Day 4-8 Severe Weather Outlook Issued on Sep 20, 2020
Updated: Sun Sep 20 08:32:03 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
Wed, Sep 23, 2020 - Thu, Sep 24, 2020
D7
Sat, Sep 26, 2020 - Sun, Sep 27, 2020
D5
Thu, Sep 24, 2020 - Fri, Sep 25, 2020
D8
Sun, Sep 27, 2020 - Mon, Sep 28, 2020
D6
Fri, Sep 25, 2020 - Sat, Sep 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 200830
SPC AC 200830
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0330 AM CDT Sun Sep 20 2020
Valid 231200Z - 281200Z
...DISCUSSION...
There are substantial differences in medium-range guidance regarding
the placement of Tropical Cyclone Beta across the vicinity of east
TX by Day 4/Wednesday. There might be a low-end severe risk across
parts of east TX into LA and perhaps the lower MS Valley/Southeast
on Day 4/Wednesday and Day 5/Thursday. However, shear and
instability are both forecast to be rather weak over these areas.
Otherwise, severe potential across the remainder of the CONUS should
remain limited through Day 6/Friday, as more substantial low-level
moisture will likely be confined to parts of east TX into LA and the
lower MS Valley/Southeast. By the end of the week and into next
weekend, guidance is coming into somewhat better agreement regarding
the placement and amplification of large-scale upper troughing over
the central CONUS. Some potential for greater low-level moisture
return appears possible ahead of this upper trough across much of
the central/eastern CONUS by Day 7/Saturday, but predictability
regarding any severe potential remains low.
..Gleason.. 09/20/2020
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