Dry and breezy today, atmospheric river takes aim at California on Friday

April 2, 2018 – Dry and warm through Wednesday with breezy north winds today. Wetter pattern returns for the end of the week.

Discussion

Partly cloudy skies cover interior NorCal early this morning. Current temperatures are a little milder across most of the region and generally range from the upper 20s and lower 30s in the mountain valleys to the 50s in the Central Valley.

Weakening cold front currently along the OR/CA border will move south through NorCal today. It is expected to be dry, however latest models are indicating potential for some sprinkles or light showers over the high Sierra south of Lake Tahoe this afternoon – so we’ll be watching this trend today.

Skies will clear out behind the front and breezy north winds will develop through the Central Valley. High temperatures today are expected to be around 5-10 degrees cooler compared to the weekend.

Ridging will build back in for Tuesday with milder temperatures and lighter winds. Clouds will begin to increase Wednesday and thicken on Thursday as deeper moisture begins to impinge on the West Coast ahead of the late-week precip event. Light precip may begin as early as late Thursday across the far northern portion of the state as warm-advection and IVT increase.

Extended discussion (Friday through Monday)

Atmospheric river takes aim at California on Friday with widespread moderate to heavy precipitation across Interior NorCal that continues Saturday. Precip turns more showery Sunday. NAEFS moisture anomalies are +6 standard deviations above climatology with a 30 year return interval Fri/Sat.

Early QPF estimates suggest 1 to 2.5 inches in the Central Valley through early Sunday with 2 to 4+ inches in the foothills and mountains. Snow levels will be above pass levels through Saturday afternoon, lowering Saturday night into Sunday to around 4500 to 5500 feet.

Breezy to windy conditions expected Friday and Saturday. Will need to look into adding thunderstorms over the Central Valley Saturday if models continue to show increased instability.

Showers look to decrease Sunday as subsidence increases with dry weather Sunday night into Monday under upper ridging. Next Pacific frontal system begins to spread precip over western portions of CWA Monday afternoon into evening.