SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0231 AM CDT Tue Sep 05 2023 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST...CENTRAL APPALACHIANS...MID-ATLANTIC AND ARK-LA-TEX... ...SUMMARY... Thunderstorms, associated with marginally severe wind gusts and hail, will be possible on Thursday across parts of the Northeast, Mid-Atlantic and central Appalachians. Additional storms with a marginal severe threat may develop in parts of the Ark-La-Tex. ...Northeast/Central Appalachians/Mid-Atlantic... An upper-level trough, and an associated cold front are forecast to move eastward across the central Great Lakes and Ohio Valley on Thursday. At the surface, a moist airmass will be in place ahead of the front with surface dewpoints mostly in the upper 60s to lower 70s F. This will contribute to the development of moderate instability in most areas ahead of the front by afternoon. As surface heating takes place during the day, isolated to scattered thunderstorms will likely form ahead of the front across much of this moist airmass. NAM forecast soundings around 21Z from central New York southward to northern Virginia suggest that deep-layer shear will remain relatively weak. However, MLCAPE is forecast to peak in the 1500 to 2000 J/kg range across much of the region. This, combined with steep low-level lapse rates, could be enough for a marginal wind-damage threat in areas that heat up the most. ...Ark-La-Tex... A mid-level anticyclone will be in place across the Desert Southwest on Thursday, as flow remains northwesterly across much of the south-central U.S. Moisture return is forecast to take place across the southern Plains during the day. By afternoon, a southeast-to-northwest corridor of maximized low-level moisture is forecast from Arkansas to southern Kansas. As surface temperatures warm and low-level convergence increases along this corridor during the mid to late afternoon, isolated to scattered thunderstorms are forecast to develop. NAM forecast soundings suggest that MLCAPE will peak in the 2000 to 3000 J/kg range from Arkansas into southeast Oklahoma, where 0-6 km shear is forecast to be in the 30 to 35 knot range. This could be enough for marginal severe threat. Strong gusts and hail would be the primary hazards. ..Broyles.. 09/05/2023
