Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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717 FXUS62 KMLB 241827 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 227 PM EDT Tue Sep 24 2024 ...New DISCUSSION, MARINE, HYDROLOGY... .DISCUSSION... Issued at 208 PM EDT Tue Sep 24 2024 Key Messages: ...Tropical Storm Helene will lift north into the eastern Gulf of Mexico this week and strengthen... ...Heavy rain and tropical storm-force winds are an increasing concern... ...A plume of deep moisture may remain behind and keep a threat for heavy rainfall into the weekend... Current-Tonight...Warm & humid conditions continue, with mainly dry conditions as a dry airmass is in place with stability limited (warm aloft). Any ISOLD precip confined to Okeechobee, St. Lucie, and Martin counties. Still less than a 10pct chance northward. Still carry a small PoP (20-30pct) this evening and overnight across the Treasure Coast and the adjacent local coastal waters as low-level winds increase creating friction, as well as deepest moisture here too. E/ESE winds 10-15 mph (15-20 mph along coast) with higher gusts diminishing to 5-10 mph over the interior this evening, remaining elevated 10-15 mph along the immediate coast. Overnight mins in the M-U70s, with around 80F at the immediate coast and barrier islands and conditions remaining muggy. .Previous Extended Forecast Discussion Modified... Wed-Mon...Model guidance remains consistent in forecasting Tropical Storm Helene in the NW Caribbean to lift north into the SE Gulf of Mexico while strengthening further into Wed-Thu. Confidence on size, intensity and forecast track continues to increase. This storm is forecast to have a large wind field once it matures, extending far to the east of the center while in the Gulf of Mexico. The GFS and ECMWF ensembles remain consistent showing a strengthening upper ridge over the SW Atlc and a developing cut-off low over MO/AR that steers this tropical cyclone north to north northeast up thru the eastern Gulf of Mexico and across the NE gulf coast later this week. While it remains too early to describe specific impacts for EC FL, heavy rainfall and tropical storm-force winds are becoming an increasing concern. A few tornadoes will also be possible in the rainbands. Models show a brief dry slot across the area Thu night/early Fri then a plume of deep moisture redevelops over the FL peninsula late Fri into the weekend long after the tropical system has departed. This would produce high rain chances and a continued threat for heavy rainfall, on ground that may be largely saturated. Offshore flow on Fri will produce hot temperatures in the lower 90s even at the coast with peak heat indices 104-108F. Continued hot and humid this weekend with deep moisture supporting scattered storms and heat indices 100-105F. Some drier air is forecast to move in Mon and lower rain chances. We are in peak hurricane season. Check weather.gov/mlb and hurricanes.gov for the latest updates, and take the time to check on your hurricane preparedness kits and plans. && .MARINE... Issued at 208 PM EDT Tue Sep 24 2024 Afternoon-Tonight...Moderate E/ESE flow near 15 knots will produce choppy seas of 3 to 4 feet with winds increasing 14-18 kts tonight. Will likely need a Caution headline tonight south of the Cape for winds increasing to 15-20 kts and seas building up to 6 ft. Lower coverage of showers into tonight (20-40pct southward from near Melbourne Beach and includes ISOLD lightning storm mention) as drier air filters down from the north. Seas building 4-5 ft near shore. Previous Extended Marine Forecast Discussion Modified... Wed-Sat...Tropical Storm Helene is forecast to continue to strengthen over the northwest Caribbean, moving north into the eastern Gulf of Mexico mid week. Boating conditions are forecast to deteriorate further Wed into Thu as southeast winds increase 20 kts Wed and 25-30 kts Wed overnight, strengthening further 30-35kts (potentially 40kts for some) during Thu with seas building 7-10 ft (peaking at 12 ft offshore Volusia and Brevard Thu aftn/night). At least Small Craft Advisories look likely by Wed aftn but it is possible Tropical Storm Watches and Warnings will become necessary for much of the Atlc coastal waters. Deep moisture lifting northward will support a high coverage of showers and storms beginning late Wed into Fri. Winds will become S/SW Fri and gradually decreasing into Fri night with seas subsiding below 5 ft along the coast due to the offshore component but remaining 6-7 ft offshore. Flow turns SW on Sat and decreases below 15 kts and this will allow seas to gradually fall below 5 ft offshore. && .HYDROLOGY... Issued at 208 PM EDT Tue Sep 24 2024 The Saint Johns River at Astor is forecast to remain in Moderate Flood Stage through at least Saturday before falling into Minor Flood Stage on Sunday. However, any additional heavy rainfall associated with Tropical Cyclone Helene later this week may halt the river`s decline and will have the potential to cause additional rises. && .AVIATION... (18Z TAFs) Issued at 154 PM EDT Tue Sep 24 2024 VFR prevails, remaining dry at the terminals today. East winds around 12 kts this afternoon with occasional gusts between 16-20 kts. Overnight winds between 6-12 kts. Have introduced VCSH at all terminals tomorrow by mid to late morning. Coverage of showers and gusty winds increase into the afternoon on Wednesday as the outer bands of Helene move across the Florida peninsula. && .PRELIMINARY POINT TEMPS/POPS... DAB 76 89 77 88 / 0 40 70 90 MCO 76 90 77 88 / 0 60 70 90 MLB 79 89 78 90 / 10 60 70 80 VRB 78 89 77 91 / 20 70 80 70 LEE 76 90 76 86 / 0 50 70 90 SFB 76 89 77 87 / 0 50 70 90 ORL 77 90 77 88 / 0 60 70 90 FPR 78 89 77 91 / 20 70 80 70 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Tropical Storm Watch for FLZ044>046-053-144. AM...None. && $$ DISCUSSION...Sedlock AVIATION...Law