SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1241 PM CDT Sun Jul 04 2021 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF THE NORTHERN HIGH PLAINS... ...SUMMARY... Scattered strong to severe storms are possible mainly over a portion of the northern High Plains Monday afternoon and evening with more isolated coverage farther south across the central and southern High Plains. Locally severe gusts and hail are the main threats. Other strong to severe storms may occur over the Great Lakes region. A tornado cannot be ruled out over a portion of southern Florida Monday night in association with Elsa. ...Northern High Plains... Shortwave trough currently approaching southern OR will crest the upper ridge and continue into the northern High Plains late Monday afternoon and evening. At the surface a stalled front will extend east from a lee low over western SD through southern SD and into IA. A lee trough will stretch southward from the low through the central High Plains. Somewhat richer low-level moisture will return northward along and south of the stalled front into SD with dewpoints in the upper 50s to near 60 F beneath elevated mixed layer plume. MLCAPE should increase to between 1500 and 2000 J/kg as the surface layer warms during the afternoon. Storms will likely develop over the higher terrain and spread east into the High Plains. Other storms may initiate along the stalled front. Vertical wind profiles will be characterized by southeasterly low-level flow veering to westerly with height, but with modest speeds aloft resulting in 30-40 kt effective bulk shear. Both multicell and some supercell structures will be possible with damaging wind and large hail the main threats. Some upscale growth into an MCS may occur before activity weakens later in the evening. ...Great Lakes... Shortwave trough currently over MN will continue slowly east through the Great Lakes during period, while a cold front moves through upper MI and northern lower MI, with trailing portion likely to stall across southern WI into IA. Near-surface dewpoints in the upper 60s F and diabatic heating will contribute to moderate instability with 2000+ J/kg MLCAPE during the afternoon. A few storms may develop along this boundary, but the deeper forcing attending the shortwave trough will remain generally north of the front. While wind profiles with weak shear will support multicells, a 35+ kt low-level jet will reside across this region. Primary threat with storms that develop will be locally strong to damaging gusts. An upgrade to SLGT risk might be warranted in day 1 outlooks once uncertainties regarding storm coverage have been mitigated. ...Southern FL... Based on latest forecast from NHC regarding tropical storm Elsa, have introduced a MRGL risk for a tornado or two across a portion of southern FL, mainly for Monday night. ..Dial.. 07/04/2021 Read more LIVE: spc.noaa.gov
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