MD 2239 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF NORTHERN AND CENTRAL NEBRASKA…SOUTHEASTERN SOUTH DAKOTA AND WEST CENTRAL IOWA
Mesoscale Discussion 2239
NWS Storm Prediction Center Norman OK
0850 PM CDT Wed Oct 11 2023
Areas affected…portions of northern and central
Nebraska…southeastern South Dakota and west central Iowa
Concerning…Severe potential…Watch unlikely
Valid 120150Z – 120415Z
Probability of Watch Issuance…20 percent
SUMMARY…Increasing low-level warm advection may support additional
thunderstorms capable of isolated hail this evening. Confidence in
storm coverage and severity is low and a watch is not expected.
DISCUSSION…As of 0140 UTC, regional IR satellite imagery showed
cooling cloud tops along a band of convection across portions of the
central Plains. Located along and north of a warm front emanating
from a deepening lee low over eastern CO, convection is expected to
continue to slowly deepen and increase in coverage near the frontal
corridor through this evening and into the overnight hours. Area
VADs and surface obs show low-level mass response ahead of the
deepening low, along with a moderately strong low-level jet. Favored
by the uptick in low and mid-level warm advection, forcing for
ascent should continue to build this evening supporting additional
storm development. While not overly robust, sufficient buoyancy
(~500-1000 J/kg of MUCAPE) along the warm front should support a few
stronger updrafts. Bolstered by a band of westerly mid-level flow
associated with the deepening low, 30-40 kt effective shear may also
support some organization of these updrafts into sustained
multicells or transient supercell structures. Generally north of the
surface warm front and with nocturnal cooling ongoing at the
surface, storms should remain elevated with the main risk being
isolated hail with the more sustained/robust updrafts. Hi-res
guidance varies on the degree of storm coverage/intensity through
this evening, casting uncertainty on how widespread any severe risk
will be. However, current radar and observational trends do suggest
a few stronger storms with hail potential may evolve over
north-central NE and spread into portions of southern SD and western
IA tonight.
..Lyons/Guyer.. 10/12/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…DMX…FSD…OAX…GID…LBF…UNR…
LAT…LON 41389491 41249657 41279934 41540048 41580061 42210136
43050101 43280048 43629845 43569762 43369652 43139586
42669435 42249336 41639310 41429388 41389491
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