SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1117 AM CST Mon Feb 03 2025
Valid 041200Z - 051200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Scattered weak thunderstorm development is possible along the
western slopes of the Sierra Nevada, and near Oregon coastal areas,
late Tuesday into Tuesday night. Otherwise, the risk for
thunderstorms appears negligible across much of the nation.
...Discussion...
Downstream of a blocking high, centered to the southeast of the
Aleutians, models indicate that large-scale mid-level troughing will
be maintained across and offshore of the Pacific Northwest, though
an embedded low may reform to the south-southwest of Vancouver
Island. To the east of this regime, large-scale mid-level ridging
may continue to slowly build across the northern U.S. Great Plains
and adjacent Canadian Prairies into the Great Lakes region, while a
short wave perturbation digs within northwest flow to its northeast
and east. In a separate branch of westerlies, emanating from the
southern mid-latitude Pacific, a notable short wave perturbation is
forecast to accelerate inland across the California coast and Great
Basin/Rockies by 12Z Wednesday, ahead of an inland advancing
perturbation within the more prominent cyclonic regime to the north.
In lower-levels, it appears that surface troughing will slowly begin
to deepen to the immediate lee of the Rockies, as the center of an
expansive cold surface ridge shifts from the Canadian Prairies and
northern U.S. Great Plains into the Great Lakes, beneath the more
strongly confluent mid-level flow. The shallow leading edge of the
seasonably cold air mass may stall across parts of the southern
Great Plains into Ohio Valley, while advancing offshore of the
northern and middle Atlantic Seaboard. At the same time, a
southerly return flow of moisture is forecast to develop from parts
of the western Gulf Basin into the southern U.S. Great Plains and
lower Mississippi Valley.
...California/Sierra Nevada...
In advance of the perturbation emanating from the southern
mid-latitude Pacific, low/mid-level moistening, differential thermal
advection and strong lift, aided by a strengthening upslope flow
component, may contribute to weak destabilization along the western
slopes of the Sierra Nevada by Tuesday afternoon. Forecast
soundings suggest that thermodynamic profiles may become supportive
of convection capable of producing lightning by early Tuesday
evening, if not earlier.
...Oregon coastal areas...
Models indicate that lower/mid-tropospheric cooling will lead to
increasing boundary-layer destabilization near coastal areas through
the period. As this occurs, some convection, within a broader area
of continuing convective development, may deepen through
sufficiently cold layers aloft to support occasional lightning.
...Ozark Plateau/Mid South...
Beneath low-amplitude large-scale mid-level ridging across the
southern Great Plains through the lower Mississippi Valley and
Southeast, it appears that low-level moistening and warming will
contribute to increasing potential instability. Models indicate
that this will generally remain capped by a relatively warm/dry
layer further aloft. However, it is possible that an area of
strengthening lower/mid-tropospheric warm advection may become a
focus for deepening elevated convective development by late Tuesday
night, somewhere across the Ozark Plateau/Mid South vicinity. This
may include isolated weak thunderstorm development, but the extent
of this potential, and exactly where, remain uncertain, resulting in
the maintenance of thunderstorm probabilities below 10 percent.
..Kerr.. 02/03/2025
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