SPC AC 020522

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1222 AM CDT Thu Jul 02 2020

   Valid 021200Z - 031200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A PORTION OF
   THE GREAT PLAINS INTO THE LOWER MISSISSIPPI VALLEY AND IN PARTS OF
   NEW ENGLAND...

   ...SUMMARY...
   Clusters of strong to locally severe thunderstorms may develop today
   across parts of the Great Plains into lower Mississippi Valley, and
   in northern New England.  Severe gusts and hail are the hazards.

   ...Great Plains...
   A belt of moderate cyclonic mid-level flow will largely remain
   across the northwestern CONUS today with the southeastern fringe of
   stronger flow over the western Dakotas.  A mid-level ridge axis will
   be located farther east over the mid-upper MS Valley.  An effective
   boundary extending south from the Canadian border will extend into
   the central High Plains as a lee trough.  In the vicinity of the
   boundary, low-level convergence and strong heating will contribute
   to a gradual erosion of convective inhibition by mid-late afternoon.
   A moist boundary layer featuring mid 50s to 60s F dewpoints will
   contribute to moderate instability from the Dakotas into the central
   High Plains.  Widely spaced strong to severe thunderstorms capable
   of large hail/severe gusts are possible from the late afternoon into
   the evening.  

   Farther south across the OK vicinity, a very moist airmass featuring
   70s F dewpoints will become strongly unstable by midday.  Despite
   very little large-scale forcing for ascent, widely scattered
   thunderstorms are possible initially near a southeast-northwest
   oriented boundary and subsequently near convective outflow.  This
   activity will probably begin during the afternoon and continue into
   the early evening.  Severe gusts and large hail are the primary
   risks.

   ...Lower MS Valley...
   A very moist boundary layer will become strongly unstable by the
   early afternoon from AR into southern MS.  Model guidance indicates
   a few possible clusters of thunderstorms perhaps developing from
   near early-day activity over the Ozarks and in a separate area
   farther south in MS.  Damaging gusts and marginally severe hail are
   possible with the stronger cores.  This activity will likely
   diminish during the early evening.

   ...Northern New England...
   A belt of moderate northwesterly flow will overspread northern New
   England as a mid-level low meanders east into the western Atlantic
   away from the Northeast U.S.  Strong heating coupled with orographic
   ascent, and weak large-scale ascent associated with an impulse
   embedded in the flow, will support widely scattered storms by
   midday.  Additional storms and increasing convective coverage are
   expected during the afternoon as storms move south into VT/NH and
   the Adirondacks.  Gusty winds with localized wind damage and perhaps
   marginally severe hail are the threats with these storms.

   ..Smith/Bentley.. 07/02/2020

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