Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Feb 08 2023 17:24:44 ACUS02 KWNS 081724 SWODY2 SPC AC 081723 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CST Wed Feb 08 2023 Valid 091200Z - 101200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHEAST AND THE GREAT LAKES/OHIO VALLEY... ....SUMMARY... Isolated severe thunderstorms are possible on Thursday across the Southeast including parts of Alabama, north Florida and Georgia, as well as the Midwest including Indiana, Ohio, and southern Michigan. ....Synopsis... A mid-level shortwave trough and attendant jet streak will move across the Great Lakes/Ohio Valley region on Thursday. Meanwhile, the larger-scale positively tilted trough will amplify across the central CONUS and into the Southern Plains. A ~1000mb surface low is expected to be located in the vicinity of central Illinois at 12Z Thursday. This surface low is expected to maintain its intensity around 1000 mb as it moves northeast into southern Ontario by Thursday evening. A cold front will trail this surface low and could be the focus for severe convective wind gusts across portions of the Great Lakes/Ohio Valley during the day Thursday. Farther south along the cold front, limited forcing should keep thunderstorm activity minimal in eastern Tennessee/Kentucky. However, more robust convection is expected across portions of the Southeast where low-level Gulf moisture should provide ample instability for a few strong to severe storms amid broad, weak ascent. ....Ohio Valley/Great Lakes... An unseasonably moist low-level airmass will be present ahead of the cold front Thursday morning with a HREF ensemble mean dewpoint in the mid 50s across eastern Indiana. This will result in low-level buoyancy along and ahead of the cold front Thursday morning. In fact, convection will likely remain quite shallow with forecast soundings showing an equilibrium below 3km. However, strong forcing from frontal convergence and dCVA across the region should lead to a fast moving broken line of convection during the day. Lightning is unlikely with this activity due to its shallow nature, but convection along the cold front could bring strong to potentially severe winds to the surface given the 70-75 knot 1km flow across the region. Extensive cloud cover and minimal boundary layer heating should keep mixing depth shallow. However, if even brief clearing can occur ahead of the front with some boundary layer heating, a greater threat for severe wind gusts will likely occur. If this were to occur, it would be most likely across portions of north-central and northeast Ohio where some CAM guidance suggests some clearing could occur during peak heating. ....Gulf Coast from far southeast Mississippi to southwest Georgia/Florida Panhandle... Remnant Gulf moisture with low to mid 60s dewpoints will remain ahead of the cold front across southeast Mississippi on Thursday morning. This best moisture will only extend around ~75 miles inland and therefore the marginal severe weather threat will be confined to areas in closer proximity to the coast. The cold front will move slowly east across this region during the day before stalling by Thursday afternoon across the central Florida Panhandle. Weak height falls across the region and convergence along the front should be sufficient for storm development during the day. A few strong to severe storms are possible, including the potential for supercell structures given 35-40 knots of effective shear. However, weak instability (400-700 J/kg MLCAPE) and weak lapse rates (~ 6 C/km) will foster a thermodynamic environment which is less than favorable for a more widespread threat. The primary threats will be damaging winds from any supercell structures or bowing segments which develop. In addition, a tornado or two is possible given the significant directional shear in the lowest 1km, but the relatively weak flow in this layer (less than 25 knots) and the aforementioned limited thermodynamic environment should mitigate the overall tornadic threat. ...Bentley.. 02/08/2023 $$ = = = 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) .