Valid 290100Z – 291200Z
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
FAR SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA…
Marginally severe thunderstorms are possible this evening across
parts of the Lower Colorado River Valley.
…Far Southeast California/Southwest Arizona…
The latest water vapor imagery shows an upper-level trough in the
eastern Pacific with an associated upper-level low near San
Francisco. Ahead of the system, mid-level flow is from the southwest
across the Desert Southwest. A subtle shortwave trough is moving
northeastward through Nevada and southern California with a band of
convection located just ahead of the feature. The airmass ahead of
this band of storms is characterized by weak instability with
surface dewpoints in the lower to mid 50s F. In spite of the weak
instability, strong deep-layer shear will be maintained across the
region as the exit region of a mid-level jet moves over the Lower
Colorado River Valley. The mid-level jet will also enhance lift.
These factors could be enough for a marginal severe threat along the
leading edge of a fine line that is currently moving through far
southeast California. Strong gusty winds and hail will be possible
as the line moves into southwest Arizona later this evening.