962 FXUS62 KJAX 261452 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 1052 AM EDT Sun Jun 26 2022 ...HIGH RISK OF RIP CURRENTS CONTINUES THIS AFTERNOON AT AREA BEACHES... .UPDATE... Late morning surface analysis depicts high pressure (1022 millibars) centered off the Mid-Atlantic coast and extending its axis southwestward across the Deep South. Meanwhile, weak inverted troughs were located along the northern Gulf coast and also extending from the northern Bahamas westward across south FL. Otherwise, a cold front extended from the Great Lakes to the southern Plains, and this feature was moving slowly southeastward. Aloft...deep-layered ridging centered over the Ozarks was flattening and expanding eastward in response to a potent shortwave trough that was migrating eastward across Ontario and Lake Superior. Latest GOES-East derived Total Precipitable Water imagery indicates that an unseasonably dry air mass has overspread our area, with PWAT values of 1.1 - 1.3 inches, which is about 10% of normal for late June. Despite convergent onshore flow, only a few isolated showers have developed over the near shore Atlantic waters, with just a few brief showers making it onshore along and east of the I-95 corridor. A healthy cumulus field was otherwise expanding westward across our area, and temperatures at 15Z were rising through the mid and upper 80s. Dewpoints ranged from the mid 60s near the Altamaha River to the lower 70s throughout northeast and north central FL. The unseasonably dry air mass in place over our region will limit chances for deep convection this afternoon. Short-term, high resolution guidance suggests that a few showers will line up along an inland-moving Atlantic sea breeze boundary this afternoon for locations along and west of U.S. Highway 301. However, measurable rain chances are less than 20 percent at most locations today, and thunderstorm activity seems unlikely given the dry and increasingly subsident air mass in place, as the morning sounding at Jacksonville displayed a stout inversion based around 750 millibars (around 8,500 feet) that will be slow to erode this afternoon based on model forecast soundings. Dewpoints will crash to the upper 50s this afternoon for locations to the northwest of Waycross and through the 60s elsewhere, and plenty of sunshine will result in highs reaching the low to mid 90s for locations west of U.S.-301 and upper 80s at coastal locations. Weak inverted troughing currently stretching from the northern Bahamas and across the FL peninsula will pivot northward overnight as surface ridging off the Mid-Atlantic coast retreats eastward. Slightly deeper moisture will approach north central FL towards sunrise from the south, possibly resulting in some low-topped convection developing during the predawn and early morning hours on Monday for locations south of St. Augustine and Palatka. Pockets of low stratus ceilings may also develop at inland locations in north central FL and the Suwannee Valley during the predawn and early morning hours. Fair skies, the dry air mass in place, and decoupling winds will allow lows to fall to the mid and upper 60s at most inland locations, while a light onshore breeze keeps coastal lows in the 75-80 degree range. Troughing aloft will progress eastward through the eastern Great Lakes and the Ohio Valley on Monday, which will push a weakening cold front into the southeastern states by the evening hours. Meanwhile, inverted troughing will push onshore along the northeast FL coast and will weaken by the afternoon hours. Low level flow will veer to east-southeasterly as this weak trough pushes onshore, and there may be just enough low level moisture and convergence for widely scattered convection to develop along the inland-moving Atlantic sea breeze boundary from the late morning through the afternoon hours for locations south of the Interstate 10 corridor. A few thunderstorms developing ahead of the approaching frontal boundary could also approach the Altamaha/Ocmulgee/Alapaha Rivers from the north towards sunset tomorrow as well. Mainly dry weather will continue for locations along and north of I-10, where inland highs will soar to the mid 90s, and dewpoints will once again crash to the upper 50s and lower 60s. Highs at coastal locations will reach the upper 80s to around 90 before the sea breeze pushes inland. && .MARINE... High pressure centered off the Mid-Atlantic coast will push eastward and weaken tonight as a weak trough pushes northward from the northern Bahamas towards the northeast Florida waters. Breezy east-northeasterly winds this afternoon and evening will shift to east-southeasterly overnight, with the approaching trough possibly developing a few showers and thunderstorms over our local waters overnight through early Monday afternoon. The trough will then shift inland on Monday afternoon and weaken. Seas of 3 to 4 feet will prevail both near shore and offshore through Monday evening. Meanwhile, a weakening frontal boundary will enter the southeastern states on Monday night, stalling just northwest of our local waters on Tuesday. Showers and thunderstorms will gradually increase over our local waters from Tuesday afternoon through Thursday as this boundary dissipates over our region and high pressure in the wake of this boundary shifts eastward from the Ohio Valley to offshore of the Mid-Atlantic coast. Onshore winds will prevail for most of this week over our local waters, with speeds remaining below Caution levels outside of thunderstorm activity. Seas of 2-3 feet are expected both near shore and offshore from Tuesday Rip Currents: Breezy onshore winds will combine with an arriving longer period east-northeasterly ocean swell to keep a high risk in place at all area beaches today. This long period swell will continue through