Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 251114 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 714 AM EDT Mon Mar 25 2024 .KEY MESSAGES... - A critically dry air mass and an increase in southeast downslope winds will result in increased fire danger through late this evening. - Above normal temperatures return today before another round of rainfall late tonight and Tuesday. A few thunderstorms will be possible across the area late tonight and Tuesday morning. - Temperatures cool to within a few degrees of normal from Tuesday through Friday, with the threat for sub-freezing temperatures returning for many valley locations on Wednesday and Thursday nights. && .SHORT TERM...(Today through Tuesday) Issued at 452 AM EDT MON MAR 25 2024 A pronounced surface high pressure continues to wedge down the east side of the Appalachians while a strong cyclone continues over the Central Plains. This is causing an increased pressure gradient over the western slopes of the Appalachians and a modest increase in downslope southeasterly winds. This combined with an already exceptionally dry air mass in the lowest 10,000-ft of the atmosphere will produce very low humidity today bottoming out as low as the upper single digits to mid-teens across much of eastern Kentucky and greatly increase the risk of wildfires through this evening. Already, humidity values across parts of eastern Kentucky, especially over the higher terrain along the Virginia border and adjacent ridges to the northwest are below 30 percent RH, which is an unusually poor humidity recovery. Given the warm downslope drying conditions with gusts approaching 20 mph or higher at times, the forecast high temperatures for this afternoon remain well above deterministic NBM guidance in the lower to mid 70s. The air mass moistens overnight from southwest to northeast and from the mid-levels to the lower levels of the atmosphere as the aforementioned low pressure system begins to push a cold front across the Mississippi River Valley toward our forecast area. Drier air impinging on the moisture aloft will provide enough instability to warrant mention of showers with a slight chance of thunderstorms after midnight and lasting through Tuesday morning, and given the very dry low-levels gusty winds will be a threat with heavier showers and elevated storms initially. Increased cloud cover will likely keep temperatures well into the 40s to near 50 degrees, but lower 40s are possible in the far eastern sheltered valleys where dry air will linger through much of the night. Southeast winds will also increase this evening into the overnight, especially in our far southwest corner of the CWA, such as Wayne County, and may also increase to Wind Advisory criteria tonight over and just downstream of the high terrain of southeastern Kentucky. A Wind Advisory may be needed for all or parts of these areas for later today into Tuesday morning. The cold front will continue to slowly march east across the Bluegrass State, and will likely remain west of the forecast area at the end of the short term period early Tuesday evening. QPF looks to be primarily one-quarter to one-half inch, with some areas less, with many models depicting a dry slot causing shower chances to diminish from west to east as the afternoon progresses. Given expected breaks in rainfall during the day Tuesday and with continued southerly flow ahead of the front, highs will still reach into the 60s for most locations. .LONG TERM...(Tuesday night through Sunday) Issued at 452 AM EDT MON MAR 25 2024 The 25/00z model suite is initially in good agreement on Tuesday evening showing a broad upper level trough extending from an ~527 dam low over southern Manitoba down into northern Mexico. At the surface, an ~994mb low is passing over the Upper Great Lakes while an associated cold front sweeps out an arc through the Ohio Valley, across Central Kentucky and extends into the Lower Mississippi Valley. The trough will translate eastward across the Mississippi Valley on Wednesday pass across the Ohio Valley/Southern Appalachians on Thursday and depart off the Mid-Atlantic Coast on Friday. A low- amplitude upper level ridge will build across the Central CONUS behind the departing trough and remain in place through the remainder of the forecast period. At the surface, the cold front will precede the trough, crossing eastern Kentucky Tuesday night. Thereafter, high pressure will build eastward from the Plains as it drift toward Florida by the weekend. The initially chilly northerly winds behind the cold front will turn back to southerly on the backside of the high by Friday night. Theta-e gradient analysis shows frontal boundary formation from the Chesapeake Bay to the southern shores of Lake Michigan Friday and Friday night. That front may sag south somewhat during the latter part of the weekend and potentially spark convection but there is still uncertainty with regard to available instability. The sensible weather will feature any showers diminishing from west to east on Tuesday night and Wednesday as the cold front plods through the area. A stray shower could linger into Wednesday night adjacent to the Virginia border. Clouds will likewise breakup gradually from west to east. Look for a mild Wednesday morning with low temperatures in the mid 40s to lower 50s and highs in the upper 50s to near 70, west to east. Cooler air will continue to move in Wednesday night as high pressure builds east bringing widespread lows in the 30s. The greatest chance for frost and freezing temperatures on Wednesday night will be in valleys and low-lying areas along and west of the Pottsville Escarpment. The cooler, drier airmass will continue to infiltrate on Thursday with highs only achieving the 50s while dew points retreat back into the 20s under mostly sunny skies. This will set the stage for the coldest temperatures of the forecast period on Thursday night when clear skies and light winds will permit temperatures to drop back into the upper 20s in cooler valleys and lower to middle 30s elsewhere. Frost is likely for many. Looking ahead to Friday, temperatures will moderate back into the 60s for most locations under ample sunshine. Continued moderation of daily maximum temperatures to near 70 can be expected for both weekend days. The next chances for precipitation will also come next weekend. && .AVIATION...
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(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 713 AM EDT MON MAR 25 2024 VFR conditions are expected through the TAF period, with decreasing confidence at the end of the TAF period as high-based showers and storms begin to move into the forecast area. Light southeast winds will gradually increase in strength through the day, then become stronger and gusty through the overnight hours while gradually veering to a southerly direction at times. Despite the increasing winds, even stronger winds just above the surface overnight tonight warrant a mention of LLWS.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CMC LONG TERM...GEERTSON AVIATION...CMC

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