Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 09 2024 19:36:15 ACUS01 KWNS 091936 SWODY1 SPC AC 091934 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0234 PM CDT Mon Sep 09 2024 Valid 092000Z - 101200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NEW YORK... ....SUMMARY... Isolated damaging winds remain possible this afternoon across parts of New York. ....20Z Update... No changes have been made to the Day 1 Convective Outlook. With storms continuing to increase in coverage and intensity over western NY, atop marginal boundary-layer-based instability, an instance or two of damaging gusts remain possible with one of the stronger storms. Similarly, a severe gust cannot be ruled out with one of the stronger storms over the Interior West given the presence of steep tropospheric lapse rates. Please see the previous outlook (below) for more details. ...Squitieri.. 09/09/2024 ..PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Sep 09 2024/ ....New York... Within large-scale upper troughing over the Northeast and eastern Canada, an embedded shortwave trough over southern Ontario and the upper Great Lakes will continue to move across the Northeast this afternoon and evening. Ascent associated with this shortwave trough and related mid-level jet is supporting isolated thunderstorms across southern Ontario and vicinity. This activity will spread east-southeastward this afternoon across parts of NY. The airmass over this region should become only weakly unstable as filtered daytime heating occurs, with poor mid-level lapse rates, persistent cloud cover, and modest low-level moisture limiting destabilization. Still, gradually increasing west-northwesterly winds at low/mid levels will foster around 25-35 kt of deep-layer shear. This should support modest thunderstorm organization, with multicells/small clusters potentially evolving along and downstream of Lake Ontario. Isolated strong to damaging winds should be the main threat with this convection as it moves across much of NY this afternoon and early evening, before eventually weakening with eastward extent with the loss of daytime heating. ....Northern/Central Rockies and High Plains... Isolated to widely scattered thunderstorms should develop this afternoon over portions of the northern/central Rockies as a weak shortwave trough continues eastward. Low-level moisture and related instability are both expected to remain rather meager into the High Plains, which should limit updraft intensities. Still, isolated strong/gusty winds may occur with this high-based activity across parts of MT/WY where low-level lapse rates can become steepened. Greater low-level moisture is present farther east into the Dakotas, along/east of a weak surface low/trough. But, increasing low/mid-level temperatures and a strong cap should generally inhibit thunderstorm development through much of the day with eastward extent across the northern/central Plains. $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .