ACUS01 KWNS 121218
SWODY1
SPC AC 121217

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0617 AM CST Thu Dec 12 2024

Valid 121300Z - 131200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms appear unlikely through tonight.

...Synopsis/Discussion...
A mid/upper-level cyclone -- initially over northern ON -- will
break down as another develops across central QC today, within the
same larger-scale troughing regime.  As the resulting low ejects
northeastward over northern QC, and synoptic ridging moves from the
Rockies to the Plains States, heights will rise over most of the
central/eastern CONUS.  The air mass east of the Rockies mostly will
remain too dry and/or stable for thunderstorms, behind the cold
frontal passage related to the departing eastern trough.  One
exception may be in the lake-effect regimes east of the lower Great
Lakes, where steep low/middle-level lapse rates will support plumes
of heavy convective snow.  However, shallowness of buoyancy/ELs
precludes more than very brief/isolated lightning potential at most,
and the threat appears too conditional and limited for outlook areas.

A cyclone now located off the coast of OR and northwestern CA will
move inland and devolve slightly to a strong shortwave trough,
reaching northern CA and western/southern NV by 00Z.  By 12Z, the
trough will reach southern ID, UT and AZ.  Strong DCVA/cooling aloft
is expected immediately to its east today and tonight, from the
Great Basin to the Colorado Plateau and UT/southwestern WY.
However, with dry air in low levels over most of the region,
midlevel moisture/buoyancy should remain too weak and isolated for
enough lightning to justify an outlook area.

..Edwards/Jewell.. 12/12/2024

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