Scientific Forecaster Discussion
000 FXUS62 KMLB 181941 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 341 PM EDT Fri Aug 18 2017 .DISCUSSION... Current-tonight...Pending boundary collisions to occur over the next 2H will dictate PoP coverage for the rest of the afternoon as upr drying has limited convective development over much of the area so far this aftn. The evening forecast features a chc of storms inland with isolated coverage at the coastal counties through around 10 PM. The potential remains for some gusty winds and locally heavy rain through dusk should some stronger storms develop with collisions. Sat-Sun...Upper low downstream of the FL peninsula over Yucatan channel wl continue slowly west. Overall moisture values remain temporarily on the low side area wide and PoP guidance/forecast is reduced below climo Sat. Temps will run a few degrees above climo with afternoon heat indices approaching 105 to 107. From Prev disc... Slug of deep, tropical moisture advects from SE to NW across CWA to east of trough axis late Sat night and into Sun. With deep SE flow of moist conditions (PW 2.00-2.25 inches), coverage of showers with embedded storms will increase over the Atlantic late Sat with scattered activity working onshore, especially SE coast, with some isolated nocturnal showers possible even far inland. High coverage of showers/storms expected Sun areawide, with best chance over central/south CWA (50-60 POP). Mon-Thu...Ridge axis re-establishes north of CWA next week, resulting in long fetch of onshore flow across central FL. Moisture levels lessen early in the week as inverted trough exits west, causing diurnal storm coverage to return to climo values (generally 30-40 POPs, possibly a little higher near Lake Okeechobee and southern Treasure Coast). Global models continue to display run-to-run inconsistency with handling of next tropical disturbance. With unfavorable conditions for significant development, best course of action at this point is to show increase of shower/storm coverage Wed/Thu as swath of higher PW reaches area in association with inverted trough. Max temps near to slightly above normal, with mins at least several degrees above climo, with some coastal locations remaining near 80 for mins given onshore flow across warm waters. && .AVIATION... VFR outside of showers/thunderstorms. Another afternoon and evening of scattered to numerous showers and thunderstorms with the highest chances over the far interior, and TEMPO groups have been added for LEE, ISM, MCO, and SFB. For the coastal sites, most showers/storms that form along the east coast sea breeze should be to the west, but some storms could make it back to the coast late this afternoon and evening from DAB to VRB. Not confident enough for TEMPO groups as of right now. The majority of the activity should end over the interior around sunset and a few hours later for the coastal sites. && .MARINE... Tonight...Fairly quiet over the waters with wind wave of 1-2 ft near the coast and around 2-3 ft over the outer waters. Storm coverage will be very sparse at best. Sat-Sun...light SE winds increasing to 10-15 kt, especially across southern waters late Sat/early Sun as axis of inverted trough reaches south FL. Seas 2-3 ft, up to 4 ft in Gulf Stream. Scattered to locally numerous showers and storms moving onshore, especially southernmost waters. Mon-Tue...Long SE fetch near 15 kt with seas building to 4-5 ft, except 3 ft over northern near-shore waters. Onshore flow becomes more easterly Tue and perhaps lessing a bit as ridge axis builds far to the north. Long fetch should allow seas to remain elevated at 4-6 feet across offshore waters and 3-4 ft closer to shore. Scattered onshore moving showers/storms. && .PRELIMINARY POINT TEMPS/POPS... DAB 76 92 75 89 / 20 20 30 40 MCO 75 97 77 93 / 30 20 20 50 MLB 77 93 77 88 / 20 20 30 60 VRB 74 92 76 89 / 20 20 40 60 LEE 77 96 77 95 / 30 30 20 50 SFB 76 96 77 93 / 30 20 20 50 ORL 77 97 78 93 / 30 20 20 50 FPR 74 93 76 89 / 20 20 40 60 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None.