midweek as onshore winds diminish, resulting in a moderate risk from Monday through Wednesday at area beaches. && .FIRE WEATHER... Breezy east-northeasterly surface and transport winds will overspread our area early this afternoon, resulting in marginally high daytime dispersion values for much of inland southeast GA and the Suwannee Valley. An unseasonably dry air mass will remain in place through Monday across inland southeast GA and northern portions of the Suwannee Valley through Monday, where minimum relative humidity values may briefly approach critical thresholds during the afternoon hours as temperatures soar to the low and mid 90s. Easterly transport winds will diminish on Monday and Tuesday, with fair dispersion values expected at most locations. Showers and thunderstorms will increase in coverage across our region beginning on Tuesday afternoon and evening, continuing thereafter through Friday. && .PREV DISCUSSION [821 AM EDT]... .NEAR TERM [Today Through Tonight]... Low level ridge axis will be across the Carolinas most of the day while weak low level troughing will extend from south central FL northeast into the western Atlantic. This supports the east- northeast flow through 850 mb and fairly rich low level moisture but pretty dry in the layer from about 800-400 mb. This will support scant rain chances today, around the 10-20 percent range, mainly over northeast FL but a lone shower possible in southeast GA. The dry air aloft will make it a bit difficult for thunderstorm development but a couple storms possible far south zones this aftn. Winds will be east-northeast up to 10-15 mph and gusty, mainly breezy for the coastal zones. The persistent east flow supports elevated rip current risk at the coast--see marine section below. Highs will be tempered by the flow and cumulus clouds with upper 80s coast and lower to mid 90s further inland. Tonight, ridge axis to the north weakens, while the low level trough to the south of the area will be lifting a little northward with some broad weak troughing being noted in guidance oriented southwest to northeast from southern zones to the offshore waters. Overall dry conditions persist but some weak isolated showers remain possible over waters tonight and along the northeast FL coast. Lows tonight will again be able to drop down into the 60s, with the mid 60s inland southeast GA, upper 60s inland northeast FL and lower to mid 70s toward the coast. .SHORT TERM [Monday Through Tuesday Night]... After a largely dry day Sunday, deeper moisture to the south will begin to push back into the area as flow veers southeasterly ahead of an approaching front to the northwest. As moisture creeps back northward, the combined influence of a coastal trough and the Atlantic sea breeze should support a few showers and thunderstorms generally south of I-10 during the afternoon. By Tuesday, the aforementioned front will decelerate to a stall just north of the Altamaha/Ocmulgee River basins. Increased moisture, pooled ahead of the front and advected from the south, will support diurnal scattered showers and thunderstorms. Forecast soundings indicate a fairly weak steering flow (SE around 5 mph) and should allow a more central merger near Highway 301 of the Atlantic/Gulf sea breeze collision. Slow storm motion will heighten the risk of localized heavy rain fall and could result in isolated flooding. A subtle shortwave riding along the frontal boundary may continue widely scattered showers and embedded storms across the Suwannee Valley and southeast GA overnight into Wednesday morning. Highs along the immediate coast will benefit from the sea breeze with highs in the mid/upper 80s while inland areas will read in the low/mid 90s. .LONG TERM [Wednesday Through Sunday]... Unsettled weather is expected through latter half of the upcoming week and into the weekend with prolonged southeasterly flow and deep moisture remaining entrenched across the area. A diffuse frontal zone will sag a bit further south toward the FL/GA state line where it will stall Wednesday and eventually dissipate through Friday. This boundary will be primary focus for scattered to numerous thunderstorms Wednesday and Thursday before convection becomes forced solely by the sea breeze subsequent outflow interaction. The Tropical Upper Tropospheric Trough has become less of a factor as it is progged to gradually fill/warm as it approaches FL. Typical summery temperatures are expected into next weekend with highs in the low 90s inland and upper 80s to near 90 at the coast. .AVIATION... [Through 12Z Monday] Brief periods of MVFR ceilings of 2,000 - 2,500 feet will be possible through around 16Z at the SGJ and SSI coastal terminals. Otherwise, VFR conditions will prevail at the regional terminals through at lest 06Z Monday. Low stratus clouds may then develop after 07Z at VQQ and GNV, where MVFR to IFR conditions are possible towards 09Z. East-northeasterly surface winds will remain sustained at 10-15 knots at SGJ through around 02Z. East- northeasterly surface winds will increase to around 5 knots elsewhere through 14Z, followed by winds shifting to easterly and increasing to around 10 knots towards 16Z. Surface winds will then shift to southeasterly by 03Z, with sustained speeds diminishing to around 5 knots or less at the regional terminals. && .PRELIMINARY POINT TEMPS/POPS... AMG 94 65 96 69 93 / 10 0 10 10 50 SSI 88 76 89 77 88 / 20 10 10 20 30 JAX 90 68 92 70 91 / 10 10 10 10 30 SGJ 88 75 89 76 89 / 20 20 20 10 30 GNV 92 68 93 71 92 / 10 10 30 10 50 OCF 93 69 93 72 92 / 10 10 30 20 50 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through late tonight for Coastal Duval- Coastal Flagler-Coastal Nassau-Coastal St. Johns. GA...High Rip Current Risk through late tonight for Coastal Camden- Coastal Glynn. AM...None. &&