHARAN DUST CURRENTLY ACROSS PUERTO RICO AND
HISPANIOLA AND NORTHWARD INTO THE WESTERN ATLANTIC WILL PUSH INTO
THE CENTRAL BAHAMAS BY WEDNESDAY MORNING. A WEAK AREA OF VORTICITY
FROM AN OLD UPPER LOW WILL PUSH NORTHEAST...BRINGING COOLER
TEMPERATURES ALOFT (AROUND -7.5C AT 500MB). THE FLOW ALOFT WILL
VEER TO THE SOUTH AS WELL...AND A BRIEF MOISTURE SURGE IS FORECAST
AHEAD OF THE SAHARAN DUST WITH PWATS INCREASING TO 2-2.25 INCHES.
THIS WILL LEAD TO GOOD RAIN CHANCES ACROSS THE REGION. THE
STEERING FLOW WILL ALSO RELAX THROUGHOUT THE DAY...AND LOCALLY
HEAVY DOWNPOURS ARE POSSIBLE.

DRY AIR AND SAHARAN DUST PUSH INTO THE REGION QUICKLY ON
THURSDAY...WITH PWATS FALLING FROM 2 INCHES IN THE MORNING TO
LESS THAN 1.5 INCHES BY THE AFTERNOON ALONG THE SOUTHEAST COAST.
SO MAINLY DRY CONDITIONS WILL PREVAIL FOR THE SOUTHEAST COASTAL
AREAS...WITH THE BEST RAIN CHANCES ACROSS THE LAKE REGION THURSDAY
AFTERNOON. STRONG STORMS WITH GUSTY WINDS ARE POSSIBLE.

FRIDAY AND SATURDAY...THE UPPER RIDGE WILL WEAKEN ONCE AGAIN WITH
A SHORTWAVE TROUGH RIDING SOUTHEAST INTO THE MID ATLANTIC
STATES...AND THEN PUSHING OFF THE EASTERN SEABOARD. THIS WILL
PROVIDE NORTHERLY FLOW ALOFT ACROSS SOUTH FLORIDA. THE SURFACE
RIDGE AXIS NEAR LAKE OKEECHOBEE ON FRIDAY WILL REMAIN ALMOST
STATIONARY. ANOTHER LOW LEVEL TROUGH WILL PUSH INTO NORTH FLORIDA
OVER THE WEEKEND BEFORE STALLING. THE 850MB RIDGE WILL BISECT THE
REGION THROUGH THE PERIOD. DRY AIR AND SAHARAN DUST WILL ENGULF
SOUTH FLORIDA...AND ONLY MEAGER RAIN CHANCES ARE EXPECTED.

SUNDAY AND MONDAY...SLIGHT MOISTENING IS FORECAST TO TAKE PLACE
EACH DAY...BUT SIGNIFICANT DRY AIR WILL REMAIN IN THE MID
LEVELS. A SHEAR AXIS MAY PUSH INTO THE LAKE REGION IN SUNDAY
AFTERNOON AND THEN REMAIN ACROSS SOUTH FLORIDA THROUGH EARLY NEXT
WEEK. DEEP EASTERLY FLOW WILL RESUME...WITH THE BEST CHANCES OF
RAIN ACROSS THE INTERIOR WEST AND TOWARDS THE GULF COAST.

HIGHS ARE FORECAST TO BE IN THE LOW 90S EVERYDAY...WITH LOWS IN
THE 70S TO AROUND 80 DEGREES. HEAT INDICES ARE FORECAST TO BE
100-105F EACH AFTERNOON.

AVIATION...
WITH SURFACE LOW PRESSURE DEPARTING NORTH FL, SE TO E FLOW WILL BE
MORE UNIFORM ACROSS SOUTH FLORIDA THAN YESTERDAY. THIS SHOULD
KEEP THE MOST NUMEROUS THUNDERSTORMS OVER THE INTERIOR. VCTS WAS
USED AT TMB IN CASE ANY OUTFLOWS STIR UP ANY CONVECTION THERE, BUT
WENT WITH VCSH ELSEWHERE MORNING THROUGH EARLY AFTERNOON. APF GULF
BREEZE EXPECTED AROUND 18Z.

