740 FXUS63 KJKL 261131 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 731 AM EDT Wed Apr 26 2023 .UPDATE... Issued at 705 AM EDT WED APR 26 2023 Mostly clear skies have prevailed through the night allowing temperatures to bottom out in the lower and mid 30s in the Coalfield Valleys, as per the Kentucky Mesonet, Middlesboro AWOS and COOP reports. Multiple Coalfield valley COOPs are reporting frost this morning. Therefore, the Frost Advisory will remain in effect until expiration. Minor adjustments were made to the forecast grids to bring them in line with the latest observations. Updates have been issued. && .SHORT TERM...(Today through Thursday) Issued at 359 AM EDT WED APR 26 2023 Key Messages: 1. Patchy to areas of frost expected early this morning, primarily in the deeper Coalfield valleys and sheltered hollows. 2. Temperatures will remain below normal through the short-term period. 3. Moderate to high chances for a wetting rainfall arise from the southwest on Thursday. At 755z, mostly clear skies prevailed across the forecast area under an area of weak mid-level height rises. This clearing has allowed temperatures to fall back into the mid 30s in the typically colder Coalfield Valleys, likely allowing the formation of frost. Over the ridges, west of I-75 and north of I-64, temperatures remain milder. Clouds are more prevalent to our north, west and south. To our north, a weak cold front is draped near the Ohio River. Meanwhile to our southwest, a disturbance is moving up the Tennessee Valley with an area of showers. Heading through the morning, mid and high cloud cover will increase from the west southwest as that disturbance nears. However, it does appear that any associated rain showers will stay south of the KY/TN border. Meanwhile, the remnants of the cold front to the north will slowly settle southeast of I-64 with little more than some increased mid-level cloud cover. This combination of systems will lead to varying amounts of filtered sunshine, warming temperatures into the upper 60 to lower 70s south of the Mountain Parkway and generally mid 60s to the north. By later in the day, clouds should start to thin as the disturbance departs and the front largely dissipates. The thinning cloud cover should allow for another quick drop off in temperatures this evening, particularly in valleys. However, unlike the prior night, clouds will increase and thicken quickly again overnight as an upper level low, presently near the Four Corners region, and its surface reflection approach the Lower Ohio Valley. This will keep the threat of frost away as temperatures bottom out in the upper 30s to mid 40s at most locations. A few mid 30s cannot be ruled out in the coldest valleys north of the Mountain Parkway. Rain chances with the system's warm front arrive in the Lake Cumberland area by around sunrise on Thursday and spread northeastward, reaching the Big Sandy basin by late afternoon. Model guidance has generally trended faster with the arrival of precipitation and have thus increased PoPs to around 60 percent area-wide. If the 00z CAM suite solution is realized, categorical PoPs will spread across the entire forecast area by late in the afternoon. There is also a small chance for an embedded rumble of thunder with this activity, highest chances over the southwestern third of the forecast area. Maximum temperatures on Thursday should generally be in the lower to middle 60s due to the thicker cloud cover and rainfall. A few upper 60s to lower 70s readings cannot be ruled out close the West Virginia border where sunshine will prevail the longest. .LONG TERM...(Thursday night through Tuesday) Issued at 537 AM EDT WED APR 26 2023 Key Messages: * Widespread rainfall Thursday night into early Friday, with another round possible on Sunday. Additional low-end rain chances remain in the forecast early next week. * Near to slightly above normal temperatures this weekend will cool off to well below normal by early next week. The models remain in general agreement with an amplified long wave pattern to be in place through the extended portion of the forecast. Smaller-scale feature predictability has also come into somewhat better agreement compared to last night, especially through Saturday. There is still some uncertainty looming from Sunday through Tuesday. A short wave trough will swing from the middle Mississippi Valley through the Ohio Valley Thursday night, with a reflective surface low following suit. This system will continue its journey towards the Great Lakes on Friday, with an attendant cold front moving through eastern Kentucky during the day. This weekend, a southern stream low will move east out of the southern Plains, while a stronger northern stream low moves southeast out of south central Canada. Models have trended slower and further south with the southern stream low, while trending further north with the northern stream low. Consequently, the blended PoPs have lowered from Saturday through Sunday compared to last night, with a more pronounced lull occurring from Friday night into Saturday. An uptick in the PoPs will generally peak on Sunday, as another cold front moves through the region. Cooler showers will linger into early next week, although even these are a bit less now, as the core of the upper level low looks to gyre further north. Showers, along with a few embedded thunderstorms, will move through our area Thursday night into Friday, with a break in the action by late Friday night into Saturday. The next cold front takes aim at the area Saturday night into Sunday, bringing another round of rainfall. A few showers will linger through Tuesday, as deep troughing becomes entrenched across the eastern CONUS. Gusty winds will also occur Monday and Tuesday, although probabilities for seeing stronger gusts have trended lower. Temperatures will average near normal through the weekend, with highs ranging from the upper 60s to lower 70s, and lows in the 50s. Temperatures will then dip to well below normal by Monday and Tuesday, with highs retreating to the 50s and 60s, while lows cool off to the upper 30s to lower 40s, depending on how much cloud cover persists. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) ISSUED AT 731 AM EDT WED APR 26 2023 VFR conditions will prevail through the forecast period while winds remain light and variable. However, clouds will thicken and start to lower at the end of the forecast period ahead of approaching low pressure. && .JKL WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 9 AM EDT this morning for KYZ104-106>117- 119-120. && $$ UPDATE...GEERTSON SHORT TERM...GEERTSON LONG TERM...GEOGERIAN AVIATION...GEERTSON