Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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164 FXUS62 KMLB 181443 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 1043 AM EDT Wed Sep 18 2024 ...New UPDATE... .UPDATE... Issued at 1040 AM EDT Wed Sep 18 2024 We are off to a quiet start this morning with temperatures climbing into the mid 80s under mostly clear conditions. Not a whole lot has changed in this update from the early morning forecast. A slightly more dominant west coast sea breeze today will help fuel shower and lightning storm development this afternoon. Storm motions will be generally from west to east as a result. By the time some of this activity reaches the coast early in the evening, a collision with the east coast sea breeze will provide another focus for lightning storms through midnight. The strongest activity will be capable of gusty winds around 50 mph, frequent lightning strikes, and locally heavy rainfall. Hi-res guidance today compared to yesterday indicates lower bulk shear values, though storm-scale boundary collisions along a locally backed coastal breeze this afternoon/evening could allow a couple of storms to weakly rotate. Outside of the storm potential later on, temperatures are still forecast to push into the low 90s for most, pushing heat indices into the 100-105 degree range. Also, a high risk for life- threatening rip currents remains at area beaches. && .PREVIOUS DISCUSSION... Issued at 422 AM EDT Wed Sep 18 2024 Key Messages: - Scattered showers and storms increase in coverage along the coast late this afternoon and into the evening. - A high risk of rip currents continues at all area beaches. - High astronomical tides promote elevated water levels this week, a Coastal Flood Advisory continues. Current-Tonight... Quiet and calm early this morning under mostly clear skies. Clear skies are expected to continue into late morning, initiating early surface heating. GOES-16 precipitable water analysis indicates a modest moisture column (~ 1.6-1.8") while surface dew points are observed in the mid 70s. Scattered showers and storms are forecast across much of the area into the afternoon as the east coast sea breeze develops and mesoscale boundary collisions occur. CAMs key in on the greatest coverage (~60%) occurring in vicinity of the I-95 corridor late in the afternoon and into the evening as storms push back towards the coast. Coverage then dissipates or moves offshore into the late evening. Model soundings indicate drier air above 700mb, and DCAPE values of 1,000-1,200 J/Kg suggest the potential for localized wind gusts of 40-50 mph where an updraft can sustain itself and dry air mixing can occur. Otherwise, storm hazards include occasional to frequent lightning strikes and locally heavy rainfall. High temperatures are forecast to range the low 90s with peak heat index values between 100-105. A high risk of life threatening rip currents continues at area beaches today. This evening`s high tide cycle is forecast near minor flood stage and the Coastal Flood Advisory continues. Thursday-Friday... Mid level troughing and associated vorticity pulses slide southeastward across the state. A weak surface boundary settles near the Florida Straits on Friday. Diurnal showers and storms are forecast, and a gradient of dry air will keep the highest coverage across the south each day (~60%). Continued dry air advection will cut down PoPs along and north of the I-4 corridor on Friday (~20-30%). Westerly steering flow continues on Thursday, becoming light and variable into late week. Primary storm hazards include occasional to frequent lightning strikes, wind gusts of 40-50 mph, and locally heavy rainfall. High temperatures range the upper 80s to lower 90s each afternoon. Minor coastal flooding concerns are expected to continue, focused around each high tide cycle. Saturday-Tuesday... Ridging across the central U.S. flattens as a 500mb cutoff low progresses eastward. Troughing along the eastern U.S. coast is nudged further seaward. High pressure builds at the surface and northeast flow develops locally. A moisture boundary remains in place across the Florida Straits with dry air situated to its north. Onshore flow should provide enough low level moisture to support isolated to scattered showers each afternoon. High temperatures are forecast to range the upper 80s. && .MARINE... Issued at 422 AM EDT Wed Sep 18 2024 Today-Tonight...Favorable boating conditions return as seas subside to 3-4 ft. Light and variable winds become onshore near the coast as the east coast seabreeze develops. Coverage of offshore moving lightning storms increases late this afternoon and into the evening (40-60%). Thursday-Sunday...Seas of 3-4 ft continue. A weak pressure gradient will continue to promote light and variable winds on Thursday. Winds become northeast Friday and into the weekend as a surface boundary moves south of the local waters. Showers and storms decrease in coverage by the weekend. && .AVIATION... (12Z TAFs) Issued at 725 AM EDT Wed Sep 18 2024 VFR conditions prevailing outside of convection. Westerly winds this morning will veer onshore with the development of the east coast sea breeze around 16-18Z. The sea breeze will then push inland this afternoon, reaching MCO/ISM by late afternoon. The sea breeze is not currently forecast to make it to LEE. Scattered to numerous showers and storms are expected today, mainly after 20Z. TEMPOs have been included for all sites except LEE, with storms forecast to linger along the coast through around 01Z. Lightning strikes, gusty winds to around 45 kts, and locally heavy rainfall will be possible. Convection will diminish after sunset, as will winds. Light and variable flow overnight. && .HYDROLOGY... Issued at 422 AM EDT Wed Sep 18 2024 The Saint Johns River at Astor is forecast to remain in Moderate Flood stage through the weekend and into early next week. The potential exists for small additional rises if locally heavy rainfall develops over the river basin. Farther upstream, a slow and steady rise of the Saint Johns at Deland, Sanford, and Geneva is expected to continue, so interests along the river should monitor for future forecast updates. && .PRELIMINARY POINT TEMPS/POPS... DAB 91 73 90 73 / 60 50 40 10 MCO 92 74 91 73 / 40 30 50 20 MLB 90 73 89 74 / 50 60 50 50 VRB 91 73 90 72 / 50 60 60 50 LEE 91 74 90 73 / 30 20 40 10 SFB 91 73 91 73 / 50 30 50 10 ORL 92 75 92 75 / 40 30 50 20 FPR 91 73 90 72 / 50 50 60 50 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 2 PM EDT Friday for FLZ141-154-159- 164-347-447-647-747. AM...None. && $$ UPDATE...Schaper AVIATION...Leahy