Day 4-8 Severe Weather Outlook Issued on Nov 21, 2021
Updated: Sun Nov 21 09:23:03 UTC 2021
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
Wed, Nov 24, 2021 - Thu, Nov 25, 2021
D7
Sat, Nov 27, 2021 - Sun, Nov 28, 2021
D5
Thu, Nov 25, 2021 - Fri, Nov 26, 2021
D8
Sun, Nov 28, 2021 - Mon, Nov 29, 2021
D6
Fri, Nov 26, 2021 - Sat, Nov 27, 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 210921
SPC AC 210921
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0321 AM CST Sun Nov 21 2021
Valid 241200Z - 291200Z
...DISCUSSION...
Medium-range guidance is in good agreement that expansive upper
troughing will be in place across the western and central CONUS
early D4/Wednesday. Several shortwave troughs are forecast to move
within this parent upper trough as it gradually moves eastward.
Guidance has trended towards a more split-flow solution, with a more
progressive shortwave trough moving through the northern stream
across the Upper Midwest/Upper Great Lakes on D5/Thursday. At the
same time, a closed cyclone is forecast to develop off the coast of
the Baja Peninsula.
A surface low associated with the progressive northern-stream
shortwave trough will move eastward just ahead of it while an
attendant cold front sweeps southeastward across much of the Plains
on D4/Wednesday and through the remainder of the southern Plains and
the MS and OH Valleys on D5/Thursday. Thunderstorms are possible in
the vicinity of this front as it moves across OK and TX, modest
buoyancy and displacement south/east of the stronger flow should
limit severe-storm chances.
..Mosier.. 11/21/2021
CLICK TO GET WUUS48 PTSD48 PRODUCT
weather.gov 
@NWSSPC
