Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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931 FXUS62 KJAX 111745 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 145 PM EDT Tue Jun 11 2024 ...New AVIATION... .SYNOPSIS... Issued at 423 AM EDT Tue Jun 11 2024 Early morning surface analysis depicts a stalling frontal boundary that was situated near the FL/GA border. Aloft...deep troughing continues to dig over the eastern third of the nation, with ridging in place from the Southern Plains northward through the Mississippi Valley and the western Great Lakes. Otherwise, cutoff troughing was located over the Texas and Oklahoma panhandles. Latest GOES-East derived Total Precipitable Water imagery indicates that the much anticipated surge of deep tropical moisture is nudging into north central FL, with PWATS of around 2 inches in place along the Interstate 4 corridor, while values elsewhere across our region remaining around or just below 1.5 inches, which is below climatology for June 11th. Southwesterly flow on the northern periphery of the tropical moisture surge are developing low-topped convection along the Nature coast, with a few showers also developing over Marion County. Otherwise, low stratus ceilings were developing for locations near the Altamaha River in southeast GA following late evening convection, while mostly mid and high altitude cloudiness in place elsewhere across our region. Temperatures were in the 70s for inland locations as of 08Z, ranging to around 80 along the northeast FL coast. Dewpoints generally ranged from the mid 60s to lower 70s. && .NEAR TERM... (Today and Tonight) Issued at 423 AM EDT Tue Jun 11 2024 Troughing over the eastern U.S. will tend to gradually fill today and tonight, with northwesterly flow keeping a drier air mass in place to the north of a stalled frontal boundary for inland southeast GA. This drier air mass should quickly erode low stratus ceilings that are developing near the Altamaha River by the mid- morning hours. Meanwhile, deep tropical moisture residing over the FL peninsula will struggle to lift into northeast FL, with PWATS finally rising above 1.5 inches by late afternoon. Values over north central FL should approach 2 inches by early afternoon, fostering increasing chances for beneficial showers and embedded thunderstorms through the afternoon hours. Scattered convection is expected to develop along the inland moving Atlantic sea breeze boundary by late afternoon along the I-95 corridor, and the moistening atmosphere should allow for convective outflows to develop additional showers and thunderstorms for the rest of northeast FL through around sunset, with coverage likely remaining isolated over the Suwannee Valley, where a pocket of drier and more subsident air will be stubborn to erode. Filtered sunshine should boost highs to the low and mid 90s, except upper 80s along the southeast GA coast, where breezy onshore winds will develop earlier in the afternoon, and also for far southern portions of north central FL, where thicker multi-layered cloudiness will prevail to the north of widespread convection that will be ongoing for locations along and south of the I-4 corridor. The drier air mass over inland southeast GA and the Suwannee Valley should allow dewpoints to fall through the 60s this afternoon, while dewpoints remain in the lower 70s across north central FL and at coastal locations today. Low level flow will become more southerly overnight, while the filling trough along the U.S. eastern seaboard keeps the frontal boundary stalled near the FL/GA border, with weak cyclogenesis progged along this boundary near the northeast FL coast towards sunrise. Gradually deepening moisture should allow for scattered showers and possibly a few thunderstorms to continue overnight for northeast and north central FL, while a drier air mass finally begins to retreat northward and away from southeast GA after midnight. Thickening multi-layered cloud cover from south to north overnight should keep lows in the lower 70s for most inland locations, with upper 70s expected along the Atlantic coast. && .SHORT TERM... (Wednesday through Thursday night) Issued at 423 AM EDT Tue Jun 11 2024 A weakening frontal boundary will slowly trek through the area on Wednesday and Thursday. The SW flow ahead of the frontal boundary will continue to bring tropical moisture into our southern locations of NE FL, PWAT values near 2". Chances of showers and thunderstorms increase into the afternoon on Wednesday from north central FL towards the FL/GA border. Thursday, we can expect a similar story in terms of spread of showers and storms for NE FL and SE GA, with the highest chances over the north central FL counties. A Marginal risk for excessive rainfall currently in place which includes north central FL on Wednesday and Thursday, with the risk of spreading a bit north