Day 4-8 Severe Weather Outlook Issued on May 21, 2020
Updated: Thu May 21 08:27:03 UTC 2020
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
Sun, May 24, 2020 - Mon, May 25, 2020
D7
Wed, May 27, 2020 - Thu, May 28, 2020
D5
Mon, May 25, 2020 - Tue, May 26, 2020
D8
Thu, May 28, 2020 - Fri, May 29, 2020
D6
Tue, May 26, 2020 - Wed, May 27, 2020
(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 210824
SPC AC 210824
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0324 AM CDT Thu May 21 2020
Valid 241200Z - 291200Z
...DISCUSSION...
Amplified cyclonic mid-level flow may be maintained across parts of
the Intermountain West, U.S Rockies and Plains into Sunday, but a
couple of branches constituting it are forecast to increasingly
split. It is possible that embedded short wave perturbations could
contribute to considerable thunderstorm development ahead of an
eastward and southeastward advancing cold front, from southern
portions of the Plains into the Upper Midwest. However, the extent
to which any of this activity may become severe remains unclear, due
to weakening deep-layer wind fields and shear, and uncertain impacts
from preceding convection, among other factors.
Thereafter, the stronger westerlies may trend more zonal and shift
to the north the Canadian/U.S. border early next week. Models do
suggest some renewed amplification is possible during the middle to
latter portions of next week, with mid/upper troughing developing
southward toward the central Canaadian/U.S border vicinity.
However, guidance, in general, indicates continuing low potential
for organized severe weather on a regional scale.
..Kerr.. 05/21/2020
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