Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 302046 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 346 PM EST Wed Nov 30 2016 .SHORT TERM...
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(This evening through Thursday night) Issued at 345 PM EST WED NOV 30 2016 As of mid afternoon, a mid level ridge was in place from the Caribbean to the Bahamas while another ridge was located over the Eastern Pacific. A broad area of mid level troughing extended from much of the Western Conus into the Central Conus. Within this trough a closed low was nearing the Western Great Lakes while a shortwave trough was nearing the Lower OH Valley. At the sfc, an area of low pressure was over the Great Lakes region with a cold front extending south through the Ohio Valley and into the TN Valley. At this time, the front is moving further into Eastern KY with the main band of much needed rain finally shifting into WV and VA. Another sfc trough and associated band of low and mid clouds associated with the returns over Central Ky is also approaching. The closed upper level low should meander to the Northern Great Lakes/Eastern Ontario region with the sfc low moving further to the north and east. The shortwave nearing the Lower OH Valley at this time will work across the area through this evening although another weak shortwave moving around the closed low will pass through the Lower OH Valley and approach the Great Lakes tonight. The core of the coldest air aloft, with 850 mb temperatures around -3C to -5C moving across the area late tonight and into the day on Thursday. The cold advection aloft will steep lower level lapse rates and additional isolated to scattered showers will be possible as the lead shortwave moves through. Colder air will work in at the lower levels, but moisture will linger near 850 and below and the colder temperatures aloft should promote a considerable amount of low clouds tonight and lingering into the day on Thursday. Surface high pressure over the Southern Plains will build northeast toward the TN and OH Valleys tonight. Mid level heights are expected to rise on Thursday into Thursday evening as the closed low departs further west and a western trough digs toward the Four Corners region. Meanwhile sfc high pressure is expected to build across the southern states and into the Lower OH Valley and Southern Appalachians. Low level moisture is expected to linger and a rather substantial cu and stratocu field should be in place or develop on Thursday and this combined with the rather cold 850 mb temperatures should lead to below normal temperatures for Thursday. During this time, the high will usher drier air into the region and some clearing or partial clearing should support temperatures dropping off to near the freezing mark if not the upper 20s on Thu night. .LONG TERM...(Friday through Wednesday) Issued at 259 PM EST WED NOV 30 2016 There will be plenty more opportunities for rain through the long term period as an active weather pattern sets up across the CONUS. We start out with zonal flow aloft but this transitions to southwesterly flow next week as a cutoff low over northern Mexico ejects northeastward and is followed by the establishment of a deep and broad trough out west, with ridging up the East Coast. High pressure at the surface will control our weather through Saturday with dry but chilly conditions expected. A weak ripple in the flow aloft passing across the Ohio Valley combined with diffluence aloft to our southwest results in a weak overrunning event Saturday night into Sunday. Light precipitation will overspread the area from southwest to northeast Saturday night. Temperatures will be borderline for rain or snow, and will include both at the onset, but precip should become all rain during the day Sunday as temperatures warm into the 40s. Models have trended drier Sunday night as our overrunning event quickly pushes off to the east. The next solid chance for precip then arrives late Monday into Tuesday morning as the upper low over northern Mexico opens up and ejects northeastward. This should be all rain with temperatures well above freezing. We will then maintain a small rain chance Tuesday afternoon through Wednesday as models are varying with their timing of another weather maker entering the scene from the west. This last system still looks poised to bring some cold air south into our region to end the work week.
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&& .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) ISSUED AT 110 PM EST WED NOV 30 2016 The main band of rain continues to shift into WV and VA with isolated showers behind it. Initial CIGS varied widely, from IFR to VFR, with the worst conditions generally in the southern and southeast part of the area. Between 18Z and 0Z most locations should experience improvement to VFR. However, cigs and or vis may still drop to MVFR at times as additional isolated to scattered showers are expected through 3Z behind the main band. Low level moisture is projected to linger so some 5 KFT or lower VFR or MVFR CIGS are expected from then through the end of the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JP LONG TERM...ABE AVIATION...JP

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