textproduct: Miami - South Florida

KEY MESSAGES

Updated at 631 PM EDT Sun Oct 18 2026

- Strong winds with the incoming frontal boundary is expected to lead to increasingly hazardous marine and beach conditions for the next few days. Elevated seas and near Gale force winds will be observed.

- Drier conditions for most of the region today, but some shower activity is still expected mostly across portions of SE Florida.

SHORT TERM

(Rest of today through Monday) Issued at 405 PM EDT Sun Oct 18 2026

Two imperative weather features that are having a local influence on our weather today in South Florida are being noted on surface analysis: strong high pressure to our north and a stalling cold front to our south. Anomalously strong surface high pressure centered over the Allegheny Plateau a little over 1,000 miles north of South Florida is reading 1038 mb on the Weather Prediction Center's (WPC) most recent 12Z analysis map, which is good for the 100th percentile (suggestive of record-level MSLPs) for the date according to HREF climatology guidance. Closer to home just to our south over the Florida Straits, SPC mesoanalysis data illustrates a minor, but evident, kink in surface winds along what is a cold front that was able to bypass our region late last night/early this morning. Perhaps a better way to identify the front aside from this faint orientation of surface winds is an abundance of moisture in the form of showers and thunderstorms over the territorial waters of the Bahamas and across the aforementioned Florida Keys and Straits. KEYW's (Key West Int'l Airport) ACARS sounding and mesoanalysis are both representative of this deep plume of moisture with PWATs of 2.2- 2.3" overlaying this general region around the vicinity of the front.

Aloft, an elongated longwave trough has continued to traverse eastward across the eastern United States and dig southward into South Florida. The mean upper-level flow upstream of this trough has resulted in the advection of drier air down the Florida peninsula, which is not only being displayed on GOES mid-level water vapor imagery but is also being accurately reflected in regional ACARS soundings, such as at KRSW (Ft. Myers Southwest Florida Int'l Airport) with a stout dry layer extending from around the 750 mb isobaric height upwards through the rest of the atmospheric column and a corresponding PWAT designation of 1.40". This dry air has not quite reached the southernmost portions of South Florida just yet, which can also be confirmed by KFLL and KMIA's latest ACARS profile soundings with an abundance of low-level saturation from around 950 mb to 700 mb. Crowded isopleths (lines of constant PWAT) are being noticed across much of South Florida on SPC mesoanalysis with the intrusion of this drier air being depicted by PWATs of 1.2-1.7" (45- 65th percentiles) from the vicinity of Lake Okeechobee southward to around Alligator Alley. Southeast Florida is still entrenched in a soggier air mass near the proximity of the aforementioned cold front with PWATs ranging between 1.8 and 2.2" (80-95th percentiles for the date) down through the southernmost portions of the peninsula.

Due to the heavy saturation over SE Florida, we have been observing a dense, shallow-layer cumulus deck stream across this section of the peninsula downwind of our northeasterly surface-850 mb flow. Over the Florida Straits where we currently have ongoing convection along the immediate surface cold front, upper-level cirrus/anvil debris is seen streaming in the opposite direction from southwest to northeast parallel to the mean flow over SE Florida, indicative of the strong flow aloft we have in place with the presence of the southward-digging upper trough. Enough sunshine, however, is penetrating the cloud layer over SE Florida to allow SBCAPE to slowly grow to 1000 J/Kg over Broward and Miami-Dade according to RAP analysis, which could allow for some low-topped showers and perhaps a rumble of thunder or two in the most vertically-matured cores to develop over these respective regions through the remainder of the afternoon. With the strength of our northeasterly surface flow as a result of a tight pressure gradient between the record-strong ridge mentioned earlier over the Allegheny Plateau and the cold front to our south, we should expect the initiation of these showers to be mainly triggered by coastal convergence over extreme SE Florida (on top of the marginal CAPE we will have in place). Overall dynamics for widespread, heavy precipitation similar to what we saw yesterday will just not be there today, with forcing much weaker now that we sit behind the frontal boundary, cloud cover + poor superficial heating , and dry air aloft limiting convective potential. Shower activity should therefore be quite isolated in coverage (our grids might be overestimating today's PoPs over SE Florida of 40-60%) but transient in nature due to our enhanced gradient winds, which is of good news especially given how much rain our eastern metros received yesterday. WPC still has metro and coastal Miami-Dade and Broward Counties under a marginal risk of flash flooding for the forecast period, mainly due to the antecedent conditions that transpired yesterday. Anything we see with regards to flooding today, however, should be few and far in between given the accelerated motion of showers and overall lack of optimism in widespread, heavy precipitation by the CAMs (convective allowing models). Every evolving run amongst the models this afternoon continues to show most developing showers today staying over the local Atlantic waters and Biscayne Bay and perhaps grazing coastal/extreme southern Miami- Dade which, if trends continue, should only continue to prevent any flood threat from actually materializing. Digressing from all the talk about precipitation, main story of the day across South Florida should be those gusty to blustery northeasterly winds with NBM suggesting gusts getting to as high as 25-35 mph across mainland South Florida (which have already been confirmed thus far today taking a look at local observations) and higher gusts over the local waters.

