PREVIOUS DISCUSSION
Issued at 445 AM EDT Wed Sep 11 2024

Key Messages:

- Locally heavy rainfall and flooding concerns last through the end of the week

- Continued rises on the St. Johns River with Astor approaching Moderate Flood Stage

Today-Tonight...Anomalously high moisture content across central Florida and a stationary front nearby will lend to continued high rain chances for much of the area today. This morning, the stationary boundary is bisecting the Florida Peninsula as Hurricane Francine churns northeastward toward the Louisiana Gulf Coast. Pre-dawn coverage of showers and an isolated storm has increased over the adjacent Atlantic waters, and some of this activity is moving onshore. Radar estimates that a few locations from Sanford to New Smyrna Beach and farther south along the coast have already received 0.50" to 1.00" of rainfall this morning.
Rain, briefly heavy at times, will continue through mid morning (especially along the immediate coast).

Light, variable surface flow will gradually increase out of the east-northeast later today, while mid level steering flow remains west-northwesterly. Sufficient moisture, instability, and modest upper level support will result in another day of scattered to numerous showers and lightning storms for many east-central Florida locations. With PW near or above daily climatological maximums (2.4"+), any convection will be capable of very efficient rainfall rates of 1-3" per hour. Flooding concerns continue to mount, especially in portions of the Greater Orlando metro area and Martin County, where soil saturation is greater than 75-85 percent. Slow storm motions and the potential for repeated heavy rainfall over some of these same locations today has presented us with another marginal risk of excessive rainfall from WPC. Total rain accumulations of 2-4" in spots across the forecast area with locally higher amounts of 5-6" are within the realm of possibility once again. This could quickly result in ponding of water on roadways and in low-lying/urban areas. Area streams and rivers are likely to experience additional rises due to continued heavy rainfall. If encountering floodwater, especially while driving, turn around and seek drier ground.

Activity will begin to dissipate after sunset and shift back toward the coast, eventually moving largely offshore later tonight. Temperatures through the day will be impacted by cloud cover and continued rain chances, only reaching the mid 80s to around 90 degrees (far south). Lows overnight into Thursday will fall into the 70s, staying a degree or three warmer along the coast.

Thursday-Friday...This forecast maintains chance to likely PoPs (50 to 70 percent) through late week, as the stalled front over central Florida is slow to retreat northward. Onshore flow gradually veers SE on Thursday and becomes light out of the west- southwest on Friday. Weaker support aloft may allow future forecasts to adjust PoPs down just a touch on Thursday, and model guidance is in lesser agreement regarding QPF on Friday. Until CAM data becomes available and global models line up with either a drier/wetter solution later this week, a consensus-leaning forecast was preferred for now. The threat for localized flooding will persist with a greater focus across northern portions of east central Florida. High temperatures trend up just a degree or two each day with the upper 80s to low 90s anticipated both days. Lows stay in the mid to upper 70s.

Saturday-Tuesday...The synoptic pattern this weekend will be a tale of Francine's remnants and a developing surface trough/low off of the southeast U.S. coast. Drier air marks a pattern change from late Saturday into Sunday and early next week, as lower PW wrap into central Florida on a belt of north-northwesterly flow.
The highest rain chances Saturday focus from Orlando eastward, including areas across the south (Okeechobee to the Treasure Coast). Sunday through Tuesday, we see rain chances drop sharply into the 30-45 percent range, again with the best opportunity for measurable precipitation near Lake Okeechobee and along the Treasure Coast. High temperatures will moderate each day, generally hovering around the 90 degree mark. Overnight temps stay in the 70s with a lean toward the upper 70s at the coast.

MARINE
Issued at 445 AM EDT Wed Sep 11 2024

Today-Tonight...Persistent high rain and lightning storm chances remain over the local waters today, as a stalled surface boundary stays nearby. Onshore winds increase to around 15 kt north of Sebastian Inlet, approaching 20 kt (gusts to 25 kt) over the offshore Volusia waters this afternoon and evening, before decreasing into Thursday. Small craft should exercise caution over the offshore Volusia waters as a result. Seas 3-5 ft with heights approaching 6 ft in the offshore Volusia waters later today/tonight. Locally higher seas are possible in the vicinity of heavy rain and gusty lightning storms.

Thursday-Sunday...High rain chances last through late week before decreasing later in the weekend. Generally favorable boating conditions are forecast outside of rain and storms, with seas around 2-4 ft (up to 5 ft well offshore). By Sunday, conditions over the Gulf Stream will become poor as seas build to at least 5-6 ft and NNE winds 10-15 kt resume.

PRELIMINARY POINT TEMPS/POPS
DAB 85 76 88 76 / 70 60 60 20 MCO 89 76 89 76 / 70 40 70 20 MLB 87 76 89 76 / 70 60 60 30 VRB 88 76 90 76 / 70 60 60 30 LEE 88 76 89 76 / 70 30 70 20 SFB 87 76 89 76 / 70 50 70 20 ORL 88 76 90 77 / 70 40 70 20 FPR 89 76 90 76 / 70 60 60 30

MLB WATCHES/WARNINGS/ADVISORIES
FL...None.
AM...None.