Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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824 FXUS63 KJKL 090615 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 215 AM EDT Sun Jun 9 2024 .KEY MESSAGES... - The next passing cold front will bring increasing rain chances to eastern Kentucky early this morning and through the day. - Cooler air will be reinforced across the region early this week, before temperatures modify back to above normal by the end of the period. && .UPDATE... Issued at 150 AM EDT SUN JUN 9 2024 No significant changes to the forecast with just the inclusion of the latest obs and trends for the T/Td/Sky grids with this update along with tweaking PoPs on account of the current CAMs guidance. These minor adjustments have been sent to the NDFD and web servers. UPDATE Issued at 1055 PM EDT SAT JUN 8 2024 The forecast is on track so no significant changes are needed with the late evening update. Did blend in the latest hourly observations into the grids with the forecast. UPDATE Issued at 726 PM EDT SAT JUN 8 2024 There are no changes to the forecast. Radar shows precipitation falling out of mid-level clouds but no stations are measuring precipitation. Will keep low-end PoPs in the forecast to account for the possibility of sprinkles or light showers through the evening. With no changes to the forecast, will forego issuing a new zone forecast product until the late evening period. && .SHORT TERM...(This evening through Sunday night) Issued at 435 PM EDT SAT JUN 8 2024 Late this afternoon, an enlongated upper level trough extended from the vicinity of Maine across Quebec to Ontario. One upper level low was moving within this general area of troughing and centered in the Maine vicinity with another upper level low centered in Ontario northeast of Lake Superior. To the south an upper level ridge was centered over the Lower MS Valley vicinity and extended west into the Southern Plains and across portions of the Southeast. One disturbance in the west to northwest flow aloft from the Plains and Central Conus into the eastern Conus and OH Valley region was moving across the Commonwealth at this time with some light showers and sprinkles associated with it. Meanwhile, another shortwave extended from the upper level low into the western Great Lakes/Upper MS Valley vicinity south toward the mid MS Valley area. At the sfc, high pressure was centered across the southeastern Conus/Southern Appalachian region while a sfc low was moving across the Lower MI Area with the associated frontal zone southwest to near the KS/OK border and then northwest near the front range area of WY and CO. Tonight and Sunday, the initial shortwave will pass east though the evening while the upper low in Ontario moves toward Quebec and sends a couple of shortwave troughs across the Great Lakes and into parts of the Northeast to OH Valley. At the same time, the sfc low currently in the MI vicinity should track to the Northeast U.S coast and the off the eastern seaboard while the the trailing front sags into the OH Valley to Southern Plains. This boundary should continue sagging south across eastern KY on Monday and then south of the area on Sunday night. High pressure should nose into eastern KY for Sunday night while a secondary front to the north becomes diffuse near the OH Valley in advance of stronger high pressure building into the Upper MS Valley. Isolated to perhaps scattered showers are possible through early this evening, though this may not amount to more than sprinkles as upstream there have been no measurable rainfall reports over central KY. A lull in between systems is expected overnight though clouds should continue to stream into the area on west to northwest flow as the next couple of shortwaves approach along with the cold front. Convection upstream may track into portions of the OH and TN Valley overnight or additional development may occur as moisture is gradually advected toward eastern KY. A gradient in PW is anticipated near or west of I 75 into south central KY/the Lake Cumberland region late tonight and would be the most favored area for convection late tonight. Additional convection is anticipated on Sunday ahead of the front and as the shortwaves cross the Commonwealth. The deepest moisture will be in the south, generally from the Hal Rogers Parkway/KY 80 corridor south. This area will have the best chance for showers and some storms on Sunday though PW from about the Mountain Parkway south should be at least 1 inch or more into early afternoon and activity north to the area should be more scattered in nature and then more isolated further north. The cloud cover should keep temperatures more uniform compared to the past couple of nights tonight, though clearing on Sunday night may allow for a modest ridge/valley temperature split as drier air begins to arrive. Some valley fog is not out of the question tonight, especially where any convection occurs. Following additional anticipated convection on Sunday, more in the way of valley fog should occur over the deeper southern and eastern valleys. .LONG TERM...(Monday through Saturday) Issued at 320 PM EDT SAT JUN 8 2024 At the surface, the period starts off with high pressure nosing east and cold front pushing toward the Gulf Coast. The mid-levels we will see a trough extending from the Northeast into the Ohio Valley. These features will continue to usher in a drier and slightly below below normal temperatures for Monday. This as ensemble mean of PWAT values from the EPS/GEFS/GEPS show us staying below 1 inch. The dry weather and near normal temperatures hold on through mid-week with surface high pressure remaining in place across the Ohio Valley. After this, there is good agreement in the ensembles and deterministic on the surface high pressure pushing east some and we see some moisture return albeit on the lower end, with around 1 inch PWATs. We will keep the the mainly around a 15-20 percent PoPs in the afternoon on Thursday mainly in the Cumberland Valley and higher terrain given some uncertainty on the mid- and upper level pattern noted in some of the ensembles and deterministic guidance. Then there is decent agreement on a cold front dropping across the Ohio Valley by the end of the week into the weekend. Even so, there is disagreement on the timing and location of this boundary and therefore leads to uncertainty on when PoP chances will be highest and even how high to go with PoPs. For now, stuck close to the NBM, which keeps PoPs Friday and Saturday generally in the 20 percent range or less. This seems reasonable given the front looks weaker, with little change in moisture. Overall not expecting much in the way of rainfall through the period, with combined ensemble guidance mean of the EPS/GEFS/GEPS showing probability of less than a quarter of an inch through the period being around 60-70 percent. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) ISSUED AT 215 AM EDT SUN JUN 9 2024 Extensive cloudiness will continue into the morning, with more extensive and lower cigs working in with shower and possibly thunderstorm activity toward morning, mainly not until after sunrise. KLOZ and KSME stand the best chance of being impacted by this activity, with lesser chances at the other TAF sites through the day. As a result VFR conditions will prevail through at least 12Z, with the best chances for MVFR cigs/conditions occurring between 14 and 20Z, when there is also the slight chance for a thunderstorm. Light and variable winds are expected through the morning before becoming west and then northwest at generally 10 kts or less this afternoon. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JP LONG TERM...DJ AVIATION...CMC/GREIF