textproduct: Miami - South Florida

KEY MESSAGES

Updated at 615 AM EST Thu Dec 18 2025

- Isolated to scattered showers will be possible out ahead of an approaching cold front today into tonight. An isolated thunderstorm cannot be ruled out this afternoon. - Warm temperatures will remain in place through the end of the week out ahead of the approaching front.

- A high risk of rip currents will continue across the Atlantic Coast beaches through this evening.

UPDATE

Issued at 615 AM EST Thu Dec 18 2025

Added some patchy fog to the grids over interior South FL this morning and again early Friday morning, with a strip of higher fog probabilities along Alligator Alley. Area cams are showing some pockets of dense fog along I-75 early this morning, and guidance suggests fog potential again for early Friday morning. Issued an SPS for inland Collier, Broward, and Miami-Dade until 8 AM this morning.

SHORT TERM

(Today through Friday) Issued at 131 AM EST Thu Dec 18 2025

Mid level ridging will slowly get pushed further off to the east today as an approaching mid level shortwave pushes eastward across the Gulf. This shortwave will rapidly push across the Florida Peninsula and into the western Atlantic on Friday. At the surface, a cold front will extend southwestward from the Great Lakes region down into the Deep South and into the northern Gulf today. This front will push southeastward into Northern and Central Florida tonight and it will be moving through South Florida as Friday progresses. With the mid level shortwave being quickly shunted off to the northeast, the best mid level dynamics will remain well off to the north, and the surface front will be in a weakening state as it approaches and moves through the area.

Out ahead of this front, winds will gradually veer and become southeasterly today while mid to upper level winds will remain southwesterly. This will allow for ample moisture advection to take place throughout the atmospheric column today as PWATs rise across all of South Florida. By later this afternoon, the latest forecast model soundings show PWAT values ranging between 1.3 and 1.6 inches area wide. As moisture advection continues throughout the day, this will be supportive of a low end chance of showers mainly during the afternoon hours and then into tonight as the front approaches. An isolated thunderstorm cannot be ruled out later in the afternoon, however, chances will remain very limited as the main source of mid to upper level support remains well north of the area.

The front will be in a meager state as it moves through the area on Friday and may actually dissipate as it moves through. The only noticeable change in sensible weather will be a wind shift from southwesterly early in the day to west northwest during the afternoon hours. Lingering moisture will remain present across the region on Friday and could spark off an isolated shower or two especially during the morning. Drier air will start to push into the Lake Okeechobee region in the afternoon as high pressure builds in from the north, however, a moisture gradient may set up as the front washes out leaving higher PWAT values (1.2 to 1.5 inches) in place across east coast as well as south of Alligator Alley. High temperatures on Thursday and Friday will generally rise into the lower 80s across most areas. Highs in the mid 80s will be possible across the interior especially on Friday with southwesterly flow ahead of the front.

LONG TERM

(Friday night through Wednesday) Issued at 131 AM EST Thu Dec 18 2025

Moving into the upcoming weekend, a mid level zonal pattern develops over South Florida as a mid level ridge to the south tries to expand northward. At the surface, strong high pressure to the north will rapidly move eastward into the Atlantic heading into Saturday and Sunday. This area of high pressure looks to be the main synoptic feature that will affect the sensible weather across the region during this time frame. Winds will veer and become east northeast early on Saturday and they will remain this way through the entire weekend. While high pressure will bring mostly dry conditions to the area during this time frame, some lower level moisture advection will be occurring along the east northeasterly wind flow. This will be just enough moisture for a slight chance of showers along the breeze mainly over the east coast, however, any shower that develops will be low topped and rather short lived. High temperatures over the weekend will generally rise into the lower 80s across the east coast to the mid 80s across interior portions of Southwest Florida.

Heading into the early portion of next week, the forecast becomes more uncertain as the latest global and ensemble guidance show a strengthening ridge developing over the Southern Plains and expanding eastward across the Gulf. At the surface, guidance is hinting at the potential of a weak backdoor cold front pushing into the region during this time frame, however, the latest guidance suite is having trouble with the timing of this feature. The latest GFS suite of guidance looks to be a bit slower than the ECMWF guidance suite. In any event, strong high pressure trying to build in behind this frontal boundary will increase the pressure gradient over South Florida leaving breezy east to northeasterly wind flow in place. With the weak frontal boundary nearby combined with increasing east northeasterly wind flow, a low end shower chance will remain in place throughout Monday and Tuesday especially across the east coast. High temperatures on Monday and Tuesday will remain near climatological normals for this time of year.

AVIATION

(12Z TAFS) Issued at 615 AM EST Thu Dec 18 2025

E/SE winds 10-15 kts today with afternoon gusts of 20-25 kts. Winds tonight around 5 kts or less. Scattered showers and isolated thunderstorms possible today, mainly over northern portions of the forecast area. Patchy fog possible early this morning and again early Friday morning over interior portions of South FL.

MARINE

Issued at 131 AM EST Thu Dec 18 2025

A moderate southeasterly wind will develop across most of the local waters today before shifting and becoming south to southwest tonight as a cold front approaches the region. These winds could become fresh over portions of the Atlantic waters today and tonight. Seas across the Atlantic waters will generally range from 3 to 5 feet today before subsiding to 2 feet or less on Friday. Seas across the Gulf waters will remain at 2 feet or less through the end of the week. Isolated to scattered showers will develop over the local waters today and tonight. An isolated thunderstorm cannot be ruled out later this afternoon into this evening. Winds behind the front shift and become west northwest across all local waters Friday afternoon.

BEACHES

Issued at 131 AM EST Thu Dec 18 2025

A high risk of rip currents will continue today across the Atlantic Coast beaches due to persistent onshore flow. This risk will decrease across the Atlantic Coast beaches on Friday as an offshore flow develops.

PRELIMINARY POINT TEMPS/POPS

Miami 82 72 85 69 / 20 10 10 0 West Kendall 83 68 86 65 / 10 10 0 0 Opa-Locka 82 71 86 69 / 20 10 10 0 Homestead 82 71 85 68 / 10 10 10 0 Fort Lauderdale 80 72 84 69 / 20 10 10 10 N Ft Lauderdale 81 72 84 69 / 20 10 10 10 Pembroke Pines 83 71 86 68 / 20 10 10 10 West Palm Beach 82 71 85 69 / 20 20 10 10 Boca Raton 82 71 86 69 / 20 10 10 10 Naples 84 69 81 61 / 10 10 10 0

MFL WATCHES/WARNINGS/ADVISORIES

FL...High Rip Current Risk through this evening for FLZ168-172-173.

AM...None. GM...None.