textproduct: Miami - South Florida

KEY MESSAGES

Updated at 318 PM EDT Mon Apr 20 2026 - A cold front will approach the region today, bringing scattered showers and thunderstorms through this evening.

- Some of the stronger storms could produce gusty winds and result in localized flooding.

- Hazardous marine conditions expected to develop in the wake of the front this week.

UPDATE

Issued at 318 PM EDT Mon Apr 20 2026

A cold front continues to push through South Florida this afternoon, with isolated to scattered convection developing behind this boundary. So far, it's mostly been showers and locally heavy downpours, but as we continue to push through the afternoon and early evening hours, more lightning activity can be expected, particularly over the east coast metro areas. The latest HREF and HRRR/RRFS indicate showers and storms will persist through about 03Z, particularly into the greater Miami metro.

Beyond 03Z, winds will remain breezy but not gusty. Temperatures will cool into the low 60s inland with coastal areas in the upper 60s to lower 70s. Elevated fire weather conditions may develop Tuesday afternoon under gusty northeasterly flow and minimum relative humidity values in the 35-45% range inland. Cooler temperatures and pleasant conditions can be expected through Wednesday as northwesterly flow aloft leads to quiet weather. Expect highs in the upper 70s east with lower to middle 80s west and inland through Wednesday.

On Thursday, a mid-level shortwave embedded within the broad northwesterly flow will move through South Florida, bringing additional rain chances back into play.

SHORT TERM

(Today through Tuesday) Issued at 346 AM EDT Mon Apr 20 2026

Unsettled weather conditions will be likely across South Florida today as a cold front approaches the region. Satellite imagery and surface analysis early this morning show the front already draped across central Florida, with a few isolated showers starting to pop up along the Martin/Palm Beach counties boundary. Shower and thunderstorm activity will continue to increase through the morning as the front moves over the area, and probabilities should peak in the 50-60% range later this afternoon. Rainfall accumulations today could range from 1-2 inches across the area, but there's a 1 in 10 chance of 2-4 inches or more of rain in isolated spots. This could lead to localized flooding, especially for any areas along and south of Alligator Alley, and areas with poor drainage.

Some of the thunderstorms that are forecast to develop could be strong in nature given the forecast environmental parameters, and the strongest could produce some sub-severe gusty winds and even small hail (penny sized or smaller). When it comes to the wind threat, the forecast lapse rates, DCAPE values and PWATs are all within range of the criteria needed for severe damaging winds, but the forecast instability is too low (SBCAPE < 2000 J/kg). As for the hail threat, the instability and lapse rates are there, but the temperatures aloft will be slightly too warm (500mb Ts ~10 degC), and CAPE in the hail growth zone too low, for any hail that does develop in a strong thunderstorm to grow to an inch or more in size. As such, chances of severe impacts looks to be very marginal this afternoon, but we cannot discount the possibility of some gusty winds or small pea-sized hail with the strongest storms.

Most guidance shows the front clearing the area by this evening and eventually stalling out along the Florida Straits. High pressure will build behind the front on Tuesday, and a dry, breezy air mass will work in over the region, with PWATs dropping back into the 0.5- 0.8 inch range and sustained northeasterly winds 10-15 mph with higher gusts. Temperatures will also drop by a few degrees behind the frontal passage, with highs in the upper 70s and lower 80s on Tuesday. Lows could dip into the upper 50s across the interior, and down to the 60s along the coasts.

LONG TERM

(Tuesday night through Sunday) Issued at 346 AM EDT Mon Apr 20 2026

The aforementioned surface high developing over the western Atlantic will remain the dominant synoptic feature for at least one more day, supporting relatively stable conditions across South Florida through Wednesday. Ensemble guidance remains in good agreement showing PWAT values below normal for this time of year (under 1 inch), indicative of a dry airmass lingering in the wake of the previous frontal passage. Breezy onshore flow will persist along the Atlantic coast through Wednesday as the previous front remains stalled over the Florida Straits. While isolated coastal or sea breeze-driven showers cannot be fully ruled out, the overall pattern favors suppressed coverage and mostly dry conditions across the region.

