Porter Ranch, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

814
FXUS66 KEKA 261214
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
514 AM PDT Sat Apr 26 2025

.SYNOPSIS...Showers activity continues through the day, tapering off
by Sunday afternoon. Breezy northwest winds will develop along the
coast and exposed ridges through Sunday. A dry warming trend is
expected Sunday through mid next week.


&&

.DISCUSSION...As the low becomes a bit more organized
about its rotational mass, making its way to the central CA
coastline, the PACNW is receiving the top of the ccw easterly
meridional flow aloft-delivering moisture in the form of clouds and
precipitating into showers. Despite cold air advecting into the
area, the clouds will limit the overnight minimum temps. Along with
moisture and cloud cover, the likelihood of frost is low Saturday
morning. HREF is showing quite a bit of clearing Sunday which could
introduce the need for a frost product for overnight lows into
Monday morning. Eastern Humboldt and Trinity county are forecast for
33-36F in elevations below 3000ft, along hwy 36 east of Bridgeville
and hwy 3 up to Lewiston as well as central Mendocino north of
Willits-Sunday late night into Monday before dawn.

Otherwise, showers will continue across the northern half of the
CWA and expand southward toward Mendocino and Lake county by the
afternoon today. Rain rates will be moderate with precipitation
continuing through to Sunday morning, tapering off as the low
proceeds on a southeast trajectory.

High temperatures are forecasted to be 5 to 15 degrees below normal
today. ECMWF Extreme Forecast Index (EFI) is signaling highs in the
60th-80th percentile with below normal temperatures for the interior
areas in southern Humboldt, interior Mendocino and Lake County.
Overnight temperatures are expected to remain in the 40s across the
valleys due to lingering low level moisture.

Breezy northwest winds will developed along the coast this afternoon
through Sunday as surface high pressure begins to build, tightening
the pressure gradient. Gusts from 25 to 35 mph are forecast for the
coastal headlands and exposed ridges, with the strongest winds over
the more prominent exposed terrain. HREF probabilities indicates
there is a 50 to 75% chance of wind gusts greater than 30 mph for
the North Coast this evening, then increasing chances up to 50%
across the Mendocino Coast late tonight.

Sunday, clearing skies are expected and temperatures will start to
warm back up again as high pressure begins to build downstream, in
the wake of the trough. Inland areas are expected to see highs in
the 60s. Areas with valley fog are expected to develop Sunday night
into Monday. High pressure continues to build in through the week
with highs around 80 for the inland areas by Wednesday.

Ensemble clusters and deterministic models show the high pressure
shifting eastward on Thursday. Most of the cluster members (78%)
suggest an upper level trough approaching the area next Friday.
However, uncertainties exist with the positioning of the low and
whether or not this will impact our CWA. /ZVS /EYS



&&

.AVIATION...Upper level low spinning ccw near 35N, -126W will
continue to track southeastward toward central California. Multi-
layered cloud cover and moist air will continue to wrap around the
low, resulting in lowered ceilings and LIFR/IFR conditions for the
coastal terminals. These periods of reduced flight categories will
persist with a steady low level NW flow and a shallow humid layer.
The occurrence of wrap around precipitation will increase the chance
for IFR and MVFR conditions outside the terminal aerodrome airspace.
Surface pressure gradients will begin to tighten today as the low
tracks southeastward while high pressure builds toward the NW
California coast. Gusty north-northwesterly winds and low level
turbulence are anticipated for coastal aerodromes, especially at
KCEC, in the afternoon. /DB /EYS


&&

.MARINE...Light NW winds continue tonight and will gain strength
through the day. Waves are forecasted to build to 9-10 feet or so in
the next 24 hours as winds build. These deteriorated marine
conditions are forecasted through the weekend and remain hazardous
into early next week.

On Synoptic scale, a weak surface low pressure center off the
Central California coast is moving east-southeastward through the
weekend. Surface high pressure will build toward the Pacific NW
Saturday afternoon resulting in a tighter pressure gradient over NW
CA coastal waters causing an increase in northerly winds. These
winds will build to near gale force gusts over much of the coastal
waters with localized areas forecasted to reach gale force this
afternoon south of Pt. St. George. Wind waves will build to 9-10ft @
9 seconds through the evening. This is close to the threshold for a
hazardous seas warning for primarily the outer waters (10 to 60NM
from shore) into Sunday morning, however, a small craft advisory has
been issued through the weekend. Winds will remain elevated with
near gale gusts expected into the coming work week.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 3 PM this afternoon to 9 AM PDT
     Monday for PZZ450-455-470-475.

&&

$$

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