(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.
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 300820
SPC AC 300820
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0220 AM CST Tue Nov 30 2021
Valid 031200Z - 081200Z
Medium-range model output indicates that a substantially more
amplified/blocked regime may evolve across the southern mid-latitude
and subtropical eastern Pacific into southwestern portions of North
America, including a large-scale trough and/or developing closed low
near Baja early next week. However, there might not be significant
change to the northern mid-latitude westerlies, with strong flow
persisting through much of the period in a broadly anticyclonic belt
across the eastern Pacific into the northern U.S. Great Plains,
before transitioning to broadly cyclonic east of the Mississippi
Valley. Although a couple of strengthening short wave perturbations
progressing through this regime might be accompanied by thunderstorm
development across parts of the south central U.S., it appears that
trailing reinforcing intrusions of cool and/or dry air will preclude
deep boundary-layer moistening over much of the Gulf of Mexico.
This seems likely to continue to negate, or at least temper, the
risk for severe weather.
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