Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jul 19 2023 06:04:32 ACUS01 KWNS 190604 SWODY1 SPC AC 190603 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0103 AM CDT Wed Jul 19 2023 Valid 191200Z - 201200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE UPPER MIDWEST INTO THE CENTRAL PLAINS... ....SUMMARY... Scattered severe thunderstorms capable of producing large to very large hail and damaging winds appear possible Wednesday from the central Plains into the Upper Midwest. Isolated strong to severe thunderstorms may also occur from the Ozarks into the lower Ohio and Tennessee Valleys, along with the Carolinas and Mid-Atlantic. ....Synopsis... A strong shortwave trough now in the Dakotas will move southeastward today through the upper Midwest. At the surface, a cold front will be situated from Minnesota into the central Plains. The cold front will merge with a lee trough in eastern Colorado. An old outflow boundary is located from Missouri into parts Mississippi/Alabama. Within the Northeast/Mid-Atlantic, at least modestly strong mid-level winds will exist on the southern periphery of an upper-level low. At least one MCV will be present in the southern Appalachians which is forecast to move eastward into North Carolina/Virginia. ....Upper Midwest/Central Plains... The cold front will be the primary focus for convection during the afternoon. Modest warm advection in South Dakota/Nebraska has helped sustain some convection Tuesday evening. Some guidance suggests some of this convection may linger into Wednesday morning. While this does complicate the forecast as to where potential cloud cover/outflow will be, the general expectation for supercells to develop either along the front or outflow remains the same. With upper-50s F dewpoints within the upper Midwest currently, there will likely be only a narrow corridor of destabilization ahead of the front where moisture return occurs. Effective shear will generally be perpendicular to the front at around 45-50 kts. Large to potentially very large hail will be possible given long, straight hodographs. Potentially scattered storms are also expected underneath the trough in northern Minnesota. Large hail will also be possible here, though destabilization may be a bit more limited. In eastern Colorado, storm development is expected along the lee trough. Scattered storms will develop within a adequately sheared, but limited moisture environment. These storms will likely quickly grow upscale as outflows merge. Severe wind gusts will be the primary hazard, but some marginally sever hail may occur with the strongest storms early in the convective cycle. This activity may spread east/southeast into western Kansas and the Raton Mesa vicinity. ....Missouri into the Mid-South... Convection is ongoing from northern Missouri into western Kentucky Tuesday night. With CAM guidance not handling the timing/location of this convection very well, forecast uncertainty in the evolution of this activity is medium to high. Some guidance does suggest that convection in Missouri will grow upscale and impact parts of western Tennessee this morning. However, with the amount of storms that could persist ahead of such a complex developing does not lend to increased confidence in greater wind damage potential. A Slight risk could be needed should observational and convective trends Tuesday night warrant. Additional storm development is possible Wednesday evening into the overnight across parts of Missouri and Illinois as another low-level jet and associated warm advection increases. Large hail and wind gusts would be possible with this activity as deep-layer shear and mid-level lapse rates will remain favorable. ....Southeast... Early day storms in the Mid-South will eventually move into parts of the Southeast. While buoyancy may be high, shear will quickly decrease with southward extent. Some wind damage will be possible with any more organized clusters. ....Mid-Atlantic into the Carolinas... A moist airmass will be in place east of the Appalachians. With an MCV approaching the area, storms may develop by early afternoon. Observed mid-level lapse rates from Tuesday evening soundings are relatively poor. Furthermore, cloud cover will also be present early in the day and limit surface heating and low-level lapse rates. Isolated wind damage and marginally severe hail are possible. ...Wendt/Leitman.. 07/19/2023 $$ = = = 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) .