textproduct: Eureka

KEY MESSAGES

* Light rain Saturday night and again Monday afternoon in Del Norte and Humboldt counties. * Minor coastal flooding is likely around Humboldt Bay from Sunday through Tuesday.

* Breaking waves of 20 to 25 feet are expected today and these may coincide with a very high tide generating significant wave run-up.

* Stronger storm systems with more rain late in the week.

SYNOPSIS

A series of cold fronts are expected to bring light rain in the north early Sunday and again on Monday. Mainly dry and unseasonably warm conditions are expected on Tuesday and Wednesday. Thursday may start to see some cooling, but still generally dry conditions. Friday and into the weekend may see some more significant rain.

DISCUSSION

A cold front is moving through bringing some rain and southerly wind to Del Norte and Humboldt counties. Rain is expected to come to an end in the morning. Behind the front winds are expected to turn northerly again. Areas farther south and east are expected to see some clouds in morning, especially in the valleys. High temperatures are generally expected to be 5 to 10 cooler than today, especially in the north.

Sunday night southerly winds and clouds are expected ahead of another frontal boundary. This is expected to be slightly stronger than the system early Sunday and rainfall is expected to make it slightly farther east and south. There is a 70 percent chance in Del Norte county of over a half inch of rain. This drops to only a 30 percent by Trinidad and quickly lower as goes farther south. A wetting rain is possible in northwestern Trinity county and possibly some of the higher terrain in western Trinity such as South Fork Ridge. Much of Mendocino and Lake counties are expected to remain dry as well as eastern Trinity county. This will generally keep temperatures a few degrees cooler than Sunday.

Tuesday is expected to see some warming and dry once again as high pressure builds into the area. Many of the inland areas are expected to warm into the 70s again with upper 70s possible in the south. Wednesday may be even warmer in many areas. Locations in the shade such as the deeper valleys will remain cooler.

Thursday an upper level trough approaches the area, but the models are still not in very good agreement on the prospect for rain. Two of the ensemble clusters show show light to moderate rain while the two others show no rain. This split generally continues on Friday, although the two wet clusters show heavier rain. Saturday all four of the clusters are starting to show rain, but there are still some pretty big differences in the amounts. So the potential continues for a pattern switch to a wetter pattern, but so far we aren't really seeing anything that would increase our confidence in it actually happening. MKK

AVIATION

A front continues to near the region, arriving at KCEC first bringing light to moderate rain. Winds shifting away from southerly should be expected with frontal passage. Ceiling heights are expected to remain around MVFR levels. They may briefly drop lower. Farther south and east low clouds are expected to continue to expand. At this point low clouds are expected to make it into KUKI, but confidence is low on this. Rainfall should clear up by 17Z and ceilings should raise to VFR levels, accompanied by light northerly winds. MKK/BB

MARINE

Moderate to fresh southerly winds mainly north of Cape Mendocino continue early this morning as a front approaches the area. These will ease in the morning and become northerly again.

The main concern is a large WNW swell that will quickly build in tonight. The swell will reach 17 to 20 ft by Sunday morning, with a period up to 17 seconds. There is still some uncertainty on the size of this swell and it is possible this will come in larger than expected. Also, the swell may have slowed down slightly so have pushed back the start of the hazardous seas warning in the north to 15Z or 7am. The swell will then ease Sunday night through Monday.

Southerly fresh breezes develop again Monday with another front. These are expected to diminish with gentle to moderate southerly breezes on Tuesday and early Wednesday. Wednesday afternoon southerly winds may briefly increase before diminishing again.

BEACH HAZARDS

A large swell of 16 to 20 feet at 17 seconds is expected to arrive Sunday morning creating large breaking waves of 22 to 24 feet for west to northwest facing beaches through the day. A High Surf Advisory remains in place for this threat. Extra caution is advised near beaches this weekend due to the increased swell activity. These waves are also expected to arrive at the same time as the high tide and this will allow waves to run farther up on the beach.

COASTAL FLOODING

Water levels inside Humboldt Bay continue to run 1.2 to 1.3 feet over the astronomical tides. Southerly winds early this morning may increase these slightly with water levels inside Humboldt bay reaching 8.8 to 9.0 ft on Sunday. The large swell on top of this high water may impact some areas even inside Humboldt Bay.

Outside of Humboldt Bay on the open coast, Crescent City and Arena Cove tide gauges are running 0.5 to 1.0 feet above astronomical tides. The southerly winds may increase this slightly too. These are expected to remain below flood advisory levels; however, the large breaking waves may briefly flood minor roads and parking lots that are exposed at high tide. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... High Surf Advisory from 7 AM to 10 PM PST Sunday for CAZ101- 103-104-109.

Coastal Flood Advisory from 10 AM to noon PST Sunday for CAZ103.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory from 10 AM to noon PST Sunday for PZZ415.

Small Craft Advisory until 7 AM PST Sunday for PZZ450-470.

Hazardous Seas Warning from 7 AM to 8 PM PST Sunday for PZZ450-470.

Small Craft Advisory until 4 PM PST Monday for PZZ455.

Small Craft Advisory until 9 AM PST Sunday for PZZ475.

Hazardous Seas Warning from 9 AM to 8 PM PST Sunday for PZZ475.