SPC AC 051630

   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

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