Mesoscale Discussion 0166
NWS Storm Prediction Center Norman OK
0305 PM CDT Thu Mar 22 2018
Areas affected...Central CA
Concerning...Severe potential...Watch unlikely
Valid 222005Z - 222200Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated hail and perhaps a brief tornado possible for the
next few hours across portions of central CA.
DISCUSSION...Recent radar imagery has shown a subtle increase in
storm strength over the past hour. This increase is likely tied to
increased forcing for ascent from the shortwave trough currently
traversing the region. Cloud cover has also thinned across the
region, allowing for more diurnal heating and a resulting increase
in instability. Current mesoanalysis estimated MUCAPE over 500 J/kg
throughout much of the central CA valleys.
Winds throughout the Sacramento Valley have veered southwesterly,
reducing the low-level shear and overall tornado potential in that
area. However, given the strong mid/upper-level flow, 0-6 km bulk
shear remains strong (i.e. over 50 kt), and the potential for
transient storm organization still exists. Given the veered
low-level flow, the primary severe threat in this area is hail, some
of which may approach severe thresholds. An isolated tornado cannot
be completely ruled out, especially in areas of localized stronger
and/or backed surface winds. Winds are still a bit more
southeasterly across the San Joaquin Valley, which favors more
low-level shear and a relatively higher (albeit still low) tornado
threat. Overall, the isolated nature of the threat will preclude the
need for a watch.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 37592127 38032154 38462168 38862161 39072114 38952073
38782058 38462048 38232036 37862019 37411983 37011953
36601918 36141957 36482050 37592127