091
FXUS62 KMFL 161105
AFDMFL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
705 AM EDT TUE SEP 16 2025
..NEW AVIATION
SHORT TERM
(TODAY THROUGH WEDNESDAY)
ISSUED AT 117 AM EDT TUE SEP 16 2025
A PATTERN CHANGE IS AHEAD FOR SOUTH FLORIDA, AND TODAY WILL SERVE AS
THE BRIDGE BETWEEN THE BRIEF RESPITE OF DRY WEATHER WE HAVE
EXPERIENCED OVER THE LAST TWO DAYS AND A WETTER, MORE IMPACTFUL
PATTERN DURING THE SECOND HALF OF THE WORK WEEK. ALL THINGS MUST
COME TO AN END, AND THE DRIER AIR ALOFT THAT HAS SUPPRESSED
CONVECTIVE ACTIVITY WILL WANE IN INFLUENCE AND SCOPE ACROSS THE
OUR AREA STARTING TODAY. ZOOMING OUT AND TAKING A BIG PICTURE
LOOK AT THE SYNOPTIC FEATURES IN PLAY, AN EXPANSIVE SPRAWLING CUT-
OFF LOW CURRENTLY OVER THE SOUTHEASTERN UNITED STATES WILL REMAIN
STATIONARY TODAY, EFFECTIVELY BLOCKED BY PERSISTENT MID-LEVEL
RIDGING TO THE EAST OVER THE WESTERN ATLANTIC WATERS. AN
ASSOCIATED WEAK SURFACE LOW JUST TO THE EAST OF THE MID-LEVEL CUT
OFF LOW IS FORECAST TO GRADUALLY MOVE ONSHORE ACROSS COASTAL NORTH
CAROLINA LATER TODAY. THIS DISTANT SURFACE LOW IS WORTH
MENTIONING AS IT STILL REMAINS ATTACHED TO A WEAK STALLED OUT
FRONTAL BOUNDARY THAT WE DEALT WITH LAST WEEK, WITH THE BOUNDARY
STILL REMAINING ELONGATED FROM THE FAR OFFSHORE WESTERN ATLANTIC
WATERS INTO THE FLORIDA STRAITS EARLY THIS MORNING.
WHILE SOUTH FLORIDA WILL STILL REMAIN TO THE NORTH OF THE STALLED
FRONTAL BOUNDARY OVER THE FLORIDA STRAITS, THE UPTICK IN ATMOSPHERIC
MOISTURE ACROSS THE REGION SHOULD CORRELATE WITH HIGHER SPATIAL AND
TEMPORAL COVERAGE OF SHOWERS AND STORMS DURING THE AFTERNOON HOURS
TODAY (40-60%) AS OPPOSED TO THE MORE SPARSE COVERAGE EXPERIENCED
YESTERDAY. AREA-WIDE PRECIPITABLE WATER VALUES WILL INCREASE BACK
INTO THE 1.9 TO 2.1 RANGE BY THIS AFTERNOON WHICH IS ABOVE
CLIMATOLOGICAL NORMS AND NEAR THE 90TH PERCENTILE FOR THE DATE.
EVEN WITH MOISTURE RETURN IN THE MID-LEVELS OF THE ATMOSPHERE
TODAY, THERE WILL STILL BE ENOUGH RESIDUAL MID-LEVEL DRY AIR TO
SUPPORT THE POTENTIAL OF AN ISOLATED STRONG TO SEVERE THUNDERSTORM
DURING THE AFTERNOON AND EARLY EVENING STORMS. THE MAIN THREAT
WILL ONCE AGAIN BE THE POTENTIAL OF AN ISOLATED STRONG (45 TO 55
MPH) TO MARGINALLY SEVERE WIND GUST. THE GREATEST COVERAGE OF
SHOWERS AND STORMS IS ONCE AGAIN EXPECTED ACROSS INLAND AREAS AS
THAT IS WHERE SEA-BREEZE AND OUTFLOW BOUNDARIES ARE FORECAST TO
CONVERGE DURING THE MID TO LATE AFTERNOON HOUR. HIGH TEMPERATURES
WILL ONCE AGAIN REACH THE UPPER 80S TO LOW 90S WITH SHARP
TEMPERATURE FLUCTUATIONS POSSIBLE IN AND AROUND SHOWER AND
THUNDERSTORM ACTIVITY.
