SPC AC 041944

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0244 PM CDT Mon Jul 04 2022

   Valid 042000Z - 051200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE UPPER  MS VALLEY/SOUTHWEST GREAT LAKES AND MT TO THE WESTERN
   DAKOTAS...

   ...SUMMARY...
   A few tornadoes and scattered damaging gusts are possible through
   this evening centered on a portion of the Upper Mississippi Valley
   and southwest Great Lakes regions. Scattered large hail and isolated
   severe gusts are possible across parts of Montana into the western
   Dakotas from late afternoon through tonight.

   ...20z Update...

   The previous outlook remains on track. The only changes made with
   the 20z update were to expand the 2 percent tornado area across
   northeast ND into a small part of northwest MN given ongoing trends
   and reports of a funnel near Grand Forks ND. Otherwise, ongoing
   convection across southern WI/northern IL will pose a short term
   severe threat for another couple of hours. Reference MCDs 1356 and
   1357 for more information on near term severe potential. Additional
   thunderstorms are expected to develop across portions of WI/MI later
   this afternoon/evening and may impact similar areas of northern IL
   into northern IN later this evening. Severe thunderstorms are also
   still expected to develop across parts of MT into the western
   Dakotas through this evening. For short term severe potential across
   parts of central MT, reference MCD 1358.

   ..Leitman.. 07/04/2022

   .PREV DISCUSSION... /ISSUED 1127 AM CDT Mon Jul 04 2022/

   ...Upper MS Valley and southwest Great Lakes...
   A non-severe MCS is ongoing from western WI to the IA/IL border
   area. While the northern portion will likely further decay, remnants
   of the southern portion may persist across northern IL into IN this
   afternoon. Weak mid-level lapse rates and just-in-time moisture
   return should limit more widespread intensification potential, but
   isolated damaging wind gusts will be possible into late afternoon as
   the boundary layer further destabilizes. 

   In the wake of the MCS and its attendant convectively induced
   shortwave impulse, large-scale ascent should be suppressed to the
   northwest of the low-level warm theta-e advection regime that is
   expected to persist from the Mid-MO Valley to southern WI. While
   there is low confidence in timing of redevelopment, areal extent
   will likely be focused near the IA/MN/WI/IL border. The degree of
   boundary-layer destabilization is questionable and its plausible
   that redeveloping convection will remain slightly elevated atop it.
   In addition, convective mode should tend to evolve into a
   west/east-oriented cluster. But rather enlarged low-level hodograph
   curvature owing to the southwesterly jet and modest surface
   temperature-dew point spreads favor a conditional threat for a few
   tornadoes. Consolidation of clusters into a forward-propagating MCS
   is possible tonight across northern IL into northwest IN with
   scattered damaging winds becoming the primary threat until
   convection weakens overnight.

   ...MT to the Dakotas...
   Despite minor weak mid-level height rises, presence of 50s surface
   dew points banked up to the northern Rockies will foster scattered
   thunderstorm development by late afternoon off the higher terrain in
   MT. More isolated thunderstorms will likely initiate off the Black
   Hills and are possible in north-central/northeast ND near a weak
   surface low. A belt of enhanced mid-level southwesterlies to
   westerlies will be maintained downstream of the weakening closed low
   near northwest WA. This will foster 40-50 kt effective bulk shear
   supporting potential for several supercells with mid-level updraft
   rotation. Larger buoyancy should be confined to southern SD into
   southeast ND, more muted values from 750-1500 J/kg are expected to
   the northwest. This will likely be a limiting factor to greater
   intensities with significant hail and wind potential expected to be
   very isolated/conditional. Large hail should be the primary threat
   with more isolated swaths of severe wind gusts focused on eastern MT
   into southwest ND this evening/tonight.

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z