Valid 081200Z – 091200Z
…NO SEVERE THUNDERSTORM AREAS FORECAST…
Scattered thunderstorms are expected on Sunday over parts of the
southwestern states and isolated storms are possible late near the
Strong upper trough, currently located along the Pacific coast, will
dig southeast to a position from central CO – southern CA by 09/12z.
As this occurs, strong 500mb jet will sag southeast and vertical
profiles will cool substantially north of the jet. Latest model
guidance allows a corridor of weak instability to develop as lapse
rates steepen, especially during the day when some boundary-layer
heating is expected. Forecast soundings suggest the
strongest/deepest convection will attain heights necessary for
lightning, and for these reasons will maintain at least 10% thunder
probabilities across much of the southwestern US.
Weak short-wave trough is forecast to eject across the eastern Gulf
States late in the period to near the NC coast by 09/12z. This
feature should induce a surface trough off the Atlantic coast which
may be drawn inland across eastern NC during the overnight hours.
Weak warm advection and moistening profiles suggest some threat for
lighting with the strongest convection, primarily after 06z.