Day 4-8 Severe Weather Outlook Issued on Dec 31, 2020
Updated: Thu Dec 31 09:46:02 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
Sun, Jan 03, 2021 - Mon, Jan 04, 2021
D7
Wed, Jan 06, 2021 - Thu, Jan 07, 2021
D5
Mon, Jan 04, 2021 - Tue, Jan 05, 2021
D8
Thu, Jan 07, 2021 - Fri, Jan 08, 2021
D6
Tue, Jan 05, 2021 - Wed, Jan 06, 2021
(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 310944
SPC AC 310944
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CST Thu Dec 31 2020
Valid 031200Z - 081200Z
...DISCUSSION...
...Sunday/Day 3 to Monday/Day 5...
An upper-level trough is forecast to move northeastward across the
central Appalachians on Sunday and across New England on Monday. A
cold front is forecast to move southward across the Florida
Peninsula on Sunday, along which thunderstorm development may take
place during the day. Behind the front, surface high pressure is
forecast to settle in across much of the southern half of the
nation. As a result, thunderstorm activity is expected to be
minimized from Sunday night into Monday.
...Tuesday/Day 6 to Thursday/Day 8...
On Tuesday, the medium-range models are in good agreement, moving an
upper-level trough quickly eastward into the southern Rockies. Under
that scenario, moisture advection would increase across the Texas
Coastal Plain. Marginally severe storms can not be ruled out over
south-central Texas as the upper-level trough approaches the
southern Plains Tuesday night.
On Wednesday and Thursday, the upper-level trough is forecast to
progress quickly eastward across the Gulf Coast States. At this
time, moisture return is forecast to remain weak ahead of the
trough. That would limit the potential for severe storms to coastal
areas from Louisiana to the Florida Panhandle. The current thinking
is that any severe threat with this system will remain isolated.
However, uncertainty is substantial at this range in the forecast
period.
..Broyles.. 12/31/2020
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