U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 160521 
Storm Prediction Center ac 160520 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1120 PM CST Fri Feb 15 2019 

Valid 161200z - 171200z 

..no severe thunderstorm areas forecast... 

thunder potential will be mostly confined to the Pacific coast 
region from western Oregon to central California. 

..Pacific coast... 

Weak large-scale forcing for ascent will be noted along the Pacific 
coast through early afternoon within a broader cyclonic flow-regime 
across the western US. Two distinct disturbances will dig southeast 
toward northern California in the wake of early-day short-wave ridging which 
could aid convective threat along the coast. Latest guidance 
suggests thermal profiles will cool within northwesterly flow which 
will allow lapse rates to steepen as 500mb temperatures drop below 
-30c. While buoyancy will remain weak, forecast soundings suggest 
100-200 j/kg MUCAPE will be adequate for convection to penetrate 
levels necessary for lightning within the strongest updrafts. For 
these reasons 10% thunder line will be maintained from the or coast 
into portions of central California. 

.Darrow/squitieri.. 02/16/2019 


Mesoscale Discussion

acus11 kwns 141850 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 141850 

Mesoscale discussion 0104 
National Weather Service Storm Prediction Center Norman OK 
1250 PM CST Thu Feb 14 2019 

Areas affected...central California - particularly within the San 
Joaquin Valley 

Concerning...severe potential...watch unlikely 

Valid 141850z - 142045z 

Probability of watch issuance...5 percent 

Summary...isolated/briefly severe convection may occur through the 
afternoon across the discussion area. A ww issuance is currently 
not anticipated. 

Discussion...a band of relatively persistent convection has 
developed across portions of Calaveras and Tuolumne counties in 
California over the past hour. Within the pre-convective 
environment, sunshine has allowed for surface warming, with 60s f 
surface temperatures and mid 50s f dewpoints boosting MUCAPE values 
into the 500 j/kg range. Additionally, terrain-related backing of 
low-level flow beneath strong southwesterly mid-level winds aloft 
have boosted 0-3 km srh values to around 225 m2/s2 (based on latest 
VAD data at hnx). The cape/shear combination suggests some 
potential for convection in the discussion area to briefly rotate, 
which may result in a very isolated threat for wind damage and 
perhaps a brief tornado through at least 00z. This threat will be 
too localized/marginal for a ww issuance, although trends will 
continue to be monitored throughout the afternoon. 

.Cook/Hart.. 02/14/2019 

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


Latitude...Lon 37932104 38282090 38532041 38251990 37511934 37011918 
36891908 36511916 36281936 36241979 36412026 36832081 
37642108 37932104