Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 271906 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 306 PM EDT Thu Jul 27 2017 .UPDATE... Issued at 1222 PM EDT THU JUL 27 2017 Most significant area of precip is about to exit the eastern part of the forecast area, after having tracked across the north. Additional scattered showers/t`storms were ongoing across the area, but the coverage is much less. Overall suggestion in the mesoscale models from this morning is that the best shot at good coverage of precip later this afternoon is in the northern part of the area, but confidence in the evolution of convective development is not very high. UPDATE Issued at 1033 AM EDT THU JUL 27 2017 Showers/t`storms have become fairly widespread over the northeast portion of the area, and the POP has been increased for that area. Forcing mechanisms are weak, and nailing down when where development will occur is difficult today. Will need to further examine trends and latest model runs to see how morning convection may impact the outcome this afternoon. UPDATE Issued at 700 AM EDT THU JUL 27 2017 The forecast remains on track so far this morning. A few showers and storms will be moving across the area early this morning. These will gradually increase in coverage as the morning wears on, and should be widespread across the area by this afternoon. The best chance for rain will be from this afternoon through tomorrow, as a cold front slowly moves across the region. Other than using the latest obs and short term model data to freshen up the hourly forecast grids, no changes to the forecast were necessary. && .SHORT TERM...(Today through Friday) Issued at 311 AM EDT THU JUL 27 2017 A few rain showers have formed during the overnight, and should be moving into the area between 7 and 8Z. These should remain isolated to scattered through early this morning. This activity is likely firing up due to the presence of a weak low level jet. A few thunderstorms should begin forming across the area after the sun has been up for a couple of hours and some heating begins to occur. Through out the day today we can expect scattered showers and storms to increase in coverage as a cold front approaches from the north. The most widespread rain is anticipated tonight and Friday, as the cold front moves slowly across the region. Due to the high moisture content of the atmosphere, and the presence of the front, locally heavy rainfall will be possible at times, especially with stronger thunderstorms, or anywhere that multiple storms move repeatedly across the same locations. Based on the latest model data, the best potential for heavy rainfall should be from late this afternoon through tonight. Temperatures today will range from slightly below normal values north of the Hal Rogers Parkway, to slightly above normal values south of there. We can expect a dramatic cool down on Friday as the front moves through the area and widespread clouds and rain push across the region. Highs on Friday will likely only make to around 80. .LONG TERM...(Saturday through Thursday) Issued at 305 PM EDT THU JUL 27 2017 The extended portion of the forecast begins on Saturday with an upper level pattern that is typical of summer at this point. A stout ridge remains in place over the western CONUS with a longwave trough over the east. At the start of the period, a shortwave trough is swinging through the OH valley. At the surface, a cold front or boundary at this point will be slowly exiting KY through the southeast. Thus, with minimal CAPE and the weak boundary, there will still be a slight to low chance of showers and a thunderstorm or two by Saturday afternoon. This activity will come to an end by Saturday night as the last of the lift exits to the east. By Sunday, surface high pressure nudges into the area, coupled with the mid level ridge axis shifting east into the OH Valley as well. Given the lack of return flow and increased area of subsidence, a lengthy period of dry weather is on tap. Thus will go with a dry forecast on Sunday and continue through the end of the extended on Wednesday night. As well, the lower dew points expected and below average to average high temperatures through the period will make for pleasant weather during the extended. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) ISSUED AT 232 PM EDT THU JUL 27 2017 It`s a difficult forecast for aviation, due to a high lack of confidence in specifics over the next 24 hours. Showers/t`storms are expected at times, but exactly when is the question. Have only used a generalized forecast in the TAFs, with precip being most likely tonight into Friday, and the worst conditions overall on Friday. If specifics become more apparent, they will need to be included in later issuances. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...AR LONG TERM...SHALLENBERGER AVIATION...HAL is the U.S. government's official web portal to all federal, state and local government web resources and services.