Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 09 2023 17:38:46 ACUS02 KWNS 091738 SWODY2 SPC AC 091737 Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1137 AM CST Thu Mar 09 2023 Valid 101200Z - 111200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FRIDAY ACROSS PARTS OF SOUTHERN GEORGIA...SOUTHEASTERN ALABAMA AND NORTHERN FLORIDA... CORRECTED FOR OUTLOOK GRAPHIC ....SUMMARY... A couple of strong thunderstorms are possible across parts of southern Georgia, adjacent southeastern Alabama and northern Florida Friday, accompanied by some risk for severe weather. ....Synopsis... Models suggest that flow in the mid- and higher latitudes of the eastern Pacific through western Atlantic will remain amplified, with generally weak westerlies, as blocking highs are generally maintained near the Aleutians and across the Canadian Arctic through this period. Lower amplitude flow will prevail in the southern mid- and subtropical latitudes, with broad mid-level troughing across the central Pacific transitioning to broad ridging across the eastern Pacific through the southern tier of the western into central U.S., and broad troughing farther downstream into the western Atlantic. Within this regime, one vigorous shortwave impulse is forecast to progress inland across the northern U.S. Pacific coast and northern Rockies by late Friday night. This will be accompanied by a weakening surface cyclone and inland advancing cold front across the interior Northwest and Rockies, and deepening surface troughing to the lee of the Rockies. It appears that a plume of higher moisture content air emanating from the subtropical Pacific, initially impinging on the Sierra Nevada, before spreading into the Great Basin, will gradually be suppressed southward, ahead of the front. East of the Rockies, a weak initial surface low is forecast to gradually migrate northeastward through the Allegheny Plateau vicinity, before much more substantive cyclogenesis takes place off the Mid Atlantic coast, in response to a significant short wave trough digging southeast of the Great Lakes region. As this occurs, low-level cooling and drying, in the wake of a trailing cold front, will overspread much of the Southeast through central Gulf coast. ....Pacific Northwest into northern Rockies... Models indicate that the inland migrating short wave will be accompanied by a compact mid-level cold core, including 500 mb temperatures of -30 to -35C. This will contribute to weak boundary-layer destabilization, which may become supportive of scattered low-topped convection capable of producing lightning near Oregon coastal areas at 12Z Friday, inland toward the Montana Rockies through the day. ....California coast through the Great Basin... Forecast soundings suggest that lower/mid-tropospheric moistening, coupled with weak mid-level cooling, will be sufficient to contribute to layers of weak conditional instability. It appears that this will mostly be rooted at higher altitudes, as cloud cover and precipitation hinder surface heating and boundary-layer destabilization at lower elevations, particularly to the west of the Sierra Nevada. Aided by 40 to 70 kt westerly flow in roughly the 4,000-10,000 foot layer, strong orographic forcing for ascent may contribute to convection capable of producing lightning across the western slopes of the Sierra and Wasatch. ....Southeast... Scattered thunderstorm activity is possible Friday near the southeastward advancing cold front. The general tendency may be for this activity to form to the cool side/above the front. However, near peak afternoon instability, a window of opportunity may develop for sustained thunderstorm activity rooted within the boundary-layer, just ahead of the front across parts of southern Georgia into northern Florida. Forecast soundings suggest that the environment might become conducive for a couple of strong storms posing at least some risk for severe hail and wind, before activity weakens by Friday evening. ...Kerr.. 03/09/2023 $$ = = = 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) .