Area Forecast Discussion

KEY MESSAGES

- Warmer-than-average conditions continue today ahead of a cold front that passes through Eastern Kentucky this evening and tonight.

- This cold front will bring beneficial rainfall and perhaps a few rumbles of thunder to the area today and into tonight. - A cooling trend takes place headed into the weekend.

SHORT TERM

(Today through Thursday) Issued at 415 AM EST WED NOV 4 2026

Early this morning, an upper level low was centered in the Upper MS Valley, with a 500 mb trough south over the Central Conus. A lead shortwave was moving through sections of the Lower OH Valley to TN Valley and sections of the southeast. Upper ridging was centered along the southeast U.S. coast. At the surface, high pressure was centered along the eastern seaboard, while a sfc low was centered in the upper MS Valley with an associated cold front extending south in the MS Valley vicinity. Winds in the lowest levels, roughly 925 mb and below are southeasterly between these systems, with winds more southerly to southwest from the 850 mb level and higher in elevation. A few spotty light showers or sprinkles have occurred over portions of eastern KY during the past couple of hours, with more substantial showers upstream over central and western KY down into western and middle TN and points south. Winds have gusted as high as the 26 to 36 mph range at the higher elevation KY Mesonet station locations in Pike County (2770') and Harlan County (4000') since midnight, with gusts generally no more than 20 mph elsewhere. A few valley locations remain decoupled as of 4 AM EST, with mid to upper 50s temperatures, though most locations have been more mixy or mixed out. PW is currently analyzed in the 1.1 inch or less to 1.6 inch range from far southeast to southwest, with more substantial values to the southeast and west.

Today and tonight, the upper level low should track into the western to northern Great Lakes and become an open wave and merge with a trough to the north in Canada. At the same time, the lead shortwave trough should advance across the Lower OH Valley today and into the middle OH Valley and east of eastern KY later tonight. The sfc low should trek to the northern Great Lakes/Lake Superior area tonight, while the trailing cold front moves gradually east across the Commonwealth, likely clearing far eastern KY late tonight. As the shortwave trough and cold front approach, moisture across the region will increase with PW per the 00Z REFS reaching around 1.1 inches near the WV border to about 1.5 inches southwest (88th to 97th percentile) around dawn on Wednesday, before peaking in the 1.4 to 1.6 inch range (96th to 99th percentile) this afternoon ahead of the shortwave trough and cold front.

Widespread rainfall is expected from rounds of showers with this system that should generally be beneficial following recent dry weather since mid October. These will arrive in the west first, toward dawn or shortly thereafter and then gradually spread east and northeast. Convection should wind down from west to east later this evening and into the overnight hours. Some thunderstorms are also possible but instability will be limited with MUCAPE peaking this afternoon on the order of 200 to 500 J/kg per the RAP. Given the rather substantial forecast PW values, any training convection could produce swaths of locally higher amounts. Uncertainty remains with storm total QPF due to the nature of the convection. NBM based QPF ranges from around 0.25 inches downwind of the VA border to as much as 0.8 to 1.1 inches in the west and southwest. 00Z REFS mean QPF is around 0.4 inches downwind of VA border counties (due to downsloping effects at least initially) to around 0.8 in sections of the west and northwest. Higher end event total rainfall, 00Z REFS 95th percentile values are generally an inch or more with around 2 inches on the high end in the JKL CWA. Max amounts are in the 2 to 3 inch range. HRRR runs at times have also have also had some swaths of higher amounts into the 2 to 3 inch range for totals. The 06Z HRRR has a bit lighter swaths in or near the JKL CWA of just under 2 inches. As for FFG values, they are generally in the 1.5 to 2.25 inch range for 1 hour, with a few areas over 2.5 inches in the southwest. 3 hour FFG is generally in the 1.8 to to 2.5 inch range with some higher values in the southwest, while FFG values in the 6 hour range were mainly in the 2.4 to nearly 4 inches. Based on the 00Z REFS, max 1 hour rainfall was in the 1.1 to 1.25 inch range while max 6 hour rainfall was in the 2 to 2.5 inch range. Even if the max values materialized over the shorter time steps, these would generally fall below FFG guidance values. Rainfall rates could be sufficient for some ponding of water on roadways, particularly as leaves fall and could result in some clogging of ditches and culverts in some areas. WPC has placed all but the far southeast in a Marginal ERO for Day 1.

