Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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209 FXUS63 KJKL 300800 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 400 AM EDT Tue Apr 30 2024 .KEY MESSAGES... - Showers today, perhaps with a rumble of thunder. Not as warm. - Dry and trending warmer midweek, with near record highs on Thursday. - Unsettled weather returns for Friday and lingers through the weekend. && .SHORT TERM...(Today through Wednesday) Issued at 335 AM EDT TUE APR 30 2024 Rain showers have arrived to the far southwest counties of the forecast area as of this early-morning writing. Rain will continue to progress slowly NNE through the day. I`ve removed the thunder chance early this morning as instability is best over northern Alabama, where thunder prevails at this time. There is a subtle resurgence in instability by midday, but this varies greatly from model to model. I say subtle because there will be plenty of clouds to overcome. Lapse rates are generally be poor as well. Additionally, in the wake of this cold front, a forcing mechanism for any late-afternoon redevelopment is absent. Therefore, have generally capped the thunder at "chance" today with dry weather prevailing from west to east as this line of rain exits. Rainfall today will generally total around 0.25" to as much as 0.50". Clearing skies tonight with light wind. Add to the mix the fresh rainfall and fog is likely overnight in the valleys. 500-mb heights will be on the rise Wednesday due in part to some deepening of a trough over the Northern Rockies. This will propel our highs back into the 80s following the seasonably cool temperatures of Tuesday. .LONG TERM...(Wednesday night through Monday) Issued at 400 AM EDT TUE APR 30 2024 The 30/00z model suite analysis beginning Wednesday evening shows upper level ridging across the Tennessee and Ohio valleys while an ~543 dam low is rotating over the Saskatchewan/Montana border. A shortwave trough is passing over northern Ontario along the eastern side of the low. At the surface, an ~1006 mb low is found northeast of Sault Ste Marie. A cold front extends southward from this low to near Toronto and then southwestward through Ohio, southern Indiana/Illinois and then more westerly to another ~993 mb low over southeastern Colorado. A weak surface high pressure is found over the Central Appalachians, to the south of the aforementioned frontal boundary. The upper level ridge over our region reaches peak strength Thursday before being shunted southeastward by the upper low moving toward northwest Ontario. During this time, the surface cold front may sag a bit further south to near the Ohio River during the first portions of Wednesday night. However that boundary will then quickly retreat northward on Thursday as the low pressure in the lee of the Coloradoan Rockies races northeastward toward Ontario, eventually occluding on Friday. Across eastern Kentucky, this will set the stage for near-record warmth on Thursday and possibly Friday as southerly return flow boosts 850 mb temperatures to between 16 and 18C. Given deep mixing, this will support maximum daily temperatures in the 83 to 90 range. Eastern Kentucky should remain dry until sometime on Friday when the low pressure`s trailing cold front drifts into the Ohio Valley. Quasi-zonal flow with embedded disturbances then sets up over Ohio Valley for the weekend and early next week. These disturbances along with the wavering remnants of a frontal boundary could become a focus for diurnally modulated convection from Saturday through Monday. In sensible terms, expect near record warmth on Saturday under most sunny skies with widespread high temperatures in the mid to upper 80s. In fact, a few of the warmest valleys in the Big Sandy river basin could eclipse the 90 degree mark. Shower and thunder chances return on Friday as that cold front approaches. The arrival timing of that boundary`s associated cloud cover will dictate whether temperatures run cooler across the board, or whether ample sunshine will again be able to boost temperatures deep into the 80s. Shower and thunderstorm chances will then remain in the forecast through Monday as the front wavers nearby. While a shower or thunderstorm appears possible at about any time, the highest chances are generally during the afternoon and evening coincident with peak heating/destabilization. Daily maximum temperatures are forecast to drop back into the mid 70s to lower 80s for the Saturday to Monday timeframe. Meanwhile, nighttime lows are forecast to range between 48 and 66 throughout the forecast period, coolest Wednesday night and warmest on Thursday night. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 146 AM EDT TUE APR 30 2024 VFR conditions will give way to MVFR and fuel-alternate conditions after daybreak Tuesday. This, as a cold front slowly mores through. Rain is ongoing across central KY and TN, with thunder confined to TN. As a result, I have removed the TS mention from the TAFs. It is uncertain whether or not isolated thunderstorms redevelop late this afternoon and is something that will need to be explored for the next issuance. However, pattern recognition amid a very slow moving system suggests recovery time will be limited, implying a nil TS threat in the afternoon. Decreasing clouds and light wind to end the TAFs. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BROWN LONG TERM...GEERTSON AVIATION...BROWN