Subj : DAY2SVR: Nws Storm Predic To : All From : Mike Powell Date : Tue Jul 11 2023 15:47:00 ACUS02 KWNS 111732 SWODY2 SPC AC 111730 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue Jul 11 2023 Valid 121200Z - 131200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MID MISSISSIPPI VALLEY AND MIDWEST... ....SUMMARY... Severe thunderstorms will be possible across much of Missouri, Illinois, and adjacent portions of the central Plains and Midwest on Wednesday. Damaging winds and large hail should be the main threats, with some potential for significant (75+ mph) severe winds across parts of Missouri and vicinity. ....Synopsis... A closed upper low will remain centered over Hudson Bay and vicinity on Wednesday, while upper ridging persists over the Southwest. Between these two features, a belt of enhanced mid-level west-northwesterly flow will be present over much of the northern Plains into the Upper Midwest and mid/upper MS Valley. ....Central Plains into the Mid Mississippi Valley and Midwest... Although details remain uncertain, one or more thunderstorm clusters will likely be ongoing at the start of the period Wednesday morning across parts of IA into northern MO. An isolated threat for mainly damaging winds may continue through the morning as this activity spreads eastward across the Midwest. But, most guidance shows a general weakening trend with the morning MCS as it generally outpaces available instability with eastward extent. In the wake of this morning convection, strong daytime heating will encourage the development of moderate to strong instability along a convectively reinforced boundary that should extend across KS into MO and perhaps parts of IL. Robust convection will likely form along and south of this boundary Wednesday afternoon/evening as a shortwave trough and associated mid/upper-level jet moves eastward from the northern/central Plains over the Upper Midwest and mid/upper MS Valley. With deep-layer shear forecast to strengthen through the day with the approach of the mid/upper-level jet, initial development may be supercellular and pose a threat for large to very large hail in addition to damaging downdraft winds. This appears most probable across parts of eastern KS into western/central MO. With time, clustering/upscale growth and perhaps an intense MCS will probably occur across parts of MO and vicinity Wednesday evening as a southwesterly low-level jet modestly strengthens. Where this MCS/cluster will develop and move remains rather uncertain. But, strong buoyancy and steepened low/mid-level lapse rates should support a threat for scattered severe/damaging winds and perhaps isolated gusts of 75+ mph. Confidence in a more concentrated corridor of damaging winds remains too uncertain to include greater severe wind probabilities at this time. ....Great Lakes/Northeast... The glancing influence of a shortwave trough moving northeastward across Quebec and the Northeast should encourage at least isolated thunderstorm development along a weak cold front from parts of the Great Lakes region into New England. Weak to locally moderate instability and modest deep-layer shear should support some threat for damaging winds with the strongest cells and small clusters that develop Wednesday afternoon and early evening. ...Gleason.. 07/11/2023 $$ --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .