Rip Current in Florida, May 17, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
1253 PM EDT SUN MAY 17 2009

.AVIATION...
FOR E COAST TERMINALS...ISOLD SHRA MOVG ACRS ATLC ATTM BUT XPCT
INCRS AFT 00Z AND PSBL TSRA LTR TNGHT. INCRS IN PCPN AS DEEP
TRPCL MOISTURE ARRIVES. MAY NEED TEMPO FOR SHRA/MVFR IN LATTER
PTN OF TAF BUT WL KEEP VCSH ATTM. ESE WNDS ARND 15KT AND GUSTY
...DIMINISHING TO 9-11KT 00Z...THEN INCRG AGN AFT 14Z. AT KAPF
...WNDS ESE 1-12 KTS WITH VCSH...PSBL TSRA BUT WILL AMD AS NEEDED
...PTLY CDLY AFT 00Z WITH ENE 4-7 KT WND...INCRG FM ENE AFT 14Z.
SIMLR E CST...MAY NEED TEMPO FOR SHRA/MVFR IN LATTER PTN OF TAF
AS WELL BUT VCSH ONLY ATTM.

&&

.PREV DISCUSSION... /ISSUED 937 AM EDT SUN MAY 17 2009/

UPDATE...NO MAJOR CHANGES PLANNED TO MORNING UPDATES. EVEN THOUGH
NOT MUCH CURRENTLY ON RADAR OVER THE PENINSULA, THE 12Z MFL
SOUNDING SHOWS LOW LEVELS HAVE MOISTENED SLIGHTLY ALONG WITH MORE LOW
LEVEL INSTABILITY. THIS WOULD SUGGEST THAT WITH PLENTY OF DIURNAL
HEATING UNDERWAY, WILL SEE MORE IN THE LINE OF CONVECTION FIRING
UP LATER IN THE DAY. IN ADDITION, EAST FLOW HAS ALSO WEAKENED,
WHICH WILL ALLOW FOR WEST COAST SEA BREEZE TO SET UP BY EARLY
AFTERNOON. THIS ALONG WITH CONTINUED DEEP SOUTHEAST FLOW WILL
PRODUCE A GENERAL NORTHWEST MOVEMENT AND SHOULD SEE SOME ACTIVE
WEATHER INTERIOR AND COASTAL COLLIER COUNTY. MARINE ZONES LOOK TO
BE IN GOOD SHAPE.

30/KOB

PREV DISCUSSION... /ISSUED 721 AM EDT SUN MAY 17 2009/

AVIATION...
VFR WILL PREVAIL. A FEW SHOWERS MOVING ONSHORE COULD IMPACT THE EAST
COAST TERMINALS WITH AN OUTSIDE SHOT AT A STORM...BUT GIVEN THE LOW
PROBABILITIES WILL MAINTAIN JUST VCSH. THE BEST CHANCE OF THUNDER
WILL BE AT KAPF THIS AFTERNOON SO WILL CONTINUE WITH VCTS THERE.
EAST WINDS WILL PREVAIL EXCEPT FOR A GULF SEA BREEZE/SW WIND
DEVELOPING AT KAPF LATE IN THE AFTERNOON.

PREV DISCUSSION... /ISSUED 459 AM EDT SUN MAY 17 2009/

DISCUSSION...A RIDGE OF HIGH PRESSURE CONTINUES TO REMAIN OVER
THE WESTERN SECTIONS OF THE NORTH ATLANTIC WHILE AN INVERTED
TROUGH AND MID LEVEL LOW SLOWLY MOVES WEST ACROSS JAMAICA AND
WESTERN CUBA. AN UPPER TROUGH AND ASSOCIATED COLD FRONT IS ALSO
PUSHING INTO THE SOUTHERN PLAINS THIS MORNING.

TODAY WITH HIGH PRESSURE OVER THE ATLANTIC RIDGING INTO FLORIDA
AND THE BAHAMAS AND THE LOWER PRESSURE TO THE SOUTH, THE DEEP EAST
FLOW WILL CONTINUE TO PRODUCE FAST MOVING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS INTO AND ACROSS THE ATLANTIC AND THE EAST
COAST COUNTIES THIS MORNING, AND THEN PROVIDE EXTRA CONVERGENCE
ALONG THE WEST COAST SEA BREEZE THIS AFTERNOON AND EARLY EVENING.
THIS WILL RESULT IN SCT SHRA/ISOLD TSRA THIS MORNING AND ISOLD
SHRA/TSRA THIS AFTERNOON AND EVENING - EAST WITH ISOLD AM SHRA AND
SCT PM TSRA IN THE WEST.

