SPC AC 211250
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0650 AM CST Sat Dec 21 2024
Valid 211300Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated thunderstorms are possible this morning into early
afternoon across parts of coastal Oregon and northern California.
...Coastal OR/northern CA...
A potent mid to upper-level shortwave trough will move ashore the
northern CA/OR coast and continue northeastward into the southern
Canadian Rockies/northern Rockies vicinity through late tonight.
Weak thunderstorm activity embedded within a warm-air advection rain
shield will continue moving into the coastal range mountains this
morning before outrunning the inland penetration of scant
instability. The corridor of thunderstorms will probably shift
north along the coast into OR by midday into the early afternoon in
association with the mid-level cold pocket encroaching on the OR
coast. Elsewhere, quiescent weather or stable conditions will
preclude thunderstorm development over the remainder of the
contiguous United States.
..Smith/Goss.. 12/21/2024
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
SPC AC 210646
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1246 AM CST Sat Dec 21 2024
Valid 221200Z - 231200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Sunday.
...Discussion...
A progressive upper-level pattern will continue across the CONUS on
Sunday. A continental polar airmass will remain across the eastern
CONUS which will preclude thunderstorm potential for most of the
country. A few thunderstorms are possible along the Pacific
Northwest and northern California coasts, particularly Sunday late
afternoon and evening as the next in a series of shortwave troughs
approaches the coast. Severe storms are not currently expected given
the limited buoyancy.
..Guyer.. 12/21/2024
WUUS02 PTSDY2
SPC AC 210822
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0222 AM CST Sat Dec 21 2024
Valid 231200Z - 241200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Monday.
...Discussion...
A shortwave trough is expected to amplify over the Rockies and High
Plains in advance of a more prominent upper trough approaching the
California coast Monday night. Modest low-level moisture return will
occur across Texas in advance of a southeastward-moving cold front
crossing the southern High Plains and parts of Texas. The potential
for elevated thunderstorms should increase Monday night particularly
across North Texas and south-central/eastern Oklahoma to the
ArkLaTex. This will be as forcing for ascent and elevated moisture
transport increase regionally. Severe thunderstorms are not
currently expected given access to only weak elevated buoyancy.
..Guyer.. 12/21/2024
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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