391
ACUS48 KWNS 300852
SWOD48
SPC AC 300850

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0350 AM CDT Tue Apr 30 2024

Valid 031200Z - 081200Z

...DISCUSSION...
Models are in good agreement on Friday/D4 showing an upper trough
lifting north out of the upper MS Valley and across western Ontario,
with a deep upper low moving south just off the coastal Pacific
Northwest. High pressure will exist over the Plains in the wake of
the northern trough, and is forecast to persist into Saturday/D5 as
a secondary lobe rotates the parent Ontario low. While a moist air
mass over the southern Plains and Gulf Coast will support
thunderstorms during this period, little organization or shear is
forecast.

From Sunday/D6 onward, spread becomes large amongst the model
ensembles, especially in regard to the West Coast low and possible
trough amplification as it moves ashore. That said, the overarching
theme through D8 and perhaps beyond is for rising heights across the
East, and a mean trough across the West, which may eventually prove
favorable for moisture return, large-scale ascent and shear across
parts of the central CONUS. Some models such as the ECMWF suggest a
multi-day period of very strong to extreme instability, as well as
southwest flow aloft across the central and southern Plains toward
the MS Valley. While predictability is low that far out, the
evolution of this pattern will be watched closely.

..Jewell.. 04/30/2024