LATE TONIGHT AND MONDAY MOISTURE WILL BEGIN TO SURGE IN WHILE A
WEAKENING COLD FRONT PUSHES INTO CENTRAL OR SOUTH FLORIDA,
POSSIBLY AS FAR SOUTH AS THE LAKE REGION, AND AS THE ORGANIZING
LOW TO THE SOUTHEAST MOVES NORTH. THIS WILL ALL HAPPEN AS THE
SHORT WAVE OVER THE SOUTHERN PLAINS DIGS INTO THE GULF AND CUTS
OFF DRAGGING UP DEEP TROPICAL MOISTURE AND INCREASING PWATS TO
AROUND 2. MODELS ARE IN AGREEMENT THAT SOMETHING WILL LIKELY
DEVELOP ACROSS THE NW CARIBBEAN, CUBA, OR THE STRAITS, BUT OF WHAT
SHAPE, FORM, OR TIME IS STILL OF QUESTION, AT ANY RATE, MODELS DO
AGREE THAT MOISTURE WILL SURGE NORTH FROM THE TROPICS BETWEEN THE
CUT OFF LOW OVER THE GULF AND THE RIDGE OVER THE ATLANTIC ACROSS
FL. THE DISSIPATING COLD FRONT WILL LIKELY DISSOLVE MONDAY
NIGHT/TUES MORN, BUT ANOTHER BOUNDARY MAY DEVELOP AS THE SURFACE
LOW LIFTS NORTHWARD. THIS MAY BE PROBLEMATIC AS HELICITY WILL
LIKELY CLIMB AHEAD OF THIS SECOND BOUNDARY... AND SPEAKING OF
BOUNDARIES... WITH THE WEAKENING COLD FRONT, THE WARM FRONT LIKE
FEATURE, A POTENTIAL LOW LIFTING OUT OF THE STRAITS POSSIBLY INTO
THE CWA, DEEP TROPICAL MOISTURE, AND A MID/UPPER CUT OFF LOW TO
THE WEST, DECIDED THERE IS A VERY HIGH POTENTIAL FOR RAINFALL LATE
MONDAY AFTERNOON THROUGH TUESDAY AFTERNOON AND WENT OVER GUIDANCE,
AND SOME COULD BE VERY HEAVY AS WELL. WEDNESDAY AND THURSDAY MAY
ALSO BE HIGH POPS DAYS, BUT THIS VARIES ON WHICH MODEL IS LOOKED
UPON. THE ECMWF IS SLOW (AND THE FAVORED SOLUTION OF TAFB AND HPC
THIS MORNING) WITH THE SURFACE LOW REMAINING IN THE NE GULF
THROUGH SATURDAY AFTERNOON... THE GFS IS A LITTLE FASTER WITH
THE LOW MAKING IT TO THE PANHANDLE THURSDAY AFTERNOON. EITHER WAY
S FL STAYS IN THE DEEP SOUTH FLOW INTO THE WEEKEND, BUT IF THE LOW
IS A LITTLE CLOSER RAIN CHANCES WILL DIFFER.

MARINE...THE PRESSURE GRADIENT BETWEEN THE RIDGE TO THE NORTHEAST
AND THE TROUGH TO THE WEST AND TO THE SOUTHEAST WILL KEEP WINDS IN
THE ATLANTIC AND BISCAYNE BAY IN THE SCEC CATEGORY FOR WINDS AND
SEAS THROUGH TODAY. TONIGHT THE GRADIENT MAY RELAX SLIGHTLY,
ALTHOUGH THIS WILL BE TEMPORARY AS LOW PRESSURE TAKES SHAPE OVER
THE NW CARIBBEAN AND MOVES NORTH. THIS WILL CAUSE WINDS AND SEAS
TO INCREASE BEGINNING MONDAY AND REMAIN ELEVATED THROUGH THURSDAY.

