(All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 280848
SPC AC 280848
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0348 AM CDT Tue Mar 28 2023
Valid 311200Z - 051200Z
...Day 4/Friday -- Arklatex and Mid-MS Valley, East to OH/TN
A complex forecast scenario remains for Day 4/Friday, with a large
area of severe potential expected from the Arklatex into the Mid-MS
Valley, eastward to portions of the OH and TN Valleys. A strong
mid/upper trough is forecast to eject eastward across the Plains and
Midwest. Intense deep-layer southwesterly flow will overspread the
region as a surface low deepens over IA and shifts east/northeast
across the Great Lakes. A strong cold front attendant to the low
will sweep across the region, while strong southerly low-level flow
transports 60s surface dewpoints northward across the Midwest ahead
of the front. A bi-modal severe threat still appears possible, with
one area of enhanced potential possible closer to the surface low,
and another further south along the cold front in the Mid-South
Some forecast details still remain uncertain, including the
amplitude of the trough, and quality of northward moisture
return/destabilization over the Midwest.
Surface dewpoints will be lower near the surface low over IA and
into parts of MO/IL/and the Ohio Valley. However, stronger
large-scale ascent and more intense wind fields will be focused over
the Midwest. These areas also may remain cooler due to early day
showers and cloud cover in the strong warm advection regime.
Nevertheless, a tornado threat near the surface low still appears
possible. With time, upscale growth into a line tracking across the
Midwest seems reasonable given strong forcing and deep-layer shear
parallel to the cold front, and a transition to a damaging wind
threat may occur by evening.
Higher quality moisture and instability will reside further south
from the Arklatex toward the TN Valley vicinity. Convection will
likely develop by late morning along the cold front in the Arklatex
vicinity and spread eastward through period. Stronger large-scale
ascent will be focused further north, but intense wind fields will
still be across the broad warm sector. All hazards appear possible,
with a mixed mode of supercells and linear convection.
The upper trough will continue east on Saturday, moving offshore the
Atlantic coast by Sunday morning. Some severe potential could
persist into the Mid-Atlantic and Southeast. Destabilization ahead
of the eastward-advancing cold front likely will remain modest due
to widespread cloudiness and precipitation early in the period.
Lower amplitude flow will overspread much of the CONUS on Sunday and
severe potential appears low.
Severe potential could once again increase early next week across
parts of the Arklatex into the Mid/Lower MS and TN Valley vicinity.
Another large-scale upper trough is expected to develop eastward
across the western U.S. on Monday before moving into the central
U.S. on Tuesday. However, guidance is vastly different in the timing
of this system and how far north or south the trough will be
located. While severe potential will likely accompany this system
and probabilities will likely be needed in later outlooks,
confidence in where the greatest threat will occur is low at this
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