Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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914 FXUS63 KJKL 222001 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 401 PM EDT Wed May 22 2024 .KEY MESSAGES... - There is a potential for showers and thunderstorms at times from today through Tuesday. - A few storms this afternoon/evening and again Sunday could be strong to severe, with damaging winds and large hail being the primary threats. - An increase in clouds and the possibility of rain will lead to somewhat cooler temperatures from Thursday into the first of next week. && .UPDATE... Issued at 220 PM EDT WED MAY 22 2024 Convection is still rather sparse as a broken line advances slowly southeast into the area. The most concentrated area is arriving in our southwestern counties, and the POP in that area has been increase to 60 percent for this afternoon. UPDATE Issued at 1058 AM EDT WED MAY 22 2024 A broken line of showers/thunderstorms extends from around KBWG northeast to just north of KFGX late this morning. The general scenario in the latest model runs is for this area to continue shifting slowly southeast and persist into tonight as it makes its way through the JKL forecast area. Using chance POPs at this point, but the evolution will be watched, and there is a potential for higher POPs to be needed. Latest model runs are also now looking like additional convection arriving from the west during the night will be a little slower, and have gone with a later arrival. UPDATE Issued at 700 AM EDT WED MAY 22 2024 Did a quick update to the forecast grids using trends from the latest obs. Temperatures have been running warmer than forecast overnight, so the latest obs were used to establish new trends and to also update this mornings lows, as they were a bit too warm as well. && .SHORT TERM...(Today through Thursday) Issued at 401 AM EDT WED MAY 22 2024 A somewhat challenging forecast in the short term this time around. A cold front will approach the area from the northwest through out the day today, and will be the trigger for showers and storms around eastern Kentucky today through Thursday. The front is expected to eventually stall out somewhere along the Ohio River. The challenge will be determining how far south the front will go before it stalls. The further southeast the front goes, the higher our rain chances will be today. The position of the front varies a bit from model to model, so no solid consensus has been reached as of yet regarding the boundary. Due to this uncertainty, decided to keep precip chances a bit lower than the latest NBM data was suggesting, going more toward the lower MOS guidance for PoPs. The latest runs of the higher resolution models(HRRR, NAMNEST, CAMS, etc) differed as well with the start times and initiation of showers and storms today. Having said that, liked the latest HRRR solution for initiation and evolution of convection across our area, especially late tonight and Thursday, when the cold front is forecast to push through. In a nutshell, the highest probability for showers and storms occur during from very late tonight and through the day on Thursday during frontal passage. What we do know is with plenty of low level moisture and instability will be in place to support convection, and that showers and storms will form and move across eastern Kentucky today, especially this afternoon and evening, during peak heating. We also know that a few storms could be strong to severe and could produce damaging wind gusts or even an isolated instance of large hail. After a few days of extremely warm temperatures, things will finally cool off a bit today and Thursday due to persistent, increasing cloud cover and repeated rounds of showers and storms. Winds will be on the increase today as well and will be generally out of the southwest at 5 to 10 mph, with gusts of 15 to 20 mph possible at times. .LONG TERM...(Friday through Wednesday) Issued at 401 PM EDT WED MAY 22 2024 An active pattern is shaping up across the Ohio Valley through the extended period of the forecast. The period begin Friday, with a mid-level wave pushing toward the lower Ohio Valley and Tennessee Valley. The various ensembles and deterministic have been varying a little on placement and timing of this feature. This will give way to around a 60-80 percent chance of showers and thunderstorms mainly Friday afternoon and evening. The highs will be closer to normal in the upper 70s to lower 80s. Saturday, a ill defined frontal boundary will be nearby and this could spark off a few showers and thunderstorms (around 40-60 percent chance), but coverage looks a little less, with better mid- and upper level forcing west of the area. This as we see slight height rises ahead of another mid-level wave noted in the Plains. The weakly sheared environment would suggest anything that does form would be unorganized. Sunday into Sunday night the previously mentioned trough will push east and surface low will eject out of the Plains into the Midwest. This will send a round of showers and thunderstorms toward the Ohio Valley Sunday afternoon and another wave possible Sunday night. The parameter space right now looks a little better for more organized convection, with MUCAPE values around 1500-2500 J/kg amid 40-50 knots of effective shear. The question will be how do the multiple rounds of convection trend and how does that affect what happens downstream. This as, some of the medium range CAM solutions suggest overnight convection pushes into eastern Kentucky by Sunday afternoon. Either way it was enough for SPC to include a portion of eastern Kentucky in slight risk for severe weather given the favorable pattern. The primary hazards would be damaging wind gusts and large hail. Sunday night into Monday the previously mention low pressure is forecast to push into the Great Lakes as it becomes vertically stacked in the mid- and upper levels. This will help pull a cold front across the area by Monday afternoon. Given the uncertainty in overnight convective evolution the risk for severe weather is uncertain. Even so, some ensemble and deterministic guidance suggest the potential for marginally severe storms would be possible in far eastern and southeastern parts of Kentucky, with a cold front pushing across the area. This as EPS/GEFS/GEPS ensemble mean of greater than 1000 J/kg of CAPE matched with greater than 30 knots of bulk shear is around 30 percent. More uncertainty comes Tuesday and Wednesday, as a mid- and upper level closed low pushes across the Ohio Valley and into the Northeast. This will help send another cold front across the area during this time period with models showing several different solutions of timing and evolution. Given this stuck with the general chance range for PoPs (at around 25-40 percent peaking in the afternoon. The pattern overall looks much cooler to round out the period, with highs forecast to be in the low to mid 70s both Tuesday and Wednesday. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) ISSUED AT 220 PM EDT WED MAY 22 2024 An area of showers/thunderstorms is currently making its way into eastern KY from the west. Coverage is incomplete, and the TAFs are presently being handled with VCTS due to uncertainty of where they will hit. However, IFR or worse conditions can be expected in the heavier precip. Outside of the precip, mainly VFR conditions are expected until early Thursday morning. A more widespread area of showers/thunderstorms is forecast to arrive from the west on Thursday morning with IFR and MVFR conditions. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...AR LONG TERM...DJ AVIATION...HAL