Area Forecast Discussion
Issued by NWS Louisville, KY
Issued by NWS Louisville, KY
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057 FXUS63 KLMK 150725 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 325 AM EDT Wed May 15 2024 .KEY MESSAGES... * Active pattern with many chances of showers and storms through Wednesday. * The most likely periods for dry weather are Wednesday night through Thursday morning and Sunday night through Monday morning. * The active pattern will continue for the next several days. The most likely days for the most widespread showers and storms will be Friday-Saturday and possibly Tuesday. The main threat from these showers and storms will be locally heavy rain and possible flooding, with severe weather a lesser threat. && .SHORT TERM /THROUGH TONIGHT/... Issued at 324 AM EDT Wed May 15 2024 The stacked low pressure system that has been bringing rounds of precipitation to southern Indiana and central Kentucky is currently centered over the northwestern half of the CWA, and before the sun sets later this evening, it will make it to the Atlantic Coast. Convective showers and thunderstorms have been scattered in nature. Some areas, including Orange and Dubois Counties in Indiana, have received 3 to 4+ inches while farther east, through the Bluegrass and Lake Cumberland regions, totals have been as low as 0.1-0.2 inches in some places, but as the system moves to the east so will the totals. With weak deep layer shear and only moderate instability, we haven`t seen much in the way of severe weather, but in some areas, mainly around the low, we have seen cells training towards the center of the low which has caused isolated minor water ponding and drainage issues. This trend will continue today as scattered showers and isolated to scattered thunderstorms move east through the Lower Ohio Valley in a counterclockwise motion around the low. Later this morning, we will likely see a break in the precipitation before convection begins to increase with scattered showers and storms on the backside of the circulation early this afternoon. Coverage is expected to become more widespread during this time. Overall rainfall totals aren`t expected to be too high across the CWA, but given the nature of convection and the possibility of training or cells sitting nearly stationary over areas, there remains the risk of isolated minor flooding. Generally speaking, rainfall totals are expected to be higher over the eastern half of the CWA with lower amounts tapering to the west. Highs today will likely only hit the low to mid 70s given all the rain and cloud cover, and even though winds will be light, between 5- 10 mph, they will be variable as they follow the same general counterclockwise direction as the low moves east through the CWA. Tonight, rain will slowly taper off as the system moves farther to the east, and as upper ridging and surface high pressure, extending south from Canada, moves into the region, skies will start to clear. The best chances for clear will be over southern Indiana. With near calm winds and some remaining sky cover, lows are expected to only fall into the mid to upper 50s. Far southern Kentucky could hold onto a 60 or two. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 324 AM EDT Wed May 15 2024 Shortwave ridging on Thursday should provide a break from the waves of showers and storms, with temperatures peaking around 80 degrees. However, that break will be brief. A southern stream vort max is expected to eject from the Rio Grande on Thursday to the Ohio and Tennessee Valleys by Saturday. A surface low will drift slowly from the Ozarks to the Ohio Valley during this time as well. With plenty of moisture available, widespread showers and scattered thunderstorms are expected ahead of this system Friday into Saturday. High precipitable water values, deep warm cloud depths, weak shear, and a thin positive area on soundings suggest locally heavy downpours will be the main threat with this activity. Though general QPF amounts are in the 1-2" range for the long term, results will vary widely from one spot to the next due to the convective nature of the rainfall. As for severe storms, they can`t be entirely ruled out, but the best chances should be from the southern Plains through the lower Mississippi Valley to the Southeast where instability and shear values will be more supportive. After a possible hiatus in the rain for the second half of the weekend, chances increase again early next week as additional disturbances move east from a western upper trough...though confidence is low this far out in the forecast. && .AVIATION /06Z TAFS THROUGH 12Z THURSDAY/... Issued at 138 AM EDT Wed May 15 2024 TAFs continue to be a challenge as a low pressure system moves through the region. Rain showers with afternoon and evening thunderstorms will continue rotating around the circulation through the period. Many areas will see limited precipitation, but some showers/storms are remaining fairly stationary or training for long periods of time. This is more likely to happen near the center of the surface low and could cause several hours of rain near SDF tonight. Current ceiling observations are very bouncy going from VFR to IFR and back again. This trend is expected to continue until a layer of stratus sets up later tonight. Then, IFR ceilings are expected at all sites. Winds will continue to be light, but as the low moves through to the east, expect variable wind shifts. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ SHORT TERM...KDW LONG TERM...13 AVIATION...KDW