000
FXUS62 KMFL 121322
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
922 AM EDT SUN MAY 12 2013

.UPDATE...
NO CHANGES ARE PLANNED FOR THE MORNING UPDATES. THE 12Z MFL
SOUNDING SHOWS ONLY MODEST INSTABILITY WITH TWO SMALL INVERSIONS,
ONE AT AROUND THE 850 MB LEVEL AND ANOTHER AT 500 MB. THUS, IT
WOULD APPEAR THAT CONVECTION WILL STRUGGLE TO GET GOING MUCH LIKE
YESTERDAY AND MAY EVEN BE MORE SO TODAY. MODIFIED CAPE IS AROUND
1500 J/KG OR SLIGHTLY LESS AND THAT IS ALSO SIMILAR TO SATURDAY.
STEERING FLOW REMAINS WNW-ESE AT 5-7 KT AND BASED ON ALL OF THIS
THE HRRR DOES SHOW CONVECTION FIRING UP AT 18-19Z AND THEN
BUILDING AFTER 20Z AS IT DRIFTS TOWARDS THE EAST COAST METRO
REGION. SO ALL IN ALL, THE FORECAST LOOKS GOOD WITH A LATE
AFTERNOON/EARLY EVENING STRONG STORM POSSIBLY CAPABLE OF PRODUCING
A WIND GUST AND/OR SMALL HAIL ALTHOUGH THE PRIMARY RISK APPEARS TO
BE THE WIND GUSTS.

KOB

&&

.PREV DISCUSSION... /ISSUED 720 AM EDT SUN MAY 12 2013/

AVIATION...
CLEAR SKIES AND CALM WINDS THIS MORNING WILL GRADUALLY TRANSITION TO
SCATTERED/BROKEN CUMULUS WITH ONSHORE WINDS OF 10-15 KTS BY MIDDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED AWAY FROM THE GULF
COAST. HAVE ELECTED TO PLACE VCSH AT ALL AIRPORTS EXCEPT KAPF...DUE
TO LOW CONFIDENCE IN COVERAGE AND TIMING OF THUNDERSTORMS. GUSTY
WINDS AND SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS COULD OCCUR IN
AND NEAR SHOWERS AND THUNDERSTORMS THIS AFTERNOON.  ACTIVITY LIKELY
DIMINISHES BY SUNSET...THEN CLEARING SKIES AND CALM WINDS TONIGHT.
FOG OVER INTERIOR SOUTH FLORIDA COULD IMPACT APF LATE TONIGHT...BUT
ATTM THIS RISK APPEARS LOW.

PREV DISCUSSION... /ISSUED 350 AM EDT SUN MAY 12 2013/

DISCUSSION...
AN UPPER TROUGH WAS DIGGING INTO THE SOUTHEAST THIS
MORNING...WITH MAINLY ZONAL FLOW ACROSS SOUTH FLORIDA. A SURFACE
LOW WAS LOCATED OVER CANADA TO THE NORTH OF THE GREAT LAKES AND A
COLD FRONT WAS MOVING INTO NORTHERN FLORIDA. WINDS NEAR THE
SURFACE ARE EXPECTED TO BE OUT OF THE SOUTH TO SOUTHEAST...WITH
WESTERLY FLOW ALOFT. THE MORE SOUTHERLY LOW LEVEL FLOW WILL PUSH
THE SEA BREEZE BOUNDARY NORTHWARD AWAY FROM THE SOUTHEAST
COAST...AND THE WESTERLY FLOW ALOFT WILL PUSH STORMS BACK TOWARDS
THE EAST COAST. LOW LEVEL MOISTURE WILL POOL SOUTH OF THE FRONTAL
BOUNDARY THIS AFTERNOON...WITH PWATS AROUND 1.6-1.7 INCHES. SO THE
BEST CHANCE OF RAIN WILL BE ACROSS PALM BEACH AND BROWARD
COUNTIES. SHEAR VALUES ARE NOT AS HIGH AS YESTERDAY...AND
TEMPERATURES ALOFT ARE SLIGHTLY WARMER AS WELL. HOWEVER...AS THE
TROUGH DIGS INTO THE SOUTHEAST AND NORTHERN FLORIDA...DIVERGENCE
ALOFT WILL INCREASE. SO STRONG STORMS WILL BE POSSIBLE...AND A
STRAY SEVERE STORM CANNOT BE RULED OUT ACROSS THE INTERIOR AND
ACROSS PALM BEACH COUNTY. THE MAIN THREAT WILL BE STRONG WINDS.
HIGHS WILL BE IN THE MID 80S COASTAL AREAS TO LOWER 90S INTERIOR.