MARINE...
SOUTHEASTERLY TO EASTERLY SURFACE WINDS AVERAGING AROUND 10 KNOTS
SHOULD PREVAIL ACROSS THE ATLANTIC WATERS TODAY WITH SEAS AROUND
2 FEET OR LESS. LIGHTER AND MAINLY VARIABLE WINDS ARE EXPECTED
ACROSS THE GULF WATERS. CHANCES FOR SHOWERS AND THUNDERSTORMS ARE
POSSIBLE EACH DAY AND NIGHT ALONG THE ATLANTIC WATERS THROUGH
THE MIDDLE OF THE WEEK. MUCH DRIER AIR MAY KEEP ACTIVITY ISOLATED
OVER THE ATLANTIC WATERS THURSDAY AND FRIDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  91  77  91  77 /  30  10  50  20
FORT LAUDERDALE  91  79  91  80 /  30  10  50  20
MIAMI            92  78  92  80 /  30  10  50  20
NAPLES           91  76  91  78 /  30  10  30  10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&

SHORT TERM...10/CD
LONG TERM....10/CD

HAZARDOUS WEATHER OUTLOOK FOR SOUTH FLORIDA
NATIONAL WEATHER SERVICE MIAMI FL
643 AM EDT TUE AUG 4 2015

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
042245-
LAKE OKEECHOBEE-BISCAYNE BAY-
COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM
20 NM TO 60 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM
TO THE TERRITORIAL WATERS OF THE BAHAMAS-GLADES-HENDRY-
INLAND PALM BEACH-METRO PALM BEACH-COASTAL COLLIER-INLAND COLLIER-
INLAND BROWARD-METRO BROWARD-INLAND MIAMI DADE-METRO MIAMI DADE-
MAINLAND MONROE-COASTAL PALM BEACH-COASTAL BROWARD-
COASTAL MIAMI DADE-FAR SOUTH MIAMI DADE-
COASTAL WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING FROM
20 TO 60 NM-
643 AM EDT TUE AUG 4 2015

...SCATTERED TO NUMEROUS THUNDERSTORMS...
...SLIGHT CHANCE OF WATERSPOUTS ATLANTIC WATERS...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS: SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED
TODAY, MAINLY ACROSS THE INTERIOR. THE MAIN HAZARDS WILL BE CLOUD
TO GROUND LIGHTNING, GUSTY WINDS, AND HEAVY DOWNPOURS.

WATERSPOUTS: THERE IS A SLIGHT CHANCE OF WATERSPOUTS THROUGH THE
ATLANTIC WATERS AND BISCAYNE BAY, ESPECIALLY WITHIN ANY
CONVERGENT LINES OF CLOUDS AND/OR SHOWERS.

FLOODING: NUMEROUS SLOW MOVING THUNDERSTORMS COULD LEAD TO HIGH
WATER IN POOR DRAINAGE AREAS THROUGH PARTS OF THE INTERIOR.

WIND: THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING STRONG
WIND GUSTS OF 40-50 MPH.

TEMPERATURES: THE HEAT INDEX OVER PARTS OF THE INTERIOR MAY REACH
100 DEGREES TODAY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED EACH AFTERNOON
AND EARLY EVENING, ESPECIALLY OVER THE INTERIOR. THE PRIMARY
IMPACT FROM THESE THUNDERSTORMS WILL BE FREQUENT CLOUD TO GROUND
LIGHTNING, GUSTY WINDS AND LOCALIZED FLOODING.

MAXIMUM HEAT INDEX VALUES EACH DAY WILL REACH THE 100 TO 105
DEGREE RANGE DURING THE MIDDAY TO LATE AFTERNOON TIME FRAME ACROSS
THE INTERIOR.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

FOR MORE INFORMATION...VISIT THE NATIONAL WEATHER SERVICE IN
MIAMI WEBSITE AT WWW.WEATHER.GOV/MIAMI.