Day 4-8 Severe Weather Outlook Issued on Oct 19, 2020
Updated: Mon Oct 19 08:56:02 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, Oct 22, 2020 - Fri, Oct 23, 2020
D7
Sun, Oct 25, 2020 - Mon, Oct 26, 2020
D5
Fri, Oct 23, 2020 - Sat, Oct 24, 2020
D8
Mon, Oct 26, 2020 - Tue, Oct 27, 2020
D6
Sat, Oct 24, 2020 - Sun, Oct 25, 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 190854
SPC AC 190854
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0354 AM CDT Mon Oct 19 2020
Valid 221200Z - 271200Z
...DISCUSSION...
...Thursday/Day 4 to Saturday/Day 6...
On Thursday, an upper-level trough is forecast to move across the
Intermountain West as southwest flow remains over the central U.S. A
cold front is forecast to advance southeastward into the Upper
Midwest as a low-level jet moves into the region from the southwest.
Thunderstorms will be possible along the western edge of the
low-level jet from the central Plains northeastward into the upper
Mississippi Valley from late afternoon into the evening. Instability
is forecast to be weak suggesting any severe threat would remain
marginal.
On Friday and Saturday, the medium-range models move a cold front
southeastward across the mid Mississippi Valley and into the
southeastern U.S. Thunderstorms are expected to develop along parts
of the front both Friday and Saturday afternoon. However,
instability is expected to be weak which will again keep any severe
threat marginal.
...Sunday/Day 7 to Monday/Day 8...
Model solutions sharply diverge late in the Day 4 to 8 period. Some
solutions show an upper-level trough in the western U.S. with others
having the trough further to the east into the Great Plains. If the
model solutions with the trough further east verify, then
thunderstorms would be possible ahead of the trough on Sunday and
Sunday night from the mid Mississippi Valley and Ohio Valley
southwestward to the southern Plains. Under this scenario, the front
would move southeastward across the Ohio and Tennessee Valleys on
Monday. Isolated severe thunderstorms would be possible along parts
of the front on Monday. However, the models are forecasting weak
instability in most areas suggesting any severe threat would be
marginal.
..Broyles.. 10/19/2020
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