Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Dec 14 2022 00:47:07 ACUS01 KWNS 140047 SWODY1 SPC AC 140045 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0645 PM CST Tue Dec 13 2022 Valid 140100Z - 141200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF CENTRAL AND NORTHERN LOUISIANA INTO SOUTHWESTERN MISSISSIPPI... ....SUMMARY... Severe thunderstorms capable of producing locally damaging wind gusts and a few tornadoes remain possible tonight, mainly across parts of northern and central Louisiana into southwestern Mississippi. This continues to include the risk for a strong tornado or two. ....01Z Update... The mid-latitude westerlies across the eastern Pacific through the western Atlantic have amplified to the point that a number of mid-level cyclones have evolved. The deepest low is now centered near the northern New England coast, with a strong short wave impulse forecast to continue digging across the Northeast through tonight. Another broad, but somewhat less prominent, cyclone is beginning to stall upstream, over the middle Missouri Valley vicinity, with a weaker low farther upstream, centered across the eastern Pacific (roughly near 40N/140W). A couple of mid-level highs may also begin to become more prominent late tonight into Wednesday at somewhat higher latitudes, offshore of the British Columbia coast and over the northern Quebec vicinity. Beneath the interior U.S. low, a deep surface cyclone will gradually occlude overnight, with a significant surface cold front surging southward through the central and southern Great Plains. This is preceded by a weaker surface front, which remains the primary focus for thunderstorm development this evening (currently from southeastern Missouri into east Texas). The lead cold front is forecast to continue slowly advancing eastward and southeastward into the lower Ohio/Mississippi Valleys and northwestern Gulf coast. At the same time, a wedge of potentially cold air will be maintained across much of the Southeast, as far southwest as portions of southern Alabama into eastern Mississippi through daybreak. In between, a narrowing plume of moist confluent Gulf return flow appears likely to persist across the Louisiana coast through the lower Mississippi Valley vicinity. However, an initially strong low-level jet (30-50+ kt around 850 mb) appears likely to gradually weaken. Despite this gradual weakening, sizable clockwise curved low-level hodographs are forecast to be maintained well into tonight ahead of the southeastward advancing cold front. Particularly across parts of central and northern Louisiana into southwestern Mississippi, where a seasonably moist boundary layer will remain characterized by weak to moderate CAPE, this may continue to support discrete supercell structures that could become capable of producing tornadoes, including the risk for a strong tornado or two. Although mid/upper flow will remain at least broadly difluent across the lower Mississippi Valley region overnight, the lack of more substantive mid/upper support appears likely to remain a limiting factor with regard to potential for more widespread severe weather. The primary upstream short wave, within the broader-scale cyclonic flow surrounding the middle Mississippi Valley cyclone, is still digging across Arizona and only forecast to reach the Texas South Plains/Pecos Valley vicinity after turning eastward later tonight. ...Kerr.. 12/14/2022 $$ = = = 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) .