SPC MD 300

MD 0300 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWESTERN MO...NORTHEASTERN OK...FAR SOUTHEASTERN KS...AND FAR NORTHWESTERN AR

Mesoscale Discussion 0300
NWS Storm Prediction Center Norman OK
0658 AM CDT Tue Mar 21 2017

Areas affected...Southwestern MO...northeastern OK...far
southeastern KS...and far northwestern AR

Concerning...Severe potential...Watch unlikely 

Valid 211158Z - 211400Z

Probability of Watch Issuance...20 percent

SUMMARY...Mainly an isolated severe hail threat with elevated
thunderstorms should persist through mid-morning. Watch issuance is
unlikely in the short term.

DISCUSSION...Ahead of a subtle mid-level impulse embedded with
northwesterly flow, isolated thunderstorms have developed as of
1155Z across southwestern MO along a low-level baroclinic zone.
Farther south, isolated convection has formed across northeastern OK
on the nose of a 40 kt southwesterly low-level jet and along a weak
surface front per 11Z observations. Modifying the 06Z Lamont OK
sounding for current observations across southwestern
MO/northeastern OK reveals MUCAPE around 1100 J/kg, which is in
reasonable agreement with 11Z RAP Mesoanalysis estimates of 500-1000
J/kg MUCAPE. This elevated instability is rooted mainly at/above 700
mb owing to steep mid-level lapse rates. Although stronger mid- and
upper-level flow is displaced to the north, a modest increase in
westerly to northwesterly winds in the 700 mb to EL layer is
fostering 35-40 kt of effective bulk shear. This shear will be
sufficient in combination with the elevated instability to allow for
some updraft organization and an isolated large-hail threat in the
strongest cells for the next several hours. Convection will very
likely remain elevated through mid-morning owing to a stable and
relatively dry low-level airmass. As such, the probability of watch
issuance is unlikely in the short term, but may increase later this
morning with eastward extent across southeastern MO/northeastern AR
as the prospect for surface-based convection with greater coverage
increases.

..Gleason/Edwards.. 03/21/2017

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

ATTN...WFO...LZK...SGF...TSA...

LAT...LON   36049564 36979505 37959434 38079347 37949249 37339236
            36289281 36069372 35839487 35769545 36049564 

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