textproduct: Eureka

SYNOPSIS

Widespread light to moderate rain this afternoon through early evening will be followed by generally drier weather conditions for much of Northwest California Wednesday through Saturday. Widespread light to moderate rain is expected on Sunday.

DISCUSSION

Surface observations have been reporting gusts in excess of 50 mph (64 mph at Kneeland RAWS) this afternoon. Lower elevations around Humboldt Bay and Eel delta have gusted to 35-40 mph (KACV and KFOT) as well. So far winds have not picked up at KCEC. Gusts from 45-50 mph per the HREF mean are expected by late afternoon today. A wind advisory for strong and gusty winds for coastal Del Norte and higher elevations of Del Norte and Humboldt Counties remains in effect til 4-6 PM. Southerly winds will rapidly decrease with frontal passage after 4-6 PM as mostly light to moderate and perhaps locally heavy rain develops late this afternoon and evening. HREF continues to indicate a 1 hour window from 3-5 PM for rain rates over 0.25in/hr over SW Humboldt in the King Range. The progression of the cold front, dry antecedent conditions and low flows on the rivers will severely limit potential for any major hydrological impacts. Amounts will generally range from 0.25 to 0.50 inch through 10 PM Tue for Del Norte, Humboldt and NW Mendocino. Lesser amounts from 0.1 to 0.3 inches are expected for Lake County and southern Mendo. We posted estimated rainfall amounts for select cities on our web page and social media outlets.

Dew points remain in the mid to upper 20's across northern Trinity this afternoon. Evaporative cooling could result in lower snow levels and slushy wet snow down to 2500-3500 feet around Trinity Center this evening. No accumulations are expected. 2 to 3 inches of snow is forecast in 6 hours for Scott Mountain Pass on route 3 this evening. This is below advisory criteria for a winter weather advisory. Motorist traveling over the high mountain passes above 4500 feet this evening should be ready for slippery roads.

High pressure is expected to return Wednesday afternoon and dominate across much of the forecast areas through Saturday. Light rain or sprinkles with a series of warm fronts will be possible (20-50% chance) primarily for Del Norte and northern Humboldt, particularly in regions of southerly upslope flow. Overall it does not look too wet or impactful with amounts on the order of few one hundredths to perhaps (15% chance) for a tenth in 6 hours across Del Norte. Global ensembles and WPC guidance indicates more widespread light to moderate precipitation this weekend as another shortwave trough heads toward the Pac NW. There is still a some variability with the amounts of rain and timing, however Sunday appears to be the day when most of the rain arrives. Gusty winds will be possible as well in advance of a frontal boundary. Right now 925mb winds do not look strong enough to warrant beefing up the winds above the NBM. Multi-model ensemble continues to indicate a 40-60% chance for 0.25-0.50 inches in 24 hours ending 4 AM Mon, mostly for the northern most zones. Chance for major impacts from rain or snow remains low at this time. Drier weather is expected to return early next week, Mon-Tue, as a ridge aloft builds and light northerly to northeasterly surface winds return.

AVIATION...(18Z TAFS)

Largely VFR conditions have persisted during the day, though notably gusty south winds and upper level overcast skies have both built in during the late morning and early afternoon. Gusty winds up to near 40 kts will continue until near sunset as a quick moving cold front crosses the area. This will generate gusty surface conditions and modest low level wind shear, especially along the coast. Light rain showers will begin to impact the coast around 2 PM local time. SOme briefly heavier showers are possible through around 7 PM. MVFR visibilities will most likely prevail with brief period down to IFR. Behind the front, lingering instability will likely bringing a return to VFR conditions late overnight though the there is a 30% chance of lingering MVFR ceilings. Similarly for the interior, VFR conditions are most likely though some models indicate a chance (20%) of low valley fog around sunrise Wednesday. /JHW

MARINE

Gale conditions have built across the outer waters during the day today with some gale conditions pushing close to shore int he inner waters. Some brief gusts up to 40 kts have so far been recorded. Gale conditions will continue into the early evening as a cold front passes the area. Steep short period seas will also build along the wind, up to around 10 kts by later this afternoon.

South winds will quickly drop off behind the frond with few gusts even over 15 kts by midnight. Short period seas will also fall, with combined seas likely briefly below 6 feet Wednesday morning. Aside from some moderate gusts up to 24 kts in the outer northern waters Wednesday, wind will be mostly gentle with only moderate short period seas. That said, a steep long period swell up to 14 feet will build in Wednesday evening and persist into early Friday. More moderate conditions will them most likely build for the weekend. /JHW

EKA WATCHES/WARNINGS/ADVISORIES

CA... Wind Advisory until 6 PM PST this evening for CAZ101-102- 105-106.

Wind Advisory until 5 PM PST this afternoon for CAZ104.

NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 3 PM PST this afternoon for PZZ450-470- 475.

Small Craft Advisory until 10 PM PST this evening for PZZ455.