Day 4-8 Severe Weather Outlook Issued on Dec 29, 2020
Updated: Tue Dec 29 09:57:02 UTC 2020
Day 4 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
15 %
41,105
5,052,334
Charlotte, NC...Columbia, SC...Rock Hill, SC...Sumter, SC...Spartanburg, SC...
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
Fri, Jan 01, 2021 - Sat, Jan 02, 2021
D7
Mon, Jan 04, 2021 - Tue, Jan 05, 2021
D5
Sat, Jan 02, 2021 - Sun, Jan 03, 2021
D8
Tue, Jan 05, 2021 - Wed, Jan 06, 2021
D6
Sun, Jan 03, 2021 - Mon, Jan 04, 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 290955
SPC AC 290955
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CST Tue Dec 29 2020
Valid 011200Z - 061200Z
...DISCUSSION...
...Friday/Day 4 and Saturday/Day 5...
An upper-level trough is forecast to move northeastward across the
mid Mississippi Valley on Friday as southwest mid-level flow remains
in place along the Eastern Seaboard. The moist sector should be
located across much of Georgia and South Carolina. Thunderstorms may
develop in Georgia Friday afternoon ahead of the upper-level trough
with this convection spreading east-northeastward across South
Carolina and into southern North Carolina. Due to strong low-level
shear, a tornado threat could exist with this activity, in addition
to having a wind damage potential.
On Saturday, southwest mid-level flow is forecast to remain in place
across the Southeast as an upper-level low moves through the Ozarks.
At the surface, a cold front is forecast to advance southeastward
toward southern sections of the Atlantic Seaboard. Thunderstorm
development will be possible along the front during the day.
Although a severe threat is not expected due to weak instability,
isolated strong thunderstorms can not be ruled out in areas that
heat up sufficiently.
...Sunday/Day 6 to Tuesday/Day 8...
An upper-level low is forecast to move northeastward across the
central Appalachians on Sunday as a cold front advances southward
across the Florida Peninsula. Thunderstorm development could occur
Sunday afternoon in central Florida along or just ahead of the
front. An isolated severe threat would be possible if enough
instability can develop.
On Monday and Tuesday, surface high pressure over the central and
eastern U.S. should minimize thunderstorm potential in most of the
continental United States.
..Broyles.. 12/29/2020
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