MD 1080 CONCERNING SEVERE THUNDERSTORM WATCH 347…348… FOR PARTS OF CENTRAL AND EASTERN OK
Mesoscale Discussion 1080
NWS Storm Prediction Center Norman OK
0344 AM CDT Sun Jun 18 2017
Areas affected...Parts of central and eastern OK
Concerning...Severe Thunderstorm Watch 347...348...
Valid 180844Z - 181045Z
The severe weather threat for Severe Thunderstorm Watch 347, 348
continues.
SUMMARY...Large hail and locally strong/damaging wind gusts remain a
severe-weather threat across north-central into parts of central and
eastern OK overnight to early this morning. Given the recent
increase in storms across north-central OK and potential for
additional storms, a new WW is being considered for parts of central
and eastern OK.
DISCUSSION...Trends in mosaic radar imagery showed an increase in
storm intensity and potential severity (increase in MRMS MESH) with
storms across north-central OK since 06Z. Meanwhile, radar imagery
also indicated southward-moving gravity waves across OK, with an
associated wind shift extending generally east-west across the
middle part of the state (or along and south of I-40). This
atmospheric phenomenon indicates the presence of a strong cap as
observed by the 00Z OUN sounding. A 30-45-kt southwesterly
low-level jet extending into central OK per VWP data at FDR/TLX is
resulting in strong low-level warm advection across central and
southern OK, and supporting the continued development of new
thunderstorms from Logan to Alfalfa Counties. Cooling cloud tops
across north-central OK per IR satellite imagery are suggesting a
strengthening trend with the north-central OK storms.
00Z NAM suggests the low-level jet will veer to west-southwest by
12Z. The current motion of the Logan/Payne Counties storm is toward
the southeast. However, the veering low-level jet would suggest a
more southward trend in activity as it moves into central OK,
possibly reaching PVJ and ADH in addition to MLC by 11-12Z. The
presence of steep midlevel lapse rates per 00Z soundings,
most-unstable CAPE of 3000-3500 J/kg per objective analyses, and
effective bulk shear of 35-50 kt should result in additional strong
to severe storms developing/spreading to the south/southeast across
central and parts of eastern OK through the early morning. The
presence of strong surface-based inhibition with south and southwest
extent across OK could prove to be a limiting factor for the western
delineation of strong/severe storms, with activity remaining mainly
east of I-35 in southern OK.
..Peters.. 06/18/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TSA...OUN...
LAT...LON 36509697 36049608 35489568 34849519 34559618 34509659
34719721 35279756 35529776 35969807 36219820 36569818
36639763 36509697
from SPC Mesoscale Discussions http://bit.ly/2sLJHgL
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