103
FXUS66 KEKA 281308
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
508 AM PST Fri Feb 28 2025

.SYNOPSIS...Unseasonably warm temperatures will continue through
Friday due to a ridge of high pressure over our area. Unsettled and
much cooler weather returns Saturday and will remain through the
weekend. There will be more chances for additional rainfall and
mountain snow during the coming work week.


&&

.DISCUSSION...Coastal stratus have developed along the North Coast
overnight. Patches of dense fog has developed around Humboldt Bay
early this morning, including portions of Highway 101 between
Eureka and Arcata. Low clouds and fog are expected to scattered
out by mid morning with the diurnal heating.

Unseasonably mild temperatures continues today as a strong high
pressure dominates the synoptic pattern over Northern California,
especially across the interior. Today is expected to be the warmest
day during this winter season. ECMWF Extreme Forecast Index (EFI)
highlight highs in the 80th-90th to isolated 95th percentile
above normal temperatures, specifically across the interior. Interior
temperatures are forecast to be up to 5 degrees warmer than yesterday`s
reading, with highs from mid 70`s to low 80`s, with the potential
record be tied or break at Ukiah. See Climate Section for
details. Coastal highs are forecast to be in the upper 50`s to mid
60`s, before sea breezes developed.

The ridge aloft will shift eastward tonight into Saturday, while
an upstream elongated H5 trough approaches the Pacific NW and
Northern California. This will bring onshore flow and a shallow
marine layer with coastal stratus and fog. Temperatures will
trend downward, though it will still be pleasant with above normal
highs in the interior on Saturday.

The aforementioned elongated upper will approaches the area
Saturday evening and eventually setting over the area on Sunday.
An associated cold front will bring generally light rainfall.
Operational model guidances, particularly GFS and ECMWF, indicate
the trough evolving into a closed low over Northern California on
Sunday. This will bring continued chances of showers into Monday
morning.

Breezy west to northwest winds are expected to developed on Sunday
as the low drive southward. Chances for wind gusts over 30 mph
are high for the ridges (70%). Low to moderate for the coastal
ridges and headlands in Humboldt and Mendocino counties(50 to
80%). Winds look potentially stronger for Lake County with
moderate to high chances for wind gusts over 40 mph for the
ridges.

Snow level will start about 6000 feet on Saturday, before drop to
around 4000 feet on Sunday. Some light mountain snow is expected
on Scott Mountain Pass.

The pattern will remain relatively active next week with
additional shortwave and longwave troughing, but there is no clear
signal on where some of the smaller features impact the West
Coast, with some potential systems splitting north or south of the
forecast area. Chances for at least 0.25 inches of rainfall in 24
hours are moderate to high through much of next week, so there is
a good shot of at least additional light rainfall.

&&

.AVIATION...A swath of marine stratus continues to affect the
Humboldt Coast, north of Cape Mendocino, and extends to the Del
Norte Coast. Areas of dense fog have been observed, via satellite,
all around Humboldt Bay, with periods of IFR to LIFR conditions
affecting KACV into early this morning. The denseness of the fog
around Humboldt Bay has been exacerbated by the little to no wind
overnight and into this morning. As winds pick up slightly today,
general clearing is expected for coastal terminals; however, IFR
to LIFR conditions may return late this evening. Conditions for
most other terminals (KUKI) will be VFR with light diurnal winds.


&&

.MARINE...Gentle to moderate northerly breezes continue for the
coastal waters off the Northwestern California Coast. A westerly
swell will continue to decay throughout the day with another long
period westerly swell set to move into the coastal waters by
tonight, which will reinforce the current decaying swell.
Northerlies will continue through today and then weaken by early
Saturday as a weak trough moves onshore. More northerlies are
expected Sunday and into next week.


&&

.BEACH HAZARDS...Another long period westerly swell, peaking around
11 to 13 ft at 17 seconds by Saturday afternoon, will build into the
waters by late this evening. Sneaker waves will be a threat to the
beaches of Northwest California by late this evening and continuing
through Sunday morning. As a result, a Beach Hazard Statement has
been issued for this time frame. Be cautious when visiting steep
beaches and jetties. If the sand is wet, that means that waves have
reached that spot recently, even if you have not seen it. Remember
to never turn your back on the ocean!




.CLIMATE...

Daily High Temperature Records (February 28)

Station/Forecast/Record/Date
-------/--------/------/----
KCEC       58      75   1925
KEKA       58      72   1938
KUKI      *81      81   1901, 1926
----------------------------


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Beach Hazards Statement from this evening through Sunday
     morning for CAZ101-103-104-109.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PST this morning for PZZ450-
     455.

     Small Craft Advisory until 9 PM PST this evening for PZZ470.

     Small Craft Advisory until 9 AM PST Saturday for PZZ475.

&&

$$

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png