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SPC MD 1987

MD 1987 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WESTERN THROUGH CENTRAL NORTH DAKOTA AND NORTHWEST SOUTH DAKOTA
MD 1987 Image


Mesoscale Discussion 1987
NWS Storm Prediction Center Norman OK
1249 PM CDT Fri Sep 20 2019

Areas affected...western through central North Dakota and northwest
South Dakota

Concerning...Severe potential...Watch possible 

Valid 201749Z - 201945Z

Probability of Watch Issuance...60 percent

SUMMARY...A few storms may continue to pose a risk for mainly
isolated large hail early this afternoon. The threat for isolated
damaging wind and a couple of tornadoes will also increase later
this afternoon and evening.

DISCUSSION...Early this afternoon thunderstorms continue developing
over western ND and northwest SD, primarily within a post-frontal
zone of deeper ascent associated with a northeast-moving shortwave
trough interacting with a cold front that extends across the western
Dakotas. These storms are elevated, but effective bulk shear from
40-45 kt is supporting mid-level rotation, and radar data has
indicated occasional large hail. The downstream warm sector is
destabilizing with MLCAPE from 1500-2000 J/kg as temperatures warm
through the 80s. However, the atmosphere is still capped to surface
based parcels. By 20-21Z, convective inhibition should weaken
sufficiently for surface based storms to develop along the front.
Though mixed storms modes are likely, effective bulk shear from
30-40 kt will support some organized structures including a few
supercells and bowing line segments. Damaging wind and large hail
should be the main threats. A couple of tornadoes will also be
possible, especially with any storm interacting with warm front over
northern ND where 0-1 km hodograph size will be somewhat larger.

..Dial/Hart.. 09/20/2019

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

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

LAT...LON   47970256 48880158 48859952 48239933 47350007 45410163
            46090279 47970256 

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