BY WEDNESDAY, THE AFOREMENTIONED CUT-OFF LOW WILL BEGIN A SLOW
ACCELERATION TO THE NORTHEAST OUT AHEAD OF THE NEXT LONGWAVE TROUGH
PUSHING EASTWARD ACROSS THE CENTRAL UNITED STATES. AT THE SAME TIME,
AN UPPER LEVEL JET STREAK WILL DEVELOP ACROSS THE SOUTHEASTERN
UNITED STATES (INCLUDING NORTHERN FLORIDA AND THE GULF) WHICH WILL
PLACE SOUTH FLORIDA IN AN AREA OF ENHANCED LOW-LEVEL CONVERGENCE
(RIGHT ENTRANCE REGION). THIS SYNOPTIC BOOST OF ASCENT WILL COMBINE
WITH DEEPER MOISTURE ACROSS THE REGION AND KICK OFF THE BEGINNING OF
AN ACTIVE PERIOD FOR OUR AREA. THE SURFACE LOW MEANDERING ACROSS
COASTAL NORTH CAROLINA WILL GRADUALLY LIFT NORTHWESTWARD, DRAGGING
THAT PESKY FRONTAL BOUNDARY OVER THE FLORIDA STRAITS BACK NORTHWARDS
(PSEUDO WARM FRONT?) INTO OUR AREA. AS THE FRONT ARRIVES BACK OVER
SOUTH FLORIDA, EVEN DEEPER MOISTURE AND LOW LEVEL ASCENT IS FORECAST
TO MAKE A RETURN TO THE REGION WITH THE CONTINUANCE OF AN INCREASING
TREND IN PRECIPITABLE WATER VALUES. MAXIMUM DAILY RAIN CHANCES
INCREASE TO THE 60-80% RANGE WEDNESDAY. FORECAST MODEL GUIDANCE ONCE
AGAIN DEPICTS THE POTENTIAL OF A SATURATED ATMOSPHERE OVER SOUTH
FLORIDA WITH PRECIPITABLE WATER VALUES IN THE 2.1 TO 2.3 INCH RANGE
(NOW OVER THE THE 90TH PERCENTILE FOR SEPTEMBER 17TH). A
SATURATED ATMOSPHERE BRINGS AN INCREASED THREAT OF HEAVY RAINFALL
THAT COULD RESULT IN ACCUMULATIONS ADDING UP OVER A SHORT PERIOD
OF TIME. THE WEATHER PREDICTION CENTER (WPC) HAS PLACED THE EAST
COAST METRO AREAS OF SOUTH FLORIDA IN A MARGINAL RISK (LEVEL 1 OF
4) OF EXCESSIVE FLOODING ON WEDNESDAY. THIS MEANS THAT THERE IS A
5-15% CHANCE OF EXCESSIVE RAINFALL THAT MAY LEAD TO FLASH FLOODING
WITHIN A 25 MILE RADIUS OF A LOCATION.
HIGH TEMPERATURES WILL TREND LOWER ON WEDNESDAY DUE TO ABUNDANT
CLOUD COVER AND THE COOLING INFLUENCES OF SHOWERS AND STORMS,
FORECASTED HIGHS AREA-WIDE WILL BE IN THE MIDDLE TO UPPER 80S.
LONG TERM
(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 117 AM EDT TUE SEP 16 2025
WITH THE BACKGROUND ENVIRONMENT CONDUCIVE FOR HEAVY RAINFALL, THE
MAIN DRIVING FORCE BEHIND RAINFALL ACCUMULATIONS WILL BE THE
COVERAGE AND STORM MOTION OF SHOWERS AND STORMS ACROSS THE REGION
DURING THE SECOND HALF OF THE WEEK. OVERNIGHT MODEL GUIDANCE
CONTINUES TO HONE IN ON THURSDAY BEING THE DAY WITH THE GREATEST
POTENTIAL OF SEEING HIGHER END QPF VALUES AS THE AFOREMENTIONED JET-
STREAK NEARBY AND THE STALLED BOUNDARY DIRECTLY OVERHEAD ACT TO
PROVIDE FAVORABLE CONDITIONS FOR NUMEROUS SHOWERS AND STORMS. THE
DETERMINISTIC GFS AND EURO CONTINUE TO HINT AT A LOBE OF MID-LEVEL
VORTICITY PIVOTING ACROSS SOUTH FLORIDA ON THURSDAY WITH FORECASTED
PRECIPITABLE WATER VALUES POTENTIALLY INCREASING TO THE 2.2 TO 2.4
RANGE WHICH WOULD BE VERY CLOSE TO THE DAILY MAX VALUE FOR THE DATE.
