SPC MD 1508


MD 1508 Image

Mesoscale Discussion 1508
NWS Storm Prediction Center Norman OK
1136 AM CDT Sun Aug 16 2020

Areas affected...Parts of central and southern Oklahoma

Concerning...Severe potential...Watch unlikely 

Valid 161636Z - 161830Z

Probability of Watch Issuance...20 percent

SUMMARY...There appears at least potential for continuing
intensification of a cluster of ongoing storms across central
Oklahoma, including the Oklahoma City metro area, through 2-4 PM
CDT.  This may be accompanied by the potential for strong wind
gusts, in addition to locally heavy rain and some hail.  It still
seems unlikely that a severe weather watch will be needed, but
trends will be monitored.

DISCUSSION...Thunderstorm activity has shown some signs of
intensification and increasing organization within a small area
near/west of Enid.  This is near the leading/southeastern edge of
persistent convection that appears driven by weak warm advection
above a weak surface cold front.

Mid/upper support for activity is unclear, but the evolution of a
compact lower/mid tropospheric cyclonic circulation has become more
evident, with some signs of a developing surface cold pool.  

Convection is embedded within light (less than 10 kt) northerly
ambient deep-layer mean flow, with shear also generally weak. 
However, seasonably high boundary-layer moisture content to the
south of the convection is contributing to rather large mixed-layer
CAPE in excess of 4000 J/kg, beneath very steep mid-level lapse
rates associated with elevated mixed-layer air.  And thermodynamic
profiles are supportive of potentially strong downbursts and surface
cold pool development, in addition to some hail.

Although there is no strong signal in model output, including latest
convection allowing guidance, for the continuation of this activity,
with sufficient cold pool strengthening, there appears at least some
potential for considerable upscale growth as inhibition continues to
weak with daytime heating.  If this occurs, south-southeastward
propagation along the frontal zone seems most probable, with
activity possible impacting much of the Oklahoma City metro area.

..Kerr/Grams.. 08/16/2020

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


LAT...LON   36059768 35739706 35299639 34919663 34329751 34549818
            34759846 35589864 36059768 

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