844
FXUS62 KMFL 202022
AFDMFL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
422 PM EDT TUE OCT 20 2026
..NEW SYNOPSIS, SHORT TERM, LONG TERM, AVIATION, MARINE, BEACHES
KEY MESSAGES
UPDATED AT 357 PM EDT TUE OCT 20 2026
- HAZARDOUS MARINE AND BEACH CONDITIONS CONTINUE THROUGH TOMORROW
FOR THE ATLANTIC AND GULF WATERS.
- MINOR TO MODERATE COASTAL FLOODING POSSIBLE AS EARLY AS MID TO
LATE WEEK. PEAK TIDAL LEVELS WILL BE REACHED LATE THIS WEEKEND
INTO EARLY NEXT WEEK AND COULD REACH MAJOR FLOOD STAGE FOR
POINTS ALONG THE COAST.
- HEAVY RAIN, ISOLATED FLASH FLOODING, AND WINDY CONDITIONS ARE
FORECAST FOR THIS WEEKEND.
SYNOPSIS
ISSUED AT 357 PM EDT TUE OCT 20 2026
WATER VAPOR AND UPPER-AIR ANALYSIS DATA SHOW A FRONTAL SYSTEM OFF
THE MID-ATLANTIC COAST EMBEDDED WITHIN THE LARGER EASTERN US
LONGWAVE TROUGH. VAPOR IMAGERY AND MODEL ANALYSIS FIELDS ALSO SHOW
THAT, WITHIN THE LONGWAVE TROUGH, A COUPLE OF ELONGATED SHORTWAVES
SIT OVER THE TENNESSEE VALLEY AND GREAT LAKES REGION, AND STRETCH
BACK OVER THE CENTRAL CONUS RIDGE. AT THE SURFACE, THE 12Z WPC
ANALYSIS DEPICTS A LARGE EASTERN AND CENTRAL CONUS RIDGE WITH THE
SURFACE LOW OFF THE MID-ATLANTIC COAST ASSOCIATED WITH THE
AFOREMENTIONED FRONTAL SYSTEM. A LOCAL SURFACE ANALYSIS INDICATES
THAT A FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW STILL EXISTS ACROSS
THE NORTHEAST GULF, THROUGH NORTH-CENTRAL FLORIDA, AND UP THE
SOUTHEAST COAST. ACROSS SOUTH FLORIDA, A SURFACE TROUGH SITS ALONG
THE EAST COAST, WITH THE WARMER AND MORE MOIST MARITIME AIR
ADVECTING INLAND IN THE NORTHEASTERLY FLOW REGIME AROUND THE BROADER
SURFACE RIDGE. OBSERVED SOUNDING ANALYSIS DATA FROM 12Z THIS MORNING
REVEALS THAT SOLID NORTHWESTERLY FLOW ASSOCIATED WITH THE UPPER
TROUGH GRADUALLY TRANSITIONS TO NORTHEASTERLY BETWEEN 500-700MB WHEN
THE LOW-LEVEL RIDGE GAINS INFLUENCE. DEEP-LAYER DRY AIR WAS ABOVE
700MB, WITH A NEARLY SATURATED LOWER TROPOSPHERE. PRECIPITABLE WATER
VALUES ACROSS THE LOWER HALF OF THE STATE RANGE FROM 0.75" AT TBW,
UP TO 1.1-1.2" BETWEEN MFL AND KEY.
VISIBLE IMAGERY ACROSS SOUTH FLORIDA SHOWS BANDS OF CLOUDINESS
MOVING INLAND FROM THE NEAR SHORE WATERS AND RADAR IMAGERY THIS
MORNING SHOWED THE PRESENCE OF SCATTERED SHOWERS ALONG THE
IMMEDIATE COAST. THESE FEATURES SEEM TO BE DRIVEN BY THE VERY LOW
LEVEL THERMAL TROUGH RESULTANT FROM MARITIME INFLUENCE OVER OUR
COASTAL WATERS AND THE COOLER TEMPERATURES OVER LAND. THE
BACKGROUND NORTHEASTERLY FLOW IS LIFTING THE WARMER AND MORE MOIST
AIR AS IT ADVECTS NORTHEAST TO SOUTHWEST ACROSS THE STATE. AS THE
DAY PROGRESSES, THIS INFLUENCE SHOULD CONTINUE DIMINISHING AND
THE THREAT FOR SHOWERS SHOULD DECREASE.