A potential transition towards a more unsettled pattern may begin Thursday, as guidance continues to depict an upper level shortwave developing over the southeastern US and dropping across the Gulf on the back half of the week. There has been model to model consistency depicting a low-level disturbance developing over the Gulf in tandem with the shortwave. However, recent model trends keep this feature fairly disorganized compared to previous runs. Ensemble mean QPF values associated with this feature are generally modest, with even the high-end (90th percentile) values remaining below 0.5 inches. While some ensemble members do support higher end values, the NBM still favors a drier solution for the region.

By Saturday into Sunday, a weak frontal boundary moving into the eastern U.S. may sag closer to the region and bring at least a low-end chance for showers, though there is still considerable uncertainty in both timing and strength.

Expect temperatures to remain a few degrees below normal midweek, with East Coast highs in the upper 70s and notably cool interior lows dipping into the 50s. A gradual warming will follow into the weekend, with highs climbing into the upper 80s across most areas and overnight lows moderating into the upper 60s and lower 70s.

AVIATION

(18Z TAFS) Issued at 122 PM EDT Mon Apr 20 2026

Showers and thunderstorms of the more scattered variety will continue through the afternoon/early evening hours at all sites. Have opted to continue with the TEMPO group 18-22Z as hi-res guidance and latest radar trends support continued thunder chances at area terminals. Winds will pick up out of the ENE at 10-12 kts, with some gusts up to 20-22 kts, particularly along the Atlantic facing coast, with gusty northeasterly winds through the remainder of the period. Any shower and TS activity should wind down after 00Z. Winds will actually further increase on Tuesday morning, with gusts upwards of 25-28 kts at area terminals. VFR ceilings are expected to persist throughout the forecast period.

MARINE

Issued at 346 AM EDT Mon Apr 20 2026

Boating conditions begin to deteriorate today as a cold front approaches South Florida. Scattered showers and thunderstorms will be possible as the front moves southward, especially across the local Atlantic waters. A wind surge will be possible once the front clears overnight into Tuesday, with hazardous conditions developing and seas building up to 8-12 ft over the Gulf stream by Tuesday. Gulf seas will range from 3-6 ft.

BEACHES

Issued at 346 AM EDT Mon Apr 20 2026

Strong onshore flow and will promote a high risk of rip currents across the Atlantic coastline through the middle of the week.

FIRE WEATHER

Issued at 346 AM EDT Mon Apr 20 2026

A dry, breezy air mass will filter in across the region behind a frontal passage. This air mass could exacerbate fire weather conditions across southwest Florida on Tuesday. As of this forecast cycle, relative humidity on Tuesday are hovering in the 40-45% range, while 20 foot winds are ranging from 13-16 mph and FPFs are remain in the 2.6-3.4 range. As it stands, this raises some concerns for marginal fire weather conditions, but confidence is not quite there yet regarding impacts.

PRELIMINARY POINT TEMPS/POPS

Miami 69 78 68 78 / 20 0 0 0 West Kendall 66 80 64 79 / 20 0 0 0 Opa-Locka 69 79 67 79 / 20 0 0 0 Homestead 70 78 68 79 / 20 0 0 0 Fort Lauderdale 70 77 69 77 / 20 0 0 0 N Ft Lauderdale 69 76 68 77 / 20 0 0 0 Pembroke Pines 70 81 68 80 / 20 0 0 0 West Palm Beach 68 77 67 77 / 20 0 0 0 Boca Raton 69 77 68 77 / 20 0 0 10 Naples 65 84 62 83 / 10 0 0 0

MFL WATCHES/WARNINGS/ADVISORIES

FL...High Rip Current Risk through Wednesday morning for FLZ168-172- 173.

High Surf Advisory from 2 AM to 8 PM EDT Tuesday for FLZ168.

AM...Small Craft Advisory until 2 PM EDT Tuesday for AMZ610.

Small Craft Advisory from 8 PM this evening to 11 AM EDT Wednesday for AMZ630.

Small Craft Advisory until 11 AM EDT Wednesday for AMZ650-651- 670-671.

GM...Small Craft Advisory from 8 PM this evening to 8 AM EDT Wednesday for GMZ656-657-676.