DISCUSSION
A dry upper-level trough will continue to move over the area this weekend. Latest satellite imagery shows stratus and patchy fog blanketed much of the Humboldt coastal waters, and extended well up the adjacent river valleys. In addition, light southerly winds have been pushing the stratus northward from Santa Rosa into southern interior Mendocino County. Profilers data from Mckinleyville and Bodega Bay indicates the marine layer depth up to 2,500 feet MSL. Patchy drizzle may occur with the deepening marine layer in the vicinity of Humboldt Bay this morning. Low clouds will burn off with the daytime heating across the interior, although stratus will be stubborn to scattered along the coast.

Conditions are trending cool and moist with interior stations reporting relative humidities above 40 and temperatures 5 to 15 degrees cooler across the interior. Winds are expected to be lighter as the aforementioned trough moves over the area.
Temperatures are forecast to be likely below normal across much of the region today, with highs mostly in the 80's across the interior and low 90's for the warmest valleys. During the evening, onshore flow will push back stratus inland. Patchy drizzle may occur with a slightly deepening marine layer in the vicinity of Humboldt Bay Sunday morning.

Trough aloft with below normal 850mb temperatures will remain over the area for the remainder of the weekend and early next week, promoting below normal temperature.

Ensemble and deterministic models suggest the upper heights gradually rising across the region early next week into mid week.
A deeper push of moist air associated with a decaying front and transient 500mb shortwave trough may bring some measurable precip (most likely drizzle) to the North Coast region early next week, specifically Monday night or Tuesday. Followed by warm deep layer airmass to gradually developing mid to late week across the WRN CONUS. That evolution will favor increasing afternoon temperatures, particularly across the interior with temperatures back to upper 90's and low 100's. Additional, the marine layer will become more shallow again mid/late week and the low- level inversion will strengthen.

AVIATION
Widespread stratus has formed along the coast and is spreading into the near coastal valleys and up from the south to Ukiah. With winds expected to be lighter along the coast as an upper trough settles over the area, mixing should be significantly reduced today. This should allow the stratus to be more persistent today at the coastal terminals while the normal clearing occurs inland. IFR is likely at ACV and CEC for much or all of the next 24 hours with periods of LIFR this morning and again tomorrow night/morning. /RPA



MARINE
Northerly winds with gusts to over 25 knots will persist through midday over the outer waters resulting in continued steep seas.
Winds and seas will decay steadily later today through the early portion of the coming week as an upper trough settles over the west coast leaving a weak pressure gradient over the coastal waters. Relatively light winds and low seas will be likely through about mid week as the trough takes its time moving out of the area. By late week ridging will build over the interior west allowing the thermal trough to intensify again and northerly winds to increase over the coastal waters as the pressure gradient tightens. /RPA

EKA WATCHES/WARNINGS/ADVISORIES
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 9 AM PDT this morning for PZZ450- 455.

Small Craft Advisory until 3 PM PDT this afternoon for PZZ470-475.