Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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942 FXUS62 KJAX 260722 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 322 AM EDT Wed Jun 26 2024 ...New NEAR TERM, SHORT TERM, LONG TERM, MARINE... .NEAR TERM... Issued at 322 AM EDT Wed Jun 26 2024 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Light southerly flow today will allow the sea breezes to develop and push inland, with highs soaring into the mid to upper 90s inland, with slightly cooler temps along the coast. Heat indices will climb into the 105-112 degree range this afternoon during peak heating, prompting a Heat Advisory issuance along the Atlantic coast north of St. Johns county and in the St. Johns river basin, as well in the Suwannee valley area. Showers and thunderstorms will fire up along the Gulf sea breeze in the late morning/early afternoon hours, and progress inland, later interacting with the east coast sea breeze and sparking up numerous showers with embedded thunderstorms over NE FL. The primary hazards will be gusty winds and locally heavy rainfall as PWATs rise above 2.0" across NE FL. With drier air over most of SE GA, precipitation will be more limited, and heat indices will be lower for inland areas as opposed to NE FL. Convection will taper off after sunset with the loss of diurnal heating, lows will stay mild in the mid 70s. && .SHORT TERM... (Thursday through Friday night) Issued at 322 AM EDT Wed Jun 26 2024 Troughing aloft will dig across the southeastern states on Thursday, with southwesterly flow deepening ahead of a decelerating frontal boundary that will stall across southeast GA by Thursday night. Convection will likely get an early start along the FL Nature and Big Bend coasts, with scattered showers and thunderstorms then filling in across the rest of the Suwannee Valley and north central FL during the late morning hours as the Gulf Coast sea breeze gets propelled quickly inland. Additional forcing from the approaching frontal boundary and mesoscale boundary collisions should result in numerous showers and thunderstorms across the rest of northeast and north central FL, mainly during the early to mid afternoon hours, while convection likely increases in coverage across southeast GA during the mid to late afternoon hours along and ahead of the frontal boundary. Strengthening low level southwesterly flow will delay the development of the Atlantic sea breeze boundary until the mid-afternoon hours, with this boundary remaining pinned east of I-95 through late afternoon, allowing for another day of highs in the mid 90s all the way to the coast in northeast FL and southeast GA, while late development of of convection allows for highs to reach the upper 90s for locations north of Interstate 10. Maximum heat index values will again approach Heat Advisory criteria, especially for the coastal counties, where convection will likely not arrive until the mid afternoon hours. Storms may pulse and briefly become strong, especially at coastal locations near the pinned Atlantic sea breeze boundary and also across inland southeast GA near the frontal boundary, with stronger storms being capable of producing downburst winds of 40-50 mph along with frequent lightning strikes and briefly heavy downpours. East-northeasterly storm motion should be faster than in previous days, reducing overall rainfall amounts for our area. Convection may linger into the evening hours on Thursday for locations closer to the frontal boundary in southeast GA. Activity should diminish before midnight, with debris cloudiness gradually thinning overnight. Another round of predawn convection is expected to develop along the FL Big Bend and Nature Coasts on Friday, with convection possibly moving across north central FL and the Suwannee Valley around sunrise. Lows will generally fall to the mid 70s inland and the upper 70s at coastal locations. Troughing aloft will begin to de-amplify across the southeastern states on Friday as "Heat Wave" ridging expands eastward from Texas and the lower Mississippi Valley. Southwesterly low and mid-level flow will continue across our region as the frontal boundary dissipates near the FL/GA border. Convection will again be driven initially by the inland moving Gulf coast sea breeze, with scattered showers and thunderstorms likely progressing across the I-75 corridor during the mid to late morning hours, reaching the I-95 corridor in northeast FL by early afternoon. Convection should then increase in coverage across southeast GA during the mid to late afternoon hours along