FORECAST MODEL SOUNDINGS DURING THIS TIME FRAME CONTINUE TO DEPICT A
CLASSIC SKINNY CAPE PROFILE THAT POINTS TO THE POTENTIAL OF
EFFICIENT RAINFALL RATES THAT COULD LEAD TO LOCALIZED FLOODING
CONCERNS OVER URBAN METRO AREAS. ECENS AND GEFS ENSEMBLE GUIDANCE
SUITES DEPICT A HIGHER QPF SIGNAL ACROSS THE EAST HALF OF THE REGION
ON THURSDAY WHICH COINCIDES WITH THE RETURN AND STALL OF THE FRONTAL
BOUNDARY. WPC CLUSTER ANALYSIS ALSO HIGHLIGHTS A HEAVY RAINFALL
THREAT ACROSS THE EASTERN HALF OF THE REGION DURING THIS TIME FRAME.
THE WEATHER PREDICTION CENTER ALSO MAINTAINS A MARGINAL RISK OF
EXCESSIVE RAINFALL FOR THE EAST COAST OF SOUTH FLORIDA ON THURSDAY.
WITH THE ABUNDANCE OF CONVECTIVE ACTIVITY AND RESULTANT CLOUD
DEBRIS, HIGH TEMPERATURES MAY BE HELD IN CHECK ONCE AGAIN ON
THURSDAY WITH FORECAST HIGHS IN THE LOW TO MID 80S.
FORECAST GUIDANCE KEEPS THE STALLED FRONTAL BOUNDARY IN PLACE OVER
SOUTH FLORIDA FRIDAY WHICH WILL RESULT IN SCATTERED TO NUMEROUS
SHOWERS AND STORMS DURING THE AFTERNOON AND EVENING HOURS. HOWEVER
BY THE WEEKEND, A NOTABLE SHIFT ON THE LATEST FORECAST MODELS HAS
OCCURRED AS THEY NOW DEPICT THE POTENTIAL OF AN AREA OF LOW PRESSURE
DEVELOPING ALONG THE BOUNDARY IN THE WESTERN ATLANTIC. CYCLONIC FLOW
AROUND THIS DEVELOPING FEATURE MAY RESULT IN THE POTENTIAL OF DRIER
AIR MOVING SOUTHWARD ACROSS THE PENINSULA WHICH MAY LIMIT RAIN
CHANCES DURING THE WEEKEND AS OPPOSED TO THE MID TO LATE WORK WEEK.
UNCERTAINTY REMAINS REGARDING THIS SOLUTION HOWEVER, AND FORECAST
RAINFALL TOTALS ON SATURDAY AND SUNDAY CURRENTLY REMAIN NEAR
CLIMATOLOGICAL NORMS IN THE 50-60% RANGE. THE LESSENING OF MID-LEVEL
FLOW ALOFT WILL ONCE AGAIN RESULT IN SEA-BREEZE CIRCULATIONS
REMAINING THE MAIN FOCI OF DIURNAL CONVECTION EACH AFTERNOON AND
EVENING WHICH WILL LIKELY FOCUS THE GREATEST CONVECTIVE CHANCES
ACROSS INTERIOR AREAS EACH AFTERNOON DURING THE WEEKEND. HIGH
TEMPERATURES ON FRIDAY THROUGH EARLY NEXT WEEK WILL REACH THE UPPER
80S TO LOW 90S AREA-WIDE.
