SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1104 PM CST Tue Jan 04 2022
Valid 051200Z - 061200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated thunderstorms may occur over far eastern North Carolina on
Wednesday. Severe thunderstorms are not expected across the
continental United States.
...Synopsis...
In the mid-levels, broad cyclonic flow across much of the
northeastern CONUS will amplify, as a 100 kt jet streak moving
across the Ohio River Valley works to intensify a shortwave trough
situated over the Great Lakes. At the surface, a sub-1000-mb cyclone
over the Great Lakes should intensify further through the day as it
transits eastward into southern Quebec. Subtle confluence ahead of a
cold front associated with the strong area of low pressure will
belatedly draw moisture inland across much of the Eastern Seaboard,
supporting a few thunderstorms across the Outer Banks and coastal
vicinity.
00z RAOBS and surface observations across much of the East Coast
show dry surface conditions in the wake of a prior frontal passage.
With limited surface moisture available, thunderstorm chances will
be confined to coastal portions of NC closest to deeper moisture
return over the western Atlantic. Model projections and linear
extrapolation of current buoy observations do show upper 50s to low
60s F dewpoints will be possible near and inshore of Cape Hatteras
by 12z. Aided by surface confluence ahead of the front, and weak
mid-level height falls from the intensifying trough to the
northwest, a few thunderstorms may develop before quickly moving
offshore. In spite of meager CAPE profiles with westward extent,
model soundings do show moderate wind fields with effective shear of
40-50 kts owing to the strong flow aloft. While unlikely given the
limited buoyancy, a low chance for a strong wind gust may accompany
any robust convection that can become established before moving
offshore. Given the high uncertainty and limited potential for
strong/organized convection, severe probabilities will likely remain
below 5%.
A few peripheral lightning strikes may also occur across southern
portions of the Florida Peninsula and in the vicinity of Cape Cod.
However, these areas appear to be well below the 10% general thunder
threshold, given only subtle synoptic ascent and limited surface
moisture/buoyancy respectively.
..Lyons/Lietman.. 01/05/2022
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