textproduct: Jackson

KEY MESSAGES

- Frost is expected form in a few of the normally colder valley locations around dawn.

- A warming trend begins today with afternoon highs returning to the mid 70s to low 80s by Sunday.

- Periodic chances for showers and thunderstorms return to the area this weekend, with the greatest chances on Sunday night.

UPDATE

Issued at 850 AM EDT FRI MAY 8 2026

Refreshed the diurnal temperatures with the latest observational data from around the area, and updated the forecast with the cancellation of the Frost Advisory this morning. No major changes to the forecast, as everything remains on track.

UPDATE Issued at 750 AM EDT FRI MAY 8 2026

Minor adjustments were made to hourly grids based on trends in valley fog that is generally located south of the Mtn Pkwy and for hourly temperatures. Temperatures bottomed out in the 32 to 36 degree range in the deeper valleys and have begun to recover. The frost advisory will likely be cancelled early within the next hour as temperatures gradually rise out of the mid 30s in the cold spots.

LONG TERM

(Saturday night through Thursday) Issued at 612 AM EDT FRI MAY 8 2026

The long term period opens with broad upper level troughing over the northeastern US and mostly zonal flow over Kentucky. At the surface, weak high pressure will build Saturday evening. Clear skies will allow for radiational cooling overnight, although westerly to southwesterly flow will maintain dewpoints in the upper 40s to low 50s before winds diminish overnight. These clear skies and light winds will set the stage for a ridge-valley temperature split, but respectable dew points will likely prevent valleys from cooling further than the upper 40s; although MOS guidance is attempting to hint at lows in the mid 40s for some valley locations, even 10th percentile LREF guidance keeps dewpoints too high for this scenario to be realized. As a consequence of this moisture, patchy fog development will be favored in river valleys as temperatures approach dewpoints in our valleys, although this fog should dissipate quickly as temperatures begin to climb on Sunday morning.

Sunday will be the warmest day of the long term period. High temperatures will rise into the upper 70s and low 80s, although this warmer period will be relatively short lived. A cold front extending from a low pressure system on the ON/QC border will push into Kentucky throughout the day, with the highest rain chances for eastern Kentucky overnight. Given warm temperatures ahead of the front, instability will be low, but nonzero. Thus, thunderstorms will be possible, although given meager CAPE and unfavorable diurnal timing these storms are not expected to become severe. The most likely outcome will be additional much-needed rainfall. 00Z LREF guidance shows high confidence in PWATs greater than 1 inch (90% chance ahead of the front), with median LREF QPF sitting at around 0.25 inches for most of the forecast area; this is higher than the NBMs current output, and this is without accounting for potential convective effects. Therefore, increases in QPF may be needed in future updates if the current moist trend holds.

Following the frontal passage, northerly to north-northwesterly winds will advect colder air into the area, leading to the coolest highs of the period on Monday, even as skies clear throughout the day. Aloft, the axis of the aforementioned trough will pass over Kentucky, ushering in a pattern of persistent northwest flow at the upper levels as high pressure begins to build at the surface. This high will keep skies clear overnight Monday night, allowing for another ridge-valley temperature split. With dewpoints currently forecast to be in the mid 30s, valley fog would be the main concern with this cooling; however, given such a thin margin between fog and frost, trends will need to be monitored. Should dewpoints run slightly lower (which is not out of the question per ensemble guidance), frost potential would increase.

By Tuesday, the surface high will shift out of our area ahead of our next system. Flow will become more southerly, initiating WAA and allowing high temperatures to climb into the upper 60s to low 70s. This wind shift will also begin a period of modest moisture return. Aloft, a prominent shortwave will provide upper level support for a surface cyclone centered somewhere around the Great Lakes region. Present guidance shows significant variance in the timing and progression of this shortwave. The NBM is outputting PoPs in the 30-60% range late Tuesday into Wednesday, although this is primarily a function of temporal discrepancies among different solutions rather than a true chance of rain. Regardless of these discrepancies, it appears this system will bring another opportunity for measurable precipitation by midweek.

AVIATION

(For the 12Z TAFS through 12Z Saturday morning) ISSUED AT 753 AM EDT FRI MAY 8 2026

High pressure shifting across the area has led to clear skies and light winds and resulted in IFR or lower fog some of the deeper river valleys. Other than KSME, the TAF sites have not been affected. Other than this fog lingering as late as 13Z to 14Z, VFR is anticipated through the period. An increase in mid and high clouds will occur after 18Z as a disturbance and weakening front approach. A few showers or sprinkles are not out of the question after about 03Z through as late as 15Z, especially for KIOB and KSYM, but probabilities are less than 30 percent and even within these, sub VFR conditions may not occur. Winds will be light and variable to begin the period, becoming south to southwest at less than 10KT after 14Z. Winds will slacken again to end the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.