SPC AC 151947

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0247 PM CDT Wed Jun 15 2022

   Valid 152000Z - 161200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF WISCONSIN...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
   THE CENTRAL AND SOUTHERN APPALACHIANS TO THE CENTRAL GULF COAST
   STATES...

   ...SUMMARY...
   Scattered severe thunderstorms are likely this afternoon into
   tonight across parts of the Upper Midwest and Upper Great Lakes.
   Several tornadoes, large to very large hail, and damaging winds all
   appear likely. Some of the tornadoes could be strong.

   ...Discussion...
   The current outlook continues to accurately reflect future
   expectations, as the anticipated severe weather event begins to
   unfold across the Upper Mississippi Valley/Upper Great Lakes region.
    Storms are expected to increase substantially in coverage and
   intensity over the next few hours, in and near the newly issued
   tornado watch across this area.

   Storms are also evolving now across the central and southern
   Appalachians, and southeastward across the Savannah River Valley
   area, with a ramp-up in severe potential over the next couple of
   hours expected in this region as well.

   Given current and anticipated convective trends, only minor tweaks
   to the outlook areas appears necessary in this update.

   ..Goss.. 06/15/2022

   .PREV DISCUSSION... /ISSUED 1217 PM CDT Wed Jun 15 2022/

   ...Upper Midwest including Wisconsin/Iowa/Upper Michigan...
   A regional outbreak of severe storms is expected this afternoon and
   evening, particularly across eastern Iowa/far southeast Minnesota
   into southern/central/eastern Wisconsin and Upper Michigan. Aside
   from large hail, this includes the potential for tornadoes, some of
   which may be strong, along with a focused corridor of appreciable
   damaging wind potential.

   Related to a decayed overnight MCS, morning surface analysis shows a
   precipitation-reinforced semi-stalled boundary extending from
   west/central Iowa into southwest/central Wisconsin, with some
   persistent precipitation and a few stronger storms/differential
   heating reinforcing this boundary. A notable upper trough over the
   northern Plains will influence the region particularly later today
   into tonight with increasing large-scale forcing for ascent and
   strengthening deep-layer southwesterly winds. Modest surface
   cyclogenesis is expected along the southwest/northeast-oriented
   boundary, with the gradually deepening wave expected to help
   maintain an easterly component to the near-surface winds.

   Surface dewpoints in the lower 70s F and steep mid-level lapse rates
   will yield MLCAPE values of 3000+ J/kg especially from eastern Iowa
   into much of central/southern Wisconsin. Strong deep-layer shear and
   large hodographs will promote supercells capable of very large hail
   and a few tornadoes during the first several hours of surface-based
   initiation. A few of the tornadoes could be strong (EF2+), although
   there are some mode-related uncertainties over time. Storms are
   likely to trend upscale across interior parts (central/southern) of
   Wisconsin with damaging wind potential appreciably increasing.
   Storms will move into Lower Michigan and northern Illinois after
   sunset, with a continued risk of locally damaging wind gusts
   persisting, potentially as far east as Lower Michigan and northern
   Indiana. 

   ...Southeast/Mid-Atlantic/Northeast States...
   A hot and humid low-level air mass is in place today from the
   central/northern Appalachians and interior Carolinas southwestward
   into Mississippi/Alabama, with widespread temperatures in the 90s
   and dewpoints in the upper 60s and lower 70s. This will result in
   MLCAPE values over 3000 J/kg and steep low-level lapse rates
   throughout the region. The details of the timing and location of
   convective development remains uncertain even in the short-term, but
   multiple corridors of storms may unfold this afternoon into tonight
   on the periphery of the southern Appalachians-centered upper-level
   ridge. Sufficiently strong northeasterly flow aloft will aid in
   southwestward-propagating clusters capable of strong/damaging wind
   gusts. A conditional severe risk will exist as far north as
   west-central Pennsylvania and western New York today near the front.
   Several models also imply the potential for late-night MCS
   development centered across southern New York/west-central
   Pennsylvania into Maryland.

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