000
ACUS11 KWNS 161743
SWOMCD
SPC MCD 161742
ILZ000-MOZ000-IAZ000-162015-

Mesoscale Discussion 1506
NWS Storm Prediction Center Norman OK
1242 PM CDT Wed Aug 16 2017

Areas affected...Missouri...Southern Iowa...Extreme Western Illinois

Concerning...Severe potential...Watch possible

Valid 161742Z - 162015Z

Probability of Watch Issuance...40 percent

SUMMARY...A threat for isolated large hail and wind damage will
likely develop across parts of Missouri, southern Iowa and extreme
western Illinois this afternoon. Weather watch issuance may be
needed across parts of the region as cells increase in coverage and
intensity.

DISCUSSION...The latest surface analysis shows a 1007 mb low over
southwest Iowa with a very moist airmass extending southward from
the low across much Missouri. Surface dewpoints across southern Iowa
and Missouri are generally in the lower to mid 70s F with the RAP
estimating MLCAPE values around 1000 J/kg across much of Missouri.
The greatest instability is located in west-central Missouri where
radar imagery shows a developing line of thunderstorms to the west
and north of Springfield, MO. The WSR-88D VWP at Springfield, MO has
0-6 km shear of 20-25 kt with flow from the southwest in the low to
mid-levels. Deep-layer shear is likely stronger with northward
extent due to the presence of a mid-level jet max moving through the
central Plains. The wind shear environment along with increasing
instability and steepening low-level lapse rates over the next few
hours, should contribute to a wind damage threat associated with the
stronger multicells. Isolated large hail could also occur if a
rotating storm can organize.

..Broyles/Weiss.. 08/16/2017

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

ATTN...WFO...LSX...DVN...SGF...DMX...EAX...

LAT...LON   37099455 38399362 40029318 40839326 41129276 40829147
            39619118 38069174 37079243 36659313 36629426 37099455