RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Mon Feb 6 12:44:01 UTC 2023.
No Mesoscale Discussions are in effect as of Mon Feb 6 12:44:01 UTC 2023.
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0639 AM CST Mon Feb 06 2023
Valid 061300Z - 071200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorm potential appears minimal.
...Synopsis...
A progressive, somewhat high-amplitude wave train will characterize
the mid/upper-level pattern through the period. A strong shortwave
trough -- initially over the inland Mid-Atlantic region -- will move
offshore around midday to early afternoon, developing a closed
500-mb cyclone well offshore thereafter. Upstream, a trough was
apparent in moisture-channel imagery from the northern High Plains
across WY, UT, southern NV, and southern CA. This feature will
split through the period, with the northern segment reaching the
Upper Great Lakes by 12Z tomorrow. Meanwhile, the southern portion
will move slower and to the east-southeast, forming a closed cyclone
over parts of AZ and NM by 12Z. Isolated, brief lightning cannot be
ruled out this afternoon over northern/eastern AZ to northwestern NM
in a zone of increasing large-scale ascent preceding the mid/upper
trough. However, low/middle-level theta-e appears too weak to
support a general/10% thunderstorm area. Lack of low-level
moisture, instability and/or lift will preclude thunderstorms
elsewhere in the CONUS.
..Edwards.. 02/06/2023
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SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0240 AM CST Mon Feb 06 2023
Valid 081200Z - 091200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MISSISSIPPI VALLEY AND TENNESSEE VALLEY...
CORRECTED FOR TYPO
...SUMMARY...
At least isolated severe thunderstorms are expected Wednesday and
Wednesday night across the Lower Mississippi Valley and Tennessee
Valley.
...ArkLaTex to Tennessee Valley including LA/AR/MS/AL/TN...
Severe-weather potential is expected to increase into Wednesday
across the region. This will be as a shortwave trough/polar jet
spread northeastward from the south-central Plains/Ozarks toward the
Midwest and interface with an increasingly moist air mass across the
Lower Mississippi Valley/Tennessee Valley.
However, numerical guidance timing/spatial variability and the
likelihood of early day convection, as well as modest overall
destabilization, cast uncertainty regarding the potential and
placement of somewhat higher severe probabilities (such as a Slight
Risk) at this time. Recent NAM runs continue to be much more
east-northeastward progressive as compared to recent ECMWF/GFS
guidance.
Early day cloud cover and scattered thunderstorms will likely be
semi-persistent factors ahead of the cold front on Wednesday,
although most global guidance has trended slightly more unstable
with respect to the warm/moist sector over the prior 24-36 hr of
guidance runs. Regardless, currently thinking is the warm sector
will at least modestly destabilize Wednesday across portions of
Louisiana into Arkansas/Mississippi. At least an isolated
severe-weather potential should increase accordingly, including
damaging wind/tornado risks. This severe potential should reach
portions of Alabama/Tennessee Wednesday night.
An upgrade to a categorical Slight Risk could be warranted for
portions of the region into the Day 2 time frame as forecast details
become clearer.
...Lower Ohio Valley/Midwest...
Steady northeastward ejection of the shortwave trough and related
deepening phase of the northeastward-advancing surface cyclone from
the Ozarks to the Midwest could influence a strongly forced
low-topped convective line across the region Wednesday night, even
in the presence of minimal instability with northward extent. Given
a pronounced strengthening of deep-layer winds, along with
steepening lapse rates atop residual but eroding boundary layer
stability, at least low wind-related severe probabilities may be
warranted in future outlooks, even with thermodynamic
uncertainties/potential limitations.
..Guyer.. 02/06/2023
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CST Mon Feb 06 2023
Valid 091200Z - 141200Z
...DISCUSSION...
...Day 4/Thursday...
While instability details are uncertain, some severe potential could
persist into the coastal Southeast on Thursday, possibly including
portions of southern Alabama, northern Florida into Georgia. This
would be near/ahead of the cold front and residual upstream
convection in the presence of strong vertical shear. The scenario
does appear to warrant 15% severe probabilities at this juncture.
...Day 5/Friday...
As a secondary/prominent upper trough approaches the region, some
severe storm potential may exist from parts of Florida in the
Carolinas, and possibly other parts of the Mid-Atlantic as a
modestly moist air mass develops northward ahead of a cold front.
...Days 6-7 Saturday/Sunday...
Little if any severe-weather potential is currently expected.
...Day 8/Monday...
Related to a low-latitude upper-level trough, very early indications
are that the severe potential could begin to increase by around
Monday across the southern tier of the CONUS, initially across parts
of Texas.
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