Area Forecast Discussion
Issued by NWS Jacksonville, FL

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000 FXUS62 KJAX 210133 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 933 PM EDT Tue Apr 20 2021 .UPDATE... Low level convergence along a pre-frontal trough axis spawned a broken cluster of showers across interior SE GA this evening enhanced by a mid level impulse aloft. Expect for this convection to shift eastward toward the SE GA coast through midnight with convection gradually fading in coverage and intensity as the upper level support presses farther downstream. There is also a low chance of showers across NE FL as a broad surface low offshore of the central FL Atlantic coast tracks farther offshore, with a wake trough meandering near our southern FL zones under the passing, weak upper level impulse 03z through 09z. Low stratus could edge inland from the GOMEX tonight near this wake trough as well, affecting areas generally along and south of a Gainesville to Palatka line. With the slow moving boundaries across & near the local area this evening and saturated soils especially across parts of NE FL, intermittent patchy fog is likely at times until a drier offshore flow develops trailing the pre-frontal trough axis through sunrise. Temperatures were on track to cool to near seasonal lows in the mid to upper 50s inland to low 60s toward the Atlantic coast. && .MARINE... SSE winds near 10 kts will veer SSW through midnight then to the WNW through sunrise trailing the pre-frontal trough axis, with a low chance of showers over mainly the SE GA coastal waters tonight. Winds will increase over the outer waters trailing the trough passage to 10-15 kts. Combined seas will continue in the 3 ft range or less. A dry cold front (no rainfall expected) will push across the waters Wednesday afternoon/evening, trailed by Small Craft Advisory conditions Wed night into Thu over the outer waters. Rip Currents: Moderate Rip Current Risk for NE FL beaches Wednesday. && .HYDROLOGY... Portions of the Santa Fe basin including near Oleno State Park and Worthington Springs were in Action Stage and are expected to crest just below Minor Flood Stage Wednesday night or early Thursday. && .PREV DISCUSSION [743 PM EDT]... .NEAR TERM [Tonight through Wednesday]... Weak wave along the front to the south has moved into the Atlantic with rain shifting southeast of our area. A brief shower may occur this evening over se Ga due to convergence near a surface trough. Clouds will decrease overnight as the flow aloft becomes wnw. This may result in patchy areas of fog by morning mainly over ne Fl. Wednesday will be mostly sunny...breezy and warmer as a dry cold front moves across the area. Temperatures should reach the lower 80s area wide including the beaches due to gusty offshore winds. .SHORT TERM [Wednesday night through Friday Night]... Cold front will push se of the area by Wednesday evening as high pressure builds into the area from the northwest. Clear and cooler conditions expected as temperatures drop into the 40s over inland area with low/mid 50s near the coast. Thursday will be mostly sunny with less wind and low humidity. Winds will veer to the NE which will keep the beaches cooler. Highs will reach the upper 60s coast to low/mid 70s inland. Thursday night will be another cool night with a warming trend starting Friday as highs reach the upper 70s and low 80s under increasing cloudiness. A chance of rain is possible over se Ga Friday night as a warm front lifts north from the Gulf ahead of the next upper trough. .LONG TERM [Saturday Through Tuesday]...Vigorous upper shortwave trough will move quickly east across the southern U.S. states through the weekend. A warm front will lift north into central Georgia on Saturday with ne Fl/se Ga in the warm sector as a surface low tracks ne across the Tn Valley region. Best chance for strong to possibly severe storms for our area appear to be Saturday afternoon and evening as the approach of trough and max instability combine with strong shear. Cold front will push through the region Saturday night with rain ending by early Sunday morning with clearing conditions. Surface high pressure will build into the area with a dry nw flow aloft over the area providing quiet weather with seasonal temperatures early next week. .AVIATION... [Through 00Z Thursday] VFR conditions expected early this evening across the terminals under passing low & mid clouds (bases 4-6 kft and 8-12 kft) ahead of an approaching pre-frontal trough edging south across GA. A few light showers/sprinkles and ceiling restrictions are possible as this trough axis settles across the terminals tonight, with the highest probabilities of MVFR to IFR restrictions at GNV and SGJ as westerly flow advects low stratus from the GOMEX inland after 03z. ESE winds this evening less than 10 kts transition to SSW to W through through 12z Wed with progressive ceiling improvement from NW to SE as drier air funnels across the area with VFR for all terminals by 12z. Breezy W-NW winds will increase midday with gusts 15-20 kts as the actual surface cold front approaches. .FIRE WEATHER...Breezy westerly winds with increased temperatures and mixing heights will result in high dispersions across the area on Wednesday. Drier air advecting into the area will lower RH values into the 30 to 35 percent range during the afternoon. Minimum RH values will be critical Thursday afternoon but with lighter winds. Fuel moisture values continue to be high due to recent rainfall especially over NE Fl. && .PRELIMINARY POINT TEMPS/POPS... AMG 56 79 40 71 43 / 30 0 0 0 0 SSI 61 82 49 68 53 / 20 0 0 0 0 JAX 59 83 48 70 51 / 20 0 0 0 0 SGJ 62 82 53 68 55 / 20 0 0 0 0 GNV 58 81 46 74 48 / 20 0 0 0 0 OCF 60 83 49 77 52 / 20 0 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. &&

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