(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 260733
SPC AC 260733
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0233 AM CDT Sat Oct 26 2024
Valid 291200Z - 031200Z
...DISCUSSION...
...Tuesday/Day 4 and Wednesday/Day 5...
An upper-level trough and an associated mid-level speed max are
forecast to move across the Desert Southwest on Tuesday. Southwest
mid-level flow is forecast ahead of the system from the southern
High Plains northeastward into the upper Mississippi Valley.
Moisture advection is forecast on Tuesday within a belt of strong
low-level flow across the southern and central Plains. The moist
airmass may reach the mid Missouri Valley by Tuesday evening where
model forecasts develop scattered thunderstorms. A severe threat
will be possible across parts of the mid Missouri Valley as the
airmass moistens in response to large-scale ascent and relatively
strong deep-layer shear. Some model forecasts suggest that
convective development may be delayed until the late evening and
overnight period. The late initiation would probably keep any severe
threat isolated and marginal due the weakness in instability. Will
not add a threat area at this time due to timing uncertainty
concerning convective initiation.
On Wednesday, convective development with greater coverage is
forecast during the day from the southern Plains north-northeastward
into the upper Mississippi Valley. A moist airmass combined with
strong low-level flow and sufficient instability may result in a
severe threat during the afternoon. At this time, the potential for
severe storms appears conditional along much of the corridor from
eastern Oklahoma northeastward into Wisconsin. A severe threat area
could be needed as confidence increases over the next few model runs
concerning the area with the greatest severe potential.
...Thursday/Day 6 to Saturday/Day 8...
From Thursday to Saturday, multiple shortwave troughs are forecast
to move across the northern tier of the United States. A moist
airmass is forecast to remain in place from the southern Plains
eastward into the Gulf Coast states. Isolated to scattered
thunderstorm development will be possible over parts of this airmass
each day. However, instability and large-scale ascent is forecast to
remain relatively weak suggesting that any severe threat that
develops could remain isolated and marginal.
..Broyles.. 10/26/2024
CLICK TO GET WUUS48 PTSD48 PRODUCT