Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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338 FXUS62 KMLB 172355 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 755 PM EDT Tue Sep 17 2024 ...New AVIATION... .AVIATION... (00Z TAFs) Issued at 746 PM EDT Tue Sep 17 2024 Extended VCTS through 03Z-04Z at KMLB-KSUA for TSRA/SHRA flaring up on outflow boundaries near the stalled frontal boundary west of the terminals. Short-fused AMDs for +TSRA impacts possible as this activity shifts eastward and offshore, especially KVRB-KFPR. Overnight fog or stratus generally not expected, but there is a small chance for VIS reductions at KLEE between 09Z-14Z, though too low for mention in the TAFs. Typical diurnal seabreeze pattern and near normal afternoon SHRA/TSRA chances expected again Wednesday. && .PREVIOUS DISCUSSION... Issued at 410 PM EDT Tue Sep 17 2024 - Marginal Risk for severe storms this afternoon and early this evening, from Orlando/Titusville southward - High astronomical tides promote elevated water levels this week, Coastal Flood Advisory continues - Saint Johns River at Astor forecast to remain in Moderate Flood Now-Tonight...A stream of mid level cloud cover has shifted slightly north this afternoon to encompass areas near and south of Cape Canaveral. Farther north along and west of Interstate 95, the east coast sea breeze is weakly visible on satellite and radar, slowly moving inland. Temperatures are climbing into the mid and upper 80s with a spot or two closing in on the 90 degree mark. GOES- derived PW, RAP analysis, and the 15z XMR sounding all depict some drier air entering the mix, especially from 600mb on up. ML LI is around -6 to -7 with nearly all inhibition depleted and MLCAPE on the order of 1500-2500 J/kg. Low level lapse rates should continue to gradually steepen as the surface layer warms this afternoon, though preceding cloud cover across the south could have somewhat of an impact on the magnitude of this occurring. Also, modest mid level lapse rates may temper storm strength a bit more than previously forecast. Nonetheless, CAMs still suggest shower and lightning storm development will begin in the next 1 to 3 hours. Outflow from the initial activity and the east coast breeze will aid in additional development farther north and west through late afternoon and early evening, particularly from Sanford/Titusville southward where greater moisture availability is focused. Stronger updrafts, coupled with 25 kt of bulk shear, drier mid level air, and DCAPE around 1000+ J/kg, have the potential to produce strong to damaging wind gusts. These occurrences should remain isolated in nature, hence the Marginal Risk (1 out of 5 risk) for severe storms from the Storm Prediction Center. Activity is forecast to gradually diminish through midnight, while also drifting toward the Atlantic coast. Temperatures are expected to settle into the 70s later tonight, especially north of the Treasure Coast where additional clearing is forecast. Wednesday-Thursday...Surface winds remain light through the middle part of the week, with some form of a westerly directional component. Shower and storm chances remain similar each afternoon (40-55 PoP) with a general focus on the southern half of the area, where there is greater moisture to work with. Mid level troughing will allow weak impulses of energy to swing across the state, aiding somewhat in daytime convective development. Gusty winds, lightning strikes, and brief heavy downpours are the main threats that will accompany any storms. High temperatures are forecast to remain in the low 90s each day with overnight lows ranging through the 70s. Minor coastal flooding concerns are expected to continue, focused around each high tide cycle. Friday-Monday...Mid level ridging builds east from the western Gulf this weekend, allowing onshore surface winds to resume. A surface front is expected to settle across the Florida Straits, focusing the greatest moisture south of the forecast area. Still, PoPs around 25- 35 percent were maintained to account for sea breeze driven isolated/scattered diurnal convection. Highs will stay in the upper 80s to low 90s with overnight temps in the 70s to near 80 degrees at the coast. && .MARINE... Issued at 410 PM EDT Tue Sep 17 2024 Now-Tonight...Improving boating conditions are expected with seas decreasing to around 3-5 ft late tonight. Winds remain light, becoming offshore overnight around 5 kt. Isolated showers and lightning storms are possible, capable of producing gusty winds and locally higher seas. Wednesday-Saturday...Light offshore flow becomes onshore behind the east coast breeze each afternoon through Thursday, before more persistent ENE wind resumes Friday into next weekend. Seas are forecast to be favorable for boating, around 2-4 ft. Daily rain and lightning storm chances will continue, especially Wed-Thu. && .PRELIMINARY POINT TEMPS/POPS... DAB 73 91 73 89 / 10 40 30 30 MCO 75 92 74 91 / 20 50 20 50 MLB 75 90 75 89 / 30 50 50 50 VRB 73 91 74 90 / 30 50 40 60 LEE 74 91 74 90 / 10 40 10 40 SFB 73 91 73 90 / 20 50 20 50 ORL 75 92 75 91 / 20 50 20 50 FPR 73 91 74 90 / 30 50 40 60 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 2 PM EDT Thursday for FLZ141-154- 159-164-347-447-647-747. AM...None. && $$ DISCUSSION...Schaper AVIATION...Haley