on Thursday just south of the JAX metro area. Daytime temperature highs will begin to trend a bit lower as showers and cloud cover will keep the heat at bay, but highs are still expected to be in the lower 90s for far inland locations of NE FL and SE GA, with highs in the upper 80s along the coast and north central FL. Overnight lows will sit in the lower 70s, but in the upper 70s along the coast and the St Johns River. && .LONG TERM... (Friday through Monday) Issued at 423 AM EDT Tue Jun 11 2024 By Friday, the front is expected to move to sit just over north central FL. This will bring drier air to filter into the area behind the frontal boundary, lowering chances of showers and storms over SE GA, with best chances of showers and storms again over north central FL during the afternoon hours into Monday. Daytime temperature highs will begin in the mid 90s over SE GA to the lower 90s over inland NE FL during the end of the work week. Saturday, daytime temperatures will rise to the mid to upper 90s, with warmer temperatures expected over SE GA as most showers will be over NE FL. Heading into the upcoming week, daytime temperatures will sit in the lower 90s. Temperature lows expected to sit in the lower to mid 70s from late this week into the upcoming weekend, with warmer temperatures in the upper 70s along coastal locations. && .AVIATION... (18Z TAFS) Issued at 141 PM EDT Tue Jun 11 2024 Showers and storms initially building across north central Florida will develop over northeast Florida as the afternoon progresses, with heaviest developments occurring south of the I-10 corridor. Vicinity showers and storms are likely for most sites with GNV and potentially SGJ experiencing more abundant thunderstorm activity by around 21-22z. Developments near the coast are possible in association with the diurnal sea breeze. Convection will dissipate overnight with low level cloud decks building in more densely over GNV and VQQ by around 06-08z on Wednesday with convection beginning to redevelop by the end of the forecasted period for areas west of the I-95 corridor, with winds building in from out of the west. && .MARINE... Issued at 423 AM EDT Tue Jun 11 2024 A frontal boundary will stall across our local waters today, with showers and thunderstorms initially over central Florida gradually spreading northward towards our area this afternoon. Weak low pressure will then develop along this stalled boundary tonight over the northeast Florida waters, with this feature moving slowly northeastward through Friday. Southerly winds will likely surge to Caution levels of 15-20 knots for the offshore waters this evening before gradually diminishing after midnight. Seas of 2-4 feet will prevail both near shore and offshore today, with seas offshore building to the 3-5 foot range offshore tonight and Wednesday. Onshore winds may briefly strengthen late this week as weak low pressure center moves further away from our local waters. Periods of showers and thunderstorms will remain possible across through the upcoming weekend as the frontal boundary remains stalled. Seas of 2 to 4 feet are expected to prevail throughout our local waters from Wednesday night through at least Saturday. A stronger high pressure center will build southeastward from the eastern Great Lakes region this weekend, with another surge of onshore winds possible by Sunday and Monday as this feature wedges down the southeastern seaboard. Rip Currents: Developing onshore winds this afternoon will combine with a south-southeasterly ocean swell to create a low-end moderate rip current risk at area beaches. This lower end moderate risk will likely continue during the next few days. && .FIRE WEATHER... Issued at 423 AM EDT Tue Jun 11 2024 A dry air mass will continue today for inland locations along and north of the Interstate 10 corridor, where minimum relative humidity values will fall to around 35 percent this afternoon. Light northwesterly transport winds will prevail across inland southeast GA today, with breezy south-southwesterly transport winds for locations south of the I-10 corridor. Breezy onshore surface winds are expected to develop outside of shower and thunderstorm activity for locations along the I-95 corridor this afternoon. Elevated mixing heights will result in generally good daytime dispersion values today. Surface and transport winds will then shift to easterly on Wednesday and northeasterly on Thursday. Fair to good daytime dispersion values are forecast on Wednesday, with good to marginally high values possible on Thursday as transport winds become breezy by the afternoon hours. && .PRELIMINARY POINT TEMPS/POPS... AMG 70 92 70 92 / 20 10 10 20 SSI 79 87 76 87 / 20 20 10 30 JAX 73 90 72 90 / 30 40 10 40 SGJ 77 89 75 88 / 40 50 30 60 GNV 73 91 71 91 / 40 80 30 50 OCF 73 90 72 90 / 40 80 60 60 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$