Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Aug 04 2024 07:25:17 ACUS03 KWNS 040725 SWODY3 SPC AC 040724 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Sun Aug 04 2024 Valid 061200Z - 071200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY EVENING ACROSS PARTS OF EASTERN ILLINOIS...NORTHERN AND CENTRAL INDIANA...MUCH OF OHIO...CENTRAL AND SOUTHERN PENNSYLVANIA...NEW JERSEY...SOUTHEASTERN NEW YORK...CONNECTICUT...RHODE ISLAND AND ADJACENT PORTIONS OF MASSACHUSETTS...LONG ISLAND...NORTHERN PORTIONS OF DELAWARE...MARYLAND AND WEST VIRGINIA...COASTAL GEORGIA AND SOUTH CAROLINA...MUCH OF CENTRAL AND EASTERN MONTANA...NORTHEASTERN WYOMING...AND PARTS OF THE WESTERN DAKOTAS... ....SUMMARY... Strong storms posing at least some risk for severe weather may impact coastal Georgia and South Carolina, a corridor across the Ohio Valley into northern Mid Atlantic, and parts of the northern Rockies into adjacent Great Plains Tuesday into Tuesday evening. ....Synopsis... After reaching peak amplitude, models suggest that northwestern Canadian mid-level ridging may continue elongating eastward, while evolving troughing to its south digs toward the western and central Canadian/U.S. border vicinity. This may begin to suppress the expansive western into central U.S. ridging, but flow may remain broadly anticyclonic across much of the northern U.S. Rockies and Great Plains through this period. Downstream, it appears that the persistent/slow moving northern Quebec mid-level low will redevelop eastward offshore, to the south of Greenland, by early Wednesday, as a significant short wave impulse accelerates east of the Canadian Maritimes and contributes to cyclogenesis. However, trailing troughing is forecast to linger across the eastern Canadian provinces and much of the Northeast, as another embedded perturbation digs to the southeast of Hudson/James Bays. In lower-levels, an initial cold front is forecast to advance slowly southward into the Ohio Valley and northern Mid Atlantic, and more rapidly through the middle Mississippi Valley and central into southern Great Plains. However, within weak steering flow between the ridging in the southern mid- and subtropical latitudes, the remnant circulation of what is forecast to at least briefly become Hurricane Debby may only very slowly migrate into and across coastal southeastern Georgia Tuesday through Tuesday night. ....Coastal Georgia/South Carolina... Forcing for ascent, boundary-layer buoyancy and low-level shear conducive to convection with potential to produce tornadoes seem likely to largely continue slowly spreading east of Georgia coastal areas early Tuesday. However, it is possible that this regime could continue to impact areas perhaps as far north as South Carolina coastal areas into the day. ....Ohio Valley into Mid Atlantic... Westerly mid-level flow is forecast to begin to weaken Tuesday, and there may be a tendency for the front to advance south of the stronger lingering flow. However, it is possible that low-level moisture along the front may still contribute to sufficient instability, with daytime heating, to support scattered organizing thunderstorm activity with potential to produce locally damaging wind gusts Tuesday afternoon and evening. ....Northern Rockies and adjacent Great Plains... Forcing for ascent associated with low-level warm advection, downstream of the approaching mid-level troughing, might contribute to one or two consolidating clusters of convection spreading off the higher terrain late Tuesday afternoon. As this propagates into a more strongly heated and deeply mixed boundary layer, in the presence of strong shear (beneath 40-70+ kt flow in the 500-300 mb layer), there may be potential for this activity to organize and produce strong to severe outflow winds, despite relatively modest potential instability. ...Kerr.. 08/04/2024 $$ = = = 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) .