SPC AC 080758
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0158 AM CST Mon Jan 08 2024
Valid 101200Z - 111200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for thunderstorms appears negligible across much of the
U.S., Wednesday through Wednesday night.
...Discussion...
In the wake of a broad, but weakening, cyclone forecast to slowly
migrate east-northeast of the lower Great Lakes region, and
downstream of amplified ridging within the split westerlies across
the eastern mid-latitude Pacific, mid-level troughing appears likely
to encompass much of North America through this period. A couple of
significant short wave perturbations digging to the east of the
ridging will contribute to the maintenance of this troughing. One,
emerging from the northern mid-latitude Pacific, is forecast to
progress inland of Pacific Northwest through the Sierra Nevada into
eastern Great Basin/Colorado Plateau vicinity by 12Z Thursday.
Another, emerging from the northern Canadian Arctic vicinity, is
forecast to turn southward into the Canadian Prairies and Rockies.
In lower levels, a cold front trailing the lead cyclone appears
likely to advance away from much of the Atlantic Seaboard, while
stalling and weakening near the Florida Straits/Keys vicinity
through the southeastern Gulf of Mexico. At the same time, surface
troughing may begin to deepen to the lee of the southern Rockies
through the lower Rio Grande Valley, accompanied by modest boundary
layer moistening and northward return across the western Gulf of
Mexico. This may include surface dew point increases to around 60F
near Texas coastal areas by late Wednesday night, beneath relatively
warm, dry and capping lower/mid-tropospheric air.
Beneath cold air across the Pacific Northwest, which may include an
inland spreading cold core (around -35 C at 500 mb), some convection
capable of producing lightning appears possible near coastal areas
early in the period. Inland of the coast, probabilities for
lightning appear increasingly negligible, due to a lingering
generally cooler and drier boundary layer. However, convection with
a flash or two of lightning might not be out of the question across
parts of the northern Sierra Nevada and Sacramento Valley Wednesday
afternoon and evening.
..Kerr.. 01/08/2024
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