Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 202058
SWOMCD
SPC MCD 202057
IAZ000-NEZ000-202300-

Mesoscale Discussion 1369
NWS Storm Prediction Center Norman OK
0357 PM CDT Thu Jul 20 2017

Areas affected...Portions of central/west-central IA and adjacent
far eastern NE

Concerning...Severe potential...Watch unlikely

Valid 202057Z - 202300Z

Probability of Watch Issuance...20 percent

SUMMARY...A conditional, isolated severe risk may evolve into the
evening hours. Present indications are that Watch issuance will be
unlikely, though convective trends will continue to be monitored.

DISCUSSION...Some agitation to near-boundary-layer-based cumulus
turrets has been noted along a stalled west-east front across the
region. This is especially the case where differential heating is
augmenting baroclinic circulations on the eastern periphery of
patchy multi-layered clouds, associated with remnant convective
debris progressing across far eastern NE. The sustenance of deep
convection is highly questionable owing to weak frontal ascent and
an overall dearth of large-scale lift. Regardless, very strong
instability exists in the vicinity of the front, and the presence of
25-35 kt of effective shear may support some convective
organization. Conditional severe hail/wind potential could develop
with sustained convection -- though this risk may be isolated.
Convective trends will be monitored. If a more robust increase in
severe-storm potential were to occur, Watch issuance probabilities
could increase.

..Cohen/Coniglio/Hart.. 07/20/2017

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

ATTN...WFO...DMX...FSD...OAX...

LAT...LON   41789359 41749593 41929641 42319652 42449588 42509452
            42469295 42149264 41789359



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