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CNRFC Hydrometeorological Discussion

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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
700 AM PDT Thu Apr 15 2021

...WEAK SYSTEM TO DIVE TOWARD THE REGION FROM THE NORTHEAST ON FRI...
...WARMING TEMPERATURES THROUGH THE WEEKEND INTO EARLY NEXT WEEK...

.METEOROLOGICAL CONDITIONS (SHORT TERM: THU AM - SUN AM)...

Primary circulation associated with the cyclonic flow aloft has 
moved over the interior across the Rocky Mountains this morning. 
However...with generally northeast to northwest flow across the 
area...this will keep the door open for a secondary disturbance to 
move through the flow from Montana toward northern Nevada on Friday. 
This is expected to bring another round of light precip to northern 
and eastern NV as well as the Sierra south of Lake Tahoe. Given the 
trajectory of the system...available moisture will be minimal with 
no convergence of higher PW air evident on the models. Look for 
precip amounts to mainly remain near or below 0.10-inch with 
freezing levels only dipping down to a range of 6000- to 8000-feet 
near the s/wv trof.

This s/wv trof will rather slowly shift from north to south across 
the region on Saturday with the northeast flow remaining across CA 
and NV while a narrow upr ridge pumps up offshore with its axis 
generally along 130W. This will keep temperatures cooler than normal 
across much of NV and SE CA...with above normal temperatures across 
northern/central CA.


.METEOROLOGICAL CONDITIONS (LONG TERM: SUN AM - WED AM)...

The pattern through the extended range is expected to be 
characterized by ridging remaining fairly dominate through much of 
the period, but with weak waves aloft moving across the ridge at 
times.  Overall expect mainly dry conditions, except for possible 
light precip in NE NV Mon, followed by possible light showers across 
northern CA/NV Mon night into Tue night due to a possible more 
consolidated trough.  Most precip should be confined to coastal 
areas and higher terrain.  Expect freezing levels 9000-10000 ft in 
areas of precipitation during the period.  Overall, expect 
temperatures to remain around 5-15 degrees above normal through the 
period, except closer to normal for SE CA/NV Sun and coastal areas 
Tue.  Leaned heavily on WPC QPF guidance.