textproduct: Melbourne

KEY MESSAGES

Issued at 141 AM EDT Thu Aug 20 2026

- A Heat Advisory is in effect for all east central Florida counties between 10 AM and 7 PM for peak heat indices of 108F to 112F. Practice heat safety!

- Slight relief from high heat indices this weekend, with increased coverage of showers and storms, but high temperatures persist in the lower to mid-90s.

- Scattered to numerous showers and storms will be possible each afternoon through early next week. Gusty winds to 50-55 mph, small hail, lightning strikes, and heavy downpours will be the main storm hazards.

DISCUSSION

Issued at 141 AM EDT Thu Aug 20 2026

Today-Tonight...Little change to the overall pattern today. A stalled boundary over the Southeast keeps the Atlantic ridge axis southeast of the Florida peninsula at the surface. Aloft, an upper level low lingers over the the area. Light offshore flow continues today, initially delaying the development of the sea breeze to around 2 PM. Winds then back southeast at the coast and increase to around 10 mph. As the sea breeze moves inland through the day, this will be the primary focus for afternoon convection. Scattered to numerous showers and storms (50-60%) are forecast to develop along the boundary, then push inland. Propagation of storms will become increasingly erratic due to light storm motions, with cells developing along outflow boundary collisions. Upper level support from the low, drier air in the mid levels (DCAPE near 1000 J/kg) due to a bit of Saharan Air Layer (SAL), and steep low level lapse rates will lead to a few strong storms, capable of wind gusts to 50-55 mph. A few locally higher gusts will be possible. Other hazards include lightning strikes, locally heavy rainfall, and small hail (500 mb temperatures near -8 C). Convection looks to linger, mainly over the interior, through much of the evening hours. However, expect storms to diminish by midnight.

Hot August temperatures persist today, with highs reaching the lower to mid-90s. Humid conditions will continue to produce max heat indices between 108 to 112 degrees. Thus, another Heat Advisory has been issued from 10 AM to 7 PM for all of the forecast area, with increased precipitation and cloud cover helping to moderate heat indices by the early evening. Overnight, warm and muggy conditions continue, with lows in the mid to upper 70s.

Friday-Sunday...The upper level low lingers over the forecast area Friday, before it then weakens and is picked up by an upper level trough digging through the eastern US this weekend. At the surface, southwesterly flow under 10 mph continues, as the Atlantic ridge remains across South Florida. Near normal coverage of showers and storms will persist through the weekend, with PoPs 40-60%. Strong to borderline severe wind gusts will remain a threat from any storms, as another wave of SAL approaches the peninsula. Steering flow increases slightly through the period (from 5 kts to 10 kts) out of the southwest, helping to keep the highest convection and the east coast sea breeze over the eastern half of the state. Showers and storms will remain focused during the afternoon hours, but will linger into the evenings before drier conditions develop by around midnight.

While little changes with the overall pattern, drier air (PWATs below 2") looks to advect into the area this weekend. This will help with peak heat indices, ending the streak of advisory or near advisory conditions. However, additional Heat Advisories will be possible for at least portions of the area once again Friday. Highs remain in the lower to mid-90s, despite the somewhat lower humidity and apparent temperatures will linger at 100-106 degrees.

Monday-Thursday...The stalled boundary lifts northward next week, allowing the Atlantic ridge axis to also move northward across the area. Meanwhile, a strong upper level ridge over the southern plains looks to shunt an upper level trough across the Florida peninsula. Locally, the most appreciable change will be for southerly flow to prevail, aiding the east coast sea breeze inland each afternoon. While the highest coverage of showers and storms will move inland, in turn, widespread scattered to numerous coverage remains forecast, with upper level support from the trough. High temperatures moderate into the lower 90s, but high humidity will maintain peak heat indices 100-107. Fortunately, heat indices are forecast to remain below Heat Advisory criteria.

MARINE

Issued at 141 AM EDT Thu Aug 20 2026

Generally favorable boating conditions prevail. The Atlantic ridge axis remains south of the local waters through the weekend, maintaining overall light offshore flow. Will see the ridge shift northward next week, backing winds southerly. Regardless, daily sea breezes at the coast will produce south to southeasterly winds, with flow overall around 10 kts or less. Seas 1-3 ft.

Scattered to numerous showers and storms are forecast each afternoon. Chances for offshore-moving convection increases into the weekend, especially during the evenings. Storms will be capable of wind gusts in excess of 35 kts and the strongest could produce gusts to near 50 kts, in addition to lightning strikes and small hail.

AVIATION

(06Z TAFs) Issued at 120 AM EDT Thu Aug 20 2026

Quiet conds expected overnight through the morning hours with storm redevelopment expected after around 18Z. Light/VRB winds becoming onshore along the coastal terminals with the afternoon sea breeze. Hi-res guidance supports 40-60% coverage of showers and storms today, esp in the late afternoon/early evening. Focus seems to favor the interior and MCO area, with perhaps some activity closer to the coast on the sea breeze. Added TEMPOs for interior sites and PROB30s at the coast for storm impacts; will reassess with later updates and determine whether TEMPOs will eventually be required at most/all sites based on incoming guidance for the 12Z TAF suite.

PRELIMINARY POINT TEMPS/POPS

DAB 93 76 92 76 / 60 20 60 20 MCO 96 77 94 76 / 60 20 60 20 MLB 93 77 92 77 / 50 30 60 30 VRB 93 75 93 76 / 40 30 60 30 LEE 94 76 93 76 / 60 20 60 10 SFB 95 77 94 77 / 60 20 60 20 ORL 95 78 93 77 / 60 20 60 20 FPR 92 76 92 75 / 40 20 60 20

MLB WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory from 10 AM this morning to 7 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.