Area Forecast Discussion
Issued by NWS Jackson, KY

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS63 KJKL 092122 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 422 PM EST Sat Dec 9 2017 .SHORT TERM...
-- Changed Discussion --
(This evening through Sunday night) Issued at 408 PM EST SAT DEC 9 2017 As of mid afternoon, an upper level trough extended from eastern Canada south into the eastern Conus with an upper level ridge over the western Conus. The center of the sfc low of a clipper system is moving through the Great Lakes region with the associated cold front trailing south into Central KY while the associated mid level shortwave is approaching the region. The clipper system will track into the eastern Great Lakes this evening with the cold front moving across the area through early this evening. Snow showers and flurries are ongoing and should persist until after sunset as the colder airmass moves into the region and lapse rate rates remain rather robust. The escarpment in the Daniel Boone National Forest and the higher ridges of the southeast part of the area should be most favored for very light accumulations as winds become more of a favorable uslope direction. Temperatures are currently in the mid 30s across many areas of the eastern and southeastern sections of the area. With marginal ground temperatures, most locations should not receive more than a quarter to a half of an inch total from what has already fallen and what falls this evening. Elevations above 2000 feet may receive a bit more than these amounts. Temperatures will continue to fall and any light snow falling could initially melt on some untreated surfaces before possibly freezing or becoming slushy as additional snow showers pass resulting in slick or icy spots. An SPS has already been issued to handle this. The low level moisture will become shallower starting around 0Z or 1Z or 7 or 8 PM ESt in the western part of the area and then gradually become shallower from northwest to southeast. Enough low level moisture may linger long enough near the VA border so that flurries could linger until almost sunrise on Sunday. Low clouds should linger most of the night in many locations so ridgetops and far western locations with partial clearing will be coldest for overnight lows as coldest of the airmass moves through the area tonight. Mid level height rises will already have begun overnight behind the departing shortwave while surface high pressure begins to nose in from the Southern Plains. Mid level heights should rise further on Sunday with surface high pressure building across the Gulf States. Low level moisture and clouds is expected to diminish on Sunday morning, but additional shortwaves passing to the north should lead to bands of mid and high clouds on Sunday. This and a relatively cold airmass still in place will lead to continued cold temperatures. Dry weather will linger into Sunday night and with general mid level height rises and sfc high pressure centered to the southeast at least a moderate ridge/valley temperature split from the nocturnal inversion will be possible. COOP MOS guidance indicates this, but blended model guidance was more uniform. Opted to not go as low as the COOP MOS guidance just yet as the gradient could lead to some mixiness and although there will be periods of mostly clear skies, band of mid and high clouds aren anticipated and guidance has an increase in moisture around 850 mb and below so low clouds will also be possible. .LONG TERM...(Monday through Saturday) Issued at 230 PM EST SAT DEC 9 2017 The pattern will remain unchanged into next week with persistent upper level troughing over the eastern US with a series of weak clipper systems cross the great lakes and Ohio river valley. Models continue to advertise all of these clipper systems will struggle to bring much in the way of measurable liquid to eastern Kentucky. However, much like the system today, any of these systems may be capable of a quarter of an inch of snow. The first clipper system looks to come on through Monday night into Tuesday, with another one pegged for late Wednesday or Thursday. Temperatures will remain below normal through next week, although we could start to rebound a bit heading into next weekend.
-- End Changed Discussion --
&& .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) ISSUED AT 105 PM EST SAT DEC 9 2017 Middle and low clouds continue to spread east in advance of a cold front with southwest or west southwest winds generally in the 10 to 15KT range with some gusts up near 20kt for most ridgetop and western locations. Some scattered very light snow is likely reaching the ground in the far west as well, but CIGS and VIS remain in the VFR range. CIGS should continue to lower as the cold front approaches consistent with upstream obs over central KY and coverage of snow showers should also increase during the first 6 hours of the period. Some at least brief MVFR to IFR VIS and MVFR CIGS are possible in this. Winds should shift to the west and northwest behind the front with gusts as high as 20 to 25kt with snow shower coverage diminishing from west to east from 0Z to 6Z. Northern and eastern locations will also experience a few hours of MVFR CIGS during that time. Clouds should begin to clear and CIGS improve by the 6Z to 12Z period, giving way to VFR for all locations by the last 6 hours of the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JP LONG TERM...KAS AVIATION...JP

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.