Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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915 FXUS63 KJKL 050845 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 445 AM EDT Fri Jul 5 2024 .KEY MESSAGES... - A few thunderstorms this afternoon to early evening could produce locally heavy rainfall and strong to damaging wind gusts. - Somewhat cooler and less humid weather arrives behind a cold front over the weekend. - Warmer and more humid conditions will make a noticeable comeback on Monday and continue into next week, along with a potential for more thunderstorms. && .SHORT TERM...(Today through Saturday) Issued at 445 AM EDT FRI JUL 5 2024 08Z sfc analysis shows low pressure dropping into the northern Ohio Valley early this morning dragging a cold front into the region as it arrives. Ahead of this, skies are mostly clear over this part of the state allowing for a very small ridge to valley temperature split along with areas of valley fog. Currently, readings are quite warm running in the low to mid 70s across eastern Kentucky - a few degrees cooler in the sheltered valleys than the ridges. Meanwhile, amid light to calm winds, dewpoints are also high - in the low to mid 70s - creating a floor to the potential temperature drop through dawn. A few showers are noted trying to develop to the west and south of the Cumberland Valley which the CAMs suggest could slip in the southwest around dawn. The models, and their individual ensemble suites, are in very good agreement aloft through the short term portion of the forecast. They all depict a shortwave trough moving southeast from the Upper Midwest and entering the northern Ohio Valley today into tonight. This brings substantive height falls and a brush-by of mid level energy to eastern Kentucky through 12Z Saturday. Thereafter, the pattern loosens a bit through Saturday evening with broad southwest flow at mid levels and weak energy streaming past the state. The model spread through the short term is relatively small so the NBM was used as the starting point for the grids through Saturday afternoon with little deviation needed aside from the incorporation of the latest CAMs details for the PoPs today and tonight. Sensible weather features another hot and humid day with heat indices in a few places reaching near 100 degrees. The heat will fuel, and be mitigated in a few places, by scattered to numerous showers and storms developing through mid afternoon. The latest CAMs suggest that a convective line will move southeast into the the area towards noon with a potential for organized convection with damaging wind gusts as the main threat. Decent instability will sustain these storms through the afternoon with CAPE progged to be over 2000 J/Kg while high PWs - over 2 inches - will make heavy rain a threat with these storms and a potential for localized flooding will exist with any repeated cell training. The storm threat will diminish after dark but remain a concern well into the night. The synoptic cold front settles through the bulk of the area late tonight, but may not quite clear the JKL CWA through the day, Saturday. This will keep a small chance for a shower in the forecast along the border with Virginia to start the weekend. The front should also bring in some drier air and make for a less oppressive day, with respect to the heat and humidity, than we face today. The main changes to the NBM starting point consisted of tweaking the temperatures in order to better reflect some very limited terrain details early this morning. PoPs were adjusted more significantly today into tonight per the latest guidance from the CAMS. .LONG TERM...(Saturday night through Thursday) Issued at 400 AM EDT FRI JUL 5 2024 Surface high pressure will continue to nudge into the region for the start of the forecast period. With surface high pressure in place, temperatures will be back on the rise with highs climbing into the upper-80s to low-90s for Sunday. Surface high pressure will nudge off to the east on Monday with enhanced southwesterly flow ahead of an approaching shortwave. Temperatures on Monday are forecast to be warmer as highs are forecast to be in the low to mid-90s, coupled with warm, moist southwesterly flow, heat indices will be approaching 100 degrees to over 100 in isolated locations. Models have come into better agreement with a positively tilted trough approaching the area. At the surface, a surface low will be tracking through the Upper Great Lakes. Along and ahead of the front, increasing showers and thunderstorms are likely. As the low tracks through the Great Lakes, the front will dive southeast through the CWA. Forecast soundings, sampled ahead of the front show a marginally severe atmosphere. Can`t rule out a severe storm or two but overall, pre-FROPA environment appears to be a poor supportive environment for severe storms. Models continue to remain in very good agreement post-frontal Wednesday as deterministic runs keep PoP chances through the end of the forecast period and even possibly bring the remnants of Hurricane Beryl to the forecast area for the end of the forecast period. Overall, the period will highlighted with periods of showers and thunderstorms that`ll bring much needed rain to the area. Also, temperatures will return to more seasonal ranges as daytime highs in the mid-80s to low-90s and overnight lows ranging from the upper-50s to upper-60s. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 200 AM EDT FRI JUL 5 2024 Just a scant chance for a stray shower or thunderstorm into dawn. However, valley fog will be around, though the extent of cloud cover will be a limiting factor, but reductions to MVFR or IFR are expected for a time in much of the river valleys. At this point this should have little impact on the TAF sites. Look for a lower CIG (but still likely VFR) to develop by late morning for most of eastern Kentucky with a decent shot at some convection impacting the TAF sites. For now have gone with VCTS for much of the midday to early evening with better timing to be refined further as we get closer to the times of higher threat. Winds will average 10 kts or less, outside of any convection, generally from south to southwest. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...VORST AVIATION...CMC/GREIF