Area Forecast Discussion Issued by NWS Miami, FL
000
FXUS62 KMFL 131346 AAB
AFDMFL
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MIAMI FL
946 AM EDT THU JUN 13 2013
.UPDATE...
SURFACE HIGH PRESSURE WAS LOCATED OVER THE WESTERN ATLANTIC WATERS
EXTENDING WEST INTO SOUTH FLORIDA THIS MORNING...AS AN UPPER LEVEL
LOW WAS LOCATED OVER THE FLORIDA STRAITS. THE HIGH WILL REMAIN
NEARLY STATIONARY TODAY...AS THE UPPER LEVEL LOW MOVES EAST INTO
THE SOUTHERN BAHAMA ISLANDS. THIS WILL ALLOW FOR BOTH THE EAST AND
WEST COAST SEA BREEZES TO DEVELOP TODAY AND PUSH INLAND INTO THE
INTERIOR AREAS. ISOLATED SHOWERS AND THUNDERSTORMS SHOULD DEVELOP
ALONG THE SEA BREEZES LATE THIS MORNING INTO EARLY THIS
AFTERNOON OVER THE METRO AREAS...BEFORE INCREASING IN COVERAGE TO
SCATTERED OVER THE INTERIOR AREAS. SO HAVE A ADJUSTED THE POPS
OVER SOUTH FLORIDA TODAY TO REFLECT THE SEA BREEZES INFLUENCE.
SOME OF THE STORMS TODAY COULD BECOME STRONG THIS AFTERNOON
ESPECIALLY OVER THE INTERIOR AREAS WHERE THE SEA BREEZES
COLLIDE DUE TO THE COLD MID TEMPS OF -9C OVER THE AREA. SO WILL
CONTINUE TO MENTION STRONG STORM WORDING IN THE HWO PACKAGE FOR
SOUTH FLORIDA FOR TODAY.
REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES
ARE PLANNED.
&&
.UPDATE...54/BNB
.PREV DISCUSSION... /ISSUED 732 AM EDT THU JUN 13 2013/
AVIATION...
LIGHT LOW-LEVEL STEERING FLOW COMBINED WITH AN UPPER TROUGH OVERHEAD
AND DAYTIME HEATING WILL BE ENOUGH TO TRIGGER ANOTHER ROUND OF SCT
TSTMS TODAY ACROSS PORTIONS OF THE AREA. ALTHOUGH THE BULK OF THIS
ACTIVITY SHOULD BECOME CONCENTRATED JUST INLAND OF THE EAST COAST
AND ACROSS THE INTERIOR LOCATIONS AS THE SEA BREEZES PENETRATE
INLAND...WE WILL INCLUDE VCTS FOR ALL SITES FROM 15Z ON...THEN
AMEND AS CONDITIONS EVOLVE THROUGH THE DAY.
&&
PREV DISCUSSION... /ISSUED 332 AM EDT THU JUN 13 2013/
DISCUSSION...
ANOTHER ROUND OF POTENTIALLY STRONG THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE SOUTH FLORIDA THIS AFTERNOON AND EVENING.
MID LEVEL TROUGH AXIS WILL CONTINUE TO SLOWLY PUSH SOUTH OF THE AREA
THROUGH THE DAY. MODEL SOUNDINGS DEPICT DEEP MOISTURE REMAINING
ACROSS THE AREA WITH PWAT VALUES RANGING BETWEEN 1.75 TO 2 INCHES
AREA WIDE. MUCH LIKE YESTERDAY...STEERING FLOW IS EXPECTED TO BE
VERY WEAK SO COVERAGE OF STORMS MAY BE HIGHER THAN EXPECTED AS
CONVECTION WILL BE MAINLY OUTFLOW DRIVEN. 500 MB TEMPERATURES ARE
ALSO PROGGED IN THE -9C TO -10C RANGE FOR THE SECOND STRAIGHT DAY
WHICH IS A COUPLE OF DEGREES BELOW THE NORMAL 500 MB TEMPERATURE
FOR THIS DATE. LATEST SHORT TERM AND LOCAL MODEL GUIDANCE IS
INITIATING CONVECTION ACROSS THE SOUTHERN INTERIOR EARLY THIS
AFTERNOON AND CONTAINING MOST OF THE ACTIVITY AWAY FROM THE METRO
AREAS. HOWEVER CANNOT RULE OUT A FEW SHOWERS AND THUNDERSTORMS
AFFECTING THE METRO AREAS ESPECIALLY LATE IN THE AFTERNOON.
