(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 260834
SPC AC 260834
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0334 AM CDT Wed Jul 26 2017
Valid 291200Z - 031200Z
Despite some timing differences, medium-range model consensus is
that an expansive cold front will move off the Atlantic Coast during
the first half of Saturday/Day 4, followed shortly thereafter by the
upper trough axis. While some severe threat could exist across the
Atlantic Coast area early in the day ahead of frontal passage, and
into the afternoon and evening across the Gulf Coast states in a
relatively low-shear but unstable environment near the trailing
front, risk does not appear to warrant an areal highlight at this
As the front moves offshore and the upper pattern -- featuring a
trough in the east and a ridge in the west -- stagnates through much
of the remainder of the period, main potential for any severe risk
would appear to exist from the northern Intermountain region and
into the central and northern Plains. However, with any risk in
these areas tied to low predictability smaller-scale features aloft
cresting the upper ridge, combination of uncertainty and the
likelihood of relatively isolated/sparse risk precludes issuance of
any risk areas through the period.
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