Day 4-8 Severe Weather Outlook Issued on Dec 7, 2020
Updated: Mon Dec 7 09:33:02 UTC 2020
Day 4 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 5 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 6 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 7 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 8 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4
Thu, Dec 10, 2020 - Fri, Dec 11, 2020
D7
Sun, Dec 13, 2020 - Mon, Dec 14, 2020
D5
Fri, Dec 11, 2020 - Sat, Dec 12, 2020
D8
Mon, Dec 14, 2020 - Tue, Dec 15, 2020
D6
Sat, Dec 12, 2020 - Sun, Dec 13, 2020
(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.
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 070931
SPC AC 070931
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0331 AM CST Mon Dec 07 2020
Valid 101200Z - 151200Z
...DISCUSSION...
An upper trough over the western states will shift eastward into the
Plains through Day 5/Fri. In response to height falls, lee
cyclogenesis is expected, and a surface low will develop eastward
across the central/southern Plains vicinity on Thursday into early
Friday. Southerly low level flow ahead of the surface low and
attendant cold front will bring modest Gulf moisture northward
across east TX into the Ark-La-Miss on Friday. This system will
continue to develop eastward across the Midwest and Southeast on Day
6/Sat and early Day 7/Sun.
Isolated thunderstorm potential will increase across parts of the
southern Plains late Thursday night in a strong warm advection
regime associated with the deepening surface low and advancing
mid/upper trough. By Friday, some low-end severe potential could
exist across parts of east TX and persist eastward into the lower MS
Valley/Gulf Coast vicinity through Saturday. However, this will
largely depend on the quality of Gulf moisture return, which will
influence instability in an otherwise strongly-sheared environment.
As such, confidence remains low concerning organized severe
potential on Days 5-6/Fri-Sat, though probabilities could become
necessary in subsequent outlooks.
..Leitman.. 12/07/2020
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