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. && $$