Administrators NorthGeorgiaWX Posted March 4 Administrators Share Posted March 4 Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Mon Mar 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... A multi-day severe event appears increasingly probable for the latter portion of this week into the early weekend. For Day 4/Thursday, a 15% severe area has been introduced across parts of TX into the lower MS Valley for mainly a large hail threat Thursday night into early Friday morning. A southern-stream upper trough is forecast to eject across the Southwest/northern Mexico into the southern Plains in this time frame. Steep mid-level lapse rates should overspread the gradually destabilizing warm sector, with the ECMWF and its ensemble in particular suggesting that ample MUCAPE will be available Thursday night across parts of north-central into east TX. Any thunderstorms that can initiate in the strengthening low-level warm advection regime across this region should pose a threat for large hail given ample cloud-bearing shear to support elevated supercells. Some of this activity could become near-surface-based towards 12Z Friday morning across the lower MS Valley as surface dewpoints quickly increase into the mid/upper 60s. The severe threat will likely continue into Day 5/Friday, where a 15% severe area has been introduced from east TX into the lower MS Valley and parts of the central Gulf Coast states. There is still some uncertainty in guidance regarding the ejection of the upper trough and placement of related surface features. Regardless, there is enough agreement that rich low-level moisture will advance inland across these areas to support a threat for surface-based convection ahead of whatever activity develops across north-central TX late Thursday night into early Friday morning. Forecast soundings from both the GFS and ECMWF show strong effective bulk shear that will support the potential for supercells producing large hail, damaging winds, and tornadoes. Convection may also grow upscale into bowing line segments while continuing to pose a threat for severe/damaging winds and a few tornadoes. The main uncertainty remains how far inland/north the warm sector will be able to advance, particularly across MS/AL. For now, have opted to remain conservative with the northward extent of the 15% severe area by highlighting where at least mid 60s surface dewpoints appear probable. Some severe risk may persist into Day 6/Saturday across parts of the Southeast towards the Carolinas. However, model guidance shows substantial spread in the evolution of the upper trough at this extended time frame. Convection may also have a tendency to outpace the developing warm sector with time. While parts of FL/GA/SC/NC will be monitored for possible inclusion in a 15% severe area in later outlooks, predictability for early this weekend remains too low at this time. Read more View the full article Quote Link to comment Share on other sites More sharing options...
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