textproduct: Jackson

KEY MESSAGES

- At least northwest parts of eastern Kentucky are favored to see another round of strong to severe storms tonight, with additional chances over most if not all of eastern Kentucky on Thursday into Thursday night. - We are looking for repeated rounds of heavy rain and thunderstorms to affect eastern Kentucky through Sunday - especially northwest parts of the forecast area where between 3 and 6 inches of rain will be possible over those several days. This area remains in a Flood Watch from this evening through Sunday morning.

- Temperatures will be warmer than normal into the weekend followed by a sharp cool down to start the new work week.

LONG TERM

(Friday through Wednesday) Issued at 515 PM EDT WED APR 2 2025

The models, and their individual ensemble suites, are still in surprisingly good agreement aloft through the bulk of the long term forecast before some differences of note start to show up concerning a late period trough dropping into the Ohio Valley from the north. They all depict a deep Southwestern trough anchoring the 5h pattern through the rest of the week only slowly grinding east through Saturday while a strong ridge holds firm in the Southeast. This continues to depict a stagnant pattern aloft for most of the country into the first part of the weekend locking in an extended period of fast southwest mid-level flow into Kentucky. This will be able to scour ample moisture northeast from a wide open western Gulf of America for a near continuous flux of moisture into the region. Within the flow, several impulses of concern will ride past eastern Kentucky. One of these, in a series of them, passes through early Friday before another slides by to the north that night into Saturday morning, while a third then crosses towards that evening. By early Sunday, though, a substantial portion of the Southwestern trough finally works east into the Mid-Mississippi Valley helping to shove the blocking Southeast ridge further away from Kentucky. This will allow the pattern to start moving again for our area and also helps to pull a large trough southward from eastern Canada sending 5h height falls through this part of the state during the day, Sunday. Then, with the pattern finally on the move, a stream of energy will settle into the Ohio Valley and press south into the JKL CWA later Monday. This energy swath lingers overhead through early Tuesday before the large northern trough's axis at 5h will finally sweep east of the Ohio Valley - now faster and more dampened in the ECMWF cluster compared to the GFS solutions. This change will turn the mid-level flow more sharply to the northwest bringing a pattern more conducive for drying and colder conditions.

The still rather small model spread aloft through Saturday supported using the NBM as the starting point for the forecast grids into the weekend then have decided to used it split the difference between the still shifting cluster solutions of the various long range model systems into the first part of next week. Again made some adjustments mainly to add more terrain distinction to the temperatures in the southeast parts of the area each night through Saturday morning.

Sensible weather features a warm end to the week for most with the models now depicting the concerning boundary lying across northern parts of the JKL CWA to start the day, Friday. Model consensus has this boundary shifting north on Friday as the next sfc wave consolidates to the southwest of the state. This process looks on track to spare much of eastern Kentucky the heavy rains and stronger storms through the afternoon and into the night. However, this boundary will start to return southeast later Saturday with more strong to possibly severe storms arriving, for at least northwest portions of the area by evening, while the southeast looks to stay dry and very warm. The caveat through Saturday evening is that while the models are in decent agreement that the boundary stays west and north of the bulk of southeast Kentucky, mesoscale dynamics and outflow boundaries could help to push it further south than the models indicate so caution is urged, especially in the Flood Watch areas. Eventually, this system and the frontal structure push through the entire area mainly Sunday morning with a final incident of heavy rain before it departs. We will probably have to consider extending the Flood Watch through the day Sunday if the ECMWF trends holds in having a lingering sfc wave move along the front on Sunday and holding it up by perhaps another 12 hours.

Sharply colder weather follows behind the system into Monday and through the start of the next work week. This will bring an air mass change on northerly winds. The coldest air is indicated to arrive later Monday into Tuesday such that scattered frost and some sub freezing temperatures are anticipated for Monday and Tuesday night. The high pressure that moves into the area in the wake of the weekend system will start to shift east on Wednesday but serve to keep the weather dry and cool.

Despite the extremeness and climatological rareness of this stalled pattern, most of eastern Kentucky is expected to miss out of the higher impacts owing to the heaviest rains forecasted to stay north of the headwaters of our rivers. Even so, we need to stay vigilant for a possible shift southeast in the heavy rain axis and not let our guard down. However, as it stands now, it seems increasing likely that the western part of the state and confluence region of the Ohio and Mississippi rivers will see the historic impacts from the repeated heavy rains of such extreme durations. Meanwhile many of us here, especially those outside of the flood watch, will mostly note just an unseasonably warm stretch of weather for early April interrupted occasionally by a bout of mainly nocturnal showers and storms.

The changes to the NBM starting point consisted primarily of adjusting the PoPs for hourly temporal resolution. Did also include more terrain distinction to the low temperatures through Saturday morning and again for Tuesday night.

AVIATION

(For the 06Z TAFS through 06Z Thursday night) ISSUED AT 155 AM EDT THU APR 3 2025

VFR conditions at TAF issuance will deteriorate from northwest to southeast through the remainder of the early morning hours as a weakening line of showers and thunderstorms drops in from the northwest, potentially reaching the Kentucky/Virginia border around or after 12z. This storm line will bring the threat of high winds and potentially a brief spinup tornado. The stronger storms along the line will likely bring at least MVFR/IFR conditions, but could be briefly worse. The line of storms is expected to waver over the area on Thursday before slowly lifting back to the north later in the evening into Thursday night. Periods of MVFR conditions are likely with stronger rounds of convection. Some IFR conditions are possible, but confidence in timing and occurrence is too low to include in the TAFs.

JKL WATCHES/WARNINGS/ADVISORIES

Flood Watch through Sunday morning for KYZ044-050>052-058>060- 068-069-079-080-083-084-104-106>109-111-112-114.