Area Forecast Discussion
Issued by NWS Louisville, KY
Issued by NWS Louisville, KY
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357 FXUS63 KLMK 230545 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 145 AM EDT Thu May 23 2024 ...Updated Aviation Discussion... .KEY MESSAGES... * Strong/severe storms possible region wide this afternoon with damaging winds, hail, and very heavy rainfall being the main threats. * Stormy pattern with a risk for localized flooding Thursday through Tuesday with strong/severe storms possible Sunday. && .SHORT TERM /THROUGH FRIDAY/... Issued at 341 PM EDT Wed May 22 2024 Forecast is still on track to see scattered clusters of strong to severe thunderstorms this afternoon into the evening hour. Sfc cold front remains oriented northeast to southwest stretching from around Ft. Wayne, IN, to around Bloomington, IN curving towards Vincennes, IN and along the borders of far western KY and southern IL. Current afternoon mesoanalysis shows Td mainly in the upper 60s to even a few low 70s southern IN and most of KY. SBCAPE ranging from 1500- 3000 J/kg, with the lowest values mostly to the east/southeast where shower/storm activity has been persistent most of the afternoon. Visible satellite imagery shows partly to mostly clear skies along the Ohio River into southern IN with mostly cloudy conditions across our southern counties. Area WSR-88D continues to show a linear cluster of showers/storms along a prefrontal boundary stretching from the Bluegrass then southward along the KY/TN border. This convection stretches back into far western TN. SPC continues to keep all of central KY in a slight risk for severe storms with gusty damaging winds being the main threat as DCAPE values along and ahead of the sfc boundary across southern IN and along the OH River range from 1100-800 J/Kg. Large hail can`t be ruled out given the ample amount of instability especially seen in the hail growth zone on model soundings for later this afternoon and evening. While the tornado threat is relatively low, shear still looks to be between 30- 40kts. Hi-res CAMS like to lift the cluster of convection currently over far western TN northeastward into our southern CWA later this afternoon and evening. Feel the main focus and highest probability of strong to severe storms will be across our southern CWA along the KY/TN border but any outflow associated with these storms working into the higher instability to the north and interacting with the slow approaching sfc boundary would likely initiate additional convection north of the Parkways towards the Ohio River with the potential for some supercells and even linear development later this evening. While activity continues to along the KY/TN border, our best chance remains between 5pm EDT this evening to around 10pm EDT with the bulk of the activity pushing out between 11pm/Midnight EDT. While focus is on severe potential the other impact will be the potential for heavy rain and localized flooding. PWAT axis on mesoanalysis stretching from Memphis TN where we have a bullseye of 2.00" into the Bluegrass where we have 1.60" is where we are seeing the main focus of activity so far this afternoon. Any storms will produce very heavy rainfall and if storms train over an area localized flash flooding is a possibility. The one positive here is that the dry weather the last couple of day has allowed current 1hr FFG to range from around 1.75" at the lowest to as high as 3.00" over our CWA. Once activity pushes off and out of the area overnight we will be in a bit of a lull but a second shortwave pulse will work across the Ohio Valley overnight into tomorrow morning. This could produce another cluster of showers and storms working from the Bootheel of MO through KY and southern IN during the morning hours. Sfc boundary looks to stall out over the Ohio River for tomorrow with more scattered showers/storms possible especially during the afternoon. It`s possible we could see a lull in the activity briefly during late morning into early afternoon. The threat of severe appears to be lower but remains as SPC has the southern half of our CWA in a marginal risk (1 out of 5) for the potential for strong to severe storms. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 400 PM EDT Wed May 22 2024 Looking into the long-term, temperatures this coming week will be fairly seasonal with highs on Friday up to 5 degrees or so above normal. These slightly warmer than normal temperatures from a mix of sunshine and warm air advection will be replaced by slightly cooler than normal temperatures on Tuesday and Wednesday. This will be possible as a cold front on Monday moves through the Lower Ohio Valley which will help stop warm air advection and will begin dropping dew points into the 50s from the 60s. Precipitable water values will also drop to around an inch or below. Surface high pressure, centered to the west, should help to produce mostly sunny skies with high temperatures 5 degrees or so below normal. But before this cold front pushes through and clears the area, a series of warm and cold front moving over and around southern Indiana and central Kentucky will provide chances for showers and thunderstorms on Friday and Saturday. During most of this time, precipitable water values will vary between 1.3-1.6". Just ahead of a front, these values could reach up to 2". Model soundings and hodographs look like your typical summer day. They have plenty of instability but lack shear. This will limit the type of expected severe weather. We could see heavy rain in isolated areas which could cause some limited flooding issues and gusty winds. Sunday is worth keeping an eye on. It`s still a ways out, so the details will come into better focus, but the region will be under the exit region of an upper jet streak with backing winds towards the surface. This will produce deep layer shear for the continued instability which will help severe weather to become more organized. Hodographs currently look favorable for tornadoes, so all severe weather types are on the table. && .AVIATION /06Z TAFS THROUGH 12Z FRIDAY/... Issued at 144 AM EDT Thu May 23 2024 Low stratus is building over I-64 terminals and will continue through the remainder of the early morning. Radar shows some convection beginning to develop over north-central TN and southern IL along a cold front and weak LLJ, respectively. As these showers and storms move NE through the Ohio Valley, they will incur very limited instability and little forcing for sustainability. Showers and storms are most likely to impact BWG and HNB, while keeping other terminals precip free until the afternoon. In the afternoon, instability will increase over the region and coupled with a frontal boundary and mid-level shortwave will allow for convective initiation. VCTS is expected at all terminals with some TSRA possible. Further TAF issuances will be able to narrow a timeframe for convective impacts. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ SHORT TERM...BTN LONG TERM...KDW AVIATION...SRM