Day 4-8 Severe Weather Outlook Issued on Aug 4, 2020
Updated: Tue Aug 4 08:55:03 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
Fri, Aug 07, 2020 - Sat, Aug 08, 2020
D7
Mon, Aug 10, 2020 - Tue, Aug 11, 2020
D5
Sat, Aug 08, 2020 - Sun, Aug 09, 2020
D8
Tue, Aug 11, 2020 - Wed, Aug 12, 2020
D6
Sun, Aug 09, 2020 - Mon, Aug 10, 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 040853
SPC AC 040853
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0353 AM CDT Tue Aug 04 2020
Valid 071200Z - 121200Z
...DISCUSSION...
...Northern Plains to Upper Midwest vicinity...
Strong upper level high pressure will persist across the
south-central U.S. for much of the forecast period. Further north,
the ridge will be suppressed by a more active northern stream. Some
strong to severe thunderstorm threat could develop as early as Day
4/Fri across parts of the Dakotas eastward into MN as the area is
forecast to be glanced by a shortwave trough spreading
east/northeast across the Canadian Prairies. However, forecast
guidance differs with regards to the timing and strength of this
feature. Capping will be a concern if the shortwave impulse remains
north of the International border and while storms are likely to
develop in the vicinity of a surface boundary across the central
Dakotas, this convection may be elevated and/or ill-timed with the
diurnal cycle. While severe probabilities were considered for parts
of the Dakotas into MN on Day 4/Fri afternoon into the overnight
hours, ultimately uncertainty in storm coverage/intensity is too
great to delineate 15% severe probabilities at this time.
Beyond Day 4/Fri, a series of shortwave impulses and eventually the
main upper trough over western Canada are progged to eject eastward
across the northern Plains to the Great Lakes during the weekend and
into early next week. Some severe potential will be possible across
this area, but timing of the trough and relevant smaller-scale
boundary-layer features remains too uncertain to include 15% or
greater severe probabilities at this time.
..Leitman.. 08/04/2020
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