SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Jul 05 2021 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN HIGH PLAINS/BLACK HILLS VICINITY... ...SUMMARY... Isolated severe thunderstorms are possible from the northern Great Plains to the southern High Plains, across the Great Lakes, and in southern Florida. ...Northern Great Plains... A low-amplitude shortwave impulse near the ID/MT/WY border will progress east into the northern Great Plains through tonight. A separate lead MCV which has aided early morning convection in western South Dakota should drift east. Scattered thunderstorm development is expected along a quasi-stationary frontal zone in southeast South Dakota west-northwest to a north/south-oriented lee trough across far eastern Montana and Wyoming. Larger buoyancy will generally be confined to a narrow corridor along the south side of the surface front from the Middle Missouri Valley eastward where mid 60s surface dew points remain prevalent. More muted buoyancy is expected farther west in the MT/WY/Dakotas border region, but should reach 500-1500 J/kg. Deep-layer shear profiles will generally remain modest, but should be slightly enhanced within a confined west/east-oriented corridor ahead of the latter mid-level impulse. This may support a slightly greater severe threat in the Black Hills vicinity. Otherwise, the overall setup should favor multicell clustering with isolated severe wind and hail as the primary hazards into this evening. ...Great Lakes... A shortwave trough over Ontario and the northern Great Lakes should reach the Saint Lawrence Valley tonight. Scattered thunderstorms are ongoing at midday across northern Lower Michigan, with additional development expected this afternoon along its west/southwest flank near/ahead of the southeast-advancing front. While upper-level winds will remain weak, a swath of 30-40 kt 700-mb westerlies east of Lake Michigan renders concern for some degree of multicell clustering across Lower Michigan, although the overall magnitude of today's severe risk is still a bit uncertain. Regardless, damaging winds and some severe hail can be expected. ...South Florida/Florida Keys... Pulse to weak multicell clusters should develop north this afternoon within outer convective bands associated with TC Elsa, along the leading edge of strengthening low-level southeasterly winds. This activity may pose a threat for wet microbursts producing locally damaging winds. Tonight, low-level hodograph curvature should begin to enlarge, mainly across the Keys and the far southern portion of the Peninsula. It seems most likely that SRH will remain tempered through 12Z, but adequate for a low-probability tornado risk. ...Southern High Plains... To the west of a decaying MCS across the Permian Basin, strong/isolated severe thunderstorms are expected to develop late this afternoon in a north/south corridor mostly across eastern New Mexico. A persistent belt of confluent mid-level northerlies could aid in a couple updrafts capable of isolated, marginally severe hail and wind that develop off the higher terrain. ...Northern Montana... Storms that develop just north of the international border may develop east-southeastward into north-central Montana this evening. The environment would likely be supportive of isolated severe hail/wind potential. ..Guyer/Lyons.. 07/05/2021 Read more LIVE: spc.noaa.gov
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