SHORT TERM
(REST OF TODAY THROUGH FRIDAY)
ISSUED AT 357 PM EDT TUE OCT 20 2026
THE ABOVE MENTIONED SHORTWAVES, AND AN ADDITIONAL ONE RIDING OVER
THE RIDGE FROM THE CENTRAL PLAINS, WILL SUPERPOSITION WITH THE QUASI-
STATIONARY UPPER LOW AND RESULT IN AN UPPER TROUGH EXTENDING FROM
THE MID-ATLANTIC THROUGH FLORIDA AND INTO THE GULF. A STABLE LAYER
BETWEEN 700-900MB, INDICATED BY PACKED ISENTROPES, WILL LIKELY KEEP
THE UPPER LEVEL TROUGH FROM INFLUENCING THE SURFACE PATTERN MUCH. IN
FACT, THIS STABLE LAYER REMAINS IN PLACE THROUGH AT LEAST FRIDAY AS
ANOTHER SHORTWAVE CURRENTLY OVER ALBERTA AND SASKATCHEWAN DIVES
THROUGH THE GREAT LAKES REGION AND INTO THE SOUTHEAST. THE SENSIBLE
WEATHER WILL THEN BE PRIMARILY INFLUENCED BY FEATURES IN THE LOWER
ATMOSPHERE, AND MORE SPECIFICALLY, THE THE THERMAL TROUGH
DEVELOPMENT AND ADVECTION MENTIONED ABOVE. THE CONTINUED
NORTHEASTERLY LOW-LEVEL FLOW BETWEEN THE SURFACE RIDGE AND MID-
ATLANTIC LOW WILL RESULT IN MULTIPLE DAYS OF WIDELY SCATTERED
MORNING SHOWERS DEVELOPING NEAR THE COAST AND MOVING INLAND, MOSTLY
DISSIPATING BY EARLY AFTERNOON. OVERNIGHT LOWS WILL BE CONSISTENTLY
IN THE MID TO UPPER 60S INLAND, AND CLOSER TO 70 ALONG THE COASTS.
HIGHS WILL ALSO MOSTLY BE NEAR OR JUST BELOW CLIMATOLOGY, IN THE LOW
TO MID 80S. WINDS WILL GRADUALLY DECREASE THROUGH THE WEEK AS THE
WESTERN ATLANTIC LOW SLOWLY DRIFTS NORTHWARD.
LONG TERM
(SATURDAY THROUGH NEXT MONDAY)
ISSUED AT 357 PM EDT TUE OCT 20 2026
AS ALL THE AFOREMENTIONED SHORTWAVES EVENTUALLY SPILL INTO THE
WESTERN CARIBBEAN, THEY'LL FIND A MORE UNSTABLE REGION TO INITIATE
AND ORGANIZE CONVECTION. AT THE SAME TIME, THE UPPER TROUGH WILL
BECOME MORE POSITIVELY TILTED AS THE CORE OF THE MAIN LONGWAVE
TROUGH MOVES NORTHEAST AND A WAVE BREAKING PATTERN SETS UP WITH THE
LATEST SHORTWAVE STARTING TO CUTOFF OVER FL AND THE SW ATLANTIC.
