textproduct: Melbourne

KEY MESSAGES

Issued at 241 PM EDT Mon Aug 17 2026

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

- Heat concerns persist across east central Florida through at least mid- week due to above-normal afternoon highs and peak heat indices nearing or reaching Heat Advisory criteria.

- A tight moisture gradient today will lead to higher rain chances across the north, with increasing moisture areawide from Tuesday onward supporting a return to near-normal rain and storm chances across east central Florida.

DISCUSSION

Issued at 241 PM EDT Mon Aug 17 2026

Today-Tonight... Broad upper level high pressure across the southern US and Florida will remain in place through the day. At the surface, high pressure across the Gulf will remain in place with the Atlantic ridge axis drifting southwards as a weakening frontal boundary shifts southward across the southeastern US. Locally, offshore flow will persist, both at the surface and aloft, with flow remaining weak. The east coast sea breeze has formed this afternoon, mainly from Cape Canaveral southward, turning the winds south to southeasterly along the coast. The sea breeze is forecast to form north of Cape Canaveral as well later this afternoon, but is expected to remain fairly close to the coast. A pool of higher moisture (PW values of 2.0-2.3") will filter down across the northern part of the CWA head of the aforementioned frontal boundary, while drier air (PW values around 1.6-1.9") remains across the southern part of the warning area. This will result in better rain chances across the north, mainly from Kissimmee to Cape Canaveral northward, where rain chances are 20-50 percent this afternoon. Already this afternoon we have scattered showers and storms moving in from the west coast of Florida, and moving across Lake County and into Volusia County.

The environment will support convection this afternoon, with forecast soundings showing plenty of instability (MUCAPE 2000-2500 J/kg), ample buoyancy (Lifted Index of -5 to -7), and sufficient dry air aloft with downdraft potential (DCAPE 900-1300 J/kg). Main storm hazards today will be frequent lightning strikes, gusty winds up to 55 mph, and locally heavy downpours. Storm motion will be to the east through the day, eventually moving offshore. Any lingering activity will dissipate or move offshore this evening, becoming dry overnight with light westerly flow returning across the area.

Another hot and humid day today, with above normal temperatures forecast. Afternoon highs will climb into the mid to upper 90s across east central Florida this afternoon, which some locations will be near their daily record highs (see climate section below). These hot temperatures combined with high humidity will produce peak heat indices of 108- 112F. A Heat Advisory remains in effect for all of east central Florida through 8 PM this evening. Adequate hydration and breaks in the shade or an air conditioned building will be crucial for those spending extended periods of time outdoors. Residents and visitors alike are encouraged to practice heat safety to help avoid developing heat illness. Temperatures overnight will remain warm and muggy, with overnight lows in the upper 70s to low 80s.

Tuesday-Sunday... Upper level high pressure across the southern US will continue to broaden through the week. A trough around the Great Lakes region will slowly shift eastward towards New Brunswick by late week, deepening across the eastern US and expanding farther southward through the weekend with a series of shortwaves traversing the base of the trough. At the surface, high pressure in the central Gulf will slowly shift eastward through the week, with the Atlantic high remaining in place. Locally, the high pressure in the Gulf will maintain persistent offshore flow through the period. The east coast sea breeze is forecast to form each day, turning the winds onshore along the coast. Moisture will increase across the area this week, with forecast PW values ranging from 1.7-2.3". This will allow a return of dirunally-driven showers and lightning storms each day through the time period. Rain chances will become near normal for this time of year, with PoPs ranging between 40-60 percent each afternoon, with the sea breeze collision favoring the eastern side of the peninsula each day. Showers and storms will push offshore in the dominate westerly flow. Storms will be capable of producing frequent lightning, gusty winds of 40-50 mph, and locally heavy rainfall. Any lingering activity will push offshore or dissipate into each evening.

Hot and humid conditions will persist through at least Wednesday, with temperatures forecast to trend slightly downwards late week and into the weekend due to the higher rain chances. Additional Heat Advisories for portions of ECFL may be needed, especially through mid week. Overnight lows will be seasonable to slightly above normal each night.

MARINE

Issued at 241 PM EDT Mon Aug 17 2026

Today-Friday... Generally favorable boating conditions through the week. The Atlantic ridge axis will slowly shift south of the local Atlantic waters today and is forecast to remain south through this week. Moisture will increase over the local waters ahead of an approaching frontal boundary as it stalls and washes out across north Florida. Rain and storm chances will increase starting today north of Cape Canaveral, expanding to include all the waters from Tuesday onward. Storm movement will be offshore through the period in the dominate westerly flow. Storms will be capable of producing frequent lightning strikes, wind gusts in excess of 30 KT, heavy downpours, and locally higher seas. Outside of storms, winds will be west to southwest at 5-10 KT through the week, becoming onshore (south to southeast) each afternoon as the east coast sea breeze forms and pushes onshore. Seas 1-2 ft, with occasional 3 ft seas across the offshore waters.

AVIATION

(18Z TAFs) Issued at 150 PM EDT Mon Aug 17 2026

VFR outside of convection. Scattered storms are beginning to approach from the west-northwest this afternoon, and a short TSRA TEMPO (18Z-19Z) is ongoing at LEE. Otherwise, a PROB30 has been included at DAB (21Z-24Z) with VCTS mentioned at terminals further southward through ISM/MLB. The east coast sea breeze is struggling to develop along the immediate coast, but should still shift winds east-southeast at most coastal terminals this afternoon. A sea breeze shift is not currently forecast at inland terminals. Any convection should move eastward through the late afternoon and evening with a few showers or storms lingering along the coast from MLB northward through 01Z/02Z.

CLIMATE

Issued at 240 AM EDT Mon Aug 17 2026

Record high temperatures at local climate sites today:

Site Aug 17 Daytona 96 (1990) Leesburg 98 (2005) Sanford 97 (2005) Orlando 99 (1929) Melbourne 97 (2022) Vero Beach 98 (2022) Fort Pierce 97 (2022)

PRELIMINARY POINT TEMPS/POPS

DAB 78 94 78 94 / 20 60 30 60 MCO 78 97 79 95 / 10 60 30 60 MLB 79 96 78 94 / 10 50 20 60 VRB 76 95 76 94 / 10 40 20 60 LEE 79 95 79 94 / 10 50 30 60 SFB 79 95 79 94 / 10 60 30 60 ORL 80 96 80 95 / 10 60 30 60 FPR 77 95 76 93 / 10 40 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.