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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Tuesday, August 31, 2021

SPC Aug 31, 2021 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CDT Tue Aug 31 2021 Valid 311630Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS NORTH GA/FAR EAST-CENTRAL AL AND NORTHERN VA TO THE DELMARVA... ...SUMMARY... A couple tornadoes remain possible, mainly across far east-central Alabama into north Georgia this afternoon, with the remnants of tropical cyclone Ida. A couple tornadoes and damaging winds may also occur tonight over a portion of the Lower Mid-Atlantic States. ...Southeast States... The remnants of Ida will move northeast from northwest AL across the southern to central Appalachians through early Wednesday. A narrow overlap of 150-250 m2/s2 effective SRH coincident with meager MLCAPE generally at or below 500 J/kg should gradually shift east across far east-central AL and north GA through this afternoon. Some cloud breaks between areas of low-level confluence suggest potential still exists for a couple low-topped supercells evolving from showers that can be sustained near the AL/GA border. Farther east, a north-south band of showers and thunderstorms has also developed along the differential heating corridor from central GA into the eastern FL Panhandle. Locally damaging winds and a brief tornado will be the hazards as activity spreads northeast along the leading edge of low-level flow enhancement. Over the central the FL Panhandle, larger buoyancy owing to greater low-level moisture will continue to support a threat for locally strong wind gusts and a brief tornado into this afternoon. Further overturning and the belt of stronger flow/shear shifting away from this region should yield a diminishing threat later today. ...Lower Mid-Atlantic States... Minimal convergence and forcing for ascent along a weak surface front across northern VA to the Delmarva area suggest that convective development this afternoon should be subdued. A greater chance for isolated thunderstorms will occur this evening into the overnight as low-level warm theta-e advection increases ahead of the remnants of Ida. Most CAMs do suggest a couple supercells should develop along the baroclinic zone coincident with enlargement to hodographs as low to mid-level flow and effective shear strengthens. Residual steepness in low-level lapse rates from the warm boundary layer this afternoon in conjunction with seasonally rich low-level moisture might support a threat for damaging winds and a couple tornadoes into the overnight. ...Eastern KS to Mid-MS Valley... The remnants of early-day convection are moving southeast across the Lower MO Valley with the composite outflow arcing from north-central MO into east-central KS as of 16Z. Strong gusts should become increasingly localized along the KS/MO border in the near-term as convection is anticipated to further decay. Consensus of CAM guidance suggests convective redevelopment is most likely tied to an MCV near the IA/MO border later this afternoon. Potential exists for loosely organized multicell clustering in the eastern MO and Mid-MS Valley areas amid a modest combination of buoyancy and shear. Locally damaging winds should be the main threat. Development farther west along the trailing outflow boundary appears much more nebulous. ...Far northeast MT/northwest ND... As minor mid-level height falls overspread the northern High Plains region tonight, convergence along a surface cold front will strengthen near the MT/ND/SK border area. Intensifying low-level warm theta-e advection near this boundary may be sufficient to overcome pronounced inhibition overnight and yield an elevated supercell with a threat for severe hail. ..Grams/Lyons.. 08/31/2021 Read more LIVE: spc.noaa.gov