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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Monday, March 7, 2022

SPC Mar 7, 2022 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1143 PM CST Sun Mar 06 2022 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY FROM PARTS OF THE LOWER OHIO AND TENNESSEE VALLEYS...INTO THE ALLEGHENY MOUNTAINS AND NORTHERN MID ATLANTIC COAST... ...SUMMARY... One or two lines of showers and thunderstorms may spread into and across the Cumberland Plateau and Allegheny Mountains, into the northern Mid Atlantic coast region by early this evening, accompanied by strong to locally damaging wind gusts. ...Synopsis... While an initially prominent mid-level high over the mid-latitude eastern Pacific may begin to weaken today through tonight, models indicate that ridging may continue to build along an axis to its north, into the Alaskan Arctic latitudes. As this occurs, downstream mid-level troughing may begin to amplify east of the Canadian Rockies through the central Canadian/U.S. border area, with at least a couple of significant embedded short wave impulses. This regime will be preceded by consolidating troughing digging to the south and southeast of Hudson Bay, before turning toward the northern Atlantic coast. It appears likely that this will include a merger with another significant short wave trough, which has emerged from the Southwest over the last day or so, and likely will be in the process of accelerating across and northeast of the middle Mississippi Valley at 12Z this morning. The southern impulse is already contributing to surface frontal wave development across the Ozark Plateau into Ohio Valley, which appears likely to gradually deepen further while migrating to the east of the lower Great Lakes, before much stronger secondary surface cyclogenesis takes place near northern New England coastal areas into the Canadian Maritimes. A trailing surface cold front likely will surge offshore of the northern Atlantic coast, and through much of the Southeast and into the northwestern Gulf of Mexico, where it is expected to stall near the northern periphery of low-amplitude subtropical mid-level ridging. Another significant shortwave perturbation continues to dig within the remnant mid-level troughing over the Southwest. However, this impulse is forecast to only slowly turn toward the southern Rockies today through tonight, lagging well to the northwest of the surface cold front. Considerable thunderstorm development is well underway in association with the surface frontal wave, and substantive further upscale growth appears probable through 12Z this morning, when convection focused along the evolving warm and cold frontal zones may extend through much of the Ohio and lower Mississippi Valleys. This activity, or its remnants, is expected to spread across much of the Appalachians and the northern through middle Atlantic Seaboard by late tonight. ...Southern Appalachians through northern Mid Atlantic coast... Modest pre-frontal low-level moistening and, perhaps more notably, relatively warm layers aloft are generally forecast to limit warm sector boundary-layer destabilization today through tonight. However, given at least weak conditional instability, mid-level forcing for ascent along/ahead of the eastward advancing cold front will probably be sufficient to maintain or support new developing lines of fairly vigorous convection, particularly across the Cumberland Plateau and Allegheny Mountains vicinity into the northern Mid Atlantic coast by this evening. Coinciding with one belt of 50-70+ kt south-southwesterly flow in the 850-700 mb layer propagating to the west of the Allegheny Mountains, and another developing to the lee of the Blue Ridge into the northern Mid Atlantic coast by this evening, this convection will contribute to the downward transfer of this momentum toward the surface. It seems probable that this will contribute to at least scattered, if not more widespread, damaging wind gusts. ..Kerr/Wendt.. 03/07/2022 Read more CHECK UPDATE ZOOM GRAPHIC