textproduct: Melbourne

KEY MESSAGES

Issued at 300 AM EDT Tue Jul 21 2026

- Drier air will lift northward across east central Florida starting today as Tropical Storm Bertha shifts farther west, though isolated showers and storms cannot be ruled out this afternoon. Lower rain chances are forecast through the remainder of the work week.

- Moisture is forecast to increase this weekend and into early next week, causing rain and storm chances to return to near- normal values Saturday onward.

- Near to above-normal afternoon temperatures will persist through the period with peak heat indices exceeding 100F each day. Practicing heat safety will be key to avoid heat-related illness!

DISCUSSION

Issued at 300 AM EDT Tue Jul 21 2026

Today-Tonight...Tropical Storm Bertha remains across the northeastern Gulf and is forecast to linger, slowly moving west- northwest today. While there will continue to be no direct impacts across east central Florida, this particular set-up will keep south to southeast winds in place locally. The tight pressure gradient due to the proximity of Bertha will also keep conditions breezy and gusty at times, with wind speeds of 10 to 15 mph and wind gusts up to 20 mph possible. Wind enhancements due to the development of the east coast sea breeze will also be possible at times. While drier air is lifting northward across the Florida peninsula as seen on the GOES 19 Total PWAT viewer and will help limit rain and storm chances today, there continues to be hi-res guidance supporting isolated to scattered development this afternoon, primarily due to sea breeze interactions across the central Florida peninsula. Have kept a 20-30% chance of showers and storms across the interior this afternoon, with isolated northward-moving showers and storms possible across the local Atlantic waters. Steep low-level lapse rates, SBCAPE of 1500-2000 J/kg, and drier air aloft pushing DCAPE values to 1000+ J/kg will support frequent lightning strikes and wind gusts to 50 mph with any storms that manage to develop. Heavy downpours and minor, localized flooding also cannot be ruled out. Activity across the peninsula is forecast to diminish into the evening hours, with lingering showers and storms possible across the local waters.

Above normal temperatures in the mid 90s are forecast areawide this afternoon, combining with humid conditions to create peak heat indices of 100-107F. Adequate hydration, frequent breaks in the shade or an air-conditioned building, and lightweight, lightly colored clothing will all be crucial for those spending extended periods of time outdoors to reduce the risk of developing heat- related illness. Lows remain in the 70s.

Wednesday-Thursday...Tropical Storm Bertha will continue westward across the northern Gulf through the middle of this week, which will allow the Atlantic high to lift northwestward towards the Florida peninsula. The pressure gradient will gradually weaken across east central Florida, especially by Thursday. South to southeast winds will remain between 10 to 15 mph on Wednesday with gusts to 20 mph possible at times. By Thursday, wind speeds fall to 5 to 10 mph. Wind speed enhancements due to the sea breeze will be possible, particularly along the coast. A dry air mass in the wake of Bertha is anticipated to remain in place locally, helping to limit rain and storm chances to around 20% or less across east central Florida both Wednesday and Thursday. Any showers or storms that do manage to develop will likely be along or ahead of the sea breezes, with activity diminishing into the evening hours. Overall, anticipate mostly dry conditions across east central Florida through Thursday. The drier air will also help limit cloud coverage, and with the return of high pressure overhead, temperatures are forecast to trend warmer locally. Highs in the low to mid 90s are anticipated, with the warmest temperatures focused near and north of the I-4 corridor. Peak heat indices of 100-107F are forecast each afternoon, so those spending extended periods of time outdoors will need to remain adequately hydrated and take frequent breaks in the shade or an air-conditioned building to avoid heat-related illness. Overnight, near-nromal temperatures are forecast with lows in the 70s.

Friday-Monday...Broad mid-level ridging will remain in place across the southern US late this week, with a trough across the eastern US gradually digging southward towards Florida into this weekend and early next week. At the surface, broad high pressure is forecast to remain situated across the local Atlantic waters on Friday, with the high gradually pushing southward this weekend as a low moves offshore the Carolinas and drags a frontal boundary southward across the southeastern US. The boundary will stall across north Florida on Sunday, continuing to drift southward towards the peninsula into early next week as it weakens. Locally, lingering dry air across the area on Friday will keep rain chances a bit limited across the north, with increasing moisture across the Treasure Coast and near Lake Okeechobee causing a return of near-normal rain chances. By this weekend, a moist air mass will overspread the Florida peninsula and the typical diurnal summertime pattern is forecast, with convective activity primarily being driven by the sea breezes and their interactions. A return of westerly flow will also favor higher coverage across the eastern portions of the peninsula near the coast. By Monday, the moisture from the decaying boundary will arrive across east central Florida, with continued near-normal rain chances forecast through the afternoon hours areawide. Overall, showers and storms are forecast to diminish each evening through the overnight hours, with lingering activity possible across the local Atlantic waters.

Above normal temperatures are forecast to continue across east central Florida through Sunday, with some indication that the increasing moisture and cloud coverage will help keep temperatures closer to normal on Monday afternoon. Peak heat indices will continue to exceed 100F areawide, with some locations potentially nearing Heat Advisory criteria. Confidence in this remains low though, so will continue to monitor. Lows generally in the 70s.

MARINE

Issued at 300 AM EDT Tue Jul 21 2026

A tight pressure gradient across the local Atlantic waters from Tropical Storm Bertha in the Gulf will lead to continued poor boating conditions through at least today. South-southeast winds of 15 to 20 knots are forecast across the waters at times, with seas of 2 to 4 feet. Small craft should exercise caution across most of the local waters through tonight and across northern portions of the waters into Wednesday. By Wednesday night, Tropical Storm Bertha will move farther west across the northern Gulf, with the pressure gradient forecast to weaken across the local waters as broad high pressure returns overhead. South to southeast winds will subside to 10 to 15 knots, with seas responding by decreasing to 1 to 3 feet.

Showers and storms will continue to be possible across the local Atlantic waters each day, though drier air moving into the area will limit some potential through at least Thursday. Friday onward, expect a return of greater rain and storm chances as moisture increases.

AVIATION

(06Z TAFs) Issued at 130 AM EDT Tue Jul 21 2026

VFR conditions outside of convection through the TAF period. Light south-southeast winds will become breezy by mid morning, increasing to 10-15 KT with gusts to around 20 KT. Isolated to scattered showers and lightning storms in the afternoon, mainly after 18Z. Have included VCTS from MCO, ISM, SFB starting at 20Z and LEE starting at 18Z. Have maintained PROB30 for LEE starting at 18Z for MVFR conditions with TSRA. May need to added PROB30 for the greater Orlando area for this afternoon. VCSH for all the coastal sites, starting 20/22Z. Southeast winds will decrease into late afternoon, becoming around 10 KT, before interior sites settle around 5 KT into the evening and overnight hours.

PRELIMINARY POINT TEMPS/POPS

DAB 93 76 93 76 / 20 20 10 0 MCO 95 76 96 77 / 30 20 10 0 MLB 92 77 91 77 / 20 20 10 0 VRB 93 75 92 76 / 20 20 10 0 LEE 93 76 95 77 / 40 20 10 10 SFB 95 76 95 77 / 30 20 10 0 ORL 95 77 95 77 / 30 20 10 0 FPR 92 75 91 75 / 20 20 20 0

MLB WATCHES/WARNINGS/ADVISORIES

FL...None. AM...None.