Day 4-8 Severe Weather Outlook Issued on Nov 27, 2021
Updated: Sat Nov 27 08:52:04 UTC 2021
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, Nov 30, 2021 - Wed, Dec 01, 2021
D7
Fri, Dec 03, 2021 - Sat, Dec 04, 2021
D5
Wed, Dec 01, 2021 - Thu, Dec 02, 2021
D8
Sat, Dec 04, 2021 - Sun, Dec 05, 2021
D6
Thu, Dec 02, 2021 - Fri, Dec 03, 2021
(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 270850
SPC AC 270850
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 AM CST Sat Nov 27 2021
Valid 301200Z - 051200Z
...DISCUSSION...
It appears that mid/upper flow across North America may de-amplify
by the middle of next week, in the wake of a deep cyclone migrating
north-northeast of the Canadian Maritimes. However, guidance
suggests that the mean pattern may remain at least broadly cyclonic
east of the Mississippi Valley into the Atlantic, downstream of
broad ridging across the eastern mid-latitude Pacific into the
Rockies and Great Plains. As a weaker belt of westerlies also
lingers from the subtropical eastern Pacific through the Gulf of
Mexico and Florida Peninsula, a generally confluent mid-level regime
may maintain potentially cold surface high pressure across much of
the Gulf Coast and Southeast, inhibiting boundary-layer moistening
over the Gulf of Mexico and substantive inland moisture return.
Even if significant renewed amplification within the westerlies were
to take place east of the Mississippi Valley into the Atlantic
Seaboard late this week into next weekend, as at least some model
output has indicated, it is not clear that low-level moistening off
the Gulf of Mexico and/or western Atlantic will be sufficient to
support an appreciable risk of severe weather by that time.
..Kerr.. 11/27/2021
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