Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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353 FXUS62 KJAX 161743 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 143 PM EDT Sun Jun 16 2024 ...New AVIATION... For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf .AVIATION... (18Z TAFS) Issued at 143 PM EDT Sun Jun 16 2024 Showers and thunderstorms currently developing along the inland moving Atlantic and Gulf coast sea breezes will converge upon the Interstate 75 corridor during the mid to late afternoon hours. Vicinity showers and thunderstorms are expected during the next few hours at VQQ, with higher chances for impacts at GNV after 20Z. We kept a TEMPO group for MVFR conditions and briefly gusty winds in the 20Z-00Z window at GNV. MVFR visibilities are expected to develop at VQQ overnight, with periods of IFR visibilities possible during the predawn hours. Periods of MVFR ceilings will be possible from the predawn through late morning hours on Monday at the SSI and SGJ coastal terminals, as showers developing over the adjacent near shore waters potentially move onshore towards sunrise. These MVFR ceilings may then periodically impact the Duval County terminals after 13Z. Confidence remains too low to indicate anything other than scattered ceilings at the regional terminals during the predawn and morning hours on Tuesday. Gusty east-northeasterly surface winds that will be sustained around 15 knots this afternoon, except around 10 knots at VQQ and GNV, will persist in the 10-15 knot range overnight through the early morning hours at the coastal terminals, while speeds inland fall to around 5 knots or less after 04Z. Gusty easterly surface winds will then redevelop before 15Z Monday. && .UPDATE... Issued at 1119 AM EDT Sun Jun 16 2024 Late morning surface analysis depicts strengthening high pressure (1027 millibars) centered over New England, with a decaying frontal boundary wedging southward through the Carolinas and the southern Appalachians. Aloft...stout ridging prevails over the southeastern states, with the feature steering shortwave energy around its western periphery from the southern Plains states northeastward to the Great Lakes region. Latest GOES-East derived Total Precipitable Water imagery indicates that a drier than average air mass remains over most of our region, except for locations near the Suwannee River, where values were around 1.8 inches, which is closer to climatology. PWAT values elsewhere were generally in the 1.3 - 1.5 inch range, with higher PWATS just north of our region near the decaying frontal boundary. Our local pressure gradient is beginning to tighten as high pressure wedges down the southeastern seaboard, with breezy onshore winds taking shape at area beaches late this morning. Southeasterly low level flow has shaped a healthy cumulus field across our area, and temperatures at 15Z were already in the upper 80s and lower 90s across our area, with dewpoints mostly in the 70s. Breezy easterly winds will overspread inland locations as the afternoon progresses, with onshore winds increasing to the 15-20 mph range with occasional gusts up to 30 mph by late this afternoon and early this evening along the Atlantic coast. The strengthening surface ridge along the New England coast will generally advect a dry and subsident air mass onshore, with the Atlantic sea breeze progressing well inland towards the I-75 corridor by the late afternoon hours. This boundary will encounter higher PWAT values located along and west of the Suwannee River, with scattered to numerous showers and thunderstorms expected to erupt by late afternoon for locations along and west of I-75 in the Suwannee Valley and north central FL. In advance of the approaching Atlantic sea breeze boundary, highs will soar to the mid and possibly upper 90s across the Suwannee Valley and inland southeast GA, where dewpoints will crash through the 60s this afternoon, keeping maximum heat index values around 100. Breezy onshore winds will keep highs in the lower 90s for locations east of U.S. Highway 301, and coastal temperatures will fall into the 80s by late afternoon as onshore winds strengthen. Showers and thunderstorms developing along the I-75 corridor during the mid to late afternoon hours will progress westward across the Suwannee and Alapaha Rivers by sunset. Breezy and convergent low level easterly flow may begin to advect isolated showers developing over the Atlantic waters onshore along the northeast FL coastal counties towards sunrise on Monday. The onshore breeze will be slow to weaken along the coast overnight, keeping lows in the upper 70s to around 80 for locations east of I-95, while lows elsewhere fall to the low and mid 70s. && .MARINE... Issued at 1119 AM EDT Sun Jun 16 2024 High pressure centered over New England will strengthen as it moves slowly offshore this afternoon. This feature will result in strengthening easterly winds by late this afternoon and evening throughout our local waters, with winds and seas gradually increasing early this week as this high pressure center remains anchored off the New England coastline. Small Craft will need to Exercise Caution if venturing into our local waters on Monday and Monday night, as easterly winds strengthen to 15-20 knots and seas build to 3-5 feet on Monday and 4-6 feet by Monday evening. Small Craft Advisory conditions are expected to begin both near shore and offshore on Tuesday, as onshore winds strengthen to around 20 knots and seas build to 5-7 feet. Low pressure is expected to develop over the southwestern Atlantic early this week, with this feature gradually organizing towards midweek as it moves westward across the Bahamas, with a low risk for tropical development as this system approaches our local waters late on Wednesday night and Thursday. Please stay tuned to updates from the National Hurricane Center this week for potential changes to this forecast. Coverage of showers and thunderstorms will gradually increase across our local waters, with widespread activity likely by mid to late week. Seas will continue to build, with near shore seas climbing to the 8-11 foot range by Thursday, while seas offshore build to 9-13 feet. Rip Currents: Strengthening easterly winds this afternoon will result in building and increasingly rough surf, especially during the outgoing tide late this afternoon and early this evening. A High Risk of rip currents is expected by late afternoon at the northeast FL beaches, with a high end moderate risk for the southeast GA beaches, where wave heights should remain around 2 feet or less today. A high risk of rip currents is expected for the upcoming work week at all area beaches due to gradually strengthening onshore winds and building seas. && .FIRE WEATHER... Issued at 1119 AM EDT Sun Jun 16 2024 Easterly surface and transport winds will become breezy this afternoon, creating good to marginally high daytime dispersion values for locations along and north of the Interstate 10 corridor. Generally fair dispersion values are expected for north central FL this afternoon. A dry air mass will prevail for inland locations across southeast GA and also for northern portions of the Suwannee Valley today and again on Monday, where afternoon humidity values will fall to the 30-35 percent. Breezy easterly transport winds will prevail area-wide on Monday and Tuesday, with windy surface conditions expected along the I-95 corridor during the afternoon and early evening hours. Good to high daytime dispersion values are forecast throughout our region for the early to middle portions of this week. && .PRELIMINARY POINT TEMPS/POPS... AMG 72 92 71 91 / 0 10 10 20 SSI 80 87 80 85 / 10 30 20 40 JAX 74 90 73 88 / 10 20 20 50 SGJ 79 87 80 88 / 10 30 20 60 GNV 73 92 72 90 / 10 10 10 50 OCF 73 92 73 92 / 20 10 0 50 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through late Wednesday night for FLZ124- 125-133-138. GA...None. AM...None. && $$