236 FXUS62 KMFL 091127 AFDMFLArea Forecast Discussion National Weather Service Miami FL 727 AM EDT Tue Sep 9 2025
...New AVIATION...
.SHORT TERM... (Today through Wednesday) Issued at 128 AM EDT Tue Sep 9 2025
Persistent mid to upper level longwave troughing will continue across most of the eastern half of the country through today into Wednesday. At the surface, a stationary frontal boundary will remain firmly parked to the north over Central Florida during this time frame. This will allow for the very light south to southwest synoptic surface wind flow to continue across the region which will keep the east coast sea breeze in check and pinned over the metro areas. Deep layer moisture advection will continue to occur out ahead of the front across South Florida through the middle of the week. The latest model soundings show this abundance of moisture nicely with PWAT values generally fluctuating between 2.2 and 2.5 inches during this time frame.
These features all combined will help to produce numerous showers and thunderstorms today and Wednesday especially during the afternoon and evening hours as peak diurnal heating destabilizes the atmosphere. With high PWAT values combined with the long and skinny sounding profile of the vertical column, showers and thunderstorms will have the potential for enhanced rainfall rates ranging as high as 2 to 4 inches per hour with the stronger storms. These heavy downpours combined with a very light steering flow aloft will once again result in the potential for localized flooding across the region today and Wednesday. Multiple rounds of heavy rainfall from convective training will be likely as well especially across the east coast metro areas where the sea breeze boundary will be pinned. Because of this, WPC continues the Marginal risk (Level 1 of 4) of excessive rainfall this afternoon as well as Wednesday.
High temperatures for today and Wednesday will generally rise to around 90 across the Lake Okeechobee region and into the lower 90s across interior Southwest Florida as well as the eastern half of South Florida.
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.LONG TERM... (Wednesday night through Monday) Issued at 128 AM EDT Tue Sep 9 2025
The mid to upper level trough does show signs of deepening across the Eastern Seaboard on Thursday and Friday as a rather potent shortwave dives down through the Midwest on Thursday, and then eventually into the Mid Atlantic and Southeast on Friday. At the surface, this will help to give the frontal boundary that has been parked over Central Florida some southward momentum and will push it over South Florida during this time frame. With the front moving over the area, the latest guidance still shows an abundance of moisture pooling over South Florida out ahead of the front as guidance keeps PWAT values hovering between 2.1 and 2.3 inches on Thursday and Friday. The surface synoptic wind flow will remain rather light and variable on Thursday, however, it looks to gradually shift and take on more of a northerly direction by the end of the week. With the front over the region combined with the development of the sea breezes each day, there will be plenty of lift and instability in place to support numerous showers and thunderstorms on Thursday and Friday. With the storm motion remaining very slow combined with the deep layer moisture in place, the stronger thunderstorms will still have the potential for high rainfall rates. This could create additional localized flooding especially over the east coast metro areas which have been already saturated from previous heavy rainfall.
The forecast uncertainty rises for the upcoming weekend, however, there are some signs indicating a potential pattern change during this time frame. The feature in question will be the frontal boundary and how far south of a push it actually gets. The global and ensemble model guidance remain in disagreement with the placement of this feature as the European guidance suite shows a more potent mid level trough/low complex than the GFS guidance suite. The stronger and more potent trough would give the front the push it needs to pass through South Florida, while a weaker mid level trough would keep the front closer by over the region. If the front were to pass through, this would result in some drier air pushing into South Florida which would lower the shower and thunderstorms chances heading into Saturday and Sunday. If the front does not push far enough south, this will keep the higher rain chances in place a bit longer. The latest forecast takes a blend of the forecast models and gradually lowers the chances of showers and thunderstorms heading into the second half of the weekend and into early next week. This will continue to be monitored as the week progresses.
High temperatures on Thursday will generally range from the upper 80s to lower 90s across most of the area. Temperatures for the end of the week and into the upcoming weekend will be highly dependent on the location of the front, however, they should still remain near climatological normals for this time of year.
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.AVIATION... (12Z TAFS) Issued at 726 AM EDT Tue Sep 9 2025
Light and variable winds this morning will increase out of the SSE across the east coast terminals early this afternoon as a sea breeze tries to push inland. Another round of scattered to numerous showers and storms could develop over the South Florida terminals this afternoon into this evening. Periods of MVFR or IFR conditions will be possible in and around showers and storms. At KAPF, winds will increase out of the SSW this afternoon as a Gulf breeze pushes inland.
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.MARINE... Issued at 128 AM EDT Tue Sep 9 2025
A gentle to moderate south to southwesterly wind flow will remain in place across most of the local waters through the middle of the week. These winds will gradually shift and become more northerly heading into the end of the week as well as the upcoming weekend. Seas across the Atlantic waters will remain at 2 to 4 feet through the middle of the week while seas across the Gulf waters remain at 2 feet or less. Scattered to numerous showers and thunderstorms will be possible each day. Periods of rough seas and gusty winds will be possible near the stronger thunderstorms.
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.BEACHES... Issued at 128 AM EDT Tue Sep 9 2025
A developing northeasterly swell in the Atlantic waters could bring an elevated risk of rip currents mainly to the Palm Beaches during the middle portion of the week.
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.PRELIMINARY POINT TEMPS/POPS... Miami 90 78 91 77 / 80 40 70 30 West Kendall 90 76 91 76 / 80 40 70 30 Opa-Locka 91 78 92 77 / 80 40 70 30 Homestead 89 77 90 76 / 70 40 60 30 Fort Lauderdale 90 77 91 77 / 80 50 70 40 N Ft Lauderdale 91 78 92 77 / 80 50 70 40 Pembroke Pines 92 77 93 77 / 80 40 70 40 West Palm Beach 90 75 91 76 / 80 60 80 40 Boca Raton 91 76 92 76 / 80 50 80 40 Naples 88 78 90 77 / 80 60 70 30
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.MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. &&
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SHORT TERM...CWC LONG TERM....CWC AVIATION...Redman
NWS MFL Office Area Forecast Discussion