U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 230053 
Storm Prediction Center ac 230052 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0752 PM CDT Thu Mar 22 2018 

Valid 230100z - 231200z 

..no severe thunderstorm areas forecast... 

isolated to widely scattered thunderstorms will persist across parts 
of the west. A strong storm or two may still occur over the 
California Central Valley, but any severe risk will diminish over 
the next couple of hours. 

..California Central Valley and vicinity... 
A few stronger storms continue across portions of the Central 
Valley, but overall convective trends have been downward in the past 
hour. Expect a continued decrease in storms over the next couple of 
hours, as diurnal cooling commences. With flow aloft also progged 
to gradually weaken this evening, the marginal risk area is being 
removed this update. 

.Goss.. 03/23/2018 


Mesoscale Discussion

acus11 kwns 222006 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 222005 

Mesoscale discussion 0166 
National Weather Service Storm Prediction Center Norman OK 
0305 PM CDT Thu Mar 22 2018 

Areas affected...central California 

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 California. 

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 California 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. 

.Mosier/guyer.. 03/22/2018 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 37592127 38032154 38462168 38862161 39072114 38952073 
38782058 38462048 38232036 37862019 37411983 37011953 
36601918 36141957 36482050 37592127