Mesoscale Discussion 1017
NWS Storm Prediction Center Norman OK
0543 PM CDT Tue Jun 13 2017
Areas affected...Northeast Nebraska...eastern South Dakota...western
Minnesota...eastern North Dakota
Concerning...Tornado Watch 323...
Valid 132243Z - 140045Z
The severe weather threat for Tornado Watch 323 continues.
SUMMARY...A threat of very large hail and a few tornadoes persists
across the watch area. Severe storms are expected to eventually
develop or spread into surrounding areas to the north and east this
DISCUSSION...Surface observations, visible satellite imagery and
radar show a warm front extending from Spink county SD eastward
across central MN. Numerous supercells extend southward along the
surface trough, with strongest storm near the low in Spink county
which is also near the warm front. Radar continues to show very
large hail in most of these cells, and brief tornadoes will also
remain possible given sufficient low-level shear and a moist air
To the east, an isolated cell was noted along the warm front across
west central MN, where temperatures were approaching 90 F. A brief
tornado is not out of the question with this activity, if it can
remain rooted in the higher theta-e air south of the front.
Otherwise, hail is possible as it continues to lift northward.
Farther north into eastern ND, surface temperatures are largely in
the low 70s F, but some gradual warming is expected. However, the
boundary layer is expected to remain cool with rather poor 0-3 km
lapse rates. Thus, severe thunderstorms capable of hail appear the
most likely threat there, with new activity that forms due to warm
advection, and, as cells west of the main surface trough continue
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 42239989 43159955 44049949 45029979 45760022 46720032
47449958 47859887 48019774 47659691 46339578 45449522
44859548 43899649 42879726 42269767 42099874 42239989