Mesoscale Discussion 0109
NWS Storm Prediction Center Norman OK
1207 PM CST Tue Feb 19 2019
Areas affected...Portions of central Oklahoma and Vicinity
Concerning...Winter mixed precipitation
Valid 191807Z - 192200Z
SUMMARY...An area of precipitation lifting northward from the Red
River will encounter colder air to the north. Both freezing rain and
sleet will be possible within the I-44 corridor, including the OKC
metro area. Farther northwest, snow will be more likely. Heaviest
precipitation should occur between 2-4 pm CST.
DISCUSSION...Current radar mosaic shows an area of precipitation
moving northward out of north Texas and crossing the Red River.
Temperatures in the I-44 corridor have risen slightly since this
morning to the low 30s with upper 20s to the northwest. A
complicating factor in where the highest freezing rain potential
will exist is the warmer surface temperatures in northeast Oklahoma
leading to modest warm air advection into the discussion area.
Dewpoints remain in the low 20s in that region, however, and some
decrease in temperature due to precipitation-cooled air is possible
as drier air continues to advect in. The 18 UTC OUN sounding shows a
pronounced, saturated warm nose of +3-4C centered around 825 mb.
This would indicate that freezing rain will be the predominant
precipitation in this area, though some sleet is possible within
heavier/convective elements. Farther to the northwest, generally
colder 850 mb temperatures should keep more of the precipitation as
snow. Expect the heaviest precipitation to occur from 2-4 pm CST.