textproduct: Eureka

SYNOPSIS

Light rain overnight accumulated mostly in Del Norte. Rain will mostly cease by the late morning/afternoon. Blustery to strong northerly winds are forecast to develop behind the front on Wednesday and continue into Thursday.

DISCUSSION

As of 07z, only a few tenths of precipitation have been recorded in Del Norte, most of which being reported near Crescent City (0.28"). For interior Del Norte around 0.10-0.15 inches, with a bit higher recorded accumulation in the eastern most mountain stations. The long stretch of subtropical moisture continues into Wednesday with more precipitation likely, easing by 20z in Del Norte and picking up in the northern Humboldt coast with a minimal amount expected. Probabilities for >0.2" in 24 hours are around 25% for the Arcata airport and increases gradually as you proceed north.

The front and moisture influx will likely weaken considerably as the boundary sags SE. Some places in southern Humboldt may not get any measurable rain at all. Rain chances are forecast to decrease later today as northerlies steadily increase offshore. Residual drizzle and low clouds may persist into the afternoon and evening hours as chilly N-NW breezes develop.

Otherwise, dry and stable weather will continue for the remainder of the area through the week and into the weekend. Generally above normal high temperatures with minor heat risk is forecast as a broad flat ridge aloft dominates. There will be slight cooling in the wake of the cold front, however max temps will still be above normal. The warmest locations will continue to be in Lake, Trinity and interior Mendocino Counties where max temps will likely warm up into the lower to mid 80s toward the end of the week (Thu and Fri). Robust offshore flow, dry air and clearing skies will make for exceptional longwave cooling for wind sheltered valleys. The chance for early morning frost and subfreezing temperatures will increase for mostly the interior valleys Thursday morning and again Friday morning. Coastal areas may also have frost too but winds and cloud cover may hamper the cooling. Persistent east to northeast breezes through the night will keep the exposed ridges dry and much warmer through the night and no frost is expected for locations in the thermal belt and along mountain ridge tops.

Longer range models and national blend of models are trending wetter/colder next week, Monday March 30 to Friday, April 3rd. Higher end scenario (90th percentile) suggests multiple inches of rain spread out over multiple days while a lower end scenario (10th percentile) would yield only half an inch or less over multiple days. There is considerable variability and spread 7 day to 9 days out, but this is the first promising sign for significantly cooler and wetter weather I have seen in quite sometime.

AVIATION

A weak front continues to move through the region very early this morning. Southerly winds will quickly shift northerly for area terminals. Light to moderate rain will come to a close in Del Norte County before sunrise. Light showers are possible for terminals along the northern Humboldt Coast as well. MVFR to IFR ceilings are expected for these coastal terminals. VFR conditions are expected through the TAF period for terminals further east and south. Terminals throughout Northwest California will experience increasing northerly winds into this afternoon as the pressure gradient tightens behind the frontal passage.

MARINE

Southerly winds are quickly turning northerly as the front moves through the region. Behind the front, a strong area of high pressure strengthens in from the west over the Pacific Northwest. Northerlies will increase over the waters as the pressure gradient strengthens generating some sustained gale strength winds, with gusts currently forecast to reach over 40 kts starting this afternoon in the southern waters. The northerlies will quickly expand northward through this evening. Steep seas will reach 12 to 15 late tonight through late Thursday. Winds will begin to ease late Thursday. Gale conditions are forecast to reach into the inner zones, but the limited coverage and duration still warranted a Hazardous Seas Warning due to the combination of gales gusts and large, steep seas.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Hazardous Seas Warning from 11 PM this evening to 6 AM PDT Friday for PZZ450.

Hazardous Seas Warning from 5 PM this afternoon to 6 AM PDT Friday for PZZ455.

Gale Warning from 11 PM this evening to 6 AM PDT Friday for PZZ470.

Gale Warning from 5 PM this afternoon to 6 AM PDT Friday for PZZ475.