SPC AC 221929

   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

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0830Z