Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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682 FXUS62 KMLB 121028 CCA AFDMLB Area Forecast Discussion...CORRECTED National Weather Service Melbourne FL 628 AM EDT Wed Jun 12 2024 ...New DISCUSSION, MARINE... .DISCUSSION... Issued at 502 AM EDT Wed Jun 12 2024 - Repeated rounds of heavy rainfall are forecast to continue across Florida, regardless of development of Invest 90. - There is a risk for parts of east central Florida to receive substantial rainfall this afternoon, potentially over 7", which could lead to minor to moderate flooding. Today-Tonight...NHC continues to monitor Invest 90L, which has moved onshore over Tampa Bay early this morning and is forecast to track slowly northeastward through the day, emerging into the Atlantic waters between the Cape and Jacksonville tonight into early Thursday morning. There is only a 10 pct chance of tropical development over the next 48-hours. Regardless of development of this feature, heavy rainfall will continue to be the primary hazard. Deep tropical moisture with PWATs over 2" continues to stream across the peninsula between the stationary front to the north and the Atlantic high suppressed well to the south. We`ll continue to see rounds of scattered to numerous showers and scattered lightning storms through the day and night, with the highest coverage around peak daytime heating in the afternoon and evening. Heavier showers and storms will be capable of delivering a quick 1-2" of rainfall in an hour, leading to widespread rainfall amounts of 1-3" and locally higher amounts over 4". CAMS, especially the HRRR, have been indicating potential for banding of heavy showers along the southern to southeast periphery of Invest 90L with rainfall amounts in excess of 7", which could lead to minor to moderate flooding of low- lying, poor drainage, and urban areas. Location, timing, and intensity of these bands has been inconsistent between models and runs, and thus there`s currently low confidence where or if it will materialize. General model consensus puts the highest potential across the Okeechobee and the Treasure Coast counties (and to the south). Development of the east coast sea breeze, which will be dependent on breaks in the clouds and showers in the afternoon, would greatly increase the risk of these higher rainfall amounts along the Treasure Coast. As for the rest of the forecast, storms remain capable of occasional cloud to ground lightning and gusty winds in addition to the locally heavy rainfall. Afternoon highs mostly at or below normal, albeit muggy, and the M-U80s. A few spots well to the north could touch 90. Thursday-Saturday...Finally seeing some better model agreement late week into the beginning of the weekend. Invest 90L, in whatever form it ends up at this point, should be well northeast of east central Florida and continuing to pull away. In it`s wake, the stationary front drops south across central Florida, keeping the deep tropical moisture in place across much of the peninsula and providing a focus for continued high rain chances. Daily PoPs remain 70-90 pct area wide through at least Friday. Currently have 50-80 pct PoPs Saturday, pulled down by uncertainty as the ECM and the GFS begin to diverge again. Global deterministic and ensemble model guidance keeps widespread rainfall amounts through Sunday morning similar to previous forecasts at 5-7" to the south and 2-4" to the north. Going to stick with these values for now given the low confidence of those higher rainfall amount from Invest 90L. Other storm threats continue to be occasional cloud to ground lightning and gusty winds. Afternoon highs remain mostly at at or below normal in the M-U80s, but will likely see a few more northern spots hitting 90. Sunday-Tuesday...Should finally start to see a change in the pattern, but there continues to be uncertainty in timing. High pressure over the CONUS building into the western Atlantic and over Florida should eventually push the front to our south, and the higher moisture to the south and east. The ECM is faster and a little more aggressive, lowering rain chances as early as Sunday, while the GFS is slower and a little more conservative, keeping higher rain chances in the forecast until Tuesday. Either way, there appears to be enough moisture in moderate onshore flow to continue near normal rain chances into mid next week. Temperatures start to creep back up but still around normal in the U80s-L90s. && .MARINE... Issued at 502 AM EDT Wed Jun 12 2024 Today-Tonight...A stationary front remains draped across North Florida, just north of the local Atlantic waters, with the ridge of the Atlantic high suppressed well to the south. A weak low pressure system (Invest 90L) will track slowly northeastward from the Tampa Bay area across the peninsula, emerging off the east coast between the Cape and Jacksonville late tonight to early Thursday morning. Somewhat low confidence in the wind forecast as weakening of the invest would reduce winds while development would result in an increase. Assuming weakening, which is the most likely scenario, S-SSW 15-20 kts south of the Cape should retreat to the offshore waters this morning, where small craft should continue to exercise caution, with winds generally at or becoming 10-15 kts across the rest of the waters. Winds could become light and shift across the Volusia waters late tonight. Rounds of SCT- NUM showers and SCT lightning storms continue, which could develop bands across the local Atlantic waters, especially the Treasure Coast waters. Seas 2-4 ft. Thursday-Sunday...Invest 90L in some form departs to the northeast, dropping the stationary front south across the waters in its wake. Winds generally S-SW 5-10 kts become variable at times through Saturday, then high pressure building off the Mid- Atlantic seaboard pushes the front south and shifts winds back to easterly. Seas 1-3 ft. High moisture and the frontal boundary will continue high rain and storm chances. && .AVIATION... (06Z TAFs) Issued at 141 AM EDT Wed Jun 12 2024 Light precip south of KMCO early this morning, but will watch heavy convective band east of KTBW if it can make it towards KISM, KMCO. Otherwise, models suggest re-development near KMLB southward and will monitor if this occurs ahead of sunrise. Also, have to contend with CIG reductions to 010-020 thru the early daylight hours. May have some improvement to CIGs later this morning, but confidence is low here with present messy wx pattern. The high coverage of showers (embedded thunder - esp this aftn) continues today. Have included TEMPOs throughout the day for higher convective coverage. MVFR CIGs look to return after sunset this evening. && .PRELIMINARY POINT TEMPS/POPS... DAB 88 73 89 73 / 70 60 80 50 MCO 87 74 86 74 / 80 60 80 60 MLB 87 74 86 73 / 80 70 80 70 VRB 87 74 87 73 / 80 80 80 70 LEE 89 76 89 75 / 80 60 80 50 SFB 89 75 89 74 / 80 60 80 50 ORL 88 75 88 75 / 80 60 80 50 FPR 87 73 86 72 / 80 80 80 70 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ DISCUSSION...Haley AVIATION...Sedlock