Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CST Fri Dec 24 2021
Valid 271200Z - 011200Z
...DISCUSSION...
An upper-level ridge will remain across the southeastern United
States for much of the period. Several shortwave troughs will move
along the western periphery of this ridge through the period with
increasingly rich low-level moisture being pulled northward with
each passing wave. By 00Z on D6/Wed, dewpoints are forecast to be
70F or greater across the western 2/3rds of the Gulf of Mexico,
which is more reminiscent of late March/early April than December.
This will provide a reservoir of ample deep moisture across the Gulf
of Mexico which will continue to feed a broad warm sector across the
Southeast CONUS.
...D5/Tue - Mid-Mississippi Valley into the Ohio Valley...
Medium-range forecast guidance has come into better agreement with a
mid-level shortwave trough tracking from the Colorado Rockies to the
Upper Midwest during the day on D5/Tuesday. A sub-1000mb lee cyclone
is forecast to move eastward through the day and weaken as the
mid-level shortwave trough becomes less defined through time.
Meanwhile, the low-level jet is forecast to maintain its strength as
it shifts east toward the Ohio/Mississippi Valley region. This will
help transport low 60s dewpoints into the Ohio Valley with mid 60s
dewpoints as far north as western Tennessee. At this time, buoyancy
still appears too limited to support a widespread severe weather
threat.
...D6/Wed - Portions of the Southeast and the Mid-Mississippi
Valley...
By Wednesday morning, better instability should be in place across
the Southeast. This will likely increase thunderstorm chances along
and near a surface front somewhere in the Southeast/Mid-Mississippi
Valley. However, by this time the broader pattern appears less
favorable with mid-level height rises and only a weak surface
reflection (if any) along the front.
Beyond D6/Wed, there is considerable uncertainty regarding the
upper-level pattern. Rich Gulf of Mexico moisture should remain
across the Southeast, which could eventually result in severe
weather potential, if the right upper-level system interacts with
this broad warm sector. However, there is too much variance at this
time to decipher any potential location for severe weather concern.
Read more LIVE: spc.noaa.gov
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