Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 04 2023 17:28:18 ACUS02 KWNS 041728 SWODY2 SPC AC 041726 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Aug 04 2023 Valid 051200Z - 061200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE CENTRAL PLAINS INTO THE MISSOURI VALLEY... ....SUMMARY... Severe thunderstorms are expected across portions of the central Plains to the Lower Missouri/Middle Mississippi Valley vicinity on Saturday. Damaging gusts (some 75+ mph) and large hail (some 2+ inches) will be the primary severe weather hazards. ....Synopsis... A closed upper low currently within the northern Plains is expected to become more of an open wave and move southward/southeastward on Saturday. Mid/upper-level winds will increase through the period within the central High Plains eastward into the Missouri Valley as a result. Farther east, an MCV is forecast to track into the mid-Mississippi/lower Ohio Valley vicinity. At the surface, a remnant stationary boundary, perhaps reinforced by warm-advection precipitation, will remain from Missouri into the southern Plains. To the north, a surface low will deepen in South Dakota and eventually move into the Midwest along with its parent shortwave trough. This will act to push a cold front into the central Plains by Sunday morning. A secondary surface low is also forecast to develop in the southern High Plains. ....Central High Plains into Kansas... Upslope flow into the terrain is expected to be maintained ahead of the cold front which should approach by late afternoon. Upper 50s F to low 60s F dewpoints should be sufficient for a cluster or two of storms to develop within the terrain and spread eastward into eastern Colorado and western Kansas. There continues to be some uncertainty as to potential convection within southern Kansas into northern Oklahoma overnight Friday into Saturday morning. Weak warm advection is still predicted by most guidance even into the afternoon. What impact this activity will have on the forecast does remain unclear. Even so, moderate to strong buoyancy is expected within eastern Colorado and south of areas impacted by early precipitation. Winds at mid/upper levels will be increasing into early evening. Hodographs will consequently become more favorable for supercells and large/very-large hail. It is not clear how quickly upscale growth will occur, but an increase in 850 mb flow from the south across West Texas will likely promote increasing storm coverage during the evening. Strong/severe wind gusts will also be possible with supercells, including gusts in excess of 75 mph. The spatial extent of significant gust potential will be conditional on degree and timing of upscale growth. Damaging wind potential will persist into the evening in some fashion across Kansas into perhaps western Missouri. ....Mid-Missouri Valley... Near the surface low, storm development appears likely from southeast South Dakota into eastern Nebraska. Shear will decrease with northern extent, as will buoyancy, with the mid-level jet being generally near the Nebraska/Kansas border. However, some supercell structures appear possible that will be capable of large hail and damaging winds. A narrow corridor of backed surface winds near the low could support a risk for a tornado as well, but hodographs at mid/upper-levels do not appear favorable for sustained/strong mesocyclones. ....Lower Ohio Valley Vicinity... An MCV now in the Mid-Missouri Valley region is expected to progress into Illinois by early Saturday morning. Cloud cover and precipitation with this feature will mean some uncertainty in the magnitude and location of severe risk during the afternoon. The degree of surface heating will be the key and not all models suggest it will occur. However, there appears to be a conditionally favorable environment for marginal supercell structures capable of isolated damaging winds and a brief tornado or two. ...Wendt.. 08/04/2023 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .