Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Aug 02 2023 17:35:04 ACUS02 KWNS 021734 SWODY2 SPC AC 021733 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Wed Aug 02 2023 Valid 031200Z - 041200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR FAR NORTHEAST COLORADO...FAR SOUTHWEST NEBRASKA...AND NORTHWEST KANSAS... ....SUMMARY... Scattered severe thunderstorms are possible over the central High Plains beginning Thursday afternoon and continuing through late Thursday evening. Severe gusts in the 60-80 mph range are the primary hazard. ....Synopsis... The mean upper flow regime on Thursday will be characterized by a ridge oriented over the Great Plains and a trough centered over the lower Great Lakes/Northeast. A convectively-aided mid-level shortwave trough is forecast to move from the OH/MS River confluence into GA through the late evening. Another convectively-aided disturbance is forecast to move from eastern UT/southwest WY east into the north-central High Plains. Embedded within the larger-scale southeast Canada mid-level trough, an impulse is forecast to move southeast through its base during the period. These three features will focus strong to severe thunderstorm potential on Thursday/Thursday night. ....Central High Plains vicinity... Mid/upper westerly flow around 30-40 kt is forecast as the mid-level perturbation ejects eastward through the afternoon/evening. East/southeasterly low-level flow will maintain 60s F surface dewpoints across the region, supporting a corridor of 1500-3000 J/kg MLCAPE. Effective-shear magnitudes around 35-45 kt will support organized cells capable of large hail initially and an increasing risk for severe gusts with time. Steep 700-500 mb lapse rates will overspread the Enhanced Risk categorical area over eastern CO/western KS as 0-2 km lapse rates become adequately steep by the 22-00z timeframe. Models are is relatively good agreement in showing an organized thunderstorm cluster developing over eastern CO and becoming more expansive as it encounters increasingly rich moisture and larger CAPE. The latest CAM guidance shows a focused corridor where severe gusts are most probable and a risk for significant gusts (exceeding 75 mph) may be realized during the MCS's mature phase during the evening centered over northwest KS. This activity will continue east into central KS with a gradually reducing wind hazard into the late night. ....TN Valley vicinity... There is high confidence for a corridor of showers/thunderstorms to be ongoing Thursday morning over the lower OH Valley into TN. On the southern and western periphery of cloud debris/convective outflow, differential heating will favor additional storm development during the day across the TN Valley with more isolated storm coverage along the trailing baroclinic zone perhaps extending into the Ozarks. Appreciably strong northwesterly mid/upper flow will aid in storm organization once robust storms develop. It seems probable at least some linear configuration will evolve with the diurnal storm activity centered over northern AL. Strong heating amidst a moist/mixed boundary layer will lend potential for damaging gusts with this threat peaking during the mid-late afternoon. If uncertainty regarding mesoscale details is reduced in terms of placement of the most intense storms, additional refinement of severe probabilities may become necessary. ....Great Lakes/Northeast vicinity... Model guidance doesn't show much change to the previously issued forecast in showing a shortwave impulse embedded in the larger-scale eastern trough moving across the Great Lakes much of the period. A belt of 30-40 kt midlevel flow will overlap a seasonally moist boundary layer ahead of a south/southeast-advancing cold front. MLCAPE generally less than 1500 J/kg is forecast amid modest midlevel lapse rates. Low-level flow will be fairly light, but speed shear will support effective-shear magnitudes around 25-35 kt. Forecast soundings show elongated/straight hodographs, and marginally severe hail will be possible with stronger updrafts. Strong heating will result in steep low-level lapse rates, and strong outflow winds also will be possible. ...Smith.. 08/02/2023 $$ = = = 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) .