textproduct: Jackson

KEY MESSAGES

- Patchy frost is possible late tonight into early Friday morning in valleys of eastern KY, mainly away from rivers.

- A shower and thunderstorm potential arrives to start the weekend followed by a pattern shift that favors much above normal temperatures.

UPDATE

Issued at 805 PM EDT THU MAY 14 2026

The primary change for this update was to lower overnight temperatures a few degrees in many areas as thermometers were already running 2 to 3 degrees colder than forecast for most. An SPS for patchy frost has also been issued with a focus on sheltered valleys and hollows away from the protective nighttime fog likely to form in those valleys along larger water bodies (ie. lakes, rivers, larger creeks).

LONG TERM

(Saturday through Thursday) Issued at 536 PM EDT Thu May 14 2026

The long term forecast period is highlighted by a pattern shift and a noticeable warming trend. On Saturday, a series of shortwave disturbances are progged to propagate northeast through the Greater Ohio River Valley as ridging begins to amplify over the Southeastern CONUS. These impulses will progressively drag a surface warm front further to the north of the forecast area, and by Saturday night, the area looks to be firmly positioned within the warm sector. As that ridge axis nudges into the forecast area early next week, increasing geopotential heights and subsidence point towards a period of warmer and drier weather. Record high temperatures could be jeopardy by Monday, but before this unseasonable warmth is realized, Eastern Kentucky will experience isolated to scattered thunderstorm chances.

When the period opens on Saturday morning, models collectively resolve the aforementioned warm front to the west of the forecast area. Expect weak, southerly surface flow to shift to breezier southwesterly flow as the front lifts northeast during the AM hours. These southwesterly winds will be stacked up to the 850mb level in northern and western portions of the forecast area, resulting in relatively greater warm air advection and moisture return there. Forecast highs rise into the lower half of the 80s area wide, but dewpoints in the upper 50s are limited to those NW locales. As such, models resolve a SE->NW instability gradient within the warm sector on Saturday afternoon. The LREF Ensemble resolves a mean 500-1000 J/kg of CAPE to the NW of the KY-80 corridor, with the highest values north of I-64. Given the presence of a nearby warm front/effective boundary and the arrival of a reinforcing short wave on Saturday evening, there should be enough lift for parcels to rise. Approximately 30 knots of effective bulk shear could allow for the more sustained updrafts to organize/rotate, but any severe weather risk appears both conditional and marginal in the JKL CWA. AM cloud cover could cut into the amount of realized afternoon instability, and the further SE one goes in the forecast area, the drier the lower levels will be. Models collectively resolve a weak capping inversion and 100-150 J/kg of CIN across the area, and it is unclear if the weak surface convergence and dynamic lift from the shortwave will be enough to break through this cap. PoPs have decreased relative to this time yesterday, with the greatest chances in our Bluegrass counties. SPC has accordingly maintained a Marginal (Level 1/5) Risk for strong to severe storms there, with gusty to locally damaging winds and small hail the primary concerns. Trends in Saturday's convective parameter spacing and the positioning of the parent boundary will be monitored as this event enters the temporal range of higher-resolution, convection-allowing models, but this does not look like a widespread, significant severe weather outbreak set up.

By Saturday night, the area's sensible weather falls under the influence of the strengthening SE CONUS ridge. Expect any diurnal cumulus/cumulonimbus clouds to clear out after sunset and for ridges and valleys to decouple as a result. River valley fog could develop, especially if grounds are wet from the earlier convection, but hazardous weather is not particularly likely on Sunday and Monday. While it is true that the synoptic weather pattern favors a potent warming trend, the airmass in place across the forecast area early next week does not look particularly humid. Efficient diurnal mixing should lead to 25-35 degree dewpoint depressions, which will work to mitigate the area's HeatRisk. The baseline deterministic NBM MaxT guidance remains on the upper bound of the forecast envelope early next week, so highs were once again lowered in collaboration with neighboring WFOs. Temperatures should still climb into the upper 80s on Sunday and then towards the lower half of the 90s on Monday, but apparent temperatures should be fairly close to the actual thermometer readings. Those readings will be close to the record high values for May 17th and May 18th at the KJKL and KLOZ climate sites, and they are 10-15 degrees above climatological averages for mid-May in Eastern Kentucky. While it will be noticeably warmer outside, it will not be near heat advisory criteria. Coincidentally though, this early-season heat aligns with the 2026 National Integrated Heat Health Information System's Heat Safety Week campaign. Interests are accordingly encouraged to monitor our office's social media channels to learn more about local heat headline criteria, heat-related impacts, and heat safety/mitigation tips from Monday to Friday next week.

The early week heat is not forecast to persist through the end of the forecast period. While model spread increases towards the middle of next week, the consensus is for deeper troughing to emerge in the Great Plains by Tuesday. This will eventually drag a surface cold front towards the commonwealth, but the antecedent ridging will be slow to wean. Increasingly deep southwesterly flow around its western periphery should result in a fetch off the Gulf and more moisture in the column by midweek. This yields increasing cloud cover and the return of low-end precipitation chances on Tuesday, which introduces cascading uncertainty into Tuesday's temperature forecast. If skies stay sunnier and the chance PoPs don't come to fruition, Tuesday's temperatures could rival Monday's. Confidence in precipitation coverage is higher on Wednesday, which should mark the beginning of a cooling trend. However, the late-week sensible weather forecast depend on the evolution of the approaching cold frontal system. If the boundary stalls out amidst quasi-zonal flow aloft, we could see a wet end to the work week. If a more progressive pattern takes root, temperatures could cool back to climatological norms. Either way, interested parties are encouraged to stay tuned to future forecast updates.

AVIATION

(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 805 PM EDT THU MAY 14 2026

VFR conditions were present at TAF issuance, as a lingering cu field dissipates with the loss of diurnal heating. Mostly clear skies can be expected through the remainder of the period outside of any nighttime valley fog. At this time, SME has the greatest chance of being impacted by fog late in the night, though LOZ will need to be monitored as well. Winds will remain under 10 kts through 00z Saturday.

JKL WATCHES/WARNINGS/ADVISORIES

None.