Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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239 FXUS62 KJAX 091734 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 134 PM EDT Sun Jun 9 2024 ...New AVIATION... .UPDATE... Issued at 730 AM EDT Sun Jun 9 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 Shallow early morning inland fog will lift quickly through 9 am. Hotter and drier compared to yesterday with near record triple- digit high temperatures inland to the upper 90s along the local Atlantic coast until a late afternoon east coast sea breeze drifts slowly inland, which will bring limited relief. Satellite derived PWATs were < 1 inch across SE GA early this morning, and this axis of drier air will shift southward across our NE FL zones into the afternoon as the mean layer 1000-500 mb ridge centered across the central GOMEX early this morning shifts southward. A strong subsidence inversion noted in the 00z JAX RAOB near 775 mb of 3 degC strengthened with the morning 12z RAOB indicating the inversion now near 830 mb, with abundant drier air aloft. This drier air will mix down across the area this afternoon, limiting both diurnally enhanced cumulus and rain potential, but combined with the hot temps, bring an elevated wildfire threat to the local area. IF, big IF, there are any spits of bring showers with sea, river and lake breeze interactions late afternoon & early evening (4 pm through 8 pm), it will be near Lake George & the middle St. Johns River basin...but rain chances are only near 5%. && .NEAR TERM... (Today and Tonight) Issued at 404 AM EDT Sun Jun 9 2024 The subsident air mass may promote radiation fog development, especially for locations within a more humid environment in the Suwannee Valley and north central FL during the predawn and early morning hours. A few patches of locally dense fog cannot be ruled out early this morning. Any fog that develops will dissipate before the mid-morning hours. Ridging aloft to our west will begin to flatten today as troughing amplifies over the Great Lakes, Ohio Valley, New England, and the Mid-Atlantic states. This amplifying trough will drive a frontal boundary into the southeastern states tonight. A dry air mass will prevail area-wide today, with prevailing westerly winds likely delaying the development of the Atlantic sea breeze boundary to the early to mid afternoon hours, with this boundary only slowly moving inland towards the I-95 corridor late this afternoon. Some thin cirrus emanating from convection well upstream from our region will drift across our skies this afternoon and tonight, but plenty of sunshine and strong subsidence will only allow for a paltry, flat cumulus field to develop this afternoon along mesoscale boundaries such as the St. Johns River breeze and the inland moving Gulf and Atlantic sea breezes. Dewpoints crashing through the 50s this afternoon across inland southeast GA and locations north of I-10 and the 60s elsewhere away from the immediate coast will foster near record high temperatures region-wide today (see Climate section below for details), as inland temperatures approach 100 degrees. The late development of the Atlantic sea breeze will result in coastal highs soaring to the mid and upper 90s before cooling back towards 90s degrees as this boundary moves slowly inland late this afternoon. The dry air mass will keep maximum heat index values in check today despite the near record actual temperatures, with values generally topping out in the 100-105 range for coastal southeast GA and most of northeast and north central FL, with values around or just under 100 degrees for inland southeast GA. Cirrus cloud cover may begin to thicken somewhat overnight as convection traverses the southeastern states along and ahead of the approaching frontal boundary. This cloud cover may remain thin enough for some patchy fog to develop across inland portions of north central FL during the predawn and early morning hours on Monday. Lows tonight will generally fall to the 70-75 degree range, except mid to upper 70s at coastal locations. && .SHORT TERM... (Monday through Tuesday night) Issued at 404 AM EDT Sun Jun 9 2024 Moisture slowly begins to fill in ahead of a cold front approaching the area from the North Monday morning. Showers and thunderstorms kick off for the week beginning Monday afternoon with highest chances for precip in SE GA with values of 50-60% while NE FL will see chances in the 40-50% range. Daytime temperatures should be slightly cooler for areas behind the cold front in SE GA with values in the low to mid 90s. Areas ahead of the front will be in the mid to upper 90s range. The cold front will continue to slowly push its way through the region by Tuesday morning, cooling temperatures overnight into the low 70s inland with temps in the