Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service Sacramento California 
256 PM PDT Sat may 25 2013 


Short term discussion... 


A broad trough of low pressure continues over the West Coast 
this weekend. A weak shortwave will round the base of the trough 
and deepen into northern California tonight. Moist flow with the 
low deepening may result in some showers over the northern 
mountains late this afternoon and overnight. Cool northwest flow 
will also continue to keep temperatures mostly in the 70s for the 
valley this weekend with 50s and 60s in the mountains for daytime 
highs. 


A stronger shortwave near 150w will move over the region on 
Monday and Monday night and will likely bring some showers to the 
valley and some mountain rain. This system looks like it may 
start to produce some showers Monday morning for the mountains 
mainly north of I-80 and the north end of the valley. For the 
afternoon rain will be likely for west slopes with chances 
of showers developing for the Sacramento area. The best chances 
of precipitation for the Sacramento area and places south in the 
valley will occur Monday night. 


Some lingering chances of showers will persist on Tuesday and 
mainly for the western slopes...but for the most part the system 
will have passed through the region with only some residual 
showers in its wake remaining. Not a lot of rain is expected from 
this system within the valley with amounts ranging from trace 
to less than a tenth of an inch...while the mountains should fair 
a little better with amounts ranging from one quarter to three 
quarters of an inch of rain. Some light snow accumulations will be 
possible Monday night above 8000 feet. 


Extended discussion (wednesday through saturday) 


Unsettled weather continues Wednesday and Thursday as our region 
is sandwiched between a trough to the northeast and high pressure 
to the southwest. Lingering showers on these days will generally 
be across the foothills and mountains as well in portions of the 
Central Valley north of Interstate 80. Precipitation will taper 
off during the day on Thursday. Temperatures on Wednesday and Thursday will 
still be about 5-10 degrees below normal but the region will 
undergo a warming trend from Wednesday into the weekend. Temperatures 
in the middle to upper 80s for the valley and 60s for the mountains 
by Friday which is slightly above normal. The trough will shift eastward 
enough by Friday that we expect dry weather for Friday and 
Saturday. Jbb 


&& 


Aviation... 


VFR conditions continue today at taf sites. Clouds moving in 
this afternoon and evening as a weak wave moves across far norcal. 
Expect a slight chance of afternoon/evening showers over the 
northern mountains. Winds generally 5 to 15 knots at taf sites 
with occasional gusts 15-25 kts when the Delta breeze peaks today 
between 22-03z. Light to moderate west to southwest winds over 
ridgetops. Jbb 


&& 


Sto watches/warnings/advisories... 
none. 
&& 


$$