Mesoscale Discussion 0203
NWS Storm Prediction Center Norman OK
1105 AM CDT Thu Mar 19 2020
Areas affected...SParts of eastern Oklahoma...northern
Arkansas...southern Missouri...and adjacent portions of southeastern
Illinois...western Kentucky and northwest Tennessee
Concerning...Severe potential...Watch possible
Valid 191605Z - 191800Z
Probability of Watch Issuance...40 percent
SUMMARY...Severe weather potential with developing thunderstorm
activity may remain relatively isolated in the near term, but the
risk for damaging wind gusts and storms capable of producing
tornadoes probably will begin to increase toward 2-3 PM. Trends are
being monitored for the possibility of one or more tornado watches.
DISCUSSION...At least a couple of relatively compact clusters of
thunderstorms are ongoing across parts of central and eastern
Oklahoma, into portions of the Ozark Plateau. The westernmost of
the two, now developing northwest through north of McAlester OK, has
been the strongest and most organized, and appears aided by forcing
associated with a subtle mid-level perturbation and associated
cyclonic vorticity center which will continue to migrate around the
northwestern periphery of broad mid-level ridging.
Based on latest objective analyses, inflow of unstable air to
maintain the intensity of this activity in the near term is becoming
more unclear. However, a gradual destabilization of the boundary
layer is ongoing along and south of a developing zone of stronger
differential surface heating, across east central Oklahoma into the
lower Ohio Valley. This also appears to coincide with a strong
southwesterly confluent regime in the 850-700 mb layer,
characterized by speeds in excess of 50 kt.
Fluctuations in intensity may continue with the cluster of storms as
it migrates east-northeastward into the Ozark Plateau through early
afternoon. Eventually, though, this activity, and perhaps another
cluster now spreading east-northeast of the Fayetteville AR area,
may become better rooted in an increasingly unstable boundary-layer.
As this occurs, the potential for more substantive intensification
seems likely, and isolated discrete supercell development might also
not be out of the question near and to the immediate south.
Given the environment, including including a relatively moist
lower/mid troposphere with mixed-layer CAPE increasing in excess of
1000 J/kg, along with enlarging low-level hodographs, potential for
tornadoes may increase, along with increasing potential for strong
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 35659599 36359544 36719444 37389292 37649123 37848976
37088841 36128908 35669111 35019385 34649587 35659599