Day 1 Outlook Day 2 Outlook Day 3 Outlook Days 4-8 Outlook

Day 4-8 Outlook
Day 4 - 8 Outlook
Day 4-8 Severe Weather Outlook. A depicted severe weather area indicates a 30% or higher probability for severe thunderstorms within 25 miles of a point.
D4Fri, Sep 24, 2021 - Sat, Sep 25, 2021 D7Mon, Sep 27, 2021 - Tue, Sep 28, 2021
D5Sat, Sep 25, 2021 - Sun, Sep 26, 2021 D8Tue, Sep 28, 2021 - Wed, Sep 29, 2021
D6Sun, Sep 26, 2021 - Mon, Sep 27, 2021 (All days are valid from 12 UTC - 12 UTC)
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. 1) large differences in the deterministic model solutions,
  2. 2) large spread in the ensemble guidance, and/or
  3. 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears highly unlikely during the entire period (e.g. less than a 30% probability for a regional severe storm area across the CONUS through the entire Day 4-8 period).

Images courtesy of the NWS Storm Prediction Center
 Forecast Discussion

ACUS48 KWNS 210812
SPC AC 210810

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0310 AM CDT Tue Sep 21 2021

Valid 241200Z - 291200Z

Although short wave developments remain unclear, medium-range models
indicate that mid/upper flow will remain amplified into next weekend
through early next week, with a pattern trending toward one with
large-scale mid-level troughing inland of the Pacific and Atlantic
coasts, flanking mid-level ridging extending through much of the
Great Plains.  A series of reinforcing cool/dry intrusions through
the central and eastern U.S., western Atlantic and northern Gulf of
Mexico may maintain generally low convective potential east of the
Rockies.  At the same time, low/mid-level moisture return emanating
from the lower latitude eastern Pacific may contribute to increasing
diurnal thunderstorm development late this weekend into early next
week across the Intermountain West and Rockies.  It might not be out
of the question that there may be strengthening flow and forcing for
ascent to enhance convective development and contribute to at least
some risk of producing damaging surface gusts.  However, it is not
yet clear that this will become particularly organized or

..Kerr.. 09/21/2021