THIS WILL CREATE A PATHWAY FOR CONVECTION TO GAIN LATITUDE OUT OF
THE CARIBBEAN AND ENTER THE BAHAMAS. TRADITIONAL 500MB ENSEMBLE
CLUSTER ANALYSIS IS PRIMARILY FOCUSING ON OTHER SOURCES OF VARIANCE
IN DETERMINING EXTENDED RANGE SCENARIOS, AND THIS IS LIKELY DUE TO
OUR FOCUS AREA BEING ON THE EDGE OF THE DOMAIN AND FOCUSED PRIMARILY
ABOVE 500MB. HOWEVER, WE CAN STILL IDENTIFY A FEW SCENARIOS FROM THE
CLUSTERS TO CLUE US INTO THE FACT THAT WHERE THIS UPPER-LOW CUTS OFF
WILL HAVE AN IMPLICATION ON QPF FORECASTS THIS WEEKEND AND INTO NEXT
WEEK. THANKFULLY WPC QPF CLUSTERS CAN AT LEAST SHED LIGHT ON WHAT
THE POTENTIAL IMPACTS MAY BE DEPENDING ON THE EVOLUTION OF THE UPPER
PATTERN. WHAT WE CAN SAY IS THAT THE EAST COAST METROS WILL BE THE
TARGET OF HEAVY RAINFALL OVER THE WEEKEND. WHAT'S UNCERTAIN IS JUST
HOW MUCH AND EXACTLY WHEN. GENERALLY SPEAKING, THERE'S A LOWER
QPF SCENARIO THAT ON AVERAGE BRINGS 1-2" OF RAIN TO MUCH OF THE
SOUTHEAST COAST OF FLORIDA, THEN THERE ARE MULTIPLE MORE IMPACTFUL
SCENARIOS THAT DIFFER ON PLACEMENT OF THE HIGHEST PRECIP AMOUNTS
ACROSS THE EAST COAST FROM CAPE CANAVERAL DOWN TO HOMESTEAD. THE
HIGHER END SCENARIOS GENERALLY AGREE ON AMOUNTS BETWEEN 5-7" OVER
THE 48 HOUR PERIOD THIS WEEKEND, WITH THE POTENTIAL FOR SCATTERED
TO ISOLATED LOCATIONS RECEIVING SOMEWHERE NEAR DOUBLE THOSE
AMOUNTS. FOR THIS REASON WE REMAIN IN A SLIGHT RISK (15%) FOR
FLASH FLOODING IN WPCS DAY 5 EXCESSIVE RAINFALL OUTLOOK. WINDS AND
GUSTS (NON- THUNDERSTORM) WILL ALSO BE A CONCERN OVER THE WEEKEND
AS THE GRADIENT BETWEEN CONVECTION IN THE BAHAMAS AND AN
APPROACHING FRONT TIGHTENS. THERE'S CURRENTLY A HIGH PROBABILITY
OF SUSTAINED WINDS IN THE 25-30 MPH RANGE ACROSS EAST AND WEST
COAST METROS, WITH A MODERATE CHANCE OF GUSTS EXCEEDING 40 MPH.
THE MAIN WINDOW FOR THESE HIGH WINDS WILL BE ON SUNDAY. THE WET
PATTERN WILL LIKELY CONTINUE INTO NEXT WEEK AS THE NORTHERN STREAM
FRONTAL SYSTEM AND CUTOFF LOW INTERACT AND EVENTUALLY DISSIPATE
OR ADVECT OUT OF THE REGION.
AVIATION
(18Z TAFS)
ISSUED AT 357 PM EDT TUE OCT 20 2026
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF. NORTHEASTERLY WINDS
WILL REMAIN GUSTY TODAY - IN THE 20-25 KT RANGE. WINDS WILL
GRADUALLY WEAKEN THROUGH TONIGHT AND INTO TOMORROW BUT REMAIN OUT
OF THE NORTHEAST. SCATTERED SHOWERS WILL BE POSSIBLE LATE TONIGHT
THROUGH MID-MORNING ALONG THE EAST COAST.
MARINE
ISSUED AT 357 PM EDT TUE OCT 20 2026
ADVISORY LEVEL WINDS ARE EXPECTED THROUGH TOMORROW FOR GULF AND
ATLANTIC WATERS, THOUGH THE MAGNITUDE WILL BE GRADUALLY
DECREASING. IT'S UNLIKELY THAT SEAS WILL HAVE TIME TO FALL BELOW
ADVISORY LEVELS ALONG THE ATLANTIC COAST BEFORE OUR NEXT
WIND/SWELL EVENT THIS WEEKEND, SO THE ADVISORY WILL LIKELY
CONTINUE HERE FOR MANY DAYS. SCATTERED SHOWERS ARE FORECAST FOR
EACH OF THE NEXT FEW MORNINGS, DIMINISHING BY EARLY AFTERNOON.
AS A FRONT APPROACHES FROM THE NORTH, AND AN AREA OF LOW PRESSURE
EMERGES FROM THE SOUTH, ANOTHER STRONG WIND EVENT IS EXPECTED TO
UNFOLD OVER OUR ATLANTIC AND GULF WATERS THIS WEEKEND. SOLID
ADVISORY LEVEL CONDITIONS ARE FORECAST, WITH GALE CONDITIONS NOT
OUT OF THE QUESTION FOR ATLANTIC WATERS.