FIRE WEATHER...ISOLATED PORTIONS OF COLLIER, HENDRY, AND GLADES
COUNTIES MAY FALL INTO THE 35 TO 40% RH RANGE THIS AFTERNOON FOR
AN HOUR OR TWO, BUT MOISTURE LEVELS WILL STEADILY CLIMB TONIGHT
AND REMAIN HIGH THROUGH MOST OF THE WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  75  83  73  81 / 20 80 80 80
FORT LAUDERDALE  75  82  74  82 / 40 80 80 80
MIAMI            75  84  74  84 / 40 80 80 80
NAPLES           69  86  68  82 / 30 70 80 80

&&

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

LONG TERM...30/KOB
SHORT TERM/AVIATION...15/JR

HAZARDOUS WEATHER OUTLOOK FOR SOUTH FLORIDA...UPDATED
NATIONAL WEATHER SERVICE MIAMI FL
540 AM EDT SUN MAY 17 2009

FLZ063-066>075-168-172>174-180200-
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-
540 AM EDT SUN MAY 17 2009

...HIGH RISK OF RIP CURRENTS CONTINUES AT THE ATLANTIC BEACHES...
...ISOLATED THUNDERSTORMS, ESPECIALLY GULF COAST THIS AFTERNOON...
...A WETTER, STORMIER PERIOD MONDAY THROUGH AT LEAST TUESDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.

.DAY ONE...TODAY AND TONIGHT

RIP CURRENTS: EAST WINDS NEAR 20 MPH ACROSS THE ATLANTIC WATERS
WILL LEAD TO A HIGH RISK OF RIP CURRENTS AT THE ATLANTIC BEACHES
OF PALM BEACH, BROWARD, AND MIAMI-DADE COUNTIES. SWIMMING IS NOT
RECOMMENDED.

THUNDERSTORMS: ISOLATED THUNDERSTORMS ARE EXPECTED, FAVORING THE
GULF COAST LATE THIS AFTERNOON. LIGHTNING STRIKES WILL BE THE
PRIMARY IMPACT FROM THE STORMS, THOUGH GUSTY WINDS AND SMALL HAIL
WILL BE POSSIBLE WITH THE STORMS ALONG THE GULF COAST LATE THIS
AFTERNOON.

WIND: THUNDERSTORMS ALONG THE GULF COAST COULD PRODUCE GUSTY WINDS
TO AROUND 45 MPH THIS AFTERNOON.

HAIL: SMALL HAIL TO AROUND DIME SIZE IS POSSIBLE IN STORMS ALONG
THE GULF COAST THIS AFTERNOON.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

A BROAD TROUGH WILL DEVELOP ACROSS THE REGION MONDAY THROUGH WEDNESDAY
WITH EVEN THE POSSIBILITY OF A LOW AND WARM FRONT DEVELOPING. TIMING AND
PLACEMENT OF THESE WEATHER FEATURES ARE UNCERTAIN. HOWEVER...MONDAY
THROUGH TUESDAY LOOKS TO BE THE WETTEST AND STORMIEST PERIOD WITH HEAVY
RAINFALL POSSIBLE. ALTHOUGH THE RAIN WILL BE BENEFICIAL...EXCESSIVE
RAINFALL IN A SHORT PERIOD OF TIME COULD LEAD TO LOCALIZED STREET
FLOODING.

THUNDERSTORMS CONTAINING STRONG WIND GUSTS WILL BE POSSIBLE AS WELL.

THERE MAY BE A LOW RISK OF TORNADOES LATE MONDAY NIGHT THROUGH TUESDAY
NIGHT, DEPENDING ON WHETHER OR NOT A WARM FRONT DEVELOPS.

A STEADY AND INCREASING ONSHORE WIND ALONG THE ATLANTIC COAST MONDAY
THROUGH TUESDAY WILL CONTINUE TO KEEP AN ELEVATED RISK OF RIP CURRENTS
AT THE ATLANTIC BEACHES.

MARINE CONDITIONS WILL DETERIORATE MONDAY NIGHT THROUGH TUESDAY AS
WINDS STRENGTHEN INTO THE 20 TO 25 KNOT RANGE.

.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.

DG