Marine Weather and Tide Forecast for Melbourne, FL

PREVIOUS DISCUSSION
Issued at 331 PM EDT Thu Oct 3 2024

KEY MESSAGES...

- Locally heavy rainfall is forecast tonight along the Treasure coast with add'l potential for heavy rain late weekend into next week over east central Florida.

- Increased risk of rip currents and rough surf this weekend into next week.

Tonight...A very moist airmass south of the Cape will combine with increased easterly flow and coastal convergence to produce a heavy rain threat focused on south Brevard, Indian River, Saint Lucie and Martin counties. HRRR ensemble model guidance is showing mean rainfall amounts of 1-3" along the coast with highly localized amounts of 6"+ possible. Be especially cautious during nighttime flooding.

Friday-Saturday (previous)...Reduced moisture across the northern extent of east central Florida during this period will work to temporarily decrease rain chances for the first half of the weekend. East- northeasterly flow will persist, at times becoming gusty closer to the coast, as high pressure tries to press south along the northeast Florida coast. Temperatures slip a bit, only reaching the upper 80s each afternoon and falling into the 70s overnight. Where 2" PW can outlast the drier air, namely along a line from Leesburg to Lake O and Stuart, PoPs max out around 30-40 percent each afternoon.

Sunday-Wednesday (modified)...A shift in the pattern begins Sunday as high pressure loses its influence on the southeast U.S.
and a warm front becomes stationary across south-central FL. An area of possible tropical development will continue to be monitored in the Gulf of Mexico. NHC/WPC are depicting an elongated trough with possible low pressure over the SW Gulf moving E/NE then turning SE Tue-Wed.

What models primarily agree on is a quick return of deep moisture across central and south FL from Sunday into next week. This will result in more cloud cover, higher coverage of rain, and a few lightning storms. Instability does not appear as impressive through the extended period, owing to the tradeoff between more clouds/less diurnal heating. However, the threat of heavy rain and instances of localized flooding are expected to increase next week. In fact, the Weather Prediction Center has already outlined central and south FL in a Marginal Risk for excessive rainfall on Monday and this may be extended to Tue as well. Key features to monitor, which will determine areas with the highest QPF, include where the deepest moisture advects across the FL peninsula and the location of the frontal boundary. The GFS shows several convective clusters moving across the peninsula with very heavy rain but mostly north of the frontal boundary. It is along the front itself that episodes of heavy rainfall would be most likely early to mid week.

Finally, long period swells from distant Hurricane Kirk will make the surf zone increasingly hazardous this weekend into next week.
producing a High risk of rip currents, rough surf and minor beach erosion. The swells are forecast to peak at 4 ft/15 sec periods Sun night and Monday with potential for runup to the dune lines or seawalls (especially around high tide times). While a High Surf Advisory is not anticipated, a Coastal Flood Advisory is possible given the energy these long period swells will impart onto the beaches.

AVIATION
(00Z TAFs)
Issued at 743 PM EDT Thu Oct 3 2024

Dry at all terminals to start the 00Z TAF. Overnight showers and occasional storms are then forecast to develop along the coast from TIX southward. Have included a mention of VCSH/VCTS for now due to low confidence in overall coverage, but will continue to monitor trends for potential TSRA TEMPOs at the Treasure Coast terminals where coverage could be greatest late tonight. VCSH/VCTS at all terminals tomorrow afternoon for routine diurnal showers and storms. Light east winds overnight increase to 7-10 kts tomorrow.

MARINE
Issued at 331 PM EDT Thu Oct 3 2024

Convection will increase this eve and overnight over the Atlc waters mainly south of the Cape and push onshore over the intracoastal waters. Long period swells from distant Hurricane Kirk will reach the local waters this weekend, especially from Sunday into early next week. High pressure on Friday-Saturday breaks down later in the weekend as a surface front lifts north across the waters into early next week. Onshore flow around 12-15 kt Fri/Sat increases to 15 kt (with gusts up to 20 kt) Sun/Mon.
Seas build gradually, 4-5 ft Fri (6 ft offshore), 4-6 ft Sat/Sun (7 ft offshore), eventually reaching 5-7 ft Mon (8 ft offshore).
Scattered showers and lightning storms stay in the forecast, increasing in coverage late weekend into next week.

PRELIMINARY POINT TEMPS/POPS
DAB 75 88 75 86 / 10 30 10 40 MCO 75 89 74 88 / 10 30 10 30 MLB 77 88 76 87 / 20 30 10 20 VRB 77 88 76 88 / 40 30 10 20 LEE 75 90 74 88 / 10 30 10 30 SFB 75 89 74 88 / 10 30 10 40 ORL 76 89 76 88 / 10 30 10 30 FPR 76 88 76 87 / 40 40 10 20

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