textproduct: Melbourne

KEY MESSAGES

Issued at 200 PM EDT Thu Jun 18 2026

- Very hot and humid conditions continue into the weekend and next week. A Heat Advisory remains in effect until 7 PM this evening. Residents and visitors should remain well-hydrated and stay cool in the shade or air conditioning each day.

- Rain and storm chances increase into the weekend, bringing the potential of a few strong to severe storms and locally heavy rainfall. Minor flooding is possible in urban and low-lying areas.

- A moderate risk for rip currents continues at area beaches. Remember to swim near a lifeguard and to never enter the water alone!

DISCUSSION

Issued at 215 PM EDT Thu Jun 18 2026

Now-Tonight...Heat index values were already climbing into the upper 90s and higher at lunchtime. We are well on the way to heat indices peaking near 105-110 degrees this afternoon, thanks to south- southwesterly flow and a delayed east coast sea breeze. A Heat Advisory is in effect until 7 PM this evening, highlighting the increased risk for heat-related illness. Stay well-hydrated and limit time spent outdoors, taking frequent breaks in the shade/air conditioning. Know the signs and symptoms of heat exhaustion and heat stroke.

Higher convective temperatures and a lack of forcing early in the afternoon will delay the onset of showers and storms until late afternoon. CAMs vary a bit in overall convective coverage/evolution, but there is general agreement with storms peaking between 5-10 PM along the sea breeze collision. 12z HRRR (and previous runs) have shown a slightly more organized east coast breeze, pushing near/west of I-95, whereas other guidance has suggested a more diffuse east coast breeze. Southwesterly steering flow will tend to push any convection across the peninsula in our direction through early-mid evening, dissipating by midnight and pushing offshore. Steep low-level lapse rates and plenty of DCAPE suggest that a couple storms could become strong, capable of gusty to locally damaging winds and frequent lightning. With sea breeze and outflow boundary collisions expected, a brief funnel cloud or tornado cannot be ruled out. At the 130 PM update, SPC included the Orlando metro, Daytona Beach, and coast from Melbourne northward in a Marginal Risk for severe storms. Torrential downpours are also likely with any storm, which may lead to ponding of water on roads and in low-lying areas.

Friday-Saturday...The stretch of heat continues into the weekend, even as increased afternoon storm chances try to provide some relief. Remnants of what was Tropical Storm Arthur will push toward the Carolina coast on Friday. Models show the associated H5 vorticity reflection extending southward into northeast Florida Friday afternoon as a surface front briefly stalls over the southeast U.S. Deep moisture (PW values 2.1"+) will be present, along with slightly stronger WSW surface flow. While an east coast sea breeze may develop, especially south of Cape Canaveral, it is likely to remain pinned very near the coast or just offshore. As a result, temperatures should have plenty of time to warm into the 90s by the early afternoon. Heat index values are once again forecast to reach the 102-107F range, with a number of locations eclipsing Heat Advisory criteria. Some question remains as to how quickly showers and storms will develop Friday afternoon. Earlier onset of convection could put a lid on the higher heat indices, but confidence in this is low right now. Plan on another very hot and humid day, staying hydrated and in air conditioning (or the shade) as much as possible.

Developing storms Friday afternoon will be primarily supported by the west coast sea breeze and previously mentioned (modest) upper level support. The modeled environment suggests scattered coverage of showers and lightning storms, capable of torrential rainfall, frequent lightning, and strong to damaging wind gusts. As a result, a Marginal Risk for severe storms exists from Brevard/Osceola counties northward Friday afternoon and evening. There is also a Marginal Risk for Excessive Rainfall, meaning that any one storm could produce high rain rates and/or locally heavy rain amounts that lead to minor flooding. Activity will largely shift offshore by midnight, followed by mostly dry conditions into early Saturday. Despite another hot day forecast on Saturday (heat indices 100- 107F), 12z models suggest high coverage (60-75%) of showers and storms by the afternoon/early evening. Exact timing is uncertain, but an earlier start to rain could bring some heat relief to parts of the area. A couple of strong to severe storms cannot be ruled out, but Saturday's environment looks increasingly favorable for heavy rain/flooding potential.

Sunday-Wednesday...In the extended forecast, rain chances trend down into next week as high pressure settles over the eastern Gulf and FL Peninsula. Weak mid level ridging also builds overhead through Tuesday, with greater divergence in models solutions beyond that point. Lower rain chances mean that temperatures trend higher again next week. Highs are forecast to reach the low/mid 90s Monday onward, combining with PW 1.8-2.0" to push heat index values above 102-105F. Medium confidence exists in a Major HeatRisk developing again next week, so keep this in mind for any plans to be outside. Practicing heat safety (adequate cooling and hydration) will be necessary in avoiding heat-related illness, especially as the hot days and warm nights persist.

MARINE

Issued at 200 PM EDT Thu Jun 18 2026

Generally favorable boating conditions persist through early next week, with the exception being increased rain and lightning storm chances Friday-Sunday. SSW winds 10-14 kt back to the SE each afternoon, though the sea breeze could struggle to develop this weekend in broad westerly flow. Scattered to numerous offshore- moving showers and storms are forecast in the late afternoon and evening hours, some of which could be strong to severe. Seas 1-3 ft, higher in the vicinity of storms. Weak high pressure builds back over the waters by Monday, supporting lower rain chances and light SW flow backing to the ESE in the afternoon.

AVIATION

(18Z TAFs) Issued at 130 PM EDT Thu Jun 18 2026

Showers and storms are developing across the western portion of the Florida peninsula, with activity gradually spreading eastward through this afternoon. VCTS expands areawide between 18-20Z, with TEMPOs at all interior terminals and from DAB to MLB along the coast for VIS and CIG reductions due to TSRA as well as variable and gusty winds. Timing of the TEMPOs range between 18-03Z, with the latest ones focused along the coast. Activity will move offshore late tonight, with mostly dry conditions through the overnight hours along with light southerly winds. Winds will pick up to around 10 knots out of the southwest after 13Z tomorrow.

PRELIMINARY POINT TEMPS/POPS

DAB 77 93 77 91 / 60 30 20 80 MCO 78 95 77 93 / 60 40 20 70 MLB 80 94 78 92 / 50 50 30 80 VRB 79 95 77 93 / 30 40 40 80 LEE 79 94 78 92 / 10 20 20 50 SFB 78 95 77 93 / 60 40 20 80 ORL 79 94 78 92 / 50 40 10 70 FPR 78 94 77 92 / 20 40 40 80

MLB WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory until 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.