Marine Weather and Tide Forecast for Merritt Island, FL

PREVIOUS DISCUSSION
Issued at 231 PM EDT Tue May 20 2025

Rest of Today-Tonight...No significant changes to the forecast. A pretty healthy cu field has developed with PWATs 1.4-1.6", while gentle westerly to southwesterly flow slows development of the east coast sea breeze (in fact it remains pinned to the coast from Melbourne south), so continuing a low (10-20%) chance of showers and lightning storms just prior to and along the sea breeze collision across the eastern half of the peninsula between 5 PM and 9 PM. Otherwise hot but quiet weather persists. Most climate sites remain forecast to reach their daily high temperature records in the M90s, though that has much to do with a set of surprisingly mild record values for today (compare today's record values to the upcoming days in the Climate discussion, especially for the Orlando Metro Area). Some fog is possible in the usual spots (fields and such) north of the I-4 corridor towards morning, but chances for much else are too low for mention in the forecast.

Wednesday-Thursday...(Modified Previous Discussion) Deep layer ridging over the Florida peninsula will shift eastward into Wednesday as a cold front approaches from the west. This weak cold front is progged to move slowly across east central Florida on Thursday, but weakening forcing is resulting in some model disagreement where it ends up, with the GFS now stalling it across Central Florida Thursday night while the ECM pushes it barely into South Florida by Friday morning. Either way, warm conditions are forecast through the period despite the front. Afternoon highs will be in the low to mid 90s on Wednesday, with temperatures cooling slightly to the upper 80s to low 90s across the north on Thursday with the little the front can offer. However, temperatures will remain above normal across the south on Thursday, with highs in low to mid 90s as more daytime heating occurs ahead of the front. West to southwest winds on Wednesday increase to around 10-15 mph with gusts 20-25 mph in the afternoon, which will pin the east coast sea breeze just off the coast. Winds will become west to northwest Thursday morning before shifting northeast to east by the afternoon behind the front, with speeds remaining 10 mph or less.

Most areas will remain dry on Wednesday, but can't rule out a shower along the Treasure in the evening. Rain and lightning storm chances increase into late week as moisture out ahead of and along the front increases. There is a low to medium (20-50 percent) chance for rain on Thursday along and ahead of the front, with a low to medium (20-30 percent) chance for lightning storms.
The greatest potential for storms will be across the southern portion of the CWA where more daytime heating will occur. Some storms on Thursday may be strong, with forecast soundings showing a favorable environment with sufficient instability (MUCAPE 1000-2100 J/kg) and shear (SFC-1km shear around 20-40 KT), cooler temperatures aloft (-8 to -10 C at 500mb), as well as abundant low-level moisture (PW values between 1.5-2.0"). Thus, the primary storm threats on Thursday will be gusty winds of 50 mph, small hail, frequent lightning, and locally heavy downpours.

Friday-Monday...(Modified Previous Discussion) The residual frontal boundary gradually stalls over Central or South Florida Friday, before eventually lifting back north as a weak warm front through the weekend. Surface high pressure gradually builds behind the front through early next week. Rain chances come and go through the weekend and into next week as moisture lingers across the area. There is a low to medium (20-30 percent) chance of rain from Cape Canaveral to Orlando southward on Friday, with a low (20 percent) of lightning storms. While Saturday will be mostly dry, there is a low (20 percent) chance of rain from Orlando southward on Sunday, and a low to medium (20-30 percent) chance of rain on Monday. Light offshore winds each morning will become onshore in the afternoons with the sea breeze. Wind speeds will generally be 10 mph or less. Afternoon highs will be in the upper 80s to low 90s along the coast, and low to mid 90s across the interior each day.

MARINE
Issued at 231 PM EDT Tue May 20 2025

Rest of Today-Wednesday...Generally favorable boating conditions as high pressure over Florida and the local Atlantic waters remains in control. Light offshore winds shift southeasterly at 10-15 kts in the afternoons and evenings behind the sea breeze, increasing to around 15 kts over the Gulf Stream in the late evening and early overnight, then return to light offshore late overnight through the morning. There is a low (20%) chance for showers and a lightning storm along the sea breeze collision near the I-95 corridor in the evening.

Thursday-Saturday...A weak cold front pushes slowly through Thursday, stalls across Central or South Florida Friday, then slowly lifts north as weak warm front this weekend. There is a low to medium (20-50%) chance for showers and lightning storms, especially along the frontal passage where there is potential for stronger storms as well. Outside of storms, generally favorable boating conditions. Winds become squirrelly as the front comes and goes and the daily sea breeze circulation develops, generally shifting from offshore from the late overnight through the morning to onshore from the afternoon through the early overnight at 5-10 kts.

AVIATION
(06Z TAFs)
Issued at 143 AM EDT Wed May 21 2025

VFR conditions generally forecast through today and into tonight, as mostly dry conditions continue. Offshore winds will strengthen today, with W/SW winds 8-12 knots and gusts up to 15-20 knots especially near to north of KMLB. These winds will likely prevent the east coast sea breeze from developing/pushing inland this afternoon, but may be able to make it near or just past KVRB-KSUA later in the day, switching winds to the S/SE around 10-12 knots.
Winds then gradually diminish into the evening.

FIRE WEATHER
Issued at 231 PM EDT Tue May 20 2025

Unseasonably hot conditions continue across east central Florida through the rest of the week, impacting afternoon humidity values.
Min RHs across the interior fall between 40-45 percent Wednesday and Thursday, then a weak front pushing through Thursday decreases moisture causing min RHs to drop to 30-40 percent Friday. The front and associated moisture gradually lift back north through the weekend, but min RHs continue to drop below 40 percent across portions of the interior through the weekend. Winds Wednesday westerly to southwesterly at 10-15 mph with gusts up to 25, shifting to the southeast along the coast with the sea breeze Wednesday. Winds become more squirrelly Thursday onward between the front coming and going and the daily sea breeze development, but remain below 10 mph. Some patchy ground fog is possible north of I-4.

PRELIMINARY POINT TEMPS/POPS
DAB 95 73 86 69 / 10 10 30 10 MCO 95 75 90 72 / 10 10 50 10 MLB 94 74 88 72 / 10 10 50 20 VRB 95 72 89 72 / 10 10 60 30 LEE 92 75 89 71 / 10 10 40 10 SFB 95 75 90 71 / 10 10 50 10 ORL 95 76 91 73 / 10 10 50 10 FPR 94 71 89 71 / 10 10 60 30

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