Day 4-8 Severe Weather Outlook Issued on Jun 20, 2020
Updated: Sat Jun 20 08:48:03 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
Tue, Jun 23, 2020 - Wed, Jun 24, 2020
D7
Fri, Jun 26, 2020 - Sat, Jun 27, 2020
D5
Wed, Jun 24, 2020 - Thu, Jun 25, 2020
D8
Sat, Jun 27, 2020 - Sun, Jun 28, 2020
D6
Thu, Jun 25, 2020 - Fri, Jun 26, 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 200846
SPC AC 200846
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0346 AM CDT Sat Jun 20 2020
Valid 231200Z - 281200Z
...DISCUSSION...
...Tuesday/Day 4 and Wednesday/Day 5...
The medium-range models begin the Day 4 to 8 period in reasonable
agreement. An upper-level trough moves eastward across the
Mississippi Valley on Tuesday and Wednesday. At the surface, a cold
front advances slowly southeastward across the Ohio and mid
Mississippi Valleys extending southwestward into the southern
Plains. Thunderstorms will be possible during the afternoon and
evening on Tuesday and Wednesday, along and to the south of the
front. Some of these storms may have an isolated severe threat. The
greatest convective coverage will probably be in the mid Mississippi
and Ohio Valleys near the cold front and ahead of the upper-level
trough. Uncertainty is considerable concerning exactly where the
greatest severe threat will be on Tuesday and Wednesday.
...Thursday/Day 6 to Saturday/Day 8...
From Thursday to Saturday, model spread increases markedly. The GFS
moves the upper-level trough from the Ohio and Tennessee Valleys to
the Eastern Seaboard with another upper-level trough moving into the
central and northern Plains Friday night. The ECMWF also moves the
Ohio Valley upper-level trough to the Eastern Seaboard but is much
faster. This solution moves a subtle shortwave trough into the
northern Plains on Thursday and develops northwest mid-level flow
across the north-central states during the late week. The UKMET
looks to be compromise between the GFS and ECMWF. Although the three
solutions are different, all three suggest potential for isolated
severe thunderstorm development across parts of the central and
northern Plains eastward into the upper Mississippi Valley. However,
predictability in this area is quite low concerning where the
greatest severe threat will be from Thursday to Saturday.
..Broyles.. 06/20/2020
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