Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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828 FXUS62 KJAX 301005 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 605 AM EDT Tue Apr 30 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... (12Z TAFS) Issued at 606 AM EDT Tue Apr 30 2024 VFR conditions will prevail at the regional terminals through at least 18Z. Isolated to widely scattered showers and thunderstorms are expected to develop during the mid to late afternoon hours, mainly along mesoscale boundaries such as the Gulf and Atlantic sea breezes. Confidence in coverage remains too low to include anything other than vicinity coverage at this time. Activity may linger into the early evening hours at the Duval County terminals, as the Gulf and Atlantic sea breezes collide near U.S. Highway 301 around sunset, with any activity that manages to develop moving back towards the I-95 corridor. Fog may be more widespread during the predawn and early morning hours on Wednesday at the inland terminals, and confidence was high enough to include TEMPO LIFR conditions after 07Z at VQQ, with prevailing MVFR conditions expected at JAX, GNV, and CRG by 10Z Wednesday. Southerly surface winds will increase to 5-10 knots after 13Z at the regional terminals, with the Atlantic and Gulf sea breeze boundaries pushing inland this afternoon, resulting in surface winds shifting to southeasterly at the coastal terminals by 17Z and then spreading inland, except at GNV, where surface winds will shift to southwesterly around 10 knots by 20Z. Surface winds will then shift to southeasterly this evening while gradually diminishing. && .NEAR TERM... Issued at 315 AM EDT Tue Apr 30 2024 A shortwave aloft will pass through the region today driving a weakening frontal boundary through the SE US. Meanwhile, surface high pressure off the GA/SC coast will shift further into the Atlantic causing flow to shift to south-southwesterly. This will allow for both Atlantic and Gulf sea breezes to shift inland this afternoon and likely converge along US 17 in the evening. Southerly flow combined with the passing shortwave will provide enough moisture and instability for isolated showers and storms to develop along the sea breezes mainly along their collision. Scattered showers and storms will move across inland SE GA late this afternoon into evening as the frontal boundary swings through. Lingering low level moisture and calming winds will lead to patchy fog developing for inland areas early Wednesday morning. Highs today will be in the mid to upper 80s inland and low 80s along the coast. Overnight lows will be in the 60s. && .SHORT TERM... (Wednesday through Thursday night) Issued at 315 AM EDT Tue Apr 30 2024 A shortwave trough that will be traversing the Deep South on Tuesday night will reach the Carolina coast on Wednesday morning, resulting in deep-layer flow over our region shifting to northwesterly. A weak surface reflection of this shortwave will be left behind over our region, with slightly deeper moisture (PWATS around 1.4 inches) pooling ahead of this feature, helping to trigger mostly isolated convection along mesoscale boundaries such as the Atlantic sea breeze and the St. Johns River breeze during the late afternoon and early evening hours. Following the dissipation of fog during the early morning hours, plenty of sunshine from the mid-morning through mid-afternoon hours will boost highs on Wednesday to the upper 80s to around 90 at inland locations, while the afternoon sea breeze keeps coastal highs generally in the mid 80s. Beneath fair skies, lows will only fall to the 60s on both Wednesday night and Thursday night, with patchy to areas of radiation fog expected to develop during the predawn and early morning hours at inland locations. A weak surface pressure pattern will prevail again locally on Thursday, with ridging aloft building into our area in the wake of Wednesday`s departing shortwave trough. Low level flow will shift to easterly, with a drier and more subsident air mass advecting over our area. Just enough moisture may remain around for isolated convection to develop towards sunset where the Atlantic and Gulf coast sea breezes collide towards sunset, generally for locations in north central FL and the Suwannee Valley. The drier air mass and plenty of sunshine will allow highs to soar to near 90 degrees on Thursday, while highs top out in the low to mid 80s at coastal locations, where prevailing onshore winds will become breezy during the afternoon hours. && .LONG TERM... (Friday through Monday) Issued at 315 AM EDT Tue Apr 30 2024 Ridging aloft over our region early on Friday will flatten in response to a slowly evolving and digging trough that will encompass the Pacific Northwest, the northern Rockies, and the upper Midwest. The flattening of the ridge will allow for a more zonal flow pattern to develop, and shortwave troughs embedded within this zonal flow will traverse our area, mainly on Saturday and then again early next week. A dry air mass is expected to linger throughout much of Friday across our area, with model guidance generally keeping convection associated with the upstream shortwave trough just west of our region, although some isolated convection developing along mesoscale boundaries cannot be ruled out. Plenty of sunshine from Friday morning through the mid-afternoon hours and the lingering dry air mass will again boost highs to around 90 at most inland locations, with the afternoon Atlantic sea breeze keeping coastal highs in the low to mid 80s. Lows on Friday night will only fall to the 65-70 degree range at most locations as convective debris clouds from upstream convection filter overhead. The aforementioned initial shortwave trough that is currently expected to traverse our area on Saturday should bring at least widely scattered convection to our area, especially during the afternoon and evening hours. Weak flow aloft should preclude any severe weather threat, with longer term models also suggesting that higher CAPE values will remain west of our region. Forecast confidence then decreases late in the weekend and early next week, as the longwave trough situated over the northern tier of the nation potentially lifts into Canada, leaving behind a weak frontal boundary over the southeastern states. Some subsidence in the wake of the initial shortwave trough passage may result in less convective coverage along mesoscale boundaries on Sunday, and then the 00Z operational GFS/ECMWF guidance diverges on the timing of the next shortwave trough that could impact our area early next week. Slightly above average temperatures will continue overall this weekend and early next week, with active sea breezes moving well inland as Atlantic surface ridging extends its axis across north central FL. && .MARINE... Issued at 315 AM EDT Tue Apr 30 2024 High pressure centered off the South Carolina coast will weaken and shift eastward today as a weakening frontal boundary enters the southeastern states. South-southeasterly winds prevail this morning with a coastal surge in the afternoon as the Atlantic sea breeze shifts inland. Isolated showers and thunderstorms may develop over our local waters today into Wednesday as the dissipating frontal boundary moves over our area. Another high pressure center will then build over coastal New England late this week, resulting in onshore winds redeveloping over our local waters. A cold front is then expected to enter the southeast states by Saturday night and Sunday, possibly bringing a chance of showers and thunderstorms to our region by late in the upcoming weekend. Rip Currents: Moderate risk of rip currents continue through Wednesday with the potential for a high risk of rip currents at NE FL beaches on Wednesday. && .PRELIMINARY POINT TEMPS/POPS... AMG 85 63 88 63 / 30 30 10 0 SSI 79 67 84 67 / 10 10 10 0 JAX 85 65 88 65 / 30 20 20 10 SGJ 82 67 86 67 / 10 10 20 10 GNV 87 64 89 63 / 20 10 20 0 OCF 88 64 89 64 / 20 10 20 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$