360
FXUS66 KEKA 160709
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1209 AM PDT Mon Jun 16 2025

.SYNOPSIS...Increasing afternoon breezes and some fire weather
concerns in southern Mendocino and Lake County this week. Warmer
temperatures and minor HeatRisk concerns midweek. Cooler
temperatures and light rain possible late week.


&&

.DISCUSSION...A weak cold front is visible on satellite offshore
far northern California early this morning, and will move onshore
late morning or early afternoon. Some drizzle or light rain showers
are possible ahead of the front along the coast, particularly north
of Cape Mendocino. Some increased precipitation chances also exist
in the Trinity Horn in the afternoon, but chances remain less than
15%. Instability is also meager and thunderstorms are very unlikely
(less than 5%).

Weak ridging will begin building in behind the trough. Inland valley
temperatures are likely to warm into the low to mid 90s, with some
upper 90s in Lake County on Wednesday. Temperatures will trend lower
next Thursday as another weak shortwave trough passes to the north.
Initial analysis of this trough does not show much chance for
convective impacts, but features as this always bear watching this
time of year. The main impact appears to be stronger northerly winds
behind the front, particularly in Trinity, Mendocino, and Lake
Counties. NBM probabilities for gusts over 35 mph Friday are around
40-60%. Ridgetops are likely to have higher gusts. This could be a
fire weather concern if it pans out, as afternoon relative
humidities remain dry in the eastern portions of our area.

A seasonally anomalously strong trough is then forecast to dive
south into the region next Friday. There is currently a low chance
for some light showers with a cold upper low and front. There is the
potential some of this precipitation may be in the form of
thunderstorms with steep lapse rates and elevated instability. One
of the more "extreme" scenarios (20% chance) is over a half inch of
rain in Del Norte and perhaps a few snowflakes over the highest
peaks. Chillier low temperatures are possible behind the system as
well, with lows in the 30s likely in most of Trinity and the coldest
valleys of Mendocino and Humboldt. JB/JJW


&&

.AVIATION...16/06Z TAFs...Ceilings have already come down to 1500ft
as of 4z at KCEC. Ceilings could come down even more with NBM
suggesting ceilings below 2000ft near 80% probability. Flight
categories could degrade to IFR by 11z and lift by the daylight
hours. KACV will have similar fate as ceilings are due to drop
sooner