textproduct: Melbourne

KEY MESSAGES

Issued at 256 PM EDT Tue Aug 18 2026

- A Heat Advisory is in effect for all east central Florida counties until 8 PM for peak heat indices of 108F to 112F. Practice heat safety!

- An active weather pattern is forecast through the rest of this week, with daily afternoon showers and thunderstorms anticipated across east central Florida.

- Hot conditions will continue over the next couple of days, with temperatures then trending closer to normal late this week.

DISCUSSION

Issued at 256 PM EDT Tue Aug 18 2026

Currently...Outflow produced by storms along the northern Gulf coast yesterday has traveled to Central Florida and helped get an early start to showers and lightning storms in the surge of moisture gradually sagging south across the peninsula. This line has already pushed through the Orlando Metro and is working through the southern counties. So far the primary storm hazard has been frequent cloud to ground lightning and gusts to around 40 mph, but the environment to the south could support stronger storms.

Rest of Today-Tonight...Offshore (WNW-WSW) flow continues as a nearly stationary front draped from the Deep South to the Mid Atlantic seaboard and a broad trough sliding over the eastern US keep the Bermuda high suppressed. GOES imagery shows a considerable moisture gradient across the Florida peninsula with PWATs less than 1.5" (0.5-0.75" below normal) over South Florida increasing to 2.15" (0.1-0.25" above normal) over North Florida, and the edge of the 2" PWATs sagging south through Central Florida. Models have struggled to capture the showers and storms riding the outflow in the higher moisture, making near storm environment analysis a challenge, and offering little help with convective evolution the rest of the afternoon. Earlier storms weren't able to live up to their full potential since the early start meant less instability from daytime heating. However, as the storms and outflow push south they will move into higher instability. But then, the drier air to the south will be an increasingly significant hurdle to deep convection. To further complicate matters, the offshore flow and outflow has delayed or even impeded the onshore push of the east coast sea breeze. The boundary is likely to remain offshore from the Cape north, and may only be able to make a brief inland push to the south before storms and outflow arrive. Where the sea breeze can move inland will be the greatest potential for strong storms with gusts to 55 mph, in addition to frequent cloud to ground lightning and torrential downpours. Radar shows the boundary has begun a push near Sebastian inlet. Can't rule out stronger storms elsewhere, but chances are lower. Storms and heavy rainfall that get hung up on the boundary could produce locally heavy rainfall, though steering flow appears sufficient to keep the risk minimal.

The early rain start has at least provided respite from the heat for the northern counties where cloud cover remains, with many sites in and around the Orlando Metro reporting temperatures in the 80s rather than 90s. Temperatures could get back into the 90s if skies clear, but will likely fall short of the M-U90s previously forecast. That said, the rain may spike dew points and result in some hot, sultry conditions. Areas that don't get rain, or where skies clear quickly, are forecast to reach the M-U90s with peak afternoon heat indices to around 112F, and a Heat Advisory remains in effect for all of East Central Florida until 8 PM.

Wednesday-Monday (Modified Previous Discussion)...An active pattern will continue across east central Florida through this week and into early next week. Mid-level ridging will weaken across the Florida peninsula, with guidance still developing a mid-level low over the eastern Gulf/Florida, before getting absorbed by a trough digging southward across the eastern US this weekend. At the surface, this mid-level pattern would support persistent increasing moisture locally, with a series of decaying frontal boundaries anticipated to approach Florida through late this week while broad high pressure remains situated across the Gulf. Locally, west to southwest winds are forecast to continue areawide, with daytime heating supporting the development of the east coast sea breeze each day. The push inland during the afternoon hours will result in winds becoming more south to southeasterly behind it, with westerly winds aloft preventing too much intrusion inland. Combined with the moist air mass in place, a diurnal pattern of showers and storms will persist, with development driven primarily by the sea breezes each day. Rain and storm chances will remain near to above normal (40-60%) through the period, with storm hazards including lightning strikes, gusty winds, and heavy downpours that have the potential to produce minor, localized flooding in some spots. With steering flow remaining out of the west, activity will push offshore through the afternoon and evening hours each day, with mostly dry conditions anticipated across the peninsula through the overnight hours.

Temperatures are forecast to remain above normal over the next couple of days, then the increasing cloud cover and rain chances will lead to a trend closer to normal late this week and into the weekend. However, heat will still remain a concern through this week as high humidity pushes peak heat indices well into triple digits, with continued support from guidance that some locations across east central Florida may near and even exceed Heat Advisory thresholds. This will continue to be closely monitored and additional heat products will be issued as needed

MARINE

Issued at 256 PM EDT Tue Aug 18 2026

Generally favorable boating conditions outside of offshore moving afternoon/evening storms and heat. Westerly to southwesterly flow will continue between a front stalled across the Deep South and high pressure over the Atlantic. Winds shift south the southeast in the afternoon and evening as the sea breeze develops, which will be slowed by the offshore flow. Wind speeds outside of storms 10-15 kts. Seas 1-3 ft. Near to slightly above normal lightning storm chances return as moisture increases. Stronger storms will be capable of wind gusts 34 kts or greater, frequent cloud to water lightning, and heavy downpours.

AVIATION

(18Z TAFs) Issued at 139 PM EDT Tue Aug 18 2026

VFR conditions outside of convection through the period. There is ongoing showers and storms this afternoon. Additional showers and storms are forecast through the afternoon and early evening hours, especially along the coast where the sea breeze collision is forecast to occur. Have included VCTS starting across all the terminals at 18Z. Have added TEMPOs for MVFR conditions for the interior sites starting at 18Z for ongoing convection. Have maintained PROB30 for MVFR conditions for the coastal terminals starting around 20Z. May need to adjust timing since convection is starting and moving quicker than expected. Any lingering activity will push offshore or dissipate after 01Z. Outside of convection, westerly winds around 10 KT this afternoon with gusts up to 20 KT will become light this evening. Winds will then pick up to 5-10 KT by 15Z Wednesday.

PRELIMINARY POINT TEMPS/POPS

DAB 78 95 76 94 / 20 50 20 60 MCO 79 95 77 95 / 20 60 20 70 MLB 79 94 78 92 / 20 60 20 50 VRB 77 93 76 92 / 20 50 20 50 LEE 78 95 77 95 / 20 60 20 70 SFB 79 95 77 95 / 20 70 20 70 ORL 80 95 78 95 / 20 60 20 70 FPR 77 93 76 92 / 20 50 20 60

MLB WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory until 8 PM EDT this evening for FLZ041-044>046-053- 058-141-144-154-159-164-247-254-259-264-347-447-547-647-747.

AM...None.