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FXUS63 KJKL 051657 AFDJKL

AREA FORECAST DISCUSSION National Weather Service Jackson KY 1257 PM EDT Sun May 5 2024

KEY MESSAGES

- Shower and thunderstorm potential lasts through the next 7 days.

- Above normal temperatures are forecast through Thursday. A cold front should pass late in the week and bring readings down to near or below normal.

UPDATE
Issued at 1257 PM EDT SUN MAY 5 2024

Just issued a fairly extensive update to the short-term grids that will likely constitute most of the changes to the afternoon package. Given shower and thunderstorm activity developing raised 1-hour PoPs to a minimum of 15 for the entire area for the next few hours. Other updates will be addressed with the afternoon package, but generally not much change to the overall thinking from the previous short-term discussion below.

UPDATE Issued at 1101 AM EDT SUN MAY 5 2024

The late morning update is out. Generally lowered PoPs somewhat based on a lack of forcing for ascent for shower and thunderstorm development through this evening. A weak stationary surface front draped across the area will help trigger some activity, but rising heights aloft will make more widespread activity difficult.
Otherwise, just blended in latest observed trends to the forecast.

UPDATE Issued at 700 AM EDT SUN MAY 5 2024

Made some adjustments to this mornings hourly forecast grids using recent obs. This revealed that low temperatures at a number of locations across eastern Kentucky were running at least a few degrees cooler than forecast. Based on current trends, adjusted this mornings lows to match the obs. The updated grids have been saved, published, and sent to NDFD and remote web servers.

SHORT TERM
(Today through Monday)
Issued at 456 AM EDT SUN MAY 5 2024

Active weather expected across eastern Kentucky heading into the new work week, as a weak cold front and wave of low pressure move through the region. Isolated to scattered storms are expected to move through the area today, especially this afternoon into early this evening, during peak heating, and when instability will be maximized. A weak cold front will be the trigger for showers and storms today, but should only provide enough lift to support isolated to scattered convection, in spite of the moisture and instability that will be in place. After the first round of rain ends this evening, another round of more widespread and robust showers and storms will begin moving into our southwest counties very late tonight into early Monday morning. This second wave of rain will be in response to a wave of low pressure that forms along a slow moving cold front to our southwest. As this low moves over our area on Monday, it will allow numerous showers and scattered storms to fire during peak heating Monday afternoon.

The higher resolution models are all showing similar solutions supporting only isolated to scattered convection at best, so today's forecast was based on that data. The NAMNEST, RAP, NAM12, and HRRR were all in pretty good agreement on the extent of todays showers and storms. However, considering how unstable and moist the atmosphere will be today, decided to lean more toward scattered activity than isolated in spite of the models output. Rain chances on Monday should be much better since a stronger system will be moving through, and the atmosphere will still be quite moist and unstable. Locally heavy rainfall will be possible at times on Monday with any thunderstorms.

Temperatures will continue to average well above normal today and Monday, with highs in the upper 70s to lower 80s on tap. Winds should be out of the southwest at 5 to 10 mph today and tomorrow, and light and variable again tonight.

LONG TERM
(Monday night through Saturday)
Issued at 456 AM EDT SUN MAY 5 2024

A persistent wet weather pattern will continue in place through the first part of the long term forecast. Generalized west southwest flow in the mid/upper levels will overlie low level south southwest flow off the Gulf of Mexico. A stalled frontal boundary is forecast to be near the Ohio River Monday evening as a shortwave trough aloft departs to the east. The front is expected to shift north Monday night, then back south into KY by Wednesday morning as another shortwave trough aloft tracks by, then back north again Wednesday night. The front will finally make a strong push southeast through our area late in the week as a more substantial mid/upper level trough drops southeast over the eastern CONUS. Models are coming into better agreement for a cold frontal passage on Thursday. The presence of the frontal boundary along with the shortwave troughs should support multiple rounds of showers/thunderstorms, with likely POPs now in the forecast each period from Monday night through Wednesday night area wide.
Precip may linger into Thursday, but there is some model variation concerning the arrival of drier mid/upper level air wrapping into a deepening storm system passing to our north on Thursday. This drier air aloft will be fleeting, as the upper level trough drops into the eastern CONUS. The much colder air aloft associated with the trough should still allow for scattered showers/thunderstorms to bubble up at times even after cold fropa as we move into the weekend. Specific timing of impulses enhancing this activity remains problematic at that long time range.

Our relatively weak flow aloft presently should strengthen by Tuesday. The increasing shear will be more supportive of organized convection, with a resulting severe thunderstorm risk beginning on Tuesday and lasting until our last round of convection before cold fropa.

AVIATION
(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 700 AM EDT SUN MAY 5 2024

Mostly clear skies were ongoing at TAF issuance this morning. A few high level clouds were moving our way from central Kentucky, and should be moving over JKL and SYM be 14Z or so. Fog was noted at a few locations early this morning, but this should quickly dissipate once the sun has come up. Clouds will gradually increase through out the morning, as a weak cold front pushes through the area. Isolated showers and storms are forecast to begin popping up and moving through by 14 or 15Z, and should become scattered in nature by around 18Z this afternoon. VCSH was used to account for any showers that end up moving near a TAF site. A few thunderstorms will also be possible this afternoon through early this evening. The first batch of rain should be out of the area by 2 or 3Z tonight. Another round is expected to begin moving across the TN border between 7 and 8Z on Monday. A few showers and storms may approach SME and LOZ between 9 and 11Z on Monday. Winds today will be out of the south or southwest at 5 to 10kts, but will shift to the west after a weak front moves through. Winds tonight should be light and variable. Any fog that forms tonight should be restricted mainly to deeper and more sheltered eastern valleys.

JKL WATCHES/WARNINGS/ADVISORIES
NONE.

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