Severe Thunderstorm Warning 58, NWS Miami, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
226 PM EDT SAT JUN 29 2013

.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
THE FORECAST IN THIS PERIOD IN NOT NECESSARILY AN EASY ONE. THE
GLOBAL MODELS ARE IN VERY GOOD AGREEMENT IN SHOWING A LARGE
BLOCKING PATTERN DEVELOPING ACROSS NORTH AMERICA THIS WEEKEND BUT
THE AFFECTS OF THIS ON SOUTH FLORIDA IS A PROBLEM. A MASSIVE MID
LEVEL RIDGE IS PARKED OVER THE DESERT SOUTHWEST AND A POWERFUL MID
LEVEL RIDGE WILL BE CUTTING OFF OVER THE MID MISSISSIPPI VALLEY ON
SUNDAY THROUGH MONDAY WHILE A LARGE RIDGE IS OVER THE ATLANTIC. AT
THE SURFACE, A FRONTAL BOUNDARY WILL SLOWLY SAG SOUTH OVER THE
EASTERN U.S. THROUGH THE WEEKEND INTO EARLY NEXT WEEK WHILE A
RIDGE WILL BE LOCATED OVER THE FLORIDA STRAITS. AS THE TROUGH
DEEPENS OVER THE EASTERN STATES, DEEP LAYER MOISTURE WILL BE ON
THE INCREASE ACROSS SOUTH FLORIDA WITH A DEEP SOUTH TO SOUTHWEST
FLOW DEVELOPING. THE PWAT THIS MORNING FROM THE 12Z MFL SOUNDING
WAS 1.83 INCHES AND FORECAST SOUNDINGS ARE SHOWING THIS GOING UP
TO OVER TWO INCHES BY SUNDAY AFTERNOON THROUGH MONDAY. THE AVERAGE
PWAT FOR LATE JUNE ACROSS SOUTH FLORIDA IS JUST OVER 1.75 INCHES
SO THIS PLACES US JUST ABOVE THE 75TH PERCENTILE WHEN COMPARING IT
TO THE AVERAGES BUT BELOW CRITICAL LEVELS THAT WOULD ALERT YOU TO
FLOODING RAINS. THE STEERING FLOW WILL BE SSW-NNE SO THE GREATEST
CHANCES OF THE HEAVIER RAINS WOULD BE OVER THE INTERIOR AND EAST
COAST METRO REGIONS. ALL OF THIS IS WHAT LEADS INTO THE
TROUBLESOME FORECAST FOR THIS PERIOD. A SURFACE TROUGH THAT HAD
BEEN OVER THE NORTHWEST BAHAMAS AND FORECAST TO INTERACT WITH THE
MOISTURE HAS FALLEN APART. IN ADDITION, THE MAIN ENERGY FROM THE
TROUGH WILL REMAIN WELL NORTH OF THE REGION. ANOTHER FACTOR WILL
BE THE AMOUNT OF CLOUD COVER THAT WILL EXIST ON SUNDAY INTO
MONDAY. GUIDANCE SUGGESTS THERE WILL BEGIN TO BE AN ABUNDANCE OF
CLOUD COVER LIMITING THE DIURNAL HEATING ALONG WITH ONLY MARGINAL
INSTABILITY AND WEAK MID LEVEL LAPSE RATES. ALSO, THE MOST AMOUNT
OF RAINFALL THAT ANY OF THE MODELS DEPICT ARE AERIAL COVERAGE OF
AROUND ONE INCH WHICH WOULD TRANSLATE TO POSSIBLE TWO TO THREE
INCHES IN ISOLATED LOCATIONS. THAT IS NOT AN IMPRESSIVE TOTAL FOR
SOUTH FLORIDA AND WOULD LEAD TO TYPICAL LOCAL URBAN TYPE
FLOODING. TO SUMMARIZE, IT DOES INDEED LOOK LIKE AN INCREASED RAIN
THREAT WITH NUMEROUS SHOWERS AND POSSIBLE LOCALIZED HEAVIER RAIN BUT
IT WILL REALLY DEPEND ON THE LOW LEVEL INSTABILITY WITH THE
DIURNAL CYCLE AS TO THE CHANCES FOR HEAVIER RAIN DEVELOPING IN
THUNDERSTORMS. THE FORECAST WILL REMAIN UNCHANGED BUT THERE IS
SOME UNCERTAINTY ABOUT HOW WIDESPREAD THE ACTIVITY MIGHT BE.

.LONG TERM (TUESDAY THROUGH SATURDAY)...
THE SYNOPTIC PATTERN WILL BEGIN TO RETROGRADE TO THE WEST ON
TUESDAY WITH THE RIDGE BUILDING BACK ACROSS THE FLORIDA PENINSULA
THROUGH THE END OF THE WEEK. THIS WILL SHIFT BACK TO A DEEP EAST
TO SOUTHEAST FLOW WITH BETTER CHANCES FOR SEEING RAINFALL IN THE
INTERIOR AND SOUTHWEST COAST. THERE WILL ALSO BE SOME DRYING
TAKING PLACE WITH PWAT GOING BACK DOWN BELOW TWO INCHES SO A MORE
TYPICAL SUMMER TYPE PATTERN GOING INTO THE FOURTH OF JULY WEEKEND.

