Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 230931 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 531 AM EDT Fri Jun 23 2017 .SHORT TERM...
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(Today through Saturday) Issued at 531 AM EDT FRI JUN 23 2017 The remains of Tropical Storm Cindy were very obvious in radar and satellite imagery over AR early this morning. Meanwhile, a cold front over northern MO and northern IL was moving southeast. Models are in general agreement on the evolution of these features during the period. Interaction with the prevailing westerlies will continue to carry the tropical remnants east northeast ahead of the cold front, with a track expected to be through KY. Low to mid level wind fields will strengthen as the low approaches, and continue to transport very moist air into the area, with precipitable water expected to reach 2-2.5". A significant lull in the precip is expected through much of the day, allowing warming and destabilization. This would aid convective development as the system arrives in the afternoon and evening. Both heavy rain and severe weather are threats. In term of rainfall, the deep tropical atmosphere will support very efficient precip production. Models agree on the heaviest amounts to be in our northwest counties. This is also where the heaviest rain has already fallen. A flash flood watch was already issued area wide, but the greatest threat looks like it will be in our northwest counties. That being the case, confidence is not all that high that we will see problems in our southeast counties. However, with the watch already out, the onus is to prove that hydro problems won`t occur there. Certainly don`t want to have flips in the watch situation, so will leave it run in the southeast. In terms of severe weather, low level shear looks significant, both in terms of speed and direction. The more questionable factor seems to be the degree of surface based instability which will be present. At most, it should be rather weak for this time of year. However, with the degree of shear, any surface based instability would be a concern. Dragging down environmental winds and adding on a bit due to convection could be enough for damage. Also, the low condensation heights along with the high storm relative helicity in the soundings are supportive of brief tornadoes. Due to the warm atmosphere and lack of strong instability, hail is not a concern. The tropical remnants pull out to the east this evening, wind fields weaken, and the severe threat drops off. It will be a little while longer until the cold front passes, and some additional showers or thunderstorms could fire until it passes late tonight and early Saturday. However, mid level drying is expected when the tropical system departs, which will also allow the heavy rain threat to diminish during the night. Much drier air will arrive at the ground behind the front on Saturday. .LONG TERM...(Saturday night through Thursday) Issued at 358 AM EDT FRI JUN 23 2017 A period of drying is on the horizon and near record cool temperatures possible early next week. That said, in the wake of a cold front we will see falling heights and a building Canadian surface high pressure. The models are in fair agreement on this Canadian surface high pressure and matter of fact really strong agreement in the GFS ensemble members. Also several reinforcing waves will bring single digit 850MB temperatures into the region for the first part of next week. These temperatures will be significantly anomalous, with 500mb to 850mb temperatures expected to be 3 plus standard deviations below normal for this time of year. At the surface, the coolest day may be Wednesday morning depending on how cloud cover shakes out on Tuesday morning, but temperatures in the low to mid 50s and some valleys could drop into the upper 40s. These kinds of temperatures will be close to record temperatures for both days with JKL current record for Tuesday is 54 degrees and 53 degrees on Wednesday. However, our records at JKL may be a little weaker compared to LOZ, where LOZ records showing 48 degrees Tuesday and 50 degrees on Wednesday which may be more difficult outside of valley locations. Temperatures by Wednesday do warm, as the high pressure moves off toward the VA/NC coast line and we see increased return flow. By Thursday, the models show a little less agreement, but a wave could generate some showers by the afternoon. Past this the CPC would suggest more chances of precip becomes possible as we begin July.
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&& .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 302 AM EDT FRI JUN 23 2017 A break in the action was ongoing at the start of the period, with mostly VFR conditions. As the remnants of Tropical Storm Cindy approach from the southwest ahead of a cold front, low clouds are expected to increase overnight, with much of the area expected to see MVFR ceilings for a time late tonight or Friday morning, followed by an improvement to largely VFR during the day Friday. However, there is not a lot of confidence in the specifics of the TAFS regarding timing of MVFR versus VFR into Friday afternoon. The prospect of showers and thunderstorms will be rising during the day Friday, with the most likely time for rain being late in the day and in the evening. An eventual drop to IFR and low end MVFR conditions is expected Friday evening, as a cold front approaches and moves through. Some of the storms and heavier showers on Friday afternoon and early evening may bring high winds. Also concerning winds, LLWS has been included in the TAFS tonight and into the day Friday, until sufficient mixing occurs to dissipate it. && .JKL WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch from noon EDT today through Saturday morning for KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120. && $$ SHORT TERM...HAL LONG TERM...DJ AVIATION...HAL

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