Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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307 FXUS63 KPAH 082322 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 622 PM CDT Sat Jun 8 2024 .KEY MESSAGES... - A front will bring the risk for multiple rounds of showers and thunderstorms this evening through Sunday afternoon, especially over southeast Missouri and portions of southern Illinois and far western Kentucky. - The risk for severe weather and flash flooding remains the greatest in southeast Missouri. Between 8PM to 2AM, storms will be capable of causing damaging winds and large hail around 1 inch. An isolated brief spin up tornado also cannot be ruled out. A Flood Watch remains in effect from this evening through Sunday afternoon as 1 to 3 inches of rain, with locally higher amounts is expected with additional rounds of storms. - Next week will start off dry with slightly below normal temperatures in the upper 70s and lower 80s. A warming trend will eventually lead to above normal temperatures by the end of the week with high temperatures reaching the low 90s. Rain chances remain minimal through most of the week. && .DISCUSSION... Issued at 311 PM CDT Sat Jun 8 2024 A warm front is now approaching SW Indiana as sfc obs show winds have veered to the SW with breaks of sun across the rest of the FA. The increase in diurnal heating will allow for destabilization, especially in SEMO as an influx of theta-e/moisture will cause dewpoints to rise into the upper 60s and lower 70s. This is where model soundings show pockets of 2000-3000 J/kg of MLCAPE, along with about 40 kts of effective bulk shear setting up this evening. As a mid-level shortwave approaches, modest ascent will cause scattered thunderstorms to develop along the aformentioned boundary. Convection then grows upscale into a MCS as storms push eastward towards the Mississippi River later tonight. There is the potential for a few strong to severe storms between 8PM to 2AM, especially in SEMO where SPC has a slight risk in their D1 convective outlook. The greatest hazard of concern looks to be damaging winds with bowing segments as DCAPE initially will be 800-900 J/kg. Large hail around 1 inch is also possible given 700-500 mb lapse rates between 6.5-7.0 C/km. While the risk is low, a brief spin up tornado cannot be ruled out given sfc-1 km shear of 15-20 kts, and STP values around 1. While a few severe storms are possible, the risk looks to be confined to mainly SEMO. As for the flooding potential, recent runs of the CAMs have shifted the axis of heavy rainfall more south. The 12z HREF PMM shows a sharp gradient with locally 4 to 5 inches of rain over Carter/Ripley counties while the rest of southeast Missouri and portions of southern Illinois and far western Kentucky are still looking at 1 to 3 inches. Given that the mean cloud layer flow will be parallel to the frontal boundary orientated east- west, there is concern for training convection, especially in the Ozark Foothills that will lead to flooding. In fact, PWATs in the 99th percentile will max out around 2.00 to 2.25 inches where the ESATs also show mean specific humidity values above 13 g/kg at 850mb. Combined with thermal profiles showing skinny CAPE early Sunday morning along with a warm depth cloud layer of 12-13 kft, rain rates will also likely contribute to flooding problems with multiple rounds of storms through Sunday morning. For this reason, a Flood Watch remains in effect 7PM this evening through Sunday afternoon where WPC has a slight risk in their D1 ERO. By Sunday afternoon, a cold front will slowly sag more south allowing for dry conditions to settle over the FA Sunday evening as high pressure builds over the Ohio Valley. MaxTs will be much cooler compared to today in the upper 70s and lower 80s. Radiational cooling Sunday night will allow for minTs to fall into the mid to upper 50s. The week will also start off cooler and dry as high pressure remains in control; however, southerly return flow returns on the backside by the middle of the week. Hotter and more humid conditions are progged to return with maxTs eventually reaching the lower 90s by Thursday with minTs in the upper 60s to near 70. While NBM has slight chance PoPs progged Wednesday/Thursday across portions of the FA, think the better risk for isolated diurnal convection holds off until next weekend as it will take some time to overcome the low dewpoints in the 50s through the first half of the week. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 618 PM CDT Sat Jun 8 2024 A complex of thunderstorms is developing over southwestern MO and will be moving east this evening and overnight. KCGI is the most likely to be affected by these storms with KPAH likely seeing showers but some distant thunder. MVFR and IFR cigs are expected to move in with these storms and MVFR visbys could be possible under heavier downpours. VFR conditions are expected to return by tomorrow afternoon. Winds will be light and variable overnight for the most part and then becoming westerly then northerly tomorrow with the passage of a front. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...Flood Watch through Sunday afternoon for MOZ086-087-100- 107>112-114. IN...None. KY...None. && $$ DISCUSSION...DW AVIATION...SHAWKEY