Point St. George to Cape Mendocino CA out 10 NM Marine Forecast
|Today...Nw Winds 5 To 15 Kt. Waves W 10 Ft At 13 Seconds. Slight Chance Of Showers.|
|Tonight...N Winds 10 To 15 Kt. Waves W 9 Ft At 12 Seconds.|
|Thu...N Winds 5 To 15 Kt. Waves Nw 9 Ft At 11 Seconds.|
|Thu Night...Se Winds 5 Kt. Waves Nw 6 Ft At 10 Seconds.|
|Fri...Nw Winds 15 To 25 Kt. Waves Nw 7 Ft At 10 Seconds.|
|Sat...N Winds 15 To 25 Kt. Waves Nw 9 Ft At 9 Seconds.|
|Sun...N Winds 5 To 15 Kt. Waves Nw 7 Ft At 9 Seconds.|
| Area Forecast Discussion|
National Weather Service Eureka CA
450am PDT Wednesday September 27 2023
Another round of light rain is moving across the region this morning and tapering off in the afternoon, with heaviest rainfall totals expected in Del Norte and Humboldt Counties. Southerly winds will switch to the northwest through the day. Dry weather is expected Thursday before more rain on Friday. The heaviest amounts expected in Humboldt and Del Norte counties with lesser amounts farther south and east. Total amounts remain uncertain at this point.
An upper level low is moving into the Pacific Northwest. The associated frontal boundary is expected to bring some rain to Del Norte and Humboldt counties, but the front is dissipating as it moves onshore so areas farther south and east are not expected to see very much rain. The winds this morning are southerly and are expected to quickly switch to the northwest this afternoon behind the front.
This front is expected to move through by mid morning to early afternoon and clearing skies are expected behind it. Tonight good radiational cooling is expected across the area, but due to the recent rainfall most inland valleys are expected to see fog. This may be dense in some areas. The fog should keep most areas from seeing frost, but it is possible in the colder valleys of Trinity county if they remain clear. Southern Lake and southeast Mendocino counties may remain clear, but it still doesn't look like there will be frost that far south. Thursday afternoon breezy northwest winds are expected, especially across Lake and Mendocino counties in the afternoon. Fairly widespread gusts to 15 to 25 mph are expected. RH is only expected to drop into the mid 20s.
Thursday night into Friday another shortwave moving through northwest flow drops down and stalls over the area. This is expected to bring some rain to the area, however confidence is low on exactly how much. For example in Crescent City the NBM shows the 75th percentile about 0.9 inches while the 25th percentile is only 0.15. Farther south in Eureka the range is from zero to 0.60 inches. These amounts are higher than see on previous runs so it does appear to be trending upward. Mendocino county and Lake county are expected to see less than a tenth of an inch even at the 75th percentile, with the ensemble mean showing 0.00.
Saturday is generally expected to be dry, however some of the models are showing a few showers over interior areas with the upper level trough lingering. Afternoon temperatures are expected to be only in the upper 60s to low 70s across the area. Saturday night into Sunday morning may see additional fog in the valleys depending on how much rain falls on Friday. Valleys that remain clear and decouple from the higher elevation winds will likely see frost. This is expected to be the coldest night. Winds are also expected to remain breezy overnight, especially over the higher terrain. Winds will be north to northeast. RH recoveries on the higher terrain are expected to still be over 50 percent.
Sunday high temperatures are expected to warm into the upper 70s in the warmer interior valleys and sunshine is expected to be plentiful. Even the coast should remain fairly clear with the offshore flow. Sunday night into Monday morning is not expected to be as cold with a warmer airmass moving in. However it will likely to be drier and this will bring the potential for frost again in some of the valley locations. Monday and Tuesday the warming trend is expected to continue as high pressure builds in. This will combine with an upper level low over the Desert Southwest to bring some offshore flow which should help to keep the coastal areas mainly clear. Models are in decent agreement on highs warming into the 80s in the valleys. MKK
A large westerly swell will continue to slowly subside today, dropping back below 10 ft in the evening. This swell will continue to subside through Friday. A frontal system is moving south and east this morning, bringing increasing southerly winds across the northern waters. Northerly winds will develop across the waters in the wake of the front and ramp up this afternoon into Thursday, with strong to near Gale Force south of Cape Mendocino. A brief period of Gale Force gusts is possible in the southern waters, although coverage looks insufficient for a warning at this moment. Winds briefly diminish and shift to south over the northern waters Thursday night into Friday, ahead of another frontal system. Northerlies will redevelop Friday afternoon and rapidly accelerate across the waters into the weekend. Gale Force northerlies are forecast across the waters in the weekend. In addition, steep to very steep and hazardous seas around 10 to 15 feet will build with the increasing winds across the northern waters and southern outer waters.
.EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9pm PDT this evening for PZZ450- 470.
Small Craft Advisory until 4pm PDT Thursday for PZZ455-475.