Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 141618 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 1218 PM EDT Wed Mar 14 2018 .UPDATE...
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Issued at 1217 PM EDT WED MAR 14 2018 Flurries and a few snow showers continue to affect eastern Kentucky. With extensive cloud cover temperatures have been slow to rise. Have updated sky condition for more cloud cover this afternoon, mainly across the northeast three quarters of the forecast area, and have lowered afternoon temperatures for many areas. UPDATE Issued at 1014 AM EDT WED MAR 14 2018 Radar shows isolated snow showers and flurries continuing in the southeast part of the area, and there are also some returns over southwest OH and far northern KY. Have updated NDFD to slow the exit of snow showers in the southeast and to add flurries across much of the eastern part of the forecast area. Snow showers have been declining in the southeast so have allowed the winter weather advisory to expire. UPDATE Issued at 730 AM EDT WED MAR 14 2018 Issued an update to the forecast to input the latest observations and trend them through the morning hours. Adjusted the pops lower as the last of the snow showers have tracked further southeast into eastern Kentucky. Some of the snow showers have produced squall like conditions with a quick inch of snowfall put on the ground. Most of the showers have moves southeast so have expired another layer of the Winter Weather Advisory. The far east and southeast will remain in effect through 9am.
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&& .SHORT TERM...(Today through Thursday) Issued at 333 AM EDT WED MAR 14 2018 Current conditions across the area feature the last of a wave swing southeast through eastern Kentucky as the parent upper low slowly exits to the northeast over the Northeast CONUS. Northwest winds continue across the area heading into the dawn hours. This will keep the presence of snow showers across the area through the post dawn hours. With a rapid decrease of moisture, will be losing the moisture depth and thus the snow shower threat will be ending by mid morning. The accumulating snow over the western CWA will be coming to an end and thus will be ending the WSW at least for a portion of eastern Kentucky. In fact, dry air following in behind this impulse will drop dew points for the day today into the teens. Highs will struggle to get out of the 30s today will the colder air filtering into the region, even despite the clearing skies. Clear skies to begin this evening will allow valley temps to plummet into the 20s at least for the first part of tonight. The last piece of moisture dropping south from the exiting upper low will bring a brief period of cloud cover to mainly eastern portions of the area. This will slow the ridge to valley temperature difference. The last of the upper low will lift to the northeast for the day on Thursday allowing high pressure and clearing skies to dominate the weather. This will allow temperatures to rebound to near 60 in some areas. .LONG TERM...(Thursday night through Tuesday) Issued at 515 AM EDT WED MAR 14 2018 The models aloft are at least slightly out of step with each other through the bulk of the long term portion of the forecast. In particular, an increasing spread between the GFS and ECMWF is worrisome and significantly hampering confidence in any single model solution. They generally depict a weakening, but once closed off, trough riding east into the Ohio Valley this weekend following a brief visit of some higher heights. Even with the patch of ridging ahead of the trough - energy manages to move through Kentucky unhindered. However, it is this dampening trough that brings the troublesome weather with it for Friday night and Saturday as its energy is strung out through the state. This wave is sharper and slightly faster in the ECMWF while the GFS starts to lift heights much quicker in its wake late Saturday. Later in the weekend the models sync up better locally, but remain distinct from each with the next trough formation over the central and northern Rockies. After a brief visit from a flat ridge this fairly progressive trough will then head into the Ohio Valley for later Monday and Tuesday. The ECMWF has a much stronger lead wave with this than the GFS magnifying the differences. Accordingly, confidence is low in either specific solution. Given these discrepancies the general model blend was favored, though allowances were needed for more realistic temperatures (and dewpoints) Friday night into Saturday morning where the raw blend was used in place of the more complete SuperBlend. Sensible weather will feature a complicated and, typical of this transition season, changeable situation through the weekend. Into the cold air in place, a developing warm front will lay out through southeastern Kentucky Thursday night into Friday with showers arriving by dawn in the southern half of the CWA. The northern fringe of this could mix with snow showers, as well. The boundary will stay in place making for a wet day on Friday with the colder air still butting up against it to the northeast. As such, later that night additional precipitation will come down with a potential for light freezing rain or sleet as well as the rain to our northern counties - given a warm surge aloft but not much movement to the cold air at the sfc. Accordingly, have introduced this potential to the forecast and highlighted it as a concern in the HWO. Warm air then more effectively moves into eastern Kentucky from the southwest later Saturday into Sunday with showers a good bet as weak low pressure passes through the area. Weak high pressure nosing in from the north on Sunday afternoon and into Monday will only temporarily dry us out for a time. However, the next weather maker will quickly take shape to the west and potentially become strong over the Mid Mississippi Valley late Monday. This will place eastern Kentucky in the system`s warm sector with even a potential for a thunderstorm Monday night into Tuesday. Due to the fluidity of this situation and model disagreement have held off on including thunder in the forecast at this time. Colder weather follows later Tuesday as the sfc low passes by to the northeast - with more pcpn possible. The question is how much colder - with the ECMWF relatively mild compared to the GFS. Did not make much more than spot temperature adjustments to the Superblend - aside from the use of the raw blend Friday night into Saturday morning. Also, only made some tweaks to PoPs to try and hone in on the better times and threats of measurable pcpn like from Friday night through Saturday and again Monday night into Tuesday. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) ISSUED AT 730 AM EDT WED MAR 14 2018 The northwest flow over the area continues as the last of the snow showers will move off to the southeast. Thus will expect any MVFR cigs to improve to VFR through the morning hours. The cigs will continue to lift through the day. Winds will continue to be northwest through the day with some gusts up to 20 knots at times. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...SHALLENBERGER LONG TERM...GREIF AVIATION...SHALLENBERGER is the U.S. government's official web portal to all federal, state and local government web resources and services.