Day 4-8 Severe Weather Outlook Issued on Dec 25, 2020
Updated: Fri Dec 25 09:57:03 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
Mon, Dec 28, 2020 - Tue, Dec 29, 2020
D7
Thu, Dec 31, 2020 - Fri, Jan 01, 2021
D5
Tue, Dec 29, 2020 - Wed, Dec 30, 2020
D8
Fri, Jan 01, 2021 - Sat, Jan 02, 2021
D6
Wed, Dec 30, 2020 - Thu, Dec 31, 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 250955
SPC AC 250955
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CST Fri Dec 25 2020
Valid 281200Z - 021200Z
...DISCUSSION...
...Monday/Day 4 and Tuesday/Day 5...
The medium range models move an upper-level trough across southern
California on Monday and across the Desert Southwest Monday night.
The system is forecast to strengthen on Tuesday, moving quickly
eastward across the Rockies and into the Great Plains. Thunderstorm
development will be possible Tuesday afternoon and evening in parts
of the Great Plains and mid Missouri Valley, ahead of the trough and
to the west of a strengthening low-level jet. At this time, the
greatest chance for thunderstorms is forecast from eastern Kansas
southward into north-central Texas. Due to weak moisture return
ahead of the system, instability is expected to be too low for a
substantial severe threat. However, due to uncertainties, will
maintain "predictability too low" at this time.
...Wednesday/Day 6 to Friday/Day 8...
The upper-level system is forecast to progress eastward from the
Great Plains Tuesday night into the Mississippi Valley by Wednesday
night and to near the East Coast by Friday. Thunderstorms will be
possible each day ahead of the trough and just ahead of an
associated cold front. The potential for thunderstorm development
should progress eastward from the central Gulf Coast on Wednesday to
the Carolinas and Florida on Thursday. Surface dewpoints are
forecast to reach the 60s F across southern Louisiana, southern
Mississippi and southern Alabama on Wednesday and across Florida,
Georgia and parts of the Carolinas on Thursday. A severe threat will
be possible ahead of the front in the moist airmass if instability
can increase enough. However, uncertainty exists concerning the
timing of the upper-level trough and instability. For this reason,
will maintain "predictability too low" in the mid to late week
timeframe.
..Broyles.. 12/25/2020
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