textproduct: Eureka

SYNOPSIS

Coastal drizzle is possible very late today and into Saturday for Humboldt, with some light rainfall over Del Norte. More significant warming will begin late this weekend and next week.

DISCUSSION

A front is approaching Northwest California. This boundary is expected to weaken and drift towards Del Norte County overnight tonight and into Saturday. This will increase cloud cover over the region and perhaps bring light rain to Del Norte County and light rain/drizzle to northern Humboldt County.

Precipitation will move into the region very late tonight and persist into late Saturday morning/early afternoon. Currently, looking at NBM 24 hour probabilities of over 0.1 inches accumulation (5pm Friday 3/13 to 5pm Saturday 3/14): Del Norte County has about an 85 to 95 percent chance; northern Humboldt County has about a 50 to 70 percent chance with higher chances along the coast from about Cape Mendocino and north. More recent NBM runs even have about a 25 to 45 percent chance for 0.5 inches or more for Del Norte County in 24 hours over the same time period (5pm Friday 3/13 to 5pm Saturday 3/14).

Generally, a dominant ridge of high pressure will build over the region this weekend and into next week. There is high confidence the ridge will begin to greatly amplify through the end of the weekend. Near record high temperatures will be possible with some of the warmest valleys in Mendocino and southern Lake possibly approaching 90 degrees by early next week. As of now, the warmest days will most likely be Monday and Tuesday. These temperatures will bring some Minor level HeatRisk, with perhaps very localized Moderate levels for far southern Lake County. Most interior valleys could see temperatures in the 80s, while coastal areas could see high temperatures in the mid/high 60s to low 70s through that period.

AVIATION

Zonal flow continues to the north of the area and this has shifted flow onshore bringing some stratus to the coastal areas and up the near coastal river valleys. This is expected to generally be MVFR, but there may be a few local areas of IFR conditions. This morning CIGS are expected to lift and become VFR. Friday afternoon a weak front starts to approach the area bringing some lower clouds first to Crescent City and then farther south to ACV. The tricky part of this is the timing. The HREF is showing a 50 percent probability of CIGS below 3000 feet by 22Z at KCEC, but not until 4 to 6 hours later at KACV. Confidence grows overnight that CIGS will continue to lower and some light rain is expected by early Saturday morning. These clouds are expected to gradually make it south to the Mendocino coast as well. Areas farther inland, including KUKI, are expected to remain VFR through Friday night. MKK

MARINE

A stationary front that remains just north of the area is impacting the area. North of Cape Mendocino the winds are fairly light and there may be some local areas of west to southwest winds. Northerly winds remain breezy south of Cape Mendocino. These are generally around 15 kt with gusts to around 20 kt. This is generating some 4 to 6 foot wind driven waves. Currently there is also a northwest swell around 6 to 8 feet at 11 seconds moving through the area. A small long period southerly swell is moving through this morning and is to continue over the next several days. This pattern is expected to continue through Friday night.

Saturday a final weak frontal boundary moves by the area and high pressure starts to build into the again. Northerly winds are expected to rapidly increase behind the front in the northern waters. Current models are putting this wind increase at some point during the morning hours of Saturday, but this will be further refined in the next several forecasts. These are expected to peak around 20 to 25 kt Saturday night and Sunday morning and then start to diminish again next week. At this point any gales look to be isolated to downwind of the CAPEs, but this will need to be watched as well.

Monday winds are expected to diminish north of Cape Mendocino once again to around 5 to 15 kt, but remain around 15 to 20 south of the Cape. Tuesday and Wednesday winds are expected to gradually diminish across the area. At this point it looks like Wednesday will have the lightest winds of the week. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 11 PM PDT Saturday for PZZ455.

Small Craft Advisory until 5 AM PDT Monday for PZZ475.