279
ACUS48 KWNS 300823
SWOD48
SPC AC 300822

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0322 AM CDT Tue Sep 30 2025

Valid 031200Z - 081200Z

...DISCUSSION...
Late this work week through the weekend, medium-range models
continue to indicate mid/upper flow amplification across the
mid-latitude eastern Pacific into North America, which may lead to
the evolution of an increasingly prominent blocking high offshore of
the British Columbia/Pacific Northwest coast.  This would probably
be flanked by persistent troughing at somewhat lower latitudes,
including California coastal areas into the Great Basin.  However,
the spread within/among the model output is sizable concerning this
and subsequent developments through early next week.

Stronger and more progressive westerlies, and potential for
significant surface cyclogenesis, may remain confined to the higher
latitudes.  However, there does appear a consensus within the
medium-range output of modestly deepening surface troughing across
parts of the central Great Plains into Upper Midwest (roughly along
an axis from the Front Range through Minnesota) by this weekend,
perhaps as one notable short wave perturbation accelerates
northeastward out of the Intermountain West.  In the presence of
steep lower/mid-tropospheric lapse rates and strengthening flow,
this could provide a focus for strong thunderstorm development
Saturday and/or Sunday.  However, due to the continuing lack of a
substantive moist return flow off the Gulf, the potential for
organized severe storms still appears low.

..Kerr.. 09/30/2025