AVIATION
(12Z TAFS)
ISSUED AT 703 AM EDT TUE SEP 16 2025
NOT MUCH CHANGE IN THE TAF FOR THE 12Z ISSUANCE. STILL EXPECTED A
FEW STORMS ALONG THE EAST COAST LATER THIS AFTERNOON. INTRODUCED A
PROB30 FOR PBI AFTER 00Z FOR ANY STORMS THAT MAY DRIFT THAT WAY
FROM THE INTERIOR. STORMS SHOULD DISSIPATE OVER LAND AREAS THROUGH
THE NIGHT.
MARINE
ISSUED AT 117 AM EDT TUE SEP 16 2025
A MODERATE EASTERLY BREEZE WILL ENHANCE LATER TODAY AND CONTINUE
INTO THE MID WEEK PERIOD. SEAS ACROSS THE ATLANTIC WATERS WILL
GENERALLY REMAIN BETWEEN 2 TO 5 FEET THROUGH THURSDAY MORNING WHILE
SEAS ACROSS THE GULF WATERS REMAIN AT 1 TO 2 FEET. PERIODS OF ROUGH
SEAS AND GUSTY WINDS WILL BE POSSIBLE EACH DAY NEAR THE MOST ROBUST
SHOWER AND THUNDERSTORM ACTIVITY.
BEACHES
ISSUED AT 117 AM EDT TUE SEP 16 2025
A HIGH RISK OF RIP CURRENTS WILL CONTINUE ALONG THE PALM BEACH COUNTY
BEACHES TODAY AS ONSHORE FLOW ENHANCES THIS AFTERNOON AND A
NORTHEASTERLY SWELL IN THE ATLANTIC WATERS LINGERS. THE HIGH RISK OF
RIP CURRENT RISK WILL CONTINUE AND POTENTIALLY EXPAND FURTHER SOUTH
ACROSS THE EAST COAST BY MID-WEEK.
HYDROLOGY
ISSUED AT 117 AM EDT TUE SEP 16 2025
THE WEATHER PREDICTION CENTER'S LATEST 5 DAY QUANTITATIVE
PRECIPITATION FORECAST HAS A SWATH OF WIDESPREAD TOTALS OF 4-6
INCHES ACROSS THE EASTERN HALF OF SOUTH FLORIDA THROUGH SATURDAY
NIGHT. SIMILAR TO THE PATTERN LAST WEEK, SHARP RAINFALL GRADIENTS
MAY MATERIALIZE WITH PROBLEMATIC POCKETS OF HIGHER RAINFALL TOTALS
RESULTING IN THE POTENTIAL OF LOCALIZED URBAN FLOODING ALONG THE
EAST COAST METRO. WHILE THE FORECASTED RAINFALL TOTALS MAY SHIFT
IN NUMERICAL VALUES OVER THE NEXT SEVERAL DAYS, THE MAIN TAKEAWAY
IS THAT SATURATED SOILS OVER THE EAST COAST COULD RESULT IN A
HEIGHTENED URBAN FLOOD THREAT ACROSS THE EAST COAST METRO
PARTICULARLY ON WEDNESDAY, THURSDAY, AND FRIDAY.
PRELIMINARY POINT TEMPS/POPS
MIAMI 90 77 87 77 / 50 50 70 70
WEST KENDALL 90 76 87 76 / 60 50 70 60
OPA-LOCKA 91 77 88 77 / 50 50 70 60
HOMESTEAD 89 76 87 77 / 50 50 70 70
FORT LAUDERDALE 88 76 86 77 / 50 60 70 70
N FT LAUDERDALE 89 77 87 77 / 50 60 70 60
PEMBROKE PINES 92 77 89 77 / 50 50 70 60
WEST PALM BEACH 89 77 87 77 / 50 40 70 60
BOCA RATON 91 76 88 76 / 50 50 70 70
NAPLES 91 76 88 75 / 40 40 70 40
MFL WATCHES/WARNINGS/ADVISORIES
FL...HIGH RIP CURRENT RISK THROUGH WEDNESDAY EVENING FOR FLZ168.
AM...NONE.
GM...NONE.
SHORT TERM...HADI
LONG TERM....HADI
AVIATION...HARRIGAN
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