Mesoscale Discussion 0914
   NWS Storm Prediction Center Norman OK
   0830 PM CDT Thu Jun 10 2021

   Areas affected...Western North Dakota

   Concerning...Tornado Watch 251...

   Valid 110130Z - 110330Z

   The severe weather threat for Tornado Watch 251 continues.

   SUMMARY...The severe threat continues for WW 251. The greatest
   near-term tornado risk will likely persist across west-central ND
   were training embedded supercells may continue. Developing
   convection across northeast MT may pose a tornado risk, but
   confidence is somewhat low.

   DISCUSSION...Thunderstorms that initially developed across far
   eastern MT have only gradually moved into west/northwest ND over the
   past 1-2 hours. This is largely due to meridional flow aloft and
   weak synoptic forcing (the main cold front remains displaced to the
   west). This has resulted in a broken line of training convection
   from near KD50 in northwest ND to near KGDV in eastern MT. Although
   low-level shear remains very favorable for a tornado threat across
   northwest ND (as noted by high 0-1 km SRH values in the KMBX VWP),
   training stratiform and convective precipitation has cooled surface
   temperatures and reduced low-level lapse rates. This may hinder the
   potential for surface-based convection and the overall tornado
   threat to some degree (though severe hail/wind remain possible). 

   Further south in west-central ND, persistent warm/moist advection
   into the southern end of the line is supporting embedded supercells
   that have produced tornadoes over the past 2 hours. 100-200 m2/s2
   ESRH (per RAP mesoanalysis) near the surface warm front will
   continue to support the tornado threat in the near term. Gradual
   cold pool amalgamation along the line and interactions with
   convection emerging from the west/southwest out of central MT should
   limit the tornado potential after 03 UTC. 

   Developing convection is noted along a surface trough/remnant
   outflow boundary across northeast MT. Favorable instability and
   low-level shear along and immediately to the east of the boundary
   may support a small corridor for a tornado threat, but cooler
   temperatures closer to the ND border and storm interactions
   introduce uncertainty for this potential.

   ..Moore.. 06/11/2021

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...BIS...BYZ...GGW...

   LAT...LON   46650445 47150450 47740467 48010593 48810605 49150578
               49160350 49150244 49030207 48360226 47550271 46960302
               46580348 46470414 46650445