Day 4-8 Severe Weather Outlook Issued on Feb 23, 2021
Updated: Tue Feb 23 09:47:02 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
Fri, Feb 26, 2021 - Sat, Feb 27, 2021
D7
Mon, Mar 01, 2021 - Tue, Mar 02, 2021
D5
Sat, Feb 27, 2021 - Sun, Feb 28, 2021
D8
Tue, Mar 02, 2021 - Wed, Mar 03, 2021
D6
Sun, Feb 28, 2021 - Mon, Mar 01, 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 230945
SPC AC 230945
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0345 AM CST Tue Feb 23 2021
Valid 261200Z - 031200Z
...DISCUSSION...
Medium-range models continue to suggest that, although blocking may
linger to some degree through much of this period, an initially
prominent mid-level high and amplified ridging across the eastern
Pacific will become suppressed by a series of short wave
perturbations emerging from the upstream Pacific. As this occurs,
it still appears that a more pronounced split flow will evolve
downstream, across much of the U.S. and southern Canada. This may
include mean mid-level troughing in the southern branch, across the
southern Pacific coast through the Southwest, from which one or two
significant perturbations may emerge late this weekend into early
next week. At the same time, subtropical ridging, centered over the
southern Gulf of Mexico, may undergo a period of amplification, and
a deep mid-level low near/north of Hudson Bay may maintain some
influence, before perhaps returning northward across the Arctic
Circle vicinity by the end of the period.
This pattern could include potential for significant surface
cyclogenesis to the lee of the southern Rockies and a substantive
return flow of moisture off the western Gulf of Mexico by early next
week, accompanied by at least some increase in risk for severe
weather. However, based on sizable differences evident among the
various models, and from run to run, the predictability of the short
wave developments throughout this period appears relatively low.
..Kerr.. 02/23/2021
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