Area Forecast Discussion
Issued by NWS Louisville, KY
Issued by NWS Louisville, KY
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012 FXUS63 KLMK 281334 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 934 AM EDT Tue May 28 2024 .KEY MESSAGES... * Dry weather and below normal temperatures expected for most of the upcoming week. * Rain chances return for the weekend; severe weather is not expected at this time. && .UPDATE... Issued at 934 AM EDT Tue May 28 2024 Quiet conditions prevail this morning as surface high pressure overspreads the region. Expect winds to pick up later this morning as an approaching shortwave tightens up the pressure gradient resulting in WNW winds gusting around 20-25mph at times through sunset. Some of the latest CAM guidance does suggest isolated pop up shower potential this afternoon, but meager moisture availability and instability, combined with a notable warm layer between 750 and 700mb, should limit any development this afternoon. Will continue with silent PoPs for the morning update. Will continue monitoring an area of convection over southern MN and northern IA associated with a surface low centered near Milwaukee, WI as it makes its projected journey southeastward across IL and IN. Some models suggest weakening showers could make it into our southern Indiana counties late tonight, but aforementioned limiting factors may likely preclude this solution. Only notable update to the going forecast was to increase wind speeds a tad across southern Indiana through today; otherwise, only blended near term grids with local observations to better reflect reality. Updated products forthcoming. && .SHORT TERM /THROUGH TONIGHT/... Issued at 315 AM EDT Tue May 28 2024 Cool and quiet start to the morning with only some patchy fog anticipated in the more usual fog-prone locations. Light but steady southwesterly winds have kept the fog from becoming a bigger issue despite the clear skies and saturated soils from recent rains. Plenty of sunshine is expected today as dry air funnels in from the west and northwest and weak high pressure over the Plains slowly drifts toward us. A cu-field will likely develop by late morning or early afternoon as the boundary layer mixes out, though capping near 750mb will hamper vertical cloud growth. It`s not until late in the day that we see the cap nearly erode across northern portions of the region ahead of a weak frontal boundary, and some CAMs indicate very isolated convection is a possibility with the eroding cap. For the current forecast package, plan to run with ~10% PoPs across our northeastern zones for the late afternoon and early evening hours. Overnight, any remaining isolated showers should gradually diminish in coverage as low level CIN increases. Slightly cooler/drier air will filter in behind a weak frontal boundary. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 315 AM EDT Tue May 28 2024 Wednesday - Thursday... Large scale upper level troughing lingers over the eastern US and Canada Wednesday and Thursday. A couple of shortwave troughs will rotate cyclonically over the Upper Ohio Valley, the first on Wednesday and the second on Thursday. The first wave on Wednesday will have a bit more low to mid-level moisture to work with, although it is still fairly shallow. Deeper moisture will remain off to our northeast across OH/WV/PA. But with the aid of diurnal heating, we should see a fairly healthy cumulus field and perhaps a few showers in the Bluegrass Region. Thunder seems unlikely due to the very shallow nature of any isolated convection, but cannot completely rule it out. Most will enjoy a dry, partly sunny day with highs in the mid 70s. Narrow upper level ridging over the Plains Wednesday nudges eastward over the MS Valley by Thursday as sfc high pressure expands southeast over the Great Lakes. This setup will maintain dry northerly flow across our region. Wednesday night and Thursday look very pleasant with lows in the lower 50s and highs in the mid 70s. Thursday night - Friday... High pressure at the sfc and aloft will maintain a strong influence on our local weather through Friday. Sfc high pressure drifts southeast across the Upper Ohio Valley, with light northeasterly to easterly low-level flow. The cool NE flow and proximity of the high will result in a rather cool start to Friday. Expect lows in the mid 40s to lower 50s. Friday looks gorgeous with afternoon highs in the mid/upper 70s. Saturday - Monday... High pressure slides east of the region by the weekend as a weak low pressure system lifts northeast out of the central Plains. Strengthening southwesterly flow between the two will advect moist air back into the Ohio Valley. Increased forcing provided by low- amplitude shortwave troughs will bring daily rain/thunderstorm chances back to central KY and southern IN Saturday into early next week. We can also expect a return to relatively warmer, more humid conditions with highs in the upper 70s/lower 80s and lows in the 60s. && .AVIATION /12Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 622 AM EDT Tue May 28 2024 VFR conditions expected for most sites through the TAF period. Some patchy, shallow fog may develop in the more fog-prone locations at the start of the TAF period but should be short lived. Winds will pick up this afternoon as the boundary layer mixes out and gusts could exceed 20kts at times. Winds will subside this evening near sunset. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ UPDATE...CG SHORT TERM...DM LONG TERM...EBW AVIATION...DM