Another concern will be as the rain tapers off from west to east and mid and high clouds diminish, will be the development of either fog or low stratus. The higher resolution models generally have some saturation below 850 mb to end the period. For now have continued patchy valley fog to areas of valley fog in the grids, with lower than average confidences if this is more of stratus event or a bit of a mix of valley fog and stratus pending geographic location.

On Thursday, eastern KY should remain in southwest flow aloft with the 500mb trough axis progged to extend from James Bay into the Great Lakes to portions of the Plains. The column should continue to dry on Thursday, with PW falling from around 0.9 inches east to 0.6 inches west at dawn per the 00Z REFS to roughly 0.5 to 0.65 inches or the 50th to 60th percentile by early Thursday evening. Weak sfc high pressure should build in behind the front into the Lower OH and TN Valleys on Thursday. A trend of drier weather with decreasing clouds by the afternoon is expected.

LONG TERM

(Thursday night through Tuesday) Issued at 330 AM EST WED NOV 4 2026

Another disturbance will trek from the Mid-Mississippi Valley and move towards the OH/TN valleys to begin the long term period. At the same time, a longwave trough over the Great Lakes region will meander southward towards the Ohio River. This trough will cross the area to end the week and bring a shot of colder, drier air as we head into the weekend. Following highs in the 60s to near 70 on Friday, temperatures will drop into the 50s for highs Saturday and into the 30s for lows particularly in valleys on Sunday morning. Monday morning appears to be the coldest, with lows well into the 30s for most locations. Lingering cloud cover may impact how cold the sheltered valleys get, but it is not out of the question that some of the more sheltered valley locations may see lows in the 20s Monday morning. Due to the cold morning temperatures, frost appears likely.

At this point, a fairly quiet synoptic pattern is currently anticipated from early to the middle portion of next week, with surface high pressure building across the Ohio Valley. Model guidance has some spread in terms of the positioning and strength of troughing across the southeast CONUS early next week. The 00Z ECMWF and the 0Z EMCWF ensemble mean have ridging in the southeast to begin the week. The 0Z GFS and 0Z GFS ensemble mean keep a trough in the southeast at that time. Both scenarios would result in very minimal or no chances for rain from early to the middle of next week. The consensus is for temperatures to hovering near normal, with daytime highs in the 60s and nighttime lows in the 30s.

AVIATION

(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 110 AM EST WED NOV 4 2026

VFR generally prevailed across the area at issuance time and VFR should generally prevail through the first 6 to 9 hours of the period though . Atmospheric moisture increases ahead of an approaching low pressure system, with clouds thickening and lowering. Ceilings gradually lower from west to east toward or into the MVFR range between 14Z and around 23Z. Showers may affect western portions of the area as early as 09Z and 12Z, with areas of showers and MVFR or perhaps briefly lower reductions spreading from west to east between about 12Z and 18Z, with strengthening southerly winds in this same time frame. Winds will strengthen aloft first, so some marginal LLWS is possible initially. Surface winds should be the lightest at northeastern terminals like KJKL tonight, so confidence in LLWS remains the greatest there. Once the stronger winds start to mix down after around 15Z, any LLWS should give way to surface wind gusts of 15-25KT. Additional showers are anticipated during the last 12 hours of the period as well along and in advance of the cold front, with MVFR or lower reductions. Winds become southwest to west at 10KT or less behind the boundary late. Overall, expect flight conditions to deteriorate beyond the first 6 to 9 hours of the period as the storm system approaches and moves into eastern KY.

JKL WATCHES / WARNINGS / ADVISORIES

None.