PREVIOUS DISCUSSION
Issued at 355 PM EDT Sun Sep 15 2024

Key Messages...

- Drier air will continue to limit shower/storm development the remainder of this afternoon and evening

- Poor to hazardous boating and surf conditions will continue into early this week

- Saint Johns River at Astor forecast to remain in Moderate Flood through midweek

Currently-Tonight...Significantly drier air in the mid levels will continue lower rain chances across the area through the late afternoon. However, isolated shower/storm development (PoPs 20-30%)
will still be possible as the east coast sea breeze moves inland.
Any convection lingering after sunset should quickly diminish, with dry conditions expected overnight. HRRR guidance showing some support for patchy fog development late tonight across the southern half of east central FL, near to south of a line from Lake Kissimmee to Melbourne, so have added some patchy fog mention to the forecast over this region. However, confidence in fog development is rather low. Not as muggy into tonight, with lows in the low to mid 70s.

Monday-Wednesday...Low pressure offshore South Carolina continues to have a 50 percent chance of subtropical/tropical development as it is forecast to move north-northwest and onshore along the Carolina coastline into early this week. This system will keep a weak frontal boundary across the Florida peninsula. Some moisture recovery will occur across the area, with PW values gradually increasing to around 1.7-2.0 inches. This combined with passing mid level disturbances and cooler temps aloft should help aid in destabilization for at least scattered shower/storm development each afternoon and evening along the inland moving east coast sea breeze. PoPs will range from 30-50 percent Monday, to 40-50 percent on Tue-Wed. Isolated stronger storms will be possible, with the main threats being strong wind gusts to 40-45 mph, frequent lightning and locally heavy rainfall. Highs will continue to be closer to normal, but still very warm, in the upper 80s/low 90s Monday and low 90s most locations on Tuesday and Wednesday.
Peak heat index values will reach around 100-105F. Overnight lows will range from the low to mid 70s.

Higher astronomical tides will continue through this week and lead to above normal water levels. However, levels at this time look to remain just below Coastal Flood Advisory thresholds for the east central Florida coast. Will be keeping a close eye on observed and forecast levels, however, in case these levels end up a little higher than currently anticipated.

Thursday-Saturday...Closed low aloft over the Ohio Valley/Mid Atlantic region will eventually evolve into an open trough across the eastern seaboard into late week. This trough will shift the weak front south of central FL with a light N/NW flow across the area. PW values drop just a tad to around 1.6-1.8" across the area, but scattered shower/storm development will still be possible each afternoon and evening, with PoPs 30-50 percent. Highs drop to the upper 80s to around 90 degrees on Thursday and then mostly in the upper 80s Friday and Saturday, with lows in the low to mid 70s.

AVIATION
(00Z TAFs)
Issued at 711 PM EDT Sun Sep 15 2024

A fairly quiet night on the way. Few SHRA near ISM through 2Z, then will monitor for any MVFR CIGs or fog development after 6Z through around daybreak. The chance of this appears low (<30%). On Monday, NE winds 5-12 KT by afternoon, except E along the Treasure Coast. Slightly better chance of storms (30-40%) compared to today, mainly 16/20Z-17/01Z, for the MCO terminal.

MARINE
Issued at 355 PM EDT Sun Sep 15 2024

Tonight...Swell from low pressure off the South Carolina coast will produce poor to hazardous boating conditions across the coastal waters with sea building up to 6-8 feet. Small craft should exercise caution for seas up to 6 feet nearshore, while a Small Craft Advisory will expand to include the entire offshore waters into tonight for seas up to 7-8 feet. Winds will be light out the W/NW north of the Cape and W/SW to the south.

Monday-Thursday...(Modified Previous Discussion) Scattered showers and lightning storms will remain in the forecast. Mariners are still reminded to keep an eye to the sky westward as the storm steering flow will continue to be WRLY, which will bring offshore moving showers and storms across the local waters. There should be ECSB formation each day as light onshore winds develop each afternoon.

Winds speeds AOB 15 kts (outside of convection) through this week. Wave heights will remain elevated up to 5-6 feet nearshore and up to 6-8 feet offshore into Monday, with Small Craft Advisory continuing offshore Monday and Monday evening. Seas will gradually subside into Monday overnight with values falling to 4-6 feet Tuesday and then to 3-4 feet into midweek.

PRELIMINARY POINT TEMPS/POPS
DAB 74 87 73 90 / 20 50 20 40 MCO 75 91 75 91 / 20 50 20 50 MLB 76 90 75 90 / 10 30 20 40 VRB 74 91 75 90 / 10 30 30 50 LEE 74 89 74 90 / 20 50 20 40 SFB 74 89 74 90 / 20 50 20 50 ORL 76 91 75 91 / 20 50 20 50 FPR 74 91 75 90 / 20 30 30 50

MLB WATCHES/WARNINGS/ADVISORIES
FL...None.
AM...Small Craft Advisory until 10 PM EDT Monday for AMZ570-572-575.