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000
FXUS66 KEKA 191132
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
432 AM PDT Fri Apr 19 2024

.SYNOPSIS...Above normal afternoon temperatures will continue across
the interior valleys into early next week. A weak cold front will
bring a slight chance of light rain and drizzle to the North Coast
on Saturday followed by breezy northerly winds on Sunday.


&&

.DISCUSSION...Pics from sky depicts high clouds continues
streaming across Northern California this morning, while southerly
wind reversal aided coastal stratus moving northward reaching the
southwestern portion of Mendocino Coast. Overnight temperatures
have been running 3 to 8 degrees warmer compared to last night.

Upper level ridge weaken slightly and is expected to shift
eastward today through Saturday. Expect another pleasant day with
above normal temperatures to continue across the interior valleys
today. Interior temperatures are forecast to be few degrees
warmer compared with yesterday`s reading, with highs in the upper
70s to mid 80s. Coastal areas are expected to be near normal
temperatures, with highs forecast in the 50s. HREF guidance
indicated low stratus clouds charging up along and lapping the
Mendocino Coast throughout the day, and forming offshore over the
waters and spread onto the North Coast tonight in advance of a
weak front.

A weak front associated with a transient shortwave trough will
bring a push low level moisture and perhaps some light rain and
drizzle to Del Norte and northern Humboldt counties, primarily
during the afternoon on Saturday. Otherwise, dry weather and some
cooling of interior high temps are expected in response to breezy
west-northwest winds and greater cloud cover across the interior.

Surface high pressure will build in quickly over the Pacific
Northwest Saturday night and Sunday in the wake of the front.
Breezy northerly winds are forecast to redeveloped over mostly
coastal areas as surface pressure gradients tighten on Sunday.
NBM probabilities indicates a 60-80% chance for wind gusts from
30-40 MPH along the exposed ridges and coastal headlands of Del
Norte/Humboldt Counties on Sunday. Also, gusty west-northwest
winds will most likely develop through channeled terrain in the
interior behind the front Saturday evening.

After a brief period of interior warming and upper ridging, interior
temperatures are forecast to trend down mid to late next week and
more seasonable values as another upper-trough-complex impacts
the west coast. The magnitude and rate of cooling remains highly
uncertain at this point with 25-75th spreads on the order 10F for
high temps and 5F for low temps. Current forecast is for near
normal temperatures; highs in the 60s and lows mostly in the 40s.
There are subtle indications for convection across mainly Trinity
County on Tuesday as an upper trough with limited moisture
generates instability.

Potential for precip (showers) will also increase mid to late next
week, though amounts will most likely wont be very much with RAW
ensemble probabilities of 20% to 30% for > 1 inch of rain in
24-hours for the western slopes of Del Norte and northern
Humboldt. Stay tuned. ZVS/DB


&&

.AVIATION...VFR conditions and light offshore winds again this morning
beneath a ridge of high pressure and scattered cirrus. A marine
stratus shield observed on satellite south of Point Arena is
expected to migrate north this afternoon, but should remain south of
Cape Mendocino. Diurnally driven winds will produce westerly winds
along the coast and northerly upslope flow at UKI this afternoon
before returning to light offshore flow. Coastal southerly flow
reversal will become more substantial tonight into Saturday morning,
enhanced further by an approaching frontal boundary. HREF indicates
a strong marine stratus signature rounding the Cape during this
period, highlighting the potential for mist/fog and thick low level
stratus at the coastal terminals. Stratus may produce MVFR/IFR
ceilings reduced visibilities before the front crosses the coast
Saturday afternoon.


&&

.MARINE...Seas continue to diminish admist light northerly winds as
the last of the small crafts expire in the northern outer waters.
Light winds and a small long period swell ensure calm seas through
Saturday, with wave heights falling to 2-4 feet. Winds will briefly
turn southerly ahead of a weak frontal passage Saturday afternoon
before a swift resurgence of northerly winds behind the boundary
overnight into Sunday. NBM is still indicating 80-90% probabilities
of >34 kt gusts developing downwind of Cape Mendocino before
expanding to the northern and southern waters by Sunday afternoon.
Responsive wind waves alongside a long period NW swell will produce
steep and hazardous seas exceeding 10 feet by late Sunday. The
tightening pressure gradient developing ahead of another offshore
ridge will enable gale winds to continue in the outer waters through
Monday morning, further enhancing the sea state to wave heights 12
to 14 feet. Uncertainty remains as to how quickly the axis of
elevated winds will retreat offshore before another trough complex
approaches the PNW on Tuesday.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&

$$

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https://www.weather.gov/images/eka/zonemap.png