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000
ACUS02 KWNS 121713
SWODY2
SPC AC 121712

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1212 PM CDT Fri Apr 12 2024

Valid 131200Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL
OREGON...

...SUMMARY...
Isolated severe hail and strong gusts are possible across central
Oregon between about 2 to 8 PM PDT on Saturday.

...Oregon...

An upper low near the northern/central CA Pacific Coast will weaken
some as it shifts east/southeast over CA/NV on Saturday. Moderate
south/southeasterly low to midlevel flow on the northeastern
periphery of this system will overspread OR. Effective shear
magnitudes around 30-40 kt will overlap with a plume of midlevel
moisture and steep midlevel lapse rates. Forecast soundings show
temperatures warming into the 60s by afternoon, allowing for deep
boundary-layer mixing beneath the steep midlevel lapse rates. Modest
destabilization is forecast with generally 500-1000 J/kg MLCAPE
expected. Isolated to widely scattered thunderstorms are expected to
develop by mid to late afternoon and spread north/northwest into the
evening hours. Given ample shear and instability in conjunction with
cool temperatures aloft, isolated large hail is possible.
Additionally, inverted-v sub-cloud thermodynamic profiles may
support strong gusts with this activity as well.

...Central Plains...

A weak shortwave impulse is forecast to spread across the central
Plains during the afternoon/evening. Thermodynamic profiles indicate
a nearly saturated profile in the 600-400 mb layer. A surface trough
extending south/southwest across the Plains from a surface low over
the northern Plains/Upper Midwest will result in some poleward
transport of Gulf moisture. However, deeper boundary-layer moisture
will remain confined to TX, with generally 40s F dewpoints into
KS/NE. Strong heating during the day will likely mix out this scant
moisture, limiting instability and overall thunderstorm chances.
Nevertheless, steep midlevel lapse rates amid the elevated moist
layer will foster weak instability (generally less than 500 J/kg
MUCAPE). Convection may try to develop by late afternoon/early
evening, though potential appears very conditional. If a storm can
develop, gusty winds are possible given the deeply mixed/dry
boundary-layer.

...Great Lakes...

Elevated thunderstorms are possible during the evening/overnight
hours in a northwest flow regime and as a weak shortwave impulse
develops southeast from the Canadian Prairies to the Great Lakes.
Elevated thunderstorms are expected to develop in a warm advection
regime ahead of a southeastward-advancing cold front and to the cool
side of a warm front draped across northern WI/MI. Weak elevated
instability (generally less than 400 J/kg MUCAPE over a shallow
layer) will preclude severe potential, though a stronger cell or two
could produce small hail. Overall potential/coverage appears too low
for severe probabilities.

..Leitman.. 04/12/2024

$$