MD 0154 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF CENTRAL INTO NORTHERN CALIFORNIA
Mesoscale Discussion 0154
NWS Storm Prediction Center Norman OK
0251 PM CST Mon Feb 19 2024
Areas affected...portions of central into northern California
Concerning...Severe potential...Watch unlikely
Valid 192051Z - 192315Z
Probability of Watch Issuance...20 percent
SUMMARY...A couple of semi-discrete, low-topped supercells may form
later this afternoon, accompanied by a brief tornado or marginally
severe hail/wind risk. A WW issuance appears unlikely given the
brief, localized nature of the severe threat.
DISCUSSION...A pronounced mid-level trough and associated surface
low continue to promote strong flow fields over central into
northern CA as they linger just offshore. Some clearing of clouds
and precipitation over portions of the Sacramento Valley have
allowed surface temperatures to reach the lower to mid 60s F in
spots. While 7 C/km mid-level lapse rates (per 20Z mesoanalysis)
overspread the low to mid 60s F temperatures, the diurnal heating
has also allowed for the mixing of the low-level moisture, with
surface dewpoints only as high as 50 F in spots. These lower
dewpoints support thin SBCAPE profiles (no more than 500 J/kg in
most spots). While the DAX and BBX VADs show relatively large,
curved hodographs (300+ m2/s2 0-3 km SRH), RAP forecast soundings
suggest that such low dewpoints do not sufficiently destabilize the
boundary layer for optimal ingestion of the available SRH. While
low-topped storms (perhaps supercells) may develop later today with
a marginally severe hail/wind threat, the tornado risk is a bit more
uncertain. Nonetheless, if a robust, discrete low-topped supercell
manages to develop, a brief tornado cannot be ruled out.
Coverage of robust updrafts over the Sacramento Valley remains
uncertain, and any severe threat that can materialize should be
brief and very localized. As such, a WW issuance does not appear
likely at this time.
..Squitieri/Hart.. 02/19/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...STO...
LAT...LON 37722118 38152156 38642204 39472230 39902239 40122223
40132198 39742164 39032119 38592095 38092066 37822069
37692082 37622090 37722118
