Day 4-8 Severe Weather Outlook Issued on Jun 22, 2020
Updated: Mon Jun 22 08:46:02 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
Thu, Jun 25, 2020 - Fri, Jun 26, 2020
D7
Sun, Jun 28, 2020 - Mon, Jun 29, 2020
D5
Fri, Jun 26, 2020 - Sat, Jun 27, 2020
D8
Mon, Jun 29, 2020 - Tue, Jun 30, 2020
D6
Sat, Jun 27, 2020 - Sun, Jun 28, 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 220844
SPC AC 220844
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0344 AM CDT Mon Jun 22 2020
Valid 251200Z - 301200Z
...DISCUSSION...
...Thursday/Day 4 and Friday/Day 5...
The medium range models forecast an upper-level ridge to move across
the northern Plains on Thursday. An axis of instability is forecast
to develop Thursday afternoon across the mid Missouri Valley and
northern Plains. As the upper-level ridge approaches the upper
Mississippi Valley Thursday evening, thunderstorm development will
be possible in its wake across parts of the northern Plains. An
isolated severe threat could develop depending upon the timing of
the ridge and how much instability develops in the wake of the
ridge.
On Friday, the medium-range model solutions begin to sharply
diverge. But using an ensemble approach would place a cold front in
the eastern Dakotas Friday afternoon with moderate instability ahead
of the front in the upper Mississippi Valley. An isolated severe
threat would be possible from the front in eastern North Dakota
eastward across much of Minnesota. Uncertainty is considerable due
to the wide model spread.
...Saturday/Day 6 to Monday/Day 8...
On Saturday and Sunday, the models continue to have a large spread.
An ensemble approach can again be applied. This would suggest a
moist airmass in place from the upper Mississippi Valley eastward
into the southern Great Lakes. Isolated severe thunderstorms would
be possible along the northern edge of the stronger instability. At
this time, the most favorable corridor would be from eastern
Nebraska to western Wisconsin and then eastward to Lower Michigan.
But this is highly uncertain due to model differences.
Predictability is also low on Monday for the same reason. A general
view of the models would place the greatest instability in the
north-central U.S., where an isolated severe threat would be
possible.
..Broyles.. 06/22/2020
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