Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 291807 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 107 PM EST Tue Nov 29 2016 .UPDATE... Issued at 1147 AM EST TUE NOV 29 2016 Forecast was in good shape through the morning. Did a couple updates to make sure the near term forecast for temps, dew points, and winds was on track with the current observations. All changes made have been published and sent to NDFD/web. No forecast packaged updates were needed at this time. UPDATE Issued at 753 AM EST TUE NOV 29 2016 Showers have just about moved out. Clouds are less extensive than earlier forecasted, and central KY is mostly clear. Based on this and forecast soundings, have lowered the sky cover forecast ford today. && .SHORT TERM...(Today through Wednesday) Issued at 443 AM EST TUE NOV 29 2016 Rain was ongoing over the southeast portion of the forecast area early this morning, but the back edge was progressing toward the Virginia state line. The rain was occurring near a cold front moving east through Kentucky. The parent low is deep, stacked, and very wound up over the north central CONUS. Its initial cold front trying to pass through at our latitude is becoming oriented nearly parallel to the upper level flow, and is slowing down and losing its identity. It will not result in any real cooling. Instead, another upper level impulse rotating around the large scale low/trough will support a second cold front moving in from the west tonight. Low level flow ahead of this front and around the large scale low will advect mild and humid low level air (by November standards) into our area late today and tonight. This eventually results in unstable soundings during the night. The smaller scale models such as the WPC NAM and the NSSL WRF are indicating convection breaking out during the night and moving east into the region. Forecast soundings suggest it will be mainly elevated, but show some potential to become briefly surface based just ahead of the cold front. Shear is expected to be very strong, which certainly does cause concern for severe wx potential, especially if the convection can become surface based. Have noted SPC`s outlook, with slight risk now into the southwest part of the forecast area. Lingering precip will probably last into Wednesday morning, but will taper off for the afternoon as the cold front moves east of the area, a much cooler air mass arrives, and most moisture above 850 mb is lost. .LONG TERM...(Wednesday night through Monday) Issued at 235 AM EST TUE NOV 29 2016 Extended starts off with good model agreement and confidence, but by the end of the weekend into next week, confidence is as low as you can get with models all over the place with possible solutions. In general, expect any remaining showers to quickly exit the area Wednesday evening with dry weather returning for the remainder of the work week thanks to a surface ridge that will spread in over the region. Despite the ridge, cooler weather will persist through Saturday with temperatures slightly below normal for this time of year. By Sunday, models continue to show poor agreement on how much energy ejects out of the southwest CONUS and into our region. 00z ECMWF has backed off slightly on the strength of the system, but still has a decently wrapped up system coming across the area with some very high rainfall totals. Meanwhile, GFS brings a much weaker system across the area with very little rain. This operational run has some support of the GFS Ensembles. Depending on how much energy initially ejects out from the southwest will lead into what happens early next week. Thus, with the low confidence, opted to stay close to climatological rainfall chances (generally around 20 to 30 percent) from Sunday through the end of the period. Right now, the best rain chances look to be on Sunday and Sunday night, but this could still change. What does appear to remain somewhat confident on the forecast is that precipitation will likely remain rain through most of the period. There could be a chance for some snow flurries or snow showers if a stronger system does develop late this weekend or next week, but with the ECMWF backing off of the stronger solution, snow chances look less. && .AVIATION...
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(For the 18Z TAFS through 18Z Wednesday afternoon) ISSUED AT 106 PM EST TUE NOV 29 2016 Skies have cleared out throughout the day behind the exiting cold front. Only a few fair weather CU remain at the TAF sites. Expect VFR conditions to hold through the rest of the afternoon, before conditions begin to deteriorate once more ahead of the next approaching cold front. Winds today will generally remain under 10 knots from the SSW, though some gusts up to 15 to 20 knots cannot be ruled out through the afternoon. Rain will begin intruding into eastern KY ahead of the cold front after 0z, starting across the southwest TAF sites of KSME and KLOZ, then quickly spreading northeastward. Skies will continue to lower and deteriorate throughout the night. May not rule out some LIFR or even airport mins by daybreak. Strong winds aloft may cause some llvl wind shear concerns through much of the night as well, and any of the heavier rain showers may be able to mix some of these higher gusts down to the surface as well. There is also enough instability to possible produce thunderstorms, so kept in mention of VCTS throughout the duration of the rainfall. Given the strong wind sheer, can`t rule out the isolated potential for spin ups/small tornadoes as well. By tomorrow morning, rain showers and VCTS are expected to be in control across all of eastern KY, and gusts will begin translating down to the surface. This, in addition to MVFR or lower cigs should continue through the end of the TAF period.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...HAL LONG TERM...KAS AVIATION...JMW is the U.S. government's official web portal to all federal, state and local government web resources and services.