SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1107 PM CST Mon Jan 08 2024
Valid 101200Z - 111200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Some lightning is possible in rain and snow showers near the Pacific
Northwest coast and across parts of the northern Sierra Nevada into
the Great Basin on Wednesday. Otherwise, the risk for thunderstorms
appears negligible across much of the U.S.
...Discussion...
Downstream of amplified mid/upper ridging within the split
westerlies across the mid-latitude eastern Pacific, and in the wake
of a broad, but weakening, cyclone migrating east-northeast of the
lower Great Lakes region, cyclonic flow and seasonably low mid-level
heights likely will encompass much of North America through this
period. Within this regime, to the east of the ridging, a couple of
notable digging short wave perturbations are forecast to contribute
to amplification of the larger-scale troughing inland of the North
American Pacific coast. Models indicate that one, of northern
mid-latitude Pacific origins, will progress southeastward inland of
the Pacific Northwest coast, through much of the Sierra Nevada and
Great Basin by late Wednesday night. Another, emerging from the
northern Canadian Arctic vicinity, is forecast to turn southward
into the Canadian Rockies and adjacent Canadian Prairies.
In lower levels, a cold front trailing the departing cyclone appears
likely to continue advancing away from much of the Atlantic
Seaboard, while stalling and weakening near or south of the Florida
Straits/Keys into the southeastern Gulf of Mexico. At the same
time, surface troughing may slowly begin to deepen to the lee of the
southern Rockies through the lower Rio Grande Valley, accompanied by
northward return of a moistening boundary layer across the western
Gulf of Mexico. By late Wednesday night, this may include surface
dew point increases to near or above 60 F, beneath relatively warm,
dry and capping lower/mid-tropospheric air.
Beneath a pocket of colder air aloft associated with the inland
advancing short wave, which may include 500 mb temperatures around
-35 C, some convection capable of producing lightning appears
possible near Washington and Oregon coastal areas early Wednesday.
Potential for lightning inland of coastal areas remains unclear.
However, latest available forecast soundings suggest that there may
be enough boundary layer warming to contribute to marginally
favorable thermodynamic profiles in a corridor from near the Great
Salt Lake into parts of the northern Sierra Nevada by late Wednesday
afternoon, aided by mid/upper forcing for ascent.
..Kerr.. 01/09/2024
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