FRIDAY THROUGH SUNDAY...THE MID LEVEL TROUGH BEGINS TO GET
ABSORBED INTO A HIGH AMPLITUDE H5 SHORTWAVE EXITING THE NEW ENGLAND
STATES. THIS WILL ALLOW RIDGING TO BUILD INTO THE FLORIDA PENINSULA
FROM THE GULF OF MEXICO. THIS WILL BE ACCOMPANIED BY LOWER
1000-500MB RH VALUES YIELDING PWATS DOWN NEAR 1.25 INCHES. SHOWERS
AND THUNDERSTORMS SHOULD BE AT A MINIMUM DURING THIS TIME FRAME...20
PERCENT COVERAGE OR LESS. HOWEVER AS MID LEVEL RIDGING MOVES
OVERHEAD...HIGH TEMPERATURES WILL BEGIN TO SOAR INTO THE LOW 90S
ALONG THE EAST COAST METRO AREAS WITH MID 90S ACROSS INLAND AREAS.
THIS COMBINED WITH DEW POINTS IN THE LOW 70S WILL PRODUCE HEAT INDEX
READINGS IN THE UPPER 90S ALONG THE EAST COAST AND BETWEEN 100-105
DEGREES ACROSS WESTERN INTERIOR AREAS.
DEEP MOISTURE RETURNS BY EARLY NEXT WEEK AND SHOULD STAY THROUGH
MUCH OF THE WEEK AS A TROPICAL WAVE SOUTH OF CUBA SURGES TO THE WEST
ACROSS THE YUCATAN PENINSULA AND INTO THE BAY OF CAMPECHE. AS IT
DOES...EASTERLY FLOW WILL PREVAIL ACROSS SOUTH FLORIDA WITH CHANCES
FOR AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY.
AVIATION...
LIGHT LOW-LEVEL STEERING FLOW COMBINED WITH AN UPPER TROUGH OVERHEAD
AND DAYTIME HEATING WILL BE ENOUGH TO TRIGGER ANOTHER ROUND OF
SCT TSTMS TODAY ACROSS PORTIONS OF THE AREA. ALTHOUGH THE BULK OF
THIS ACTIVITY SHOULD BECOME CONCENTRATED JUST INLAND OF THE EAST
COAST AND ACROSS THE INTERIOR LOCATIONS AS THE SEA BREEZES
PENETRATE INLAND...WE WILL INCLUDE VCTS FOR ALL SITES FROM 15Z
ON...THEN AMEND AS CONDITIONS EVOLVE THROUGH THE DAY.
MARINE...
MAINLY BENIGN MARINE CONDITIONS ARE EXPECTED ACROSS THE AREA
WATERS OUTSIDE OF SHOWERS AND THUNDERSTORMS AS WINDS REMAIN LIGHT
THROUGH SATURDAY. FOR SUNDAY INTO EARLY NEXT WEEK, EASTERLY FLOW
RETURNS WITH WINDS AROUND 10 TO 15 KNOTS AND SEAS AROUND 3 FEET
ACROSS THE ATLANTIC WATERS AS THE NORTHERNMOST EXTENSION OF A TROPICAL
WAVE SKIRTS THE AREA.
FIRE WEATHER...
SLIGHTLY DRIER AIR IS EXPECTED TO PUSH INTO THE SOUTH FLORIDA AREA
FRIDAY THROUGH THE WEEKEND. HOWEVER...MINIMUM RELATIVE HUMIDITY
VALUES SHOULD STILL REMAIN ABOVE CRITICAL THRESHOLDS AND REMAIN
THAT WAY THROUGH NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 75 90 74 / 30 20 20 10
FORT LAUDERDALE 88 77 89 77 / 40 20 20 10
MIAMI 89 75 90 76 / 40 20 20 10
NAPLES 88 73 87 73 / 30 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...85/AG