894 FXUS62 KJAX 181140 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 740 AM EDT Fri Mar 18 2022 .AVIATION... [Through 12Z Saturday] Widespread dense fog locked in place at GNV/VQQ, with coastal TAF sites of JAX/CRG/SSI/SGJ still on the edge of some brief LIFR conds from 12-14Z. Fog lifts/dissipates between 14-15Z then VFR through the rest of the day with daytime heating and S-SW winds increasing to 10-12 knots, east coast sea breeze pushing inland will trigger possible/brief VCTS at all TAF sites except for GNV in the 22-01Z time frame. Meanwhile latest Hi-Res models trying to suggest weakening squall line pushing through SE GA and impacting SSI from 00-06Z time frame and JAX metro TAF sites around 06Z but low confidence in this scenario at this time. Medium confidence in another round of low stratus/fog developing over inland NE FL and tracking into GNV (LIFR conds) in the 07-09Z time frame and possibly reaching the JAX metro TAF sites (IFR conds) in the 09-12Z time frame. && .PREV DISCUSSION [616 AM EDT]... .NEAR TERM [Through Tonight]... Latest short-term, high resolution guidance indicates that dense fog and low stratus ceilings may expand somewhat across inland portions of southeast GA through around sunrise, with patchy fog possibly developing along the I-95 corridor and coastal locations. All guidance indicates that fog and low stratus will lift before the mid-morning hours, with southerly winds resulting in warm air advection this morning as skies clear. The storm system currently over the southern Plains states will accelerate northeastward towards the Great Lakes region by this evening. Downstream of this feature, southwesterly flow aloft will strengthen this afternoon locally, with embedded shortwave energy migrating across southeast GA early this evening. Meanwhile, weak high pressure currently in place over southeast GA will shift offshore this morning, allowing for a developing warm front over the FL peninsula to lift northward this afternoon, reaching the I-10 corridor by sunset. This weather pattern will push the squall line of strong to severe thunderstorms currently traversing the lower Mississippi Valley eastward across the Deep South and the FL panhandle this afternoon, with the squall line reaching the Alapaha/Ocmulgee/upper Altamaha Rivers late this afternoon and then weakening early this evening as activity moves southeast of Waycross and across the Suwannee River along the I-10 corridor. Bulk shear values of 40-45 knots and speeds around 50 knots in the hail growth zone across southeast GA and northern portions of the Suwannee Valley will support strong to isolated thunderstorms within this squall line, and the Storm Prediction Center has placed these locations within a marginal risk (level 1 out of 5) for severe thunderstorm development through early this evening. Damaging wind gusts of 50-60 mph and hail of penny to quarter size in diameter will be possible within embedded stronger activity along the squall line. Support aloft for the squall line will then wane by the mid-evening hours. Plenty of sunshine will occur before this squall line approaches late this afternoon, and highs will soar to the low and mid 80s inland, with a few upper 80s possible for inland locations south of Gainesville. The Atlantic sea breeze will develop and move inland this afternoon, with isolated to widely scattered showers and possibly a few thunderstorms developing along this boundary near the I-95 corridor from around St. Augustine southward late this afternoon through early this evening before activity shifts offshore. The storm system will continue to shift northeastward towards the Great Lakes region overnight, pushing the associated cold front across the FL panhandle after midnight. This boundary may develop another line of weaker convection ahead of it following the passage of the early evening squall line. Locations south of the I-10 corridor will continue to remain mostly dry. Warm air advection and cloud cover ahead of the approaching cold front will result in lows only falling to the mid and upper 60s area-wide. .SHORT TERM [Saturday Through Sunday]... A low pressure system tracking across the Great Lakes region on Saturday will bring a trailing cold front across SE GA and NE FL. The cold front will slowly approach the area from the west- northwest, and gradually move southeast across the area throughout the day on Saturday. Showers and thunderstorms are expected to focus along the boundary. An upper level trough will swing across the eastern US, and the base of the trough is expected to pass near the FL/GA border Saturday afternoon and evening. A strong