textproduct: Melbourne

KEY MESSAGES

Issued at 255 AM EDT Wed Aug 12 2026

- Heat Advisory issued for all of east central Florida today from 11am to 8pm for heat index values up to 108F-112F degrees; Remember to practice heat safety!

- A Major Heat Wave is expected with Hot and humid conditions for the next week. Maximum heat index values will reach near or at Heat Advisory criteria (108F+) each day through at least Friday; A Heat Advisory is likely for at least areas of east central Florida through the end of the week

- Mostly below normal rain chances this week. Drier air aloft due to a Saharan Dust Layer will support strong gusty winds in any lightning storms each day.

DISCUSSION

Issued at 255 AM EDT Wed Aug 12 2026

Currently-Tonight... KMLB radar imagery shows dry weather over east central Florida. GOES-19 satellite imagery and local observations indicate clear to partly cloudy skies. Temperatures are currently in the mid 70s to low 80s with dew points in the mid to upper 70s. Analysis charts show a mid/upper level high over the Gulf with 500mb heights at 594dm (90th percentile), as well as a mid/upper level trough over the eastern US coast and the western Atlantic. At the surface, high pressure (~1020mb) is centered over the eastern Gulf. Meanwhile, the 00Z XMR sounding indicates drier air than normal for this time of year, especially in the mid to upper levels.

The airmass is not expected to change much today from the 00Z XMR sounding from last night, therefore, the dry air in the mid to upper levels is expected to keep rain chances (20-50%) below normal today. Isolated to scattered showers and lightning storms are forecast to develop in the afternoon and evening as collisions occur between west-northwest surface winds, the east coast sea breeze, and outflow from previous showers/lightning storms. Rain chances diminish by around 8PM. West-northwest winds at 4-8mph are expected to turn onshore in the afternoon and evening with the east coast sea breeze mainly to the south of I-4. Hi-res guidance indicates MLCAPE up to 2,000-3,800 J/kg, 0-6km shear up to 10-30kts, PWATs up to 1.80-2.20", and conditionally unstable mid level lapse rates. The aforementioned parameters are sufficient for an isolated strong storm or two to develop which are capable of frequent lightning, wind gusts up to 30-50mph, and heavy rainfall (up to 1-2") if they can overcome the dry air in the mid/upper levels. A hot and very humid day is expected with afternoon highs in the low to mid 90s. Additionally, a Heat Advisory has been issued for all of east central Florida from 10AM to 8PM for heat index values up to 108-112F degrees. Remember to take frequent breaks from the heat, drink plenty of fluids, wear light colored clothing, and shift outdoor work away from the hottest parts of the day between the hours of 10am to 4pm. Near to above normal lows in low 70s to near 80F degrees are forecast overnight.

Thursday-Saturday... A similar and persistent forecast is expected with a continuation of the heat wave through the week with little change in the weather pattern. The 500mb ridge is forecast to expand as it builds north and east over the Gulf, as well as the southern US through Saturday. The mid/upper level trough over the western Atlantic will fill as this occurs. 500mb heights over the southern US and the state of Florida are forecast to reach the maximum percentile (598dm) for this time of year by Friday evening into Saturday. Below normal rain chances (30-40% Thursday, 20-50% Friday, and 10-40% Saturday) will continue through Saturday with mostly dry air in the mid to upper levels. Light west-northwest winds at 4-8mph are forecast to back more southerly each day. Winds will back onshore (mainly south of I-4) each afternoon and evening with the east coast sea breeze. Isolated to scattered showers and lightning storms are forecast to develop in the afternoons and evenings as collisions occur between sea breezes and outflow from previous showers/lightning storms. The potential exists for isolated strong storms capable of frequent lightning, wind gusts up to 30-50mph, and heavy rainfall (up to 1-3"). Hot and humid conditions will continue with afternoon highs in the low to mid 90s and heat index values near or at Heat Advisory criteria (heat index 108F+ degrees). A Heat Advisory is likely to be issued for at least areas of east central Florida through at least Friday. A widespread Moderate to Major HeatRisk with widespread Extreme HeatRisk mainly north of the Treasure Coast exists each day. A Major and Extreme HeatRisk effects anyone without adequate cooling and hydration.

Sunday-Tuesday... A very persistent forecast is expected with the heat wave forecast to continue through the forecast period. Ensembles, LREF-clusters, and deterministic models are in good agreement that the 500mb ridge will build over the eastern CONUS through Sunday before gradually shifting west-southwest on Monday into Tuesday. 500mb heights at the maximum percentile (597dm) are forecast through at least Sunday. The NBM has the probability of temperatures of 95F degrees or greater at 25%-80% each day with the greatest probabilities at inland locations west of I-95, as well as Stuart and Titusville. Additionally, the probability of a Major HeatRisk is likely to very likely for much of east central Florida each day; the probability of an Extreme HeatRisk is 20-50% over areas of Lake, Orange, Osceola, and Volusia counties each day. More information on HeatRisk can be accessed at wpc.ncep.noaa.gov/heatrisk. Below normal rain chances are expected each day with chances at 40% or less.

MARINE

Issued at 255 AM EDT Wed Aug 12 2026

Currently-Tonight... Favorable boating conditions are expected. Isolated to scattered generally offshore moving showers and lightning storms are forecast in the afternoon and evening. The potential exists for a strong storm capable of wind gusts at 34kts or greater. West winds at 5-15mph will turn south over the local Atlantic waters into the afternoon and evening waters, as well as onshore near the coast at 5-10mph. Seas up to 1 ft nearshore and up to 1-2ft offshore (20-60n) are expected.

Thursday-Sunday... Favorable boating conditions are expected to continue through the forecast period with high pressure over east central Florida. Below normal rain chances are forecast to continue with mostly dry conditions each day. However, isolated offshore moving showers and lightning storms cannot be ruled out on Thursday and Friday. West winds at 5-10mph are forecast to turn south over the local Atlantic waters into the afternoon and evening waters, as well as onshore near the coast at 5-10mph on Thursday. South-southwest winds at 5-15mph are expected to back south-southeast each afternoon and evening Friday to Sunday. Seas up to 1 ft nearshore and up to 1-2ft offshore are forecast to build to 1-2ft nearshore on Friday.

AVIATION

(18Z TAFs) Issued at 1255 PM EDT Wed Aug 12 2026

VFR conditions outside of convection through the TAF period. A little stronger WSW flow today is delaying the Atlc sea breeze development but wind shift out of the East will occur at coastal terminals through 20Z. Bulk of the convection looks to stay east of MCO so have maintained a VC term there. Focus for afternoon storms should be near the coast along the sea breeze so TEMPOs for TS exist for MLB-SUA. A little later TEMPO for DAB where sea breeze will be slower to form. Lingering activity will diminish by 03Z. On Thu, west northwest flow will start the day at 5-10 knots, turning onshore in a sea breeze at the coast by 18Z. Rain/storm coverage will be a little higher Thu aftn. Have started MCO with VCTS after 18Z.

PRELIMINARY POINT TEMPS/POPS

DAB 76 93 76 93 / 30 40 10 30 MCO 77 95 77 95 / 20 40 20 40 MLB 78 92 77 91 / 30 30 10 20 VRB 75 92 75 92 / 20 30 10 20 LEE 77 94 77 94 / 20 40 20 40 SFB 77 94 77 94 / 20 40 20 30 ORL 77 94 78 94 / 20 40 20 40 FPR 76 92 75 91 / 20 30 10 20

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.