Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0159 PM CST Sun Dec 22 2024

Valid 222000Z - 231200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast across the contiguous United
States through tonight.

...20Z Update...
Lightning flashes continue to be observed just offshore of the
northern CA coastline as a mid-level trough approaches the Pacific
Northwest. As the mid-level trough continues to advance toward the
coastline later this afternoon and evening, increased mid-level
cooling aloft will encourage at least isolated onshore thunderstorm
development. As such, no changes have been made to the previous
forecast.

..Squitieri.. 12/22/2024

.PREV DISCUSSION... /ISSUED 1003 AM CST Sun Dec 22 2024/

...Northern CA/Pacific Northwest coast through tonight...
Lightning flashes have been observed this morning within a
baroclinic band roughly 150 mi off the northern CA coast, in
association with a midlevel shortwave trough that will move inland
later today into tonight.  The potential for isolated lightning
flashes inland will begin this afternoon with elevated convection in
the warm conveyor belt across northwest CA/southwest OR.  Other
isolated lightning flashes may also occur this evening into early
tonight along the WA coast as steeper low-midlevel lapse rates and
weak buoyancy spread inland.

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0129 PM CST Sun Dec 22 2024

Valid 241200Z - 251200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS
SOUTH-CENTRAL/SOUTHEAST TEXAS...

...SUMMARY...
A few strong storms could occur across parts of south-central and
southeast Texas on Tuesday.

...Synopsis...
A progressive upper-level pattern will be present on Tuesday as a
positively tilted mid-level trough moves off the Northeast Coast. A
weaker positively tilted trough amplifies across the central CONUS
and a much stronger trough moves inland across the West Coast.
Overall, high pressure will dominate most of the CONUS with a weak
low-pressure center along a frontal zone in the southern Plains and
weak low-pressure in the InterMountain West. 

...Southern Plains...
Low to mid 60s dewpoints will advect inland across southern/eastern
Texas on Tuesday as low-level flow strengthens south of a developing
cold front. Mid-level cooling ahead of the approaching mid-level
shortwave trough will steepen lapse rates and result in weak to
potentially moderate instability. Thunderstorms will likely be
ongoing near the surface front Tuesday morning with the
front/composite outflow drifting slowly south during the day. Some
diurnal increase in intensity is possible from this activity. In
addition, strengthening of the low-level jet through the day may
provide enough isentropic ascent for scattered thunderstorm
development during the afternoon/evening across the open warm
sector. Initially, deep-layer shear will be weak during the morning,
but will increase to around 30 to 35 knots by the afternoon/early
evening. This could result in some rotating updrafts with the
potential for some large hail or a few wind gusts.

...Pacific Northwest/Northern California... 
A surface front will likely be located somewhere near the
northern/central California coast at 12Z Tuesday. Forecast soundings
ahead of this front show shallow/weak instability which could favor
an isolated wind gust, but lightning activity should be minimal. A
better chance for open-cell convection will be during the afternoon
along the Pacific Northwest/California coast as mid-level temps cool
and deeper instability develops. However, by this time, relatively
weak flow should limit storm organization/intensity.

..Bentley.. 12/22/2024

Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0109 PM CST Sun Dec 22 2024

Valid 231200Z - 241200Z

...NO CRITICAL AREAS...

...Update...
No modifications to the forecast are required for Day 2/Monday.
Please see the previous discussion below for additional details.

..Barnes.. 12/22/2024

.PREV DISCUSSION... /ISSUED 0142 AM CST Sun Dec 22 2024/

...Synopsis...
A weak shortwave trough will overspread the southern Rockies,
promoting weak lee cyclogenesis and locally dry/breezy conditions
over the TX Trans-Pecos region. However, these conditions will be
too marginal for any fire-weather concerns.

...Please see www.spc.noaa.gov/fire for graphic product...