&&

.AVIATION...
AFTERNOON CONVECTION WILL CONTINUE TO BUILD ACROSS THE INTERIOR
AND MOVE TOWARDS THE EAST COAST TERMINALS THROUGH 00Z. THERE COULD
BE SOME BRIEF MVFR/IFR CIG AND VSBY BUT TIMING AT ANY LOCATION
DIFFICULT SO PLACED TEMPO GROUPS IN THE TAFS BUT LEFT OUT MENTION
OF LOWER CONDITIONS AS TIMING WILL CONFINED TO 10-15 MINUTES IF IT
OCCURS AT ALL. ACTIVITY WILL MOVE OFF THE COAST THIS EVENING BUT
WITH INCREASING MOISTURE OVER THE NEXT 24 HOURS THERE COULD BE SOME
SHRA DURING THE NIGHT MOVE ONSHORE JUST ABOUT ANYWHERE.

&&

.MARINE...
SOUTHERLY WIND WILL CONTINUE TO BE ON THE INCREASE THROUGH THE
WEEKEND AND COULD REACH 15-20 KNOTS ON SUNDAY INTO MONDAY. THERE
WILL ALSO BE SOME SCATTERED THUNDERSTORMS MOVE OFFSHORE THIS
AFTERNOON AND EVENING WITH NUMEROUS THUNDERSTORMS POSSIBLE ON
SUNDAY AS THE MOISTURE AND INSTABILITY ALSO INCREASES ACROSS SOUTH
FLORIDA.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  76  89  77  87 / 30 80 60 60
FORT LAUDERDALE  77  89  79  87 / 30 80 60 60
MIAMI            77  89  77  87 / 30 80 60 60
NAPLES           76  89  75  86 / 30 60 40 50

&&

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

DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...13/SI

HAZARDOUS WEATHER OUTLOOK FOR SOUTH FLORIDA
NATIONAL WEATHER SERVICE MIAMI FL
944 AM EDT SAT JUN 29 2013

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
300445-
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-
944 AM EDT SAT JUN 29 2013

...THUNDERSTORMS POSSIBLE TODAY...
...LOCALIZED URBAN FLOODING POSSIBLE IN ATLANTIC COAST METRO AREAS...
...WATERSPOUTS POSSIBLE IN ALL SOUTH FLORIDA WATERS INCLUDING LAKE OKEECHOBEE...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS: SCATTERED TO NUMEROUS THUNDERSTORMS ARE
EXPECTED...ESPECIALLY DURING THE AFTERNOON. THUNDERSTORMS ARE
MOST LIKELY OVER THE ATLANTIC COAST METROPOLITAN AREAS.

WATERSPOUTS: THERE IS A SLIGHT RISK OF WATERSPOUTS FOR ALL MARINE
AREAS.

WIND: THE STRONGEST THUNDERSTORMS TODAY COULD PRODUCE WIND GUSTS
OF 40 TO 50 MPH.

FLOODING: TORRENTIAL DOWNPOURS MAY LEAD TO LOCALIZED URBAN
FLOODING ACROSS THE ATLANTIC COAST METROPOLITAN AREAS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORMS ARE LIKELY THROUGH AT LEAST MID-WEEK...MAINLY DURING
THE AFTERNOONS AND EVENINGS. LOCALLY HEAVY RAINFALL ASSOCIATED WITH
THIS ACTIVITY MAY LEAD TO URBAN FLOODING.

.SPOTTER INFORMATION STATEMENT...

WIDESPREAD SPOTTER ACTIVATION IS NOT ANTICIPATED, HOWEVER
INDIVIDUAL SPOTTERS ARE ENCOURAGED TO REPORT HIGH WIND, WATERSPOUTS, AND
FLOODING TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
MIAMI.

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MIAMI FL
214 PM EDT SAT JUN 29 2013

FLZ072>074-172-173-291900-
COASTAL BROWARD COUNTY FL COASTAL MIAMI DADE COUNTY FL INLAND
MIAMI-DADE COUNTY FL METRO BROWARD COUNTY FL METROPOLITAN MIAMI DADE
FL
214 PM EDT SAT JUN 29 2013

...A SIGNIFICANT WEATHER ADVISORY IS IN EFFECT FOR SOUTHEASTERN
BROWARD COUNTY...NORTHEASTERN MIAMI-DADE COUNTY...FOR THE PRIMARY
IMPACTS WILL BE UP TO NICKEL SIZED HAIL AND GUSTY WINDS OF 45 TO 55
MPH...

* UNTIL 300 PM EDT

* AT 209 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  LINE OF STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM OPA-LOCKA
  TO DORAL...AND MOVING NORTHEAST AT 15 MPH.

* THE LINE OF STORMS WILL AFFECT...
  OPA-LOCKA...
  NORTH MIAMI...
  HIALEAH GARDENS...
  SUN LIFE STADIUM...
  NORTH MIAMI BEACH...
  IVES ESTATES...
  AND SURROUNDING COMMUNITIES.

THE PRIMARY IMPACTS WILL BE UP TO NICKEL SIZED HAIL AND GUSTY WINDS
OF 45 TO 55 MPH. THESE WINDS CAN DOWN SMALL TREE LIMBS AND
BRANCHES...AND BLOW AROUND UNSECURED SMALL OBJECTS. SEEK SHELTER IN A
SAFE BUILDING UNTIL THE STORM PASSES.

LAT...LON 2589 8017 2567 8030 2572 8049 2598 8041
      2608 8030 2606 8011
TIME...MOT...LOC 1814Z 211DEG 12KT 2591 8026 2583 8036

SI