Day 4-8 Severe Weather Outlook Issued on Mar 17, 2021
Updated: Wed Mar 17 08:58:04 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
Sat, Mar 20, 2021 - Sun, Mar 21, 2021
D7
Tue, Mar 23, 2021 - Wed, Mar 24, 2021
D5
Sun, Mar 21, 2021 - Mon, Mar 22, 2021
D8
Wed, Mar 24, 2021 - Thu, Mar 25, 2021
D6
Mon, Mar 22, 2021 - Tue, Mar 23, 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 170856
SPC AC 170856
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CDT Wed Mar 17 2021
Valid 201200Z - 251200Z
...DISCUSSION...
Latest runs of the medium-range models appear to be in reasonable
agreement through Day 6 (Monday Mar. 22), depicting low severe
convective potential through the first half of the period as
ridging/high pressure generally prevails east of the Rockies Days
4-5. By Day 6, the advance of the next southwestern U.S. trough
toward/into the central and southern Plains is indicated.
Intensity/timing differences between the models with respect to this
feature continue, thus correspondingly affecting surface development
details into the southern Plains during the daytime hours. However,
it appears in any case that only modest/incompletely modified
moisture will be available to return northward into the southern
Plains ahead of this feature. As such, severe weather risk appears
low overall, at this time.
On the heels of this feature, another upper system digging southward
across the West on Day 7 may turn eastward toward the Plains Day 8.
However, model differences are too great with respect to their
handling of this system, to warrant any meaningful attempt to
ascertain potential for severe convection across the south-central
U.S. at this time.
..Goss.. 03/17/2021
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