Area Forecast Discussion
Issued by NWS Jackson, KY
Issued by NWS Jackson, KY
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745 FXUS63 KJKL 212041 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 441 PM EDT Tue Jul 21 2026 .KEY MESSAGES... - A strong cold front could produce multiple rounds of thunderstorms this afternoon and into the first part of the overnight. - There is a Slight to Enhanced Risk for severe storms this afternoon and evening, including damaging winds, large hail, and isolated tornadoes. - Torrential rainfall from persistent thunderstorms could lead to flash flooding during this time. - Mainly dry weather is expected from Wednesday night to Friday, with temperatures averaging about 5 degrees below normal. && .SHORT TERM...(This evening through Wednesday night) Issued at 316 PM EDT TUE JUL 21 2026 The incoming cold front is the big story this afternoon and evening, as storms have developed ahead of the boundary and are dropping south and southeast. An upper level shortwave is also going over the Great Lakes region, creating deep troughing across the Ohio Valley this afternoon With a primed environment, especially in our northern CWA where sheer and CAPE are at their highest, all severe modes are on the table. A Severe Thunderstorm Watch has been issued through 2Z for the NW 2/3 of the CWA, and a Flood Watch for flash flooding is in effect for all of eastern KY through 6Z. The biggest concern remains straight line wind gusts and torrential rainfall with any of the storms that move through , however, hail and isolated tornadoes are still on the table. Best instability and shear will slowly decrease as the storms continue farther southeast this evening and we start to lose daytime heating/instability, but the storms are still forecast to make it to the TN and VA border by around midnight. Heading into the overnight, showers and storms will continue along the TN border as the cold front slows it`s progression through eastern KY and deep troughing remains in place across the region. For locations north of the remaining storms and boundary, drier air will begin to filter in as winds slowly turn more northward. However, expect clouds to likely stick around through much of the night. Kept fog in the forecast, but again did not confine it to just the river valleys given that most of the CWA will have residual moisture in place with cooling temperatures. Tomorrow - Wednesday - will be very opposite of today, thankfully. Some lingering showers/thunderstorms may be possible along the TN/VA border as the boundary remains a bit more stationary to our south, but the remainder of the CWA will continue to see high pressure build in from the NW. Humidity will be reduced, with temperatures topping in the upper 70s to low 80s. Models try to show clouds mixing out throughout the afternoon, but overall there may still be some cloud cover in place through much of the day. The filtering of cold air into the region will really be evident going into Wednesday night. Especially if clouds are able to continue to clear out, temperatures will drop into the upper 50s to low 60s, some 10 degrees colder than tonight`s temperature forecast. Any clearing could also promote fog development, especially in the deeper valleys that are both cooler and more moisture ridden. Kept with the previous forecast of valley fog during the overnight. .LONG TERM...(Thursday through Tuesday) Issued at 440 PM EDT TUE JUL 21 2026 At the onset of the long term period, upper level troughing will sit over the northeast CONUS, with an additional area of troughing associated with a closed upper level low located off the Pacific Northwest coast. Ridging will prevail between these features and will be centered over the Southern Plains at the start of the extended period, with anomalously high 500 mb heights across much of the central and western CONUS. Locally, eastern Kentucky will find itself in a region of northwesterly flow aloft for several days, with the forecast area sandwiched between ridging and troughing. At the surface, an area of high pressure near the Great Lakes will keep winds northeasterly on Thursday, ushering in cooler and drier air. Highs will struggle to rise above the low 80s, and with dewpoints falling into the upper 50s and low 60s, Thursdays weather will be downright pleasant. Overnight, lows will plummet into the upper 50s and low 60s, with typical fog formation in our mainstem river valleys. PoPs will return by Friday afternoon as a shortwave embedded within northwesterly flow aloft rotates into our area. Ahead of this shortwave, the eastward translation of the aforementioned surface high will allow winds to gradually become more northerly to northwesterly over the course of the day. This will allow for modest moisture advection, and given shortwave forcing, isolated to scattered storms will be possible near the VA line on Friday afternoon. With the potential for additional embedded impulses, rain chances will continue through Saturday, although the timing and details of this activity will need to be refined in later forecast periods. By Sunday, the northeast trough will deepen along the Atlantic Coast, with flow aloft becoming increasingly northerly over the forecast area. Model spread increases significantly at this point, with rain chances dependent on embedded impulses that are difficult to resolve this far out. For now, slight to chance PoPs are forecast through the end of the period, although uncertainty remains high at this time. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) ISSUED AT 324 PM EDT TUE JUL 21 2026 A bit of a volatile TAF situation this afternoon. While most TAFs are currently VFR, a line of showers and thunderstorms is currently located to our NW and will push SE throughout the rest of the afternoon and evening, affecting the TAF sites as it does. Expect VIS and CIGS to quickly be reduced in any storms that move through the TAF sites, with heavy rain, frequent lightning, and damaging wind gusts being the primary threats. Tried to time out the line in each of the TAF sites, but expect it should move through and exit within 3 and 4 hours from arrival. Outside of any storms, conditions should be VFR, though can`t rule out some fog development, especially behind the exiting storms overnight. Predominate SW to Wrly winds are breezy this afternoon, but will diminish into the overnight outside of any storms as well, staying generally light and variable into the day Wednesday. While some lingering low clouds may stick around overnight tonight, expect things to begin mixing out during the daytime hours Wednesday as a strong area of high pressure continues to build in. && .JKL WATCHES/WARNINGS/ADVISORIES... Flood Watch until 2 AM EDT Wednesday for KYZ044-050>052-058>060- 068-069-079-080-083>088-104-106>120. && $$ SHORT TERM...JMW LONG TERM...FAGAN AVIATION...JMW