the dissipating frontal boundary. Mid-level temperatures will remain mild and east-northeasterly storm motion should remain brisk, with convection potentially pulsing as it encounters the pinned Atlantic sea breeze boundary along the I-95 corridor in northeast FL early in the afternoon, while pulsing storms then shift to southeast GA during the mid to late afternoon hours. Highs will generally reach the low to mid 90s area-wide, with heat index values expected to remain just below Heat Advisory criteria (108 degrees). Showers and thunderstorms may diminish more quickly on Friday evening as ridging aloft builds into our region and the axis of Atlantic surface ridging begins to lift northward across the FL peninsula, resulting in weakening southwesterly low and mid level flow. Lows again will fall to the mid 70s inland and the upper 70s to around 80 at coastal locations. && .LONG TERM... (Saturday through Tuesday) Issued at 322 AM EDT Wed Jun 26 2024 Ridging aloft will briefly build into the southeastern states this weekend before retrograding westward early next week as troughing progresses across the Great Lakes states and New England early next week. The axis of Atlantic high pressure will lift northward this weekend, creating a south-southeasterly low level flow across our region. This change in the flow pattern will allow for the Atlantic sea breeze boundary to progress further inland, setting up a collision with the Gulf coast sea breeze for locations along and west of U.S. Highway 301 on Saturday and Sunday afternoons, where numerous thunderstorms are forecast. Scattered convection will otherwise be possible along these inland moving mesoscale boundaries, with showers and thunderstorms generally diminishing at inland locations during the mid to late evening hours. Ridging aloft will allow inland highs to soar to the mid to upper 90s, with coastal highs remaining closer to 90 as the sea breeze develops earlier in the afternoon hours. Lows this weekend will generally fall to the mid 70s inland, ranging to around 80 at coastal locations. Troughing aloft diving southeastward towards the New England and Mid-Atlantic coasts early next week will drive another weakening frontal boundary into the southeastern states. Low and mid level flow will veer to southwesterly as the axis of Atlantic high pressure sinks southward, resulting in convection being driven by the inland moving Gulf coast sea breeze across northeast and north central FL, while numerous afternoon and evening thunderstorms develop across southeast GA near the approaching frontal boundary. Stronger storms will be possible along the I-95 corridor as convection potentially intersects a pinned Atlantic sea breeze boundary. Long range guidance indicates that troughing aloft will then progress offshore of the Mid-Atlantic and New England coasts by late Tuesday, allowing ridging to again build back into the southeastern states. Scattered to numerous mainly afternoon and evening thunderstorms are expected again on Tuesday as PWATs remain seasonably high and lighter southwesterly low and mid level flow allows for convection to develop along inland moving sea breeze boundaries. Highs will likely remain slightly above seasonal averages early next week. && .AVIATION... (06Z TAFS) Issued at 108 AM EDT Wed Jun 26 2024 Predominantly VFR conditions for sites tonight with diurnal convection expected to return by around 18-20z. There is a chance of MVFR to IFR ceilings briefly pre-dawn at GNV and VQQ, both will clear out around sunrise. PROB30s are in place for most of the TAF sites today for best timing of thunderstorms. && .MARINE... Issued at 322 AM EDT Wed Jun 26 2024 Fairly persistent troughing will be north northwest of the area through the upcoming weekend. High pressure ridge will be east of the region through Wednesday, then to the east southeast into Thursday. The high will be located to the northeast Friday through the weekend. Daily showers and thunderstorms will develop over the local waters through the weekend. Rip Currents: Moderate rip current risk for NE FL and SE GA beaches today. && .PRELIMINARY POINT TEMPS/POPS... AMG 99 74 96 74 / 30 10 50 30 SSI 91 77 93 79 / 30 10 50 30 JAX 95 74 96 75 / 50 20 60 20 SGJ 94 76 94 78 / 60 30 50 30 GNV 94 74 93 75 / 70 20 60 20 OCF 93 76 92 76 / 70 20 60 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...Heat Advisory from noon today to 7 PM EDT this evening for FLZ021-024-033-120-124-125-132-133-220-225-232-325-425. GA...Heat Advisory from noon today to 7 PM EDT this evening for GAZ153-154-162-165-166. AM...None. && $$