mid to upper 70s along the coast. Tuesday, expect rain and isolated thunderstorms chances area wide with chances increasing in the afternoon. Highest percentages will be focused on NE FL. Daytime temperatures will be in the low to mid 90s. && .LONG TERM... (Wednesday through Saturday) Issued at 404 AM EDT Sun Jun 9 2024 The cold front from the beginning of the week rebounds through the area as a stationary front Wednesday night and hangs around SE GA and the FL/GA line into the weekend. This stationary front will aid in bringing in more moisture to the area, increasing PWAT values to over 2 inches for NE FL by Thursday morning and SE GA by Thursday afternoon and into the weekend. Expect showers and thunderstorms for the rest of the week with the highest chances occurring each afternoon. && .AVIATION... (18Z TAFS) Issued at 131 PM EDT Sun Jun 9 2024 Prevailing VFR conditions today and dry weather expected at all terminals. Diurnally enhanced cumulus will develop with bases 5-7 kft with mid and high clouds increase from the NW late afternoon and overnight tonight. Westerly winds increased into the 6-11 kt range with some gusts near 15 kts with heating this afternoon. The east coast sea breeze is pinned near the Atlantic coast as inland progression is delayed by the stronger westerly flow today. Indicated SSE winds trailing the east coast sea breeze at SSI, CRG and SGJ between 20-22z then not reaching JAX/VQQ until 23-01z time frame where winds will more likely go VRB. Another round of shallow ground fog will be possible after 06z tonight, mainly near GNV and VQQ. Will include MVFR after 09z for VQQ given MAV, MET, NBH and SREF consensus. VFR after daybreak with W winds increasing through 14-16z 7-11 kts. TSRA potential approaches SSI late in the day (after 18z) Monday, outside of the TAF period. && .MARINE... Issued at 404 AM EDT Sun Jun 9 2024 A weak pressure pattern will prevail across our local waters through Monday morning, with prevailing offshore winds becoming onshore by late this afternoon over the near shore waters. A southerly evening wind surge may bring speeds up to Caution levels of 15-20 knots tonight, especially for the offshore waters. Seas of 2-4 feet will prevail both near shore and offshore through at least midweek. A frontal boundary entering the southeastern states on Monday will stall across our local waters by late Tuesday. Strong to isolated severe thunderstorms will be possible across the Georgia waters late on Monday afternoon, with this activity weakening as it pushes across the northeast Florida waters on Monday evening. A surge of tropical moisture will then lift northward from the Caribbean Sea and the Gulf of Mexico by midweek, resulting in waves of widespread showers and thunderstorms impacting our local waters into next weekend. Weak low pressure may develop over the Gulf of Mexico late this week, potentially resulting in strengthening southerly winds. Rip Currents: Prevailing offshore winds and low wave heights should keep the risk low at all area beaches through Tuesday. && .FIRE WEATHER... Issued at 404 AM EDT Sun Jun 9 2024 A hot and unseasonably dry air mass will prevail area-wide today, with long durations of critically low relative humidity values for most inland locations and near critical values by early afternoon at coastal locations. Drying fuels and breezy westerly transport winds will present an Elevated Fire Danger for northeast and north central FL, with marginally high to high daytime dispersion values forecast area-wide today. Surface wind speeds will remain just below critical thresholds this afternoon, precluding Red Flag Conditions. Westerly transport winds will increase a little on Monday and will combine with elevated mixing heights to create high to very high daytime dispersion values at most locations on Monday. Strong to isolated severe thunderstorms will be possible for locations along and north of the Interstate 10 corridor late on Monday afternoon and evening. Breezy westerly transport winds and elevated mixing heights will continue on Tuesday, with marginally high to high daytime dispersion values forecast, especially across northeast and north central FL. Widespread, significant rainfall chances increase beginning on Wednesday across our region. && .CLIMATE... Issued at 404 AM EDT Sun Jun 9 2024 Record high temperatures for today and Monday at our official local climate sites: June 9 June 10 ----------------------- Jacksonville 101/1872 100/1954 Gainesville 99/1907 99/1899 Alma, GA 99/1993 103/1954 Craig Airport 97/2006 99/2006 && .PRELIMINARY POINT TEMPS/POPS... AMG 98 74 95 71 / 0 10 60 60 SSI 97 78 94 74 / 0 0 60 60 JAX 100 73 99 73 / 0 0 40 30 SGJ 97 75 98 74 / 0 0 30 40 GNV 100 71 97 72 / 0 0 20 30 OCF 99 71 96 73 / 0 0 30 40 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$