FXUS62 KMFL 050528 AFDMFL

Area Forecast Discussion National Weather Service Miami FL 128 AM EDT Fri Jul 5 2024

New SHORT TERM, LONG TERM, AVIATION, MARINE

SHORT TERM
(Today through Saturday)
Issued at 123 AM EDT Fri Jul 5 2024

The SE US ridge will remain the main mid-lvl feature of interest through the short-term period, although it will continue to weaken and erode as troughing shifts into the central/NE US and a closed low over the Atlantic retrogrades towards it. Synoptic low-lvl flow will remain weak, favoring sea breeze-driven circulations, and the inland progression of both the Gulf and Atlantic breezes. Additionally, moisture will pool over the area with PWATs increasing back into the 2-2.2 inch range.
Consequently expect greater storm coverage today relative to yesterday, with the focus largely being just inland of the coasts along both sea breezes with initial storm propagation towards the Interior, and then potentially propagating back eastward late in the afternoon. Given the increased moisture and lack of deep-layer steering flow, localized hydro concerns will be possible with localized accumulations in the 3-5 inch range being advertised by hi-res guidance. The bulk of guidance keeps the heaviest accumulations focused over the Interior, which would help alleviate any hydro concerns, however, guidance often initiates convection too far inland in these regimes so would not rule out the potential for heavy rain along the edges of the east coast metro.

Although precipitation and convective cloud cover should be more widespread this afternoon than Thursday, the weakening of the synoptic easterly flow will allow for generally warmer temperatures than Thursday (particularly over the east coast) so yet another day of peak heat indices 105-110 (perhaps even locally higher in the Interior/west) is expected. Thus the heat advisory remains in effect for the whole area through 8 PM.

Saturday will feature a similar synoptic pattern, although a small wrinkle will be that drier mid-lvl air will impinge on northeastern portions of the area on the fringes of a cut-off low over the Atlantic, which could focus the best rain chances over the southern half of the peninsula (with perhaps even a weak northwesterly component of the low-lvl flow, pushing things into the MD/Broward vicinity later in the day).
Once again the two concerns of the day will be localized flooding due to the abundant moisture and slow storm motions, and excessive heat with advisory conditions possible once again, particularly over the north and west where precip coverage may be somewhat reduced.
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