THE FRONTAL BOUNDARY WILL MOVE INTO SOUTH FLORIDA MONDAY
MORNING...AND PATCHY FOG IS POSSIBLE...ESPECIALLY FOR THE
NORTHWESTERN HALF OF THE REGION. ALTHOUGH NOT CURRENTLY IN THE
FORECAST...DENSE FOG COULD ALSO OCCUR ACROSS THE NORTHWEST
INTERIOR. THE UPPER TROUGH WILL DIG DOWN THE PENINSULA...AND THE
REGION WILL MOVE INTO THE RIGHT ENTRANCE REGION OF A 100 KNOT
250MB JET STREAK. 0-6KM SHEAR WILL INCREASE TO AROUND 30 KNOTS AS
WELL. THE SURFACE BOUNDARY IS EXPECTED TO PUSH INTO DEEP SOUTH
FLORIDA AROUND 18Z WITH NORTHERLY LOW LEVEL FLOW. HOWEVER...DRY
AIR WILL LAG BEHIND ACROSS CENTRAL FLORIDA. AS THE EAST COAST SEA
BREEZE DEVELOPS...SCATTERED SHOWERS AND STORMS ARE EXPECTED TO
DEVELOP ALONG IT...WITH STORM MOTION TO THE SOUTH OR SOUTHEAST.
STRONG TO ISOLATED SEVERE STORMS ARE POSSIBLE..ESPECIALLY TOWARDS
THE SOUTHEAST PORTIONS OF THE AREA.

DRIER AIR WILL BEGIN TO MOVE INTO THE LAKE REGION IN THE LATE
AFTERNOON TO EARLY EVENING...WITH MUCH DRIER AIR ENCOMPASSING
SOUTH FLORIDA OVERNIGHT. PRECIPITABLE WATER VALUES WILL DROP TO
AROUND 0.75 INCHES...WHICH IS WELL BELOW NORMAL FOR THIS TIME OF
YEAR. SURFACE HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST AND
WESTERN ATLANTIC...AND BREEZY NORTHEASTERLY WINDS ARE EXPECTED ON
TUESDAY. TEMPERATURES TUESDAY MORNING WILL BE COOLER...ESPECIALLY
ACROSS THE NORTHWEST INTERIOR...WHERE LOWS WILL BE IN THE 50S. MID
60S TO AROUND 70 IS STILL EXPECTED FOR THE EAST COAST...BUT IT
WILL FEEL MUCH MORE COMFORTABLE AS DEWPOINTS DROP INTO THE 50S TO
AROUND 60. VERY PLEASANT MID MAY TEMPERATURES ARE EXPECTED ON
TUESDAY THROUGH THE END OF THE WEEK. HIGHS WILL BE NEAR 80 TO THE
MID 80S ON TUESDAY.

AN UPPER LEVEL RIDGE WILL BUILD TO THE EAST ACROSS THE GULF ON
WEDNESDAY AND HEIGHTS WILL INCREASE. HOWEVER...TEMPERATURES WILL
REMAIN AT OR BELOW NORMAL THROUGH THE END OF THE WEEK AS DRY AND
COOL EAST TO NORTHEASTERLY FLOW CONTINUES. PWATS WILL REMAIN AT
OR BELOW 1 INCH THROUGH THE END OF THE WEEK. A WEAK SHORTWAVE WILL
MOVE ACROSS THE SOUTHERN PLAINS AND INTO THE SOUTHEAST ON
THURSDAY...WITH WEAK TROUGHING THEN REMAINING OVER THE SOUTHEAST
AND FLORIDA INTO THE WEEKEND.

AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH EARLY THIS WEEK. MOSTLY CLEAR
SKIES AND NEAR-CALM WINDS EARLY THIS MORNING WILL GIVE WAY TO
INCREASING CUMULUS WITH SOUTHEAST BREEZES AT 10-15 KTS BY MIDDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE
AFTERNOON ACROSS SOUTH FLORIDA...MAINLY EAST OF NAPLES.
THUS...PROB30S MAINTAINED FOR EASTERN TERMINALS. GUSTY WINDS AND
SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS ARE LIKELY IN/NEAR
SHOWERS/THUNDERSTORMS. PRECIPITATION SHOULD DIURNALLY WANE THIS
EVENING...WITH CLEARING SKIES AND CALMING WINDS EXPECTED TODAY.

MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE TODAY OUTSIDE OF ISOLATED
STRONG CONVECTION. A COLD FRONT WILL MOVE ACROSS THE SOUTH FLORIDA
WATERS LATE MONDAY WITH STRONG HIGH PRESSURE BUILDING BEHIND THE
FRONT WITH INCREASING WIND AND SEAS MONDAY NIGHT INTO MID WEEK.

FIRE WEATHER...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY
AND MONDAY...MAINLY DURING THE AFTERNOON AND EARLY EVENING
HOURS. A FRONT WILL BRING IN MUCH DRIER AIR MONDAY NIGHT INTO
TUESDAY. RELATIVE HUMIDITY VALUES ACROSS GLADES HENDRY AND
COLLIER COUNTIES MAY FALL BELOW 35 PERCENT BOTH TUESDAY AND
WEDNESDAY AFTERNOONS...WITH WINDS OF 10-15 MPH POSSIBLE. THERE IS
A SLIGHT CHANCE THAT PATCHY FOG WILL FORM LATE TONIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  86  69  85  65 / 60 30 30 10
FORT LAUDERDALE  87  74  85  69 / 50 20 50 20
MIAMI            88  72  86  69 / 40 20 50 20
NAPLES           86  71  86  64 / 10 10 10 10

&&

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

$$