Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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086 FXUS63 KJKL 051902 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 302 PM 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. && .UPDATE... Issued at 250 PM EDT FRI JUL 5 2024 Much of the Severe Thunderstorm Watch has been cleared. Once convection clears Pike County, the remainder will be cleared. UPDATE Issued at 1245 PM EDT FRI JUL 5 2024 Heating of a humid airmass across eastern KY has occurred east of a line of showers and thunderstorms that have moved into eastern KY from Central KY. Some wind damage reports have been received from areas nearer to Interstate 75. East of this line, MLCAPE is forecast in the 1000 to 2000 J/kg range with effective shear around 30 to 40KT. Mid level lapse rates in more southern areas should be near 6C/km while low level lapse rates east of the line are expected near or in excess of 7C/km. This should be favorable for a few areas of damaging wind gusts in the eastern and southern portions of the CWA along the line as it moves deeper into eastern KY over the next couple or hours. A Severe Thunderstorm Watch is in effect into early in the evening for this scenario. UPDATE Issued at 700 AM EDT FRI JUL 5 2024 No significant changes to the forecast - just the inclusion of the latest obs and trends for the T/Td/Sky grids with this update. These minor adjustments have been sent to the NDFD and web servers. && .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 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 235 PM EDT FRI JUL 5 2024 Convection had cleared all but the KSJS vicinity at issuance time. A lull in activity may occur during the afternoon, but another round or two of isolated to scattered convection will remain possible until a cold front crosses the region this evening into the overnight and a upper disturbance passes. Reductions to MVFR and IFR if not briefly near airport mins could occur in the strongest convection. Winds will average 10 KT or less outside of any convection, from the southwest to west through 06Z and then becoming west to northwest for the balance of the period behind the cold front. Fog will also become a concern in the 06Z to 13Z timeframe when at least IFR and MVFR reductions will be possible. Some reductions due these levels due to low clouds could occur in that timeframe as well. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...VORST AVIATION...JP