upper level jet will accompany the trough, and the environment will be favorable for strong to severe storm development. Any severe storms that develop could cause locally damaging winds, and possibly hail and/or an isolated tornado. The Storm Prediction Center has issued a slight risk of severe thunderstorms for SE GA and the Suwannee Valley north of I-10. As the trough progresses eastward, the frontal boundary will push south of the area Saturday night and showers and storms will taper off. A few lingering showers will be possible Sunday morning, but the area will dry out by the afternoon and skies will clear as high pressure builds over the Southeast US. Temperatures will be above average on Saturday with highs in the upper 70s to middle 80s. As the frontal boundary moves south of the area, temperatures will drop a bit and trend near normal. Saturday night lows will be in the upper 40s and 50s, and Sunday highs will be in the 70s. Sunday night temperatures will trend slightly below normal as colder air filters in from the north with lows in the middle 40s to middle 50s. .LONG TERM [Monday Through Thursday]... High pressure will shift to the north on Monday, then shift offshore in to the western Atlantic on Tuesday. Dry weather is expected Monday and Tuesday, then the next frontal system will approach mid-week. Low pressure will track to the north across the Mid-Atlantic region on Wednesday, and bring a trailing cold front across the area Wednesday into Thursday. Showers and storms will be possible both days. Temperatures will trend near normal early in the week, then slightly above average mid-week. Temperatures are expected to return to near normal towards the end of the week. .MARINE... A brief period of dense fog may be possible over the near shore waters from around St. Augustine northward early this morning. Otherwise, Atlantic high pressure will shift eastward today as a warm front develops over the Florida peninsula and lifts northward well in advance of a cold front that will enter the southeastern states this evening. Seas of 3-5 feet will prevail both near shore and offshore today, mainly due to a longer period east- southeasterly ocean swell. A squall line of strong thunderstorms late this afternoon will weaken as it approaches the near shore waters early this evening. Southerly winds will strengthen to Caution levels of 15-20 knots tonight as the warm front lifts north of our local waters. Seas offshore will build to 4-6 feet overnight. Another round of showers and possibly a few strong thunderstorms are expected along the cold front on Saturday afternoon and evening, with strengthening northwesterly winds expected overnight in the wake of the frontal passage. High pressure will then build over the southeastern states on Sunday and will move offshore of the Carolina coast on Monday, resulting in strengthening onshore winds and building seas early next week. Rip Currents: A long period east-southeasterly ocean swell will keep a moderate rip current risk in place at all area beaches through at least Saturday. .FIRE WEATHER... A warm front will lift north across the area this afternoon, and a cold front will slowly move into the area on Saturday. Showers and storms will be possible this evening through Saturday. Winds will shift to northwesterly Saturday night as the front gradually pushes south of the area. The front will be to the south on Sunday, and high pressure will build into the region early next week. Another frontal system is expected to impact the area mid-week. .HYDROLOGY... Minor flooding will continue along most of the St. Marys River during the next several days. Minor flooding along a majority of the Santa Fe River will continue at most gauges upstream of Three Rivers Estates through early next week. && .PRELIMINARY POINT TEMPS/POPS... AMG 82 65 77 48 71 / 50 60 70 20 0 SSI 76 66 80 54 72 / 30 40 60 40 0 JAX 85 66 84 55 75 / 20 20 50 40 10 SGJ 83 67 83 58 72 / 30 30 40 40 10 GNV 86 66 83 56 76 / 20 20 40 30 10 OCF 88 66 84 58 77 / 10 10 30 30 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...Dense Fog Advisory until 10 AM EDT this morning for Baker- Bradford-Central Marion-Eastern Alachua-Eastern Clay- Eastern Marion-Eastern Putnam-Gilchrist-Hamilton-Inland Nassau-Northern Columbia-Southern Columbia-Suwannee-Trout River-Union-Western Alachua-Western Clay-Western Duval- Western Marion-Western Putnam. GA...Dense Fog Advisory until 10 AM EDT this morning for Appling- Atkinson-Bacon-Brantley-Clinch-Coffee-Echols-Inland Camden- Inland Glynn-Jeff Davis-Northeastern Charlton-Northern Ware- Pierce-Southern Ware-Wayne-Western Charlton. AM...None. &&