ACUS48 KWNS 090820
SWOD48
SPC AC 090819

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0319 AM CDT Fri Aug 09 2024

Valid 121200Z - 171200Z

...DISCUSSION...
In mid/upper levels, a zonally elongated anticyclone will build
laterally from the southern Plains into the Southwest and Gulf Coast
region through much of the day-4-8 period.  A general weakness in
heights should persist over parts of CA and the lower Colorado River
Valley region -- intermittently connected to northern-stream
troughing over the Pacific Northwest and western Canada, and to the
subtropical easterlies over MX.  Low-amplitude mean ridging should
build northward across the Rockies to the northern Rockies/northern
High Plains region, but based on deterministic GFS/ECMWF and their
ensembles, not intense enough to preclude penetration by a series of
mostly low-amplitude/low-predictability shortwaves emanating from
the Northwest troughing.

Downstream, zonal to northwesterly and largely difluent flow will
prevail over much of the northern Plains, Midwest, Great Lakes, and
Ohio Valley.  Even after the southeastern Canada/northeastern CONUS
synoptic trough departs the region day-4, the preceding frontal zone
will remain well-removed to the south, across the southeastern CONUS
to Missouri Valley, as a series of trailing shortwaves reinforce
somewhat lower-amplitude troughing in the Great Lakes and Northeast.
Especially from about day 5 onward, gradual return of favorable
moisture is likely beneath the southwestern rim of the stronger
associated flow -- from the north-central High Plains to the lower
Missouri and Tennessee Valley regions.  This general pattern
conditionally supports some MCS potential, evolving from activity
forming over the Plains and heading southeastward along or just to
the cool side of the sensible baroclinic zone.  However, day-to-day
shortwave, low-level boundary and MCV predictability is too low to
assign unconditional probabilities to any given day.

..Edwards.. 08/09/2024

= = =
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux