Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 290708 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 308 AM EDT Wed Mar 29 2017 .UPDATE... Issued at 140 AM EDT WED MAR 29 2017 Did a quick update to the grids to fine tune Sky cover and patchy valley fog through the rest of the night. Also tweaked the T and Td grids per the latest obs and trends. These have been sent to the NDFD and web servers. UPDATE Issued at 1102 PM EDT TUE MAR 28 2017 Current conditions across eastern Kentucky feature the cloud cover across the area now showing a bit more breaks. Though some of the cloud cover is hanging on over the eastern higher terrain due to some upslope. Recent observations have shown more of a northerly to north-northeast direction and thus some decrease is the upslope. So lowered the cloud cover a bit and added a bit more fog to the southern locations. If this eroding of the cloud cover continues, an update will be needed to lower cloud cover, lower temps, and add more areas of dense fog. A new zfp has issued for this update. UPDATE Issued at 743 PM EDT TUE MAR 28 2017 Current conditions across the area feature low level cloud cover in north to northwesterly flow moving south through the area. The challenging part to this update is the fact that there are noticeable small breaks win the cloud cover and where this occurs, there will likely be a drop in surface temps, especially in the valleys as well as fog development. For now, have updated to input the latest temps and dew points. Also adjusted the cloud cover slightly less but nothing worthy of a new zfp at this point. The upslope flow across the area will tend to keep the cloud cover over the area for the remainder of the night. The forecast remains on track but the current cloud cover situation will be continually be monitored. && .SHORT TERM...(This evening through Wednesday night) Issued at 312 PM EDT TUE MAR 28 2017 A shortwave trough and surface low pressure continue to depart to the north and east of the region while surface high pressure is beginning to nose into the OH Valley. Height rises are also occurring the wake of the departing shortwave trough with the axis of this ridge currently extending from the central Gulf of Mexico northwest toward the Mid Ms Valley region. Upslope flow, especially above the surface is combining with daytime heating to produce shallow light rain showers and sprinkles or drizzle. Stratocu and cumulus have been rather persistent, but breaks and thin spots in the clouds have allowed many locations to experience temperatures climbing into the low to mid 60s under the increasingly strong late March solar insolation. The surface low and shortwave trough will continue to depart to the east and northeast tonight while upper and surface ridging build into the OH Valley and Appalachians. Through this evening, isolated to scattered showers or light drizzle should persist, but wane this evening with loss of daytime heating and low levels stabilize. However, low level moisture is expected to remain trapped below a subsidence inversion tonight and the degree of clearing is uncertain though give the current rather extensive area of clouds currently over the Great Lakes and OH Valley at this time. This and model forecast soundings of persistent moisture at about 850 mb and below and time heights through this evening and tonight, only some partial clearing especially in the south is anticipated. Radiational valley fog is possible and a mix of this and stratus build down fog is also possible, though confidence in the details is not high. The axis of the upper level ride is expected to continue to move east and should move across the area Wednesday evening while the next in a series of upper level troughs/upper lows moves from the Southern Plains and begins to nears the MS Valley late. Meanwhile surface low pressure is expected to track from West TX to MO. Clouds should decrease on Wednesday morning, with milder temperatures compared to today. The pattern of upper level ridging beginning to depart and surface high pressure departing is favorable for some valley fog as well as at least a small to moderate ridge valley split with favorable net radiational cooling conditions for the normally colder eastern valley locations. .LONG TERM...(Thursday night through Tuesday) Issued at 308 AM EDT WED MAR 29 2017 A shortwave trough will advance east across the region Thursday night into early Friday morning sending widespread showers and a few thunderstorms across the region. Given good moisture and lift, will maintain the categorical pops through this period. The mid level low will cross northern Kentucky Friday afternoon with numerous showers likely well into the afternoon, making for another cloudy, cool, and damp day. Rain showers will wind down into Friday night, but may transition to some patchy drizzle as some low level moisture will remain left behind. Any drizzle will come to an end by midday Saturday with the rest of the weekend featuring a return to dry weather as a surface ridge spreads eastward across the region. Our next storm system looks to arrive on Monday and Monday night sending another round of rain showers into eastern Kentucky. Looks like pretty strong southeast winds with this system through Monday, so we`ll have to see how much that eats away at potential rainfall given the downsloping conditions. In fact, some areas may struggle to measure with the kind of solution models are currently centering around. Eventually forcing will win out and we should see some showers or storms over most of the area, certainly by Monday night. Wrap around moisture may keep a chance of showers going into mid week with another system following on the heels of this system yet again. The active and wet weather looks to continue. Models also support a continuation of the mild weather outside of a cooler day on Saturday with the clouds. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 150 AM EDT WED MAR 29 2017 Low level cigs - mainly IFR - will be in place across most of the area through the rest of the night locked in place by northerly flow. The exception will be in the Cumberland Valley where a reprieve its underway - though a period of low cigs are still possible towards dawn. Look for clearing for to overtake the rest of the TAF sites between 15 and 18Z. While fog development in the valleys will be hindered due to the persistent low level cloud cover, a few spots with visibility below IFR are anticipated through dawn but should not affect any TAF site. Winds will remain light - generally from the northeast to southeast through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JP LONG TERM...KAS AVIATION...GREIF is the U.S. government's official web portal to all federal, state and local government web resources and services.