772 FXUS63 KLMK 201729 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 1229 PM EST Thu Feb 20 2025 ...Updated Aviation Discussion... .KEY MESSAGES... * Snow showers will gradually taper off this morning, with little more than a dusting of additional accumulation in the Bluegrass. * Another cold night tonight with lows in the single digits. * Mostly dry weather through the weekend into early next week. Temperatures will rise above freezing Friday or Saturday, with above normal temps next week. && .UPDATE... Issued at 914 AM EST Thu Feb 20 2025 Other than a few light flurries and a few isolated snow showers, the bulk of the snow has ended across the CWA this morning. Various traffic cams and traffic maps show good flow around most of the highways and metro areas. Decided to cancel the remaining Winter Weather Advisory across the Blue Grass. Continue to see wind chill values near or even below 0 so will continue the Cold Weather Advisory through its scheduled time of 16z. Current visible satellite imagery shows a few low clouds lingering this morning but a large portion of the area showing mainly clear to clearing skies. Went ahead and updated the sky grids to account for current clearing. Other than that the current forecast remains on track. && .SHORT TERM /THROUGH TONIGHT/... Issued at 320 AM EST Thu Feb 20 2025 Scattered light snow showers will continue to be possible this morning, primarily over the Blue Grass, with sfc-850mb moisture present, the upper low still nearby over the upper Ohio Valley, and a little bit of help from flow off of Lake Michigan. Snow showers look less likely this afternoon as available moisture decreases slightly, the upper low moves farther away, and the component of flow off the lake lessens...though sct/bkn strotocu will persist until early evening. Northwest surface winds from very strong Canadian high pressure over the mid-Missouri Valley along with only partial sunshine will give us another cold day, with afternoon readings peaking around twenty degrees. Tonight the surface high will build directly east into the Ohio Valley, clearing skies. With the loss of cloud cover, lessening winds, and continuing fresh snow pack, it will be another frigid night. Went below guidance with lows in the single digits. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 320 AM EST Thu Feb 20 2025 Synopsis...The active weather pattern experienced during the last seven days will shortly come to an end as strong surface high pressure builds over the region this weekend and a mid-level ridge establishes along the West Coast and the Central US. As a result, shortwave energy intrusion will remain muted with weak vorticity energy tracking further north. Best chance for pattern amplification will probably arrive by the middle of next week as a decent Pacific NW trough momentarily breaks the ridge and advances towards the East Coast where it is expected to elongate thanks to constructive interference from additional shortwave energy. The aforementioned scenario will lead to warming temperatures and increasing rain chances. Model Evaluation/Confidence...Forecast confidence remains high for the weekend and early next week given good model agreement on temperatures and lack of precipitation chances. On the other hand, deterministic guidance starts to diverge by the middle of next week regarding the intensity, position, and structure of the amplifying mid-level trough and associated surface low. This, in turn, has implications in the QPF signal over the Ohio Valley. So far, the latest GFS run (20/0Z) presents the strongest surface low and wettest QPF footprint while the ECMWF and especially CMC are weaker and drier. All in all, there is sufficient model-to-model and run-to- run variability to argue for low confidence in the latter portion of the forecast. Friday - Sunday...After a frigid morning on Friday with single digit temperatures, highs in the afternoon will climb to the freezing point as surface high pressure provides dry weather with much needed solar radiation (amid a thin mid-level cloud layer). Temperatures will continue to warm up Saturday and Sunday as the surface high moves to the southeast and low-level winds shift to the southwest. Although a small-amplitude vort max will transition through the Lower Ohio Valley Saturday morning, lack of low-level moisture and high stability will most likely preclude precipitation reaching the surface with ECMWF p-type meteograms showing less than 5% of snow chances for Louisville or Lexington. Next Week...Surface high pressure will continue tracking and weakening across the Southeast US while a low pressure area moves in from the north, accompanying northern-stream shortwave troughs over the Great Lakes. This will lead to a slowly strengthening pressure gradient force and enhanced theta-e advection. Light rain chances will briefly return to the forecast on Tuesday as a weak cold front approaches from the Midwest. However, the best chances of light to moderate rainfall are more likely Wednesday into Thursday as a low pressure tracks near or over the Lower Ohio Valley. Even though confidence in rainfall amounts and location is low at the moment, it is worth monitoring the evolution of this system given the current state of rivers in the area. && .AVIATION /18Z TAFS THROUGH 00Z SATURDAY/... Issued at 1229 PM EST Thu Feb 20 2025 The trough axis associated with the mid-level closed low is pushing eastward into the Mid Atlantic this afternoon as winds continue to come out the northwest. Lingering low-level moisture has kept a broken stratus layer over parts of the area with flight categories bouncing between MVFR/VFR and even some light snow mixed in. Expect these clouds to break and the snow to end as we go through the remainder of the afternoon. Winds will remain out of the northwest with occasional gusts of 10-15kts. Strong sfc high pressure over the central CONUS will slowly continue to slowly build eastward over the Ohio Valley through the forecast period. Skies will eventually clear and winds will turn light and generally variable overnight into tomorrow. This will continue a prolonged period of VFR flight categories. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ UPDATE...BTN SHORT TERM...13 LONG TERM...ALL AVIATION...BTN