SPC AC 300601

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0101 AM CDT Tue Jun 30 2020

   Valid 011200Z - 021200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF MONTANA AND VICINITY...ACROSS THE MINNESOTA AREA...AND WITHIN A
   ZONE FROM IOWA/MISSOURI TO THE SOUTHEAST...

   ...SUMMARY...
   A few strong/locally severe storms will be possible over the Montana
   area, across portions of Minnesota and vicinity, and from the Mid
   MS/lower OH Valley area across the Mid South and Southeast on
   Wednesday.

   ...Synopsis...
   A pair of upper lows will continue to reside over the northwestern
   and northeastern portions of the U.S., while sharp ridging continues
   from central Canada and the Upper Great Lakes region to the southern
   Plains.

   At the surface, a rather weak pattern will prevail.  A weak cool
   front will cross the Southeast, while a weakening front crosses the
   Dakotas through the day.  A more prominent baroclinic zone will
   affect areas from Montana into the Great Basin through the period.

   ...Parts of Iowa and northern Missouri to the Southeast states...
   Within the broad belt of cyclonic flow aloft surrounding the
   Northeast upper low, several small-scale disturbances/vorticity
   maxima are expected to move through the moderate northwesterly flow
   field.  One prominent cluster of storms -- and limited/ongoing
   severe risk -- may exist over the Iowa/northern Missouri vicinity
   near one of these upper disturbances, which should persist/move
   southeastward through the day.  Other storms/clusters of storms will
   likely develop across the Mid South and Southeast into the afternoon
   as the airmass heats/destabilizes.  Given ample CAPE development
   expected, and the background moderate/near unidirectional flow
   through the lower and middle troposphere, a few of the stronger
   storms may be capable of producing strong wind gusts -- capable of
   mainly tree damage.  Storms will likely continue through the evening
   -- sagging southward with time across the central Gulf Coast states,
   but expect severe risk to gradually wane through the evening hours.

   ...Parts of Montana into eastern Idaho/northwest Wyoming...
   As an initial short-wave trough rotating around the main
   southwestern Canada/northwestern U.S. upper low pivots across the
   north-central U.S. and into the Canadian Prairie, a second feature
   is expected to move across Idaho and western Montana through late
   afternoon, and then into central Montana overnight.  Though
   afternoon destabilization is expected to be quite modest, strong
   forcing for ascent should support isolated storm development during
   the afternoon and evening, most prominent from Idaho and
   northwestern Wyoming into Montana.

   A belt of moderately strong (around 50 kt) west-southwesterly
   mid-level flow atop this region will result in potential for
   organization with a couple of the sustained updrafts, along with
   fast storm motions.  This -- combined with a dry sub-cloud layer
   promoting potential for evaporative downdraft enhancement, suggests
   potential for a few strong/damaging gusts locally.  Risk should
   diminish into late evening, as the boundary layer cools/stabilizes.

   ...Portions of Minnesota and vicinity...
   As the upper trough pivots across the north-central states and into
   the Canadian Prairie, showers and scattered thunderstorms may
   develop from the eastern Dakotas into Minnesota, near/ahead of the
   weakening frontal zone across the region.  Modest but sufficient
   CAPE in conjunction with southerly mid-level flow near 30 kt
   contributing to sufficient shear for multicell storm organization,
   suggests some potential for marginal hail and strong wind gusts.  As
   such, will maintain MRGL risk across this area.

   ..Goss.. 06/30/2020

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z