MD 1480 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF SOUTHWESTERN/CENTRAL/NORTHEASTERN NEBRASKA
Mesoscale Discussion 1480
NWS Storm Prediction Center Norman OK
0531 PM CDT Wed Sep 19 2018
Areas affected...Portions of southwestern/central/northeastern
Concerning...Severe potential...Watch possible
Valid 192231Z - 200030Z
Probability of Watch Issuance...40 percent
SUMMARY...Storms will likely initiate along a slow moving front
within the next hour or two. Large hail and damaging wind gusts will
be the primary threats. A WW is possible.
DISCUSSION...An area of agitated cumulus, on visible satellite
imagery, near the slow moving front in southwest Nebraska has
persisted over the past hour. Given the long residence time of
parcels within the zone of ascent as compared to the warm front
farther east, this appears to be the most likely area for initial
storm development. SPC objective analysis shows mid-level lapse
rates of 7.5-8 C/km and 50-70 kts of effective deep layer shear.
Given this environment, a few instances of large hail are possible.
Isolated severe wind gusts will also be possible with the strongest
cells. While enhanced SRH near the warm front is supportive of
low-level rotation, storms that form are expected to quickly move
north of the boundary which should limit the overall tornado threat.
A WW is possible.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 41110130 41720060 42349869 42629698 41769634 41229835
40550046 40260106 40380146 40790168 41110130