The aforementioned dry air aloft should continue to trickle down into the rest of South Florida this evening and into Monday, which will further limit the potential for widespread precipitation across South Florida and keep shower activity rather isolated and confined to the east coast as a result of continued coastal convergence (PoPs of only 10-30%). With a lack of deep saturation within the atmospheric column with the intrusion of this dry air, the potential for thunderstorms should be mostly suppressed (PoP thunder grids showing 10-20%). It will remain gusty to blustery out there on Monday, with northeasterly wind gusts again reaching 25-35 mph across South Florida as anomalously strong surface ridging to our north and the persisting frontal boundary to our south will keep a tight gradient in place.

High temperatures today will be cooler than they have been in previous days due to the southward advection of a more crisp, Fall- like air mass behind our succeeding cold front in addition to the strong NE flow and cloud cover we will have in place as they are expected to peak in the low to mid 80s this afternoon. Guidance is also showing a north-to-south reduction in dew points across South Florida beginning tonight, with values dropping to the mid 60s to low 70s across the region by daybreak Monday and, with highs only forecast to reach the low to mid 80s again, should be making it feel less oppressive out there and more like mid-October.

LONG TERM

(Monday night through Saturday) Issued at 140 AM EDT Sun Oct 18 2026

Upper-level troughing will remain anchored across the eastern CONUS and western Atlantic through much of the week, while surface high pressure builds across the Southeast US. Meanwhile, a strong low- pressure system is expected to meander off the Eastern Seaboard. The resulting tight pressure gradient will support breezy and gusty north-northeasterly winds across South Florida through mid-week. Most global guidance suites suggest this pressure gradient will begin to relax towards the latter half of the week as the offshore low-pressure system gradually lifts away, though persistent north- easterly flow will remain established across South Florida.

In terms of moisture, PWAT values are forecast to dip into the 1.1- 1.3 inch range through mid-week as dry air continues to filter into the region. Moisture values will gradually recover toward more seasonal levels of 1.4-1.5 inches by late week. With low-level convergence maximized along the Atlantic coast, isolated to scattered showers and a few embedded thunderstorms could develop each day, favoring the East Coast coastal zones, while the rest of South Florida should expect mostly dry conditions through mid-week.

The primary hazards through most of the week will remain marine and coastal concerns along the Atlantic beaches, including a high risk of rip currents as well as rough surf that could prompt beach erosion. Heading into Friday, model guidance hints at a mid/upper- level disturbance digging southward toward the region, which could support an uptick in convective activity and coverage across the eastern half of South Florida heading into the weekend.

Temperatures will trend slightly below climatological averages toward the end of the week. Daytime highs will generally start in the mid to upper 80s, cooling slightly into the low to mid 80s by late week. Overnight lows will range from the lower 70s along the East Coast to the mid to upper 60s across the interior and SW Florida.

AVIATION

(00Z TAFS) Issued at 631 PM EDT Sun Oct 18 2026

Mainly VFR conditions will prevail across all South Florida terminals through this evening and into Monday. Will keep VCSH for all east coast terminals due to the possibility of fast-moving showers pushing onshore from the Atlantic. Cannot rule out a few thunderstorms after 16Z Monday for northernmost east coast terminals, thus introduced VCTS. Gusty NE winds will persist through the entire forecast period with gusts of 20-30 knots possible.

MARINE

Issued at 140 AM EDT Sun Oct 18 2026

Hazardous conditions are expected today and into early this week as a frontal boundary pushes through the area. Strong winds at 20-30 kts with gusts occasionally reaching near Gale force are expected through Monday before starting to decrease mid-week. In addition, seas will rise to 10-14 feet in the Atlantic by the end of the day today and 6-8 feet in the Gulf. Small Craft Advisories are in effect through Wednesday across all local waters, including Biscayne Bay and Lake Okeechobee.

BEACHES

Issued at 140 AM EDT Sun Oct 18 2026

A high risk for rip currents is in effect for all Atlantic coast beaches as strong northeasterly winds set up later today and into early this week. In addition, waves will rise substantially and lead to a High Surf Advisory beginning today for the Palm beaches and Tuesday for the Broward beaches. Large breaking waves of 7-9 feet will be possible during the hours of the High Surf Advisories.

PRELIMINARY POINT TEMPS/POPS

Miami 75 84 73 84 / 30 20 30 10 West Kendall 74 84 72 84 / 30 10 20 0 Opa-Locka 75 85 73 84 / 30 20 20 10 Homestead 75 85 73 85 / 40 10 30 10 Fort Lauderdale 75 84 73 83 / 30 30 30 10 N Ft Lauderdale 75 84 73 84 / 20 30 30 10 Pembroke Pines 74 84 72 84 / 30 30 20 10 West Palm Beach 74 84 72 83 / 20 30 20 10 Boca Raton 75 84 72 83 / 20 30 30 10 Naples 70 85 67 84 / 0 10 0 0

MFL WATCHES/WARNINGS/ADVISORIES

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

High Surf Advisory until 8 AM EDT Wednesday for FLZ168.

High Surf Advisory from 2 PM Monday to 8 PM EDT Tuesday for FLZ172.

AM...Small Craft Advisory until 8 PM EDT Wednesday for AMZ610-630-650- 651-670-671.

GM...Small Craft Advisory until 8 PM EDT Wednesday for GMZ656-657-676.