textproduct: Eureka

SYNOPSIS

Cloud cover near the coast Tuesday will be persistent as a weak short wave pushes in, bringing rain late Tuesday through early Thursday. High pressure just off the coast will dominate the flow, bringing northerlies near Gale force by Wednesday afternoon.

DISCUSSION

After a seasonal precursor of fair weather days to come, Tuesday will prove to be mild as well with the exception of lingering coastal clouds. A short wave perturbation near the surface will push through late Tuesday, lasting into early Thursday. Most of the accumulation will be in Del Norte 0.7 to 1.05 inches, while Humboldt could range 0.3 to 0.6 inches. The higher yields in Humboldt will be closer to the northern border with Del Norte. This weak forcing does have a colder air mass with it but not very much in the way of integrated water vapor. PWATS are high for Del Norte/Crescent City early Wednesday which confirms what most models are in agreement on, rain accumulation of 0.9 inches for the mean. Light snow at elevations above 4000ft in the Trinity horn and the Yolla Bollys is possible as the colder air and high humidity encourages dendritic growth. It is likely 3 to 5 inches at most for the Trinity horn, and maybe 2 to 3 inches for the Yolla Bollys.

High pressure moves over the area Thursday into late week. This will help clear skies and bring chilly overnight temperatures. Near freezing temperatures are possible for most interior areas Thursday and Friday nights. Coastal areas could see a drop into the 30s, but coastal stratus could disrupt cooling.

Gusty north winds will also develop starting Wednesday afternoon. As of now, the Mendocino Coast and Lake County are the most likely to see the strongest winds, with NBM showing around a 30 to 50% chance for peak gusts over 40 mph Wednesday and Thursday. Coastal Humboldt and Del Norte have around a 50% chance to see gusts over 30 mph. Locally higher gusts of over 50 mph are possible on the highest ridges. Dry weather and breezy north winds are likely to continue at least into early next week. JB /EYS

AVIATION

The satellite is showing widespread low clouds off the coast this morning and in some of the river valleys. An approaching frontal boundary is expected to change the wind flow and the clouds will likely expand into much of the area this morning. This will bring MVFR conditions to the TAF sites in the morning. Some locations may briefly drop to IFR, but confidence is low on this. As it goes through the day the clouds are expected to lift ahead of the front and CIGS may become VFR. Tonight the is expected to bring some rain to the area and possibly MVFR conditions late tonight at KACV and KCEC. MKK

MARINE

Light winds are expected to gradually become south or southwest Tuesday north of Cape Mendocino with light northwest to west winds farther south. The southerly winds are expected to continue to expand Tuesday night. Then early Wednesday when the front moves through there is expected to be a fairly abrupt shift to northwest. The winds are also expected to increase to around 15 to 20 kt by daylight on Wednesday or possibly earlier. These winds are expected to gradually increase through Thursday night. Gale force gusts are expected to start Thursday morning in the southern waters and expand north into the northern waters Thursday afternoon. Confidence is high that there will be gale force winds, although some questions remain how far north they will make it and exactly when they will start. These may continue into the weekend at least in the southern waters. For now have held off on a gale watch, but one will likely be need starting on Thursday for at least the southern waters.

The seas are currently fairly low around 3 feet at 8 seconds and 2 feet at 12 seconds. These are expected to generally persist until the wind driven waves start to pick up on Wednesday. These winds driven waves are expected to quickly build to around 8 to 14 feet by Thursday night and remain elevated and the dominant wave into the weekend. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None.