Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0306 AM CDT Wed Mar 20 2019
Valid 231200Z - 281200Z
...DISCUSSION...
Early in the period, a weakening, negative-tilt mid-level trough
will migrate northward across the central Plains away from a
gradually moistening warm sector and dryline across portions of
Texas and Oklahoma. By D5/Sun, another wave will migrate eastward
from the Four Corners, reaching Oklahoma/Kansas by D6/Mon and the
Mid-South by D7/Tue. Subtle differences exist in the amplitude of
this trough and attendant strength of mid-level wind fields on
D6/Mon and these differences become substantial beyond that point.
However, the general consensus is that this mid-level flow will
favorably intersect a surface dryline located across western
Oklahoma and west-central Texas D5/Sun afternoon in concert with
modest deepening of a surface low and continued boundary layer
moistening. Low 60s F dewpoints should extend perhaps as far north
as central/northern Oklahoma. Supercellular wind profiles will
become common in the warm sector, and weak to moderate buoyancy will
likely foster thunderstorm development initially along the dryline -
spreading eastward with time. All modes of severe weather will be
possible, with the highest threat likely confined to the 15%
probability area. Some spatial refinements are likely with this
area in later outlook updates.
This threat should shift eastward over time in concert with eastward
progression of the surface low and continued low-level
moistening/destabilization ahead of that low across the Lower
Mississippi Valley on D6/Mon. Again, substantial differences in
model guidance appear by this time and lower confidence in any
particular corridors of heightened severe weather risk at this time.
