Day 4-8 Severe Weather Outlook Issued on Apr 24, 2021
Updated: Sat Apr 24 08:58:02 UTC 2021
Day 4 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
15 %
110,499
3,643,815
Oklahoma City, OK...Wichita, KS...Lubbock, TX...Abilene, TX...Norman, OK...
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
Tue, Apr 27, 2021 - Wed, Apr 28, 2021
D7
Fri, Apr 30, 2021 - Sat, May 01, 2021
D5
Wed, Apr 28, 2021 - Thu, Apr 29, 2021
D8
Sat, May 01, 2021 - Sun, May 02, 2021
D6
Thu, Apr 29, 2021 - Fri, Apr 30, 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 240856
SPC AC 240856
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0356 AM CDT Sat Apr 24 2021
Valid 271200Z - 021200Z
...DISCUSSION...
Guidance has continued to trend towards a less progressive, deeper
upper trough over the western CONUS D4/Tuesday before gradually
moving eastward on D5/Wednesday and D6/Thursday. Strong mid-level
flow will extend throughout the base of this upper trough and into
the southern/central Plains on D4/Tuesday. A shortwave trough is
expected to move within this southwesterly flow aloft through the
southern High Plains and into the central Plains, interacting with
the warm and moist air mass returning over the southern/central
Plains. Forecast trajectory of this shortwave (from central NM into
eastern CO/western KS) displaces it from the bulk of the warm
sector, but it should still result in enough ascent to foster storm
development, particularly as the dryline retreats across the TX
Panhandle. Strongly sheared and moderately unstable environment
coupled with this modest forcing will likely result in supercells
capable of all severe hazards during the late afternoon. Thereafter,
a strengthening low-level jet and resulting increase in isentropic
ascent will likely foster widespread thunderstorm development and
from southwest TX through western/central OK into south-central KS,
with the potential for upscale growth into an organized convective
line.
Additional severe threat may materialize on D5/Wednesday, but it
will depend largely on the convective evolution the preceding day.
Also, given that the upper trough will likely remain over the
Southwest/northern Mexico, line-parallel character of the mid/upper
flow suggest a largely anafrontal, linear convective configuration.
As such, no areas will be outlooked on D5/Wednesday with this
forecast.
From D6/Thursday through D8/Saturday, current progs of a slow-moving
upper low traversing the southern Plains suggest a limited severe
potential. In contrast, materialization of a more progressive system
would suggest increased severe potential across the Southeast and
Mid-Atlantic.
..Mosier.. 04/24/2021
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