Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 02 2023 17:30:07 ACUS02 KWNS 021730 SWODY2 SPC AC 021728 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Sun Jul 02 2023 Valid 031200Z - 041200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MONDAY THROUGH MONDAY NIGHT ACROSS PARTS OF UPSTATE SOUTH CAROLINA...MUCH OF NORTHERN AND CENTRAL NORTH CAROLINA...CENTRAL AND EASTERN VIRGINIA AND MARYLAND...INCLUDING THE DISTRICT OF COLUMBIA...DELAWARE...SOUTHEASTERN PENNSYLVANIA...SOUTHERN NEW JERSEY...SOUTHEASTERN MONTANA...NORTHEASTERN WYOMING...SOUTHERN NORTH DAKOTA...MUCH OF SOUTH DAKOTA AND PARTS OF SOUTHWESTERN MINNESOTA... ....SUMMARY... Scattered strong to severe thunderstorms and thunderstorm clusters may develop across the Mid Atlantic Region and portions of the northern Great Plains Monday into Monday night. ....Synopsis... A branch of westerlies across the northern mid-latitude Pacific through the northwestern Atlantic will remain amplified through this period. However, within this regime, an occluding cyclone over the Canadian Prairies is forecast to weaken, while a more modest secondary low migrates from northeastern Manitoba into central Hudson Bay. The initially deep associated mid-level low appears likely to become increasingly sheared across the eastern Canadian Prairies through western Hudson Bay, as downstream ridging builds across northern Quebec and Newfoundland and Labrador. To the south of this ridge, shearing mid-level troughing in a separate branch of westerlies will continue to shift east-northeastward, across northern and middle Atlantic coastal areas. It appears that weak troughing within this southern branch will also linger as far southwest as the southern Great Plains, while mid-level ridging builds to the north, across parts of the Upper Midwest into adjacent Great Lakes region. ....Northern Rockies into Upper Midwest... The frontal zone associated with the Canadian Prairies cyclone will likely provide one focus for considerable thunderstorm development Monday through Monday night. Models suggest that this front will reach northwestern Minnesota through the North and South Dakota state border and Big Horns vicinity by 12Z Monday, before southeastward motion slows or stalls. As a notable short wave impulse digs southeast of British Columbia, around the southwestern periphery of the more prominent shearing mid-level low, the front may make more substantive southward progress through southern Idaho and northern/central Wyoming by 12Z Tuesday. Forcing for ascent downstream of the digging impulse may contribute to thunderstorm initiation across and east of the mountains of northwestern Wyoming by Monday afternoon, as a more subtle preceding perturbation and downstream warm advection perhaps contribute to additional storm development across southeastern Montana into southwestern North Dakota and adjacent northwestern South Dakota. Stronger destabilization and vertical shear will become focused within/above the moist easterly post-frontal near-surface flow, from the lee of the Big Horns through northern South Dakota by peak afternoon heating. It appears that this environment will become conducive to the highest probabilities for severe convective development, which may include supercells and one or two upscale growing and organizing clusters into Monday night. ....Mid Atlantic... Southeast of the shearing mid-level troughing, a remnant belt of 20-40+ kt southwesterly flow in the 850-500 mb layer is forecast to gradually continuing shifting from the Cumberland and southern Allegheny Plateau vicinity through northern Mid Atlantic coastal areas. It appears that the southeastern periphery of this belt will overspread seasonably moist air within surface troughing to lee of the Blue Ridge, which is forecast to become characterized by large CAPE (2000-3000+ J/kg) by peak afternoon heating. This will support potential for scattered strong thunderstorm development accompanied by a risk for severe wind hail into Monday evening. ...Kerr.. 07/02/2023 $$ = = = 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) .