BEACHES
ISSUED AT 357 PM EDT TUE OCT 20 2026
HAZARDOUS SURF CONDITIONS ARE EXPECTED TO BRIEFLY IMPROVE BY
THURSDAY, BUT WILL LIKELY RETURN AT SOME POINT THIS WEEKEND. A
HIGH RIP CURRENT RISK WILL CONTINUE FOR THE FORESEEABLE FUTURE.
HYDROLOGY
ISSUED AT 357 PM EDT TUE OCT 20 2026
WE'RE BEGINNING TO COME OUT OF AN EBB IN THE ASTRONOMICAL TIDES
AS WE HEAD TOWARDS THE FULL MOON AND PEAK OF THE TIDE FORECASTS
LATE THIS WEEKEND AND INTO EARLY NEXT WEEK. OBSERVED WATER-LEVELS
ARE ALREADY OVER-PERFORMING PREDICTIONS AND WE'LL LIKELY BEGIN
REACHING MINOR FLOODING THRESHOLDS TOMORROW OR THURSDAY AT ALL OF
OUR EAST COAST TIDAL STATIONS. IT'S LIKELY WE'LL ALSO REACH
MODERATE FLOODING LEVELS BY THE WEEKEND; EVEN BEFORE THE PEAK OF
THE KING TIDE CYCLE. IT'S NOT OUT OF THE QUESTION THAT PALM BEACH
COUNTY MAY EVEN REACH MAJOR FLOODING LEVELS AT THE PEAK OF THE
KING TIDE. THE NORMAL KING TIDES ARE COMPLICATED BY THE FACT THAT
WE'LL BE DEALING WITH A COMPLEX UPPER/SURFACE LOW PRESSURE
PATTERN THAT WILL FEATURE AN APPROACHING FRONT FROM THE NORTH AND
CONVECTION RISING OUT OF THE CARIBBEAN FROM THE SOUTH. THIS WILL
LIKELY INCREASE THE ONSHORE WIND COMPONENT AND MAGNIFY THE ALREADY
HIGH TIDES. THIS IS SOMEWHAT ACCOUNTED FOR IN THE PREDICTIONS
MENTIONED ABOVE, BUT ONLY CRUDELY. FURTHERMORE, THE POTENTIAL FOR
HEAVY RAINFALL DURING PERIODS OF HIGH TIDE IS ALSO SOMETHING TO BE
AWARE OF THAT COULD FURTHER AGGRAVATE COASTAL FLOODING. IN SHORT,
WE'RE HEADING INTO WHAT COULD BE A RATHER IMPACTFUL PERIOD FOR
COASTAL FLOODING AND SENSITIVE LOCATIONS SHOULD CONSIDER
PREPARATIONS.
PRELIMINARY POINT TEMPS/POPS
MIAMI 71 85 72 84 / 10 10 10 20
WEST KENDALL 70 86 70 85 / 0 10 10 20
OPA-LOCKA 71 85 71 84 / 10 10 10 20
HOMESTEAD 71 85 70 85 / 10 10 10 10
FORT LAUDERDALE 72 84 72 83 / 20 20 30 30
N FT LAUDERDALE 72 85 72 84 / 20 20 30 30
PEMBROKE PINES 70 85 71 84 / 20 10 20 20
WEST PALM BEACH 71 85 72 84 / 20 20 40 20
BOCA RATON 71 84 71 83 / 20 20 30 30
NAPLES 66 85 68 84 / 0 0 0 0
MFL WATCHES/WARNINGS/ADVISORIES
FL...HIGH RIP CURRENT RISK THROUGH THURSDAY EVENING FOR FLZ168-172-
173.
HIGH SURF ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR FLZ168.
HIGH SURF ADVISORY UNTIL 8 PM EDT THIS EVENING FOR FLZ172.
AM...SMALL CRAFT ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR AMZ610-630.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THURSDAY FOR AMZ650-651-670-
671.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR GMZ656-657-676.
SHORT TERM...HARRIGAN
LONG TERM....HARRIGAN
AVIATION...HARRIGAN
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