Day 4-8 Severe Weather Outlook Issued on Feb 21, 2021
Updated: Sun Feb 21 09:40:04 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, Feb 24, 2021 - Thu, Feb 25, 2021
D7
Sat, Feb 27, 2021 - Sun, Feb 28, 2021
D5
Thu, Feb 25, 2021 - Fri, Feb 26, 2021
D8
Sun, Feb 28, 2021 - Mon, Mar 01, 2021
D6
Fri, Feb 26, 2021 - Sat, Feb 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 210937
SPC AC 210937
Day 4-8 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0337 AM CST Sun Feb 21 2021
Valid 241200Z - 011200Z
CORRECTED FOR TYPO
...DISCUSSION...
Medium-range model output suggests that blocking mid-level ridging
may become increasingly amplified across the mid-latitude Pacific
late this week and remain prominent through next weekend. At the
same time, it appears that a deep mid-level low at Arctic latitudes,
initially developing east-southeastward across far northern Canada,
may linger near or just north of Hudson Bay, while a subtropical
mid-level ridge builds across much of the Gulf of Mexico and
Southeast. Between these features, it appears that a branching
regime will gradually develop across the northeastern Pacific into
the western U.S. by late next weekend, with flow becoming
increasingly confluent across and east of the Great Plains.
Short wave developments within this regime are becoming more
unclear, and the pattern predictability appears to be decreasing.
It seems possible, though, that boundary-layer moistening over the
Gulf of Mexico could become increasingly supportive of severe
weather potential by late next weekend, pending short wave
developments across the southern Rockies into the southern Great
Plains.
..Kerr.. 02/21/2021
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