Area Forecast Discussion
Issued by NWS Jackson, KY

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990 FXUS63 KJKL 200008 AFDJKL Area Forecast Discussion National Weather Service Jackson KY 808 PM EDT TUE JUL 19 2016 .UPDATE...
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Issued at 808 PM EDT TUE JUL 19 2016 Storms continue to remain well south of the Commonwealth in wake of a frontal boundary pushing across the Mid-Atlantic coast through the Tennessee Valley and southeast U.S. Still seeing a lingering uncomfortable airmass remain in place, but more comfortable conditions will be in the offing later tonight into midweek. Patchy valley fog still a good bet given juicy crossover temperatures and mostly clear skies other than a few cirrus, but dry air advection should keep dense fog at bay.
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&& .SHORT TERM...(This evening through Wednesday night) Issued at 303 PM EDT TUE JUL 19 2016 Drier air continues to seep into the region as a diffuse cold front sags southward. An isolated shower or storm will remain possible close to the Tennessee and Virginia borders for a few more hours before the drier air wins out. The front will wash out just to our south and west over the next 36 hours with dewpoints dropping back into the slightly more tolerable mid to upper 60s. MCS activity rounding the top of the building upper level ridge to our northwest will bring some mid and high level clouds from time to time but expect any associated shower/thunderstorm activity to either die out before it can make it into our area, or drop by to our west. Otherwise, just the normal valley fog can be expected the next couple of nights. Very little change is expected with temperatures during this period despite the passing front. The lower dewpoints will help overnight lows tonight and Wednesday night fall into the 60s for most locations, but daytime highs on Wednesday should again reach the upper 80s to near 90. .LONG TERM...(Thursday through Tuesday) Issued at 342 PM EDT TUE JUL 19 2016 A strong upper level ridge will be in control across much of the southern half of the conus through the extended period, including the Ohio River Valley and eastern KY. The center of this upper level ridge will be over the southwest conus states Friday, spreading eastward across KY and TN through the weekend, then shifting off the Atlantic Coast Sunday night into Monday. This will allow heights to lower slightly across the region Monday into Tuesday, though still strongly influenced by the upper level ridge. Expect warming temps throughout the rest of the week with the eastward progression of the upper level ridging. Temperatures hovering around 90 on Thursday will warm to the low 90s Friday, Saturday, and Sunday with winds generally out of the SW to W in the low levels. This, combined with increasing humidity values as well, will push apparent temperatures to the mid 90s on Thursday, tipping just over 100 degrees for Friday, Saturday, and Sunday...with Saturday expected to be the warmest day. While no shortwaves or surface systems are expected to impact us through the weekend, afternoon heat and instability could be enough to spawn some isolated convection. As was noted in the previous forecast, although this instability does begin to increase each day as we head into the weekend, the lack of deep layer moisture, warm air aloft, and the lack of substantial upper level support will likely preclude best thunderstorm development. Consequently, PoPs were kept at slight chances, generally on the lower end of the blended guidance. A shortwave is expected to impact the upper Great Lakes by Sunday, with a center of low pressure moving across Indiana and Ohio during this time. This may bring a bit better instability and moisture to the region for Sunday, so did keep chance pops in for this day, mainly during peak heating in the afternoon. The cold front protruding westward from this low will near the Ohio River on Monday, then push slightly southward into a portion of the state Tuesday, correlating with the exiting upper level high shifting off the Atlantic Coast. This will allow for slightly better instability and lift, so kept chance pops during this time as well. Clouds and slightly lower heights aloft will also allow a slight cool off across the region. && .AVIATION...
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(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 808 PM EDT TUE JUL 19 2016 Fog will be the primary concern overnight into Wednesday morning. The drier airmass seeping in and exact extent of cirrus complicate things and confidence on exactly how the visibility forecast will play out is rather low. Given lower mixing of afternoon dewpoints at SME/LOZ, raised forecast visibilities to MVFR from previous IFR mention tonight, while maintaining MVFR conditions at JKL and keeping VFR criteria in play at SJS/SYM for now. Could very well see sub-VFR visibilities at these latter sites, so will continue to monitor this evening/early tonight. Ridging in place will keep north/northeast winds light through Wednesday.
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&& .JKL Watches/Warnings/Advisories... None. && $$ UPDATE...GUSEMAN SHORT TERM...ABE LONG TERM...JMW AVIATION...GUSEMAN

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