Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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376 FXUS62 KMLB 201126 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 726 AM EDT Fri Sep 20 2024 ...New AVIATION... .AVIATION... (12Z TAFs) Issued at 629 AM EDT Fri Sep 20 2024 Patchy fog this morning affecting LEE and OBE. Expect reductions to clear through around 13Z. Then, VFR conditions prevailing. Scattered showers and storms this afternoon, mainly along and inland from the Treasure Coast. VCSH developing around 20Z from MCO southward, with VCTS possible at FPR and SUA. Convection will move inland through the afternoon, clearing around sunset. Then, models suggest showers along the coast overnight (after around 5Z), pushing onshore due to NNE/NE flow. Winds around 10kts or less through the period. && .PREVIOUS DISCUSSION... Issued at 227 AM EDT Fri Sep 20 2024 KEY MESSAGES: - The best chance (30-50%) for a few lightning storms today resides closer to the Treasure Coast. This weekend, 30-40% shower/storm chances continue. - Minor coastal flooding remains possible, particularly during the late morning high tides through the upcoming weekend. Low- lying streets, yards, and docks along the barrier islands and Intracoastal may experience minor flooding. - There is a medium chance (40%) for tropical development in the northwest Caribbean or southern Gulf of Mexico next week. It is too early to determine what, if any, impacts this would bring to East Central Florida. Continue to monitor the forecast for updates. ----------Synoptic Overview---------- This morning, a weak trough extends down the U.S. East Coast. To the west, upper high pressure resides over Texas, out ahead of deep low pressure over California. Florida will remain influenced by the trough through Saturday before the upper high migrates eastward early next week. By Tuesday or Wednesday, ensemble guidance suggests ridging will become anchored near Florida as a trough pushes across the Upper Mississippi River Valley. At the surface, weak high pressure will slowly settle across the Appalachians through this weekend. Northeasterly boundary layer flow will result, and moisture values will remain near to somewhat below normal for mid/late September. The Central American Gyre is still forecast to become active over the NW Caribbean by early next week. A propensity of ensemble members eventually develops negative pressure anomalies near the Yucatan Channel. There is a medium chance of eventual tropical development from this feature. However, it`s too early to determine whether impacts will occur locally. -------Sensible Weather & Impacts------- Today & Tonight... We should start our day off fairly quietly. Some patchy fog is possible around dawn. Boundary-layer flow turns onshore today, with a few gusts to around 20 mph especially north of Cape Canaveral. Weak cyclonic flow and associated vorticity remain overhead, but moisture is limited above H7. This supports only 20-30% shower/storm chances near I-4 and the Space Coast and 40-50% chances for the Treasure Coast. Any stronger storms would have the potential to produce occasional lightning strikes, gusty winds 40-45 mph, and brief torrential rain which could cause minor flooding. Highs should reach the upper 80s to around 90F. Later tonight, a few showers may try to skirt the coast in the increasing NE flow. Lows 70-77F, warmest beachside. Minor coastal flooding is anticipated at high tide today, with water levels likely at their peak between 8 AM and noon. This Weekend... Northeast surface flow becomes well-established across the Sunshine State as high pressure nestles over the Appalachians. Ripples of moisture in the boundary layer, and lingering mid-level vorticity, lend to broad 30-40% chances for showers and a few storms. Some of this activity will extend into the overnight hours, particularly along the coast. It will be breezy at times, with a few gusts up to 20 mph each day. Highs will again range from the upper 80s to the low 90s, with lows in the low/mid 70s. A minor coastal flooding threat persists during high tide cycles through at least Sunday. The highest water levels are forecast in the late morning hours with a lesser peak in the late evening. Beach-goers should be mindful that surf will be slowly building and the rip current risk will be at least moderate, and potentially even high! Monday-Wednesday... Ensembles strongly indicate that upper ridging becomes entrenched over Florida. With increased subsidence and a further diminution of available moisture, rain/storm coverage still looks below normal for late September. At the surface, east winds will remain breezy at times, which could push a few low-topped showers onshore. We are currently carrying 10-30% measurable rain chances each day, except 20-40% for the Treasure Coast. Steady-state temperature trends are in order, with each day ranging from the upper 80s to the low 90s. Later Next Week... All eyes remain on the extended forecast as most ensemble members and their respective means congeal deep tropical moisture and lower surface pressures over the NW Caribbean or southern Gulf of Mexico. Unfortunately, that`s about where the agreement stops. The National Hurricane Center still highlights a 40% chance of tropical development with this disturbance. At this time, however, there is currently no well-defined system for models to track. Furthermore, the mid-latitude longwave pattern will be in the process of realignment. A weak trough is expected to push into the Midwest as ridging builds over the West ahead of an enhanced Pacific jet. There is a significant spread in the depth and timing of the Midwestern trough and its embedded vort maxima. All told, one should not expect a lot of clarity on this setup for 2-3 more days at least. It`s still way too early to determine whether any local impacts from this potential disturbance will occur. For now, we are showing a gradual uptick in shower/storm chances late next week. Keep checking weather.gov/mlb for updates over the next few days. && .MARINE... Issued at 227 AM EDT Fri Sep 20 2024 Boating conditions slowly become poorer over the next few days as onshore winds increase. As high pressure settles into the Appalachians, northeast winds freshen to 8-13 KT today through the weekend. There is a low to medium chance for showers and a few storms, though offshore-moving storms look less likely. By early next week, winds turn more easterly at 10-15 KT. Seas 2-4 FT through Saturday before building to 3-5 FT Sunday-Tuesday, largely driven by a northeast swell at 9-11 sec. && .PRELIMINARY POINT TEMPS/POPS... DAB 88 74 87 75 / 20 20 40 20 MCO 90 74 90 73 / 30 10 40 0 MLB 88 75 88 76 / 30 20 40 20 VRB 88 73 89 74 / 40 20 40 20 LEE 90 73 90 73 / 20 0 30 0 SFB 89 73 88 73 / 30 10 40 10 ORL 90 74 90 75 / 30 10 40 0 FPR 88 73 88 73 / 40 20 40 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 2 PM EDT Sunday for FLZ141-154-159- 164-347-447-647-747. AM...None. && $$ DISCUSSION...Heil AVIATION...Leahy