textproduct: Eureka

SYNOPSIS

Unseasonable warmth with widespread minor heat risk in the interior is forecast to abate this weekend into early next week. Coastal northerlies will increase on Saturday after passage of a front. Next chance for rain is expected Tuesday into Wednesday.

DISCUSSION

A persistent and anomalously strong ridge centered over the Desert Southwest continued to bring unseasonably warm temperatures Friday. A cold front was observed on water vapor imagery riding above the ridge. The ridge will finally begin to weaken as the front progresses southward and flow gradually turns more zonal aloft.

Little to no precipitation is expected with this front, but persistent light, coastal drizzle may accumulate a few hundredths of an inch Friday night through Saturday morning. Northerly winds will turn breezy Saturday with the passing of the front. Daytime temperatures will be significantly cooler Saturday behind the front, but inland temperatures will still remain above climatological normals with strengthening surface high pressure.

A stronger frontal system will descend southward Tuesday. Models are torn on how much precipitation falls with it, which may only be a half inch or so over northern Humboldt and Del Norte. A small percentage of ensemble members, mainly from GFS, hold 6 hour rainfall amounts of up to an inch for Del Norte. This front will contain anomalously high precipitable water values (over 200% percent of normal), enhanced 925 mb southerly winds (around 2000ft up), and relatively high IVT values. The front will be very quick moving, but a brief period of heavy rainfall rates are possible. If the low takes a farther track north, there will be much less rainfall and lighter southerly winds. The NBM 90th percentile (worst case) does show a period of maximum gusts up to 40 mph, so the systems will be watched.

AVIATION

Shallow marine stratus has advanced in ahead of a cold front. The stratus has brought LIFR CIGs down to 200 ft Friday afternoon. The front will bring chances for light drizzle and for deepening/lifting of the ceiling. Current probability for ceilings levels less than 500 ft are relative high through 12Z Saturday (40 to 60%), with a likely turn to IFR thereafter. MOS guidance is beginning to hang on to LIFR levels longer Saturday, but the pattern favors some lifting. Northerly winds will turn breezy Saturday afternoon behind the front.

MARINE

Calmer winds and seas will come to an end today as northerly winds increase over the southern waters with wind gusts over 25kts by this evening. Winds will continue to build and spread northward with gale conditions in the outer waters by Saturday afternoon. Gusts close to 25 kts will most likely push right alongshore with the afternoon sea breeze. Similar winds will persist Sunday before tapering off early next week.

Steep short period seas will build alongside the winds in excess of 11 feet at 9 seconds by Saturday night. Even where winds are weaker in the inner waters, steep seas will permeate close to shore. Wind waves will dominate the environment with only very weak swells through the weekend. /JHW

CLIMATE

Station/Forecast/Record/Date -------/--------/------/---- KCEC 64 76 1930 KEKA 62 67 2004 KUKI *91 85 1960 ---------------------------- *(Potential Tied or Broken Record)

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 11 AM Saturday to 3 PM PDT Sunday for PZZ450.

Small Craft Advisory from 11 PM this evening to 3 PM PDT Sunday for PZZ455.

Small Craft Advisory from 3 AM to 3 PM PDT Saturday for PZZ470.

Gale Warning from 3 PM Saturday to 9 PM PDT Sunday for PZZ470-475.

Small Craft Advisory until 3 PM PDT Saturday for PZZ475.