Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Feb 07 2024 05:31:25 ACUS01 KWNS 070531 SWODY1 SPC AC 070530 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 PM CST Tue Feb 06 2024 Valid 071200Z - 081200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... The risk for severe thunderstorms appears negligible across the U.S., today through tonight. ....Synopsis... Downstream of an intensifying cyclone, mid/upper ridging is in the process of building across the central into eastern mid-latitude Pacific. To the east of this ridging, a significant short wave trough is already digging offshore of the Pacific Northwest coast, and prominent downstream troughing, emerging from the southern mid-latitude and subtropical eastern Pacific, continues to accelerate northeastward, inland and through the Southwest. As the central Pacific cyclone continues to deepen and turn north-northeastward, toward the Aleutians, models indicate that the mid/upper ridging will amplify further across the northeastern Pacific today through tonight. It appears that impulse approaching the Pacific coast will continue digging through much of this period, across and inland of the California coast, generally to the west of the Sierra Nevada. The larger-scale downstream troughing is forecast to progress across and east of the Rockies, with one embedded impulse, initially approaching the southern California coast, accelerating east-northeastward across the Southwestern international border vicinity through the Texas/Oklahoma Panhandle vicinity by 12Z Thursday. A preceding impulse, emerging from the Four Corners region, is forecast to accelerate into the northern Great Plains and contribute to significant cyclogenesis across the Dakotas vicinity. ....Great Plains... By late this afternoon, models indicate an elongated area of deepening surface low pressure from the southeastern Canadian Prairies into the southern U.S. Great Plains, with perhaps one embedded low center beginning to migrate northeast of the Cheyenne Ridge vicinity. While this will be accompanied by a broad swath of strengthening southerly low-level flow through the day across the southern Great Plains toward the Upper Midwest, an initially dry low-level environment, not only across much of the Great Plains but also the lower Rio Grande Valley and western Gulf of Mexico, will preclude substantive boundary-layer moistening. Destabilization will further be hampered by cloud cover associated with mid/high-level moisture return off the Pacific, and inhibition associated with a plume of relatively warm and dry lower/mid-tropospheric air overspreading the Great Plains. However, beneath mid-level cooling, and a developing dry slot, across the high plains, models do suggest that steepening lower/mid tropospheric lapse rates may become supportive of at least very weak boundary-layer destabilization by late afternoon. It is possible that this could become supportive of widely scattered convective development, which may become capable of producing lightning. Based on forecast soundings, it remains unclear how sustained any individual storms may be, but high resolution model output suggests that potential for weak thunderstorm activity may persist through this evening, near the possible developing surface low track across west central Nebraska through south central South Dakota. ....Pacific Coast and Southwest... The risk for thunderstorms near southern California coastal areas seems likely to diminish by late this morning, as the supporting mid-level cold core shifts inland into the lower Colorado Valley. Beneath the broader mid-level cold pocket overspreading the Four Corners states during the day, the risk for scattered weak thunderstorm development will probably increase through afternoon, as insolation contributes to boundary-layer destabilization. Convection seems likely to wane quickly after sunset, due to both radiational surface cooling and the tendency for warming in mid-levels. ...Kerr/Squitieri.. 02/07/2024 $$ = = = 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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .