Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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327 FXUS62 KMLB 250916 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 516 AM EDT Wed Sep 25 2024 .DISCUSSION... Issued at 455 AM EDT Wed Sep 25 2024 Key Messages: -Tropical Cyclone Helene will lift north into the eastern Gulf of Mexico next 48 hours and produce heavy rain, strong winds and possible tornadoes. Rough, battering surf will produce dangerous conditions at the beaches. -Hot and humid late week behind "Helene" as plume of deep moisture returns and keeps a threat for heavy rain this weekend. Today...Considerable high cloudiness spiraling anticyclonically outward from TC Helene will continue to spread north across cent FL. "Helene" is currently located in the far NW Caribbean near the Yucatan channel early this morning. As "Helene" continues to intensify and begins to lift northward into the eastern Gulf later today, the SE pressure gradient across our area will tighten and produce a balmy, breezy day. Meanwhile, deep moisture is surging northward which will support a higher coverage of showers and storms with banding setting up near the east coast and spreading inland. These bands will not be directly connected to Helene yet but may be described as detached outer rainbands. Locally heavy rain will accompany these bands and training of cells is possible which would create a localized flood threat, esp where recent heavy rains have occurred. For this evening and tonight, low level shear/helicity will begin to increase and present a TC tornado threat within rainbands but decreasing instability with loss of heating calls into question the coverage and intensity of convection after sunset. Thu...As "Helene" lifts N/NE across the eastern Gulf of Mexico and makes its closest approach to EC FL, the tornado threat will increase as STP parameter maximizes (greater than 1) during the aftn/eve. So a tornado watch is a possibility for at least parts of central FL. The large envelope of winds esp on the east side of this system will produce frequent gusts to tropical storm force (39mph+) esp in passing rainbands. With 925 mb winds around 50 knots, wind gusts up to 60 mph will be possible. Fri-Tue...Models show a dry slot moving into the area from the SW on the backside of "Helene" as it lifts northward into GA then the TN Valley Thu night/early Fri. But a plume of deep moisture will remain across south FL and return northward over central FL late Fri into the weekend. Hot, breezy SW flow on Fri-Sat will produce max temps in the lower 90s even at the coast. Combined with high humidity, peak heat indices will climb to 104-108. Storm coverage looks higher on Sat when the deep moisture is squarely over the area so have drawn 60 PoP areawide. Then decreasing rain chances Sun (50 percent) and Mon/Tue (40 percent). && .MARINE... Issued at 455 AM EDT Wed Sep 25 2024 Tropical Storm Warnings are in effect for the adjacent Atlantic waters out to 60 nm. Tropical Storm Helene is forecast to continue to strengthen over the northwest Caribbean, moving north into the eastern Gulf of Mexico later today and accelerate into the FL Big Bend late Thursday. Boating conditions are deteriorating today as southeast winds increase 20 kts, then strengthening 30-40kts during Thu. Seas building 7-10 ft peaking at 13 ft offshore Volusia and Brevard Thu aftn/night. Deep moisture lifting northward will support a high coverage of showers and storms thru Thu. Winds will become SW Fri and gradually decrease near 15 knots Fri night with seas subsiding below 5 ft along the coast due to the offshore component but remaining 6-7 ft offshore. Flow remains offshore (W to SW) Sat-Sun up to 15 knots with seas subsiding 3-4 Sat and 2-3 ft Sun. There will be scattered to numerous storms pushing offshore esp Sat. && .AVIATION... (06Z TAFs) Issued at 113 AM EDT Wed Sep 25 2024 MCO IMPACTS: - Gusty crosswinds for N/S ops (ESE G20-25 KT) beginning ~ 25/15Z. - 60% chance of showers/storms after 25/18Z with occasional IFR/MVFR restrictions. - Helene to bring significant aviation impacts just beyond the TAF period (mainly Thursday). Deteriorating conditions through the TAF period due to TS Helene`s approach. For MCO and Orlando area, shower/storm chances ramp up in the afternoon hours and continue well beyond this TAF package. From MLB south to SUA, showers increase overnight and continue into the morning with TS potential increasing after around 14Z. TIX/DAB will see increasing RA/TS after 18Z. East winds 5-15 KT through daybreak, then ESE 10-20 KT G20-25 KT from late morning onward. VFR, except in/near showers and storms where dips to MVFR/IFR expected. For planning purposes: winds will continue to strengthen into Thursday as Helene moves through the NE Gulf, along with periods of rain/storms. && .PRELIMINARY POINT TEMPS/POPS... DAB 89 77 89 78 / 50 70 90 60 MCO 90 77 89 79 / 60 70 90 60 MLB 88 79 90 79 / 60 70 80 70 VRB 88 78 91 78 / 70 70 80 70 LEE 90 77 87 78 / 60 70 90 60 SFB 89 77 88 79 / 60 70 90 60 ORL 90 78 89 80 / 60 70 90 60 FPR 88 78 90 78 / 60 70 70 70 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Tropical Storm Warning for FLZ041-044>046-053-058-141-144-154- 159-164-247-254-259-264-347-447-547-647-747. AM...Tropical Storm Warning for AMZ550-552-555-570-572-575. && $$ DISCUSSION...Kelly AVIATION...Heil