textproduct: Eureka

KEY MESSAGES

* Much cooler temperatures expected with inland highs in the upper 60s to middle 70s through the week.

* There is a slight chance of thunderstorms, mainly in Trinity County, this afternoon and evening.

* An early season storm is likely to bring widespread rain to the area Wednesday and Thursday.

SYNOPSIS

An upper level low continues to deepen, bringing some light showers or drizzle tonight and Tuesday. There is slight chance for thunderstorms today as this low moves overhead. An early season storm is expected to bring widespread wetting rain Wednesday afternoon through Thursday.

DISCUSSION

An upper level low continues to approach the area deepening the marine layer and keeping interior temperatures cooler. The cooler air aloft has allowed the marine inversion to weaken. Today as this low approaches the area, it may bring some drizzle to coastal areas. This low may also bring some convective showers to the area. This convective nature may help coastal areas to clear out or lift in the afternoon. There is some instability over the interior in the models. This may need some clearing to be realized. The CAMS are showing some light convective showers over the portions of the area. The instability may be enough to produce some lightning, but confidence is low on this.

Once this first low moves through there may be a brief break in the weather by early Wednesday. Another front is expected to move in Wednesday starting in Del Norte County by late morning and spreading south into the afternoon and evening. The heaviest rain is expected in Del Norte County with 1.5 to 2.25 inches currently expected. The highest amounts will be over the higher terrain. Farther south the amounts are expected to quickly diminish. A half to three quarters of an inch is expected around Humboldt Bay and the Eel River Delta. Northern Humboldt may see up to an inch to over 1.5 inches near the Del Norte County border. Northern Mendocino and Trinity county are expected to see 0.5 to 1 inch with southern Mendocino receiving less than a half inch and portions of Lake county seeing less than a tenth of an inch. There is still the potential for some of Mendocino and Lake counties to receive little to no rain from this system.

Thursday and Friday an upper level low is expected to stall over the Pacific Northwest. This is expected to continue to bring cool and moist conditions, but rain is generally expected to be just a few showers around. For the weekend and into Monday there may be a gradual return of warmer and drier conditions. MKK

AVIATION...(06Z TAFs)

As an upper level low pressure system approaches the area, the marine layer will continue to deepen. Ceilings could get down to IFR at some coastal terminals early this morning with mostly MVFR ceilings. There could be periods of drizzle this morning as well. General cloudiness will spread throughout Northwest California through the day.

MARINE

Generally light southerly winds are expected today. The waves are expected to be dominated by a small southerly wave at 14 seconds. Tonight and Wednesday the southerly winds are expected to increase to around 20 to 25 kt in the northern waters and lighter farther south. This is due to an early season weather system moving through the area. Thursday, winds are expected to remain light and southerly. Friday it looks like the winds will become northerly again and start to increase over the weekend. MKK

FIRE WEATHER

Late this afternoon and tonight, the upper low moves overhead bringing a potential for thunderstorms. High- resolution models are supportive of isolated thunderstorms in Trinity County, with higher chances on the northern and eastern edges. Confidence is still low, at around 10-15%. These thunderstorms are likely to be a mix of wet and dry, but precipitation is expected to be little.

Wednesday afternoon and evening there is the potential for widespread wetting rain. Rainfall amounts close to two inches are possible in Del Norte and northern Humboldt counties. This will need to be watched if these amounts continue to be shown in the models for any potential impacts to recent burn scars. MKK/JB

EKA WATCHES/WARNINGS/ADVISORIES

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