Day 4-8 Severe Weather Outlook Issued on Nov 17, 2020
Updated: Tue Nov 17 09:54:02 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
Fri, Nov 20, 2020 - Sat, Nov 21, 2020
D7
Mon, Nov 23, 2020 - Tue, Nov 24, 2020
D5
Sat, Nov 21, 2020 - Sun, Nov 22, 2020
D8
Tue, Nov 24, 2020 - Wed, Nov 25, 2020
D6
Sun, Nov 22, 2020 - Mon, Nov 23, 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 170952
SPC AC 170952
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0352 AM CST Tue Nov 17 2020
Valid 201200Z - 251200Z
...DISCUSSION...
Quasi-zonal upper level pattern on Day 4/Fri will give way to a
somewhat more amplified and progressive pattern beginning Days
5-6/Sat-Sun. During this time, a series of mid/upper shortwave
troughs will migrate eastward from the western U.S. and into the
Plains. Strong surface high pressure will persist across much of the
U.S. east of the Rockies, resulting in dry, stable conditions.
However, a weak lee trough over the southern High Plains will allow
southerly low level flow to transport modest Gulf moisture northward
across the southern Plains ahead of a stalled front draped across KS
and into the lower MS/OH Valley vicinity. Surface dewpoints in the
50s to low 60s F could reside across parts of KS/OK/TX, but
cloudiness and heavy rain showers will limit instability. While
thunderstorm activity is possible for portions of the southern
Plains region during the weekend, severe potential appears limited.
Quite a bit of spread exists in forecast guidance beyond Day 6/Sun.
There is general agreement that another larger-scale trough will
eject eastward across the Rockies and into the Plains/Central U.S.
early next week. However, too much uncertainty remains at this time
scale given large spread in forecast guidance to ascertain severe
potential across parts of the southern U.S. around Days 7-8/Mon-Tue.
..Leitman.. 11/17/2020
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