Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 280624 AAD AFDJKL Area Forecast Discussion...UPDATED National Weather Service Jackson KY 224 AM EDT THU JUL 28 2016 .UPDATE... Issued at 210 AM EDT THU JUL 28 2016 Hourly grids have been updated based on trends in convection and observations. Convective allowing models were also factored in for pops. However, most recent trends seem to favor the past couple of HRRR runs over some of the other convective allowing models. This would leave the best chance for measurable rain overnight across the northern and far southeastern counties. Radar trends will be monitored for possible lower pops for much of the overnight in the southern counties. Fog could also form in some locations and might become dense. This will also be monitored. Otherwise, the region remains in a warm and moist airmass with PW analyzed in the 1.9 to 2.1 inch range across the CWA. The highest PW is generally across the middle of the CWA then extending into Central and Western KY and then south along the MS Valley. Several locations across the CWA received locally heavy rain and will be primed for high water issues if heavy rain falls in these same locations on Thursday. UPDATE Issued at 1156 PM EDT WED JUL 27 2016 The main activity at this late hour is across our southern counties. There appears to be a good lightning show and some heavy rain, but there have not been reports of impressive winds out of the current storms. Other storms more scattered in nature existed elsewhere. Models are suggesting the main show late tonight will come from the area of showers and thunderstorms over western KY as they develop toward the east and northeast. Because of heavy rain which has already occurred, the Flash Flood Watch was updated to start immediately instead of waiting until 2 am. UPDATE Issued at 630 PM EDT WED JUL 27 2016 Have updated to blend obs into the evening forecast. Clusters of thunderstorms are ongoing, but coverage has likely peaked for the time being. && .SHORT TERM...(This evening through Thursday night) Issued at 305 PM EDT WED JUL 27 2016 ...Torrential rainfall on Thursday may lead to Localized Flash Flooding... Expect scattered showers and thunderstorms to continue into the evening with the primary focus turning to the heavy rain potential tomorrow. A stalled frontal boundary has lifted north of the area and is expected to stay just north of the state through the day tomorrow. This has allowed winds to turn more southerly this afternoon. As a southern stream wave strengthens and lifts out of the Mississippi Valley overnight tonight, winds will turn a bit more southwesterly and increase in strength, allowing for an even deeper pull of moist air. This upper wave will interact with the stationary frontal boundary, as well as the potential phasing of the northern and southern stream jets, to create a large surge of warm deep moisture and lift for which storms to develop across our area. PWAT values for tonight will be well over 2 inches and will continue to increase up to 2.4 inches in some places by tomorrow afternoon. While CAPE and LI values remain decent per model soundings, the profiles are long, skinny, and moist with little wind shear. This type of profile indicates heavy rain and flash flooding concerns, moreso than severe weather. Mostly unidirectional flow in the mid and upper levels may lead to training of storms, which would likely lead to localized flash flooding. Depending on the model, anywhere from 1.5 to 3 inches of total rainfall is possible Thursday through Friday morning. Considering the extreme PWATS, any storm that does form would be a very proficient rain producer. All this considered, have decided to issue a flash flood watch for the entire area from late tonight through Friday morning. The bulk of the rain is expected to exit the area by dawn on Friday but we can expect unsettled weather to continue into the weekend. Temperatures will take a downward turn tomorrow with the onset of thick cloud cover and heavy rains, with highs in the low 80s. .LONG TERM...(Friday through Wednesday) Issued at 300 PM EDT WED JUL 27 2016 No real break in sight from the unsettled weather as models project our area remaining in northwest flow aloft with a quasi- stationary frontal boundary positioned over us over very close by throughout the period. This will bring us daily chances for showers and thunderstorms, especially during the afternoon and evening hours. These should be scattered in nature most days, although a decent shortwave shown passing through the Ohio Valley may spawn a little more widespread coverage of showers/storms on Saturday and indicated higher PoPs there. The ground should be fairly wet after the short term rainfall so at least isolated flash flooding will remain a concern, at least through the weekend. Otherwise, it will remain warm and humid throughout the period with daytime highs well into the 80s and dewpoints in the upper 60s to lower 70s. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) ISSUED AT 215 AM EDT THU JUL 28 2016 Some convection remains possible overnight, though higher chances are not anticipated at the TAF sites until the 12Z to 18Z period. Showers and a stray thunderstorm are possible, generally early in the period at JKL, SJS, and SYM as an initial disturbance lifts north. SME and LOZ could experience a stray shower and with some MVFR fog during the 7Z to 12Z period. MVFR fog is anticipated elsewhere, though the extent of fog development remains uncertain with mid and high clouds lingering. A weak disturbance is nearing the lower OH Valley and should bring convection in from the west by the 11Z to 16Z period. Convection associated with this disturbance may linger as late as 0Z, if not after. MVFR vis and or CIGS have been kept through the 20Z to 0Z period, with further reductions possible thereafter. There will likely be varying conditions and some at least brief VFR in between showers and storms cannot be ruled out between 12Z and 18Z at most sites. && .JKL Watches/Warnings/Advisories... Flash Flood Watch through Friday morning for KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JP SHORT TERM...JVM/JMW LONG TERM...ABE AVIATION...JP is the U.S. government's official web portal to all federal, state and local government web resources and services.