Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Sep 17 2025 19:47:51 ACUS01 KWNS 171947 SWODY1 SPC AC 171946 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0246 PM CDT Wed Sep 17 2025 Valid 172000Z - 181200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE RATON MESA AND SOUTHERN COLORADO FRONT RANGE INTO PORTIONS OF THE SOUTHERN HIGH PLAINS.... ....SUMMARY... Isolated severe thunderstorms are possible, mainly during late afternoon to mid-evening, across parts of the south-central High Plains. The most likely corridor is from the southern Colorado Front Range/Raton Mesa into the western Texas and Oklahoma Panhandles, where large hail, severe gusts, and a brief tornado are possible. ....20z Update... The previous forecast largely remains on track with only minor adjustments made to reflect recent convective trends. Latest GOES imagery and regional radar mosaics show convective initiation underway across the TX Panhandle into western OK along a diffuse frontal zone. This activity will likely pose some hail/wind threat as it spreads northeast into a well-mixed, but modestly sheared environment. Further west across the High Plains, low-level winds are becoming easterly as anticipated by morning guidance. This increasing upslope flow regime will promote thunderstorm development by early evening as well as aid in convective organization via elongation of low/mid-level hodographs. Recent CAM guidance continues to depict the best signal for robust convection across southeast CO into adjacent portions of NM/OK/TX within the Slight risk corridor. See the previous discussion below and MCD #2091 for additional details. ...Moore.. 09/17/2025 ..PREV DISCUSSION... /ISSUED 1140 AM CDT Wed Sep 17 2025/ ....Front Range/Raton Mesa and south-central High Plains... A prominent upper trough will continue to pivot over the northern High Plains with a base-embedded shortwave trough/speed max spreading southeastward over Colorado toward the south-central High Plains by tonight. A related front will continue to settle south-southeastward with moist low-level upslope flow in its wake across southeast Colorado/Raton Mesa vicinity and the nearby south-central High Plains. Buoyancy will be adequate for some supercells as flow aloft strengthens and low-level winds take on more of an easterly component. Bouts of large hail can be expected, with severe-caliber winds also possible, particularly with the southernmost development toward the Panhandles. A brief/low-end tornado risk may also exist near the boundary and within the immediate post-frontal environment. ....South-central/eastern Kansas to Iowa/Missouri... MCV/modest-strength cyclonic flow aloft and zones of moderate destabilization to the east of the residual early day convection and cloud debris seems likely to influence a redevelopment and intensification of convection this afternoon. Even with some MCV-related flow enhancement, deep-layer shear will remain weak overall, but some episodic severe storms could occur with locally damaging winds and some hail. ....Southern Louisiana... As a cumulus field continues to develop/expand late this morning per visible satellite imagery, scattered thunderstorm development is likely this afternoon. As the boundary layer warms and destabilizes, thermodynamic profiles will become favorable for the possibility of some localized downbursts. ....Southern Minnesota/northern Wisconsin... A few strong storms and perhaps a locally severe storm or two could occur this afternoon into evening as the upper trough interfaces with the front and moderately unstable environment, especially with eastward extent away from residual early day cloud cover/scattered precipitation. However, very weak deep tropospheric winds should keep any pulse-type severe potential rather marginal/localized overall. $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .