Subj : MESO: Mesoscale Discussion 2246 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Oct 12 2023 17:30:07 ACUS11 KWNS 121730 SWOMCD SPC MCD 121729=20 KSZ000-NEZ000-121930- Mesoscale Discussion 2246 NWS Storm Prediction Center Norman OK 1229 PM CDT Thu Oct 12 2023 Areas affected...central NE...far northern KS Concerning...Severe potential...Tornado Watch likely=20 Valid 121729Z - 121930Z Probability of Watch Issuance...80 percent SUMMARY...Storm development is expected initially near the triple point in the vicinity of I-80 and subsequently southward along the cold front. Storms acquiring supercell characteristics moving into a vorticity-rich and adequately unstable boundary layer near the warm front/triple point will be capable of tornadoes. Large hail (max size 1.5 to 2 inches in diameter) will be the primary threat with storms not posing a tornado risk. A tornado watch is likely needed by around 2pm CDT. DISCUSSION...Visible-satellite imagery shows extensive stratus across northern/eastern KS northward into NE. The stratus has begun to erode in a narrow zone immediately east of the front extending northward to the triple point. At least 1-2 hours of surface heating will act to quickly destabilize the boundary layer and erode convective inhibition as mid-level large-scale ascent/CAA continues to lift/cool the profile. Surface flow veering from southeasterly to southwesterly in the mid levels and strengthening within this layer will support updraft rotation with the more robust updrafts.=20 Of particular note, forecast soundings show large CAPE in the low to mid troposphere---indicative of potentially strong stretching potential with any rotating updrafts that manage to move into the favored zone immediately near the triple point/warm frontal zone.=20 Large hail is forecast with the more intense updrafts regardless whether the storms are in the warm sector or become elevated north of the warm front. The tornado risk will likely be confined near/south of I-80 into perhaps far northern KS where supercells can potentially harness large 0-3 km CAPE and low-level vorticity. The greatest risk for severe thunderstorms/tornadoes will probably coincide with a 3pm-7pm timeframe. ...Smith/Guyer.. 10/12/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-5yV-heauX1-0Q_wl9_GUbecIaT3Bl8xwjGAvLweNMz4kmrG1hcLd911oeXxepxr_a02wzqTx= PyAOPG8tl8xJkvGEu0$ for graphic product... ATTN...WFO...OAX...TOP...GID...LBF...GLD... LAT...LON 40980012 41809999 42149951 42189878 42029831 41609793 39989792 39439835 39209915 39259991 39530011 40980012=20 =3D =3D =3D 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) .