SPC MD 1063



MD 1063 CONCERNING SEVERE THUNDERSTORM WATCH 319… FOR EASTERN NORTH DAKOTA AND NORTHEAST SOUTH DAKOTA

MD 1063 Image

Mesoscale Discussion 1063
NWS Storm Prediction Center Norman OK
0818 PM CDT Tue Jun 30 2020

Areas affected...Eastern North Dakota and northeast South Dakota

Concerning...Severe Thunderstorm Watch 319...

Valid 010118Z - 010245Z

The severe weather threat for Severe Thunderstorm Watch 319
continues.

SUMMARY...A large hail and damaging wind threat will persist through
the evening across the eastern Dakotas.

DISCUSSION...Storms have formed along the cold front from southern
North Dakota into northern South Dakota. Convection has not been
that strong thus far, likely due to the weak effective shear and the
warm air around 3 km. The 00Z ABR sounding is a good proximity
sounding for the environment along this line. This RAOB shows
extreme instability (~3800 J/kg J/kg) and effective shear around 10
knots. In addition, CAPE is very small (35 J/kg in the lowest 3km
and likely responsible for the lack of explosive updraft development
despite the extreme instability. Additionally, the storms which have
formed in the confluence zone near Aberdeen, SD have also struggled
thus far.

While there is still a chance for strong to severe storms, the
window is shrinking as the boundary layer rapidly cools in the next
2 hours.

The best chance for severe storms will likely be in eastern North
Dakota for the next several hours. Flow is somewhat stronger in this
region based on the 00Z KBIS RAOB and the KMVX VWP. This is likely
why storms have shown slightly better organization. In addition, the
cold front is oriented more orthogonal to the low-level shear in
north Dakota, and thus updrafts have been able to stay better rooted
along the boundary.

..Bentley.. 07/01/2020

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

ATTN...WFO...FGF...ABR...BIS...

LAT...LON   47750007 48360003 48809972 49019912 48999749 48459714
            46819665 45439671 44879730 44659776 44669827 45029869
            46679957 47750007 

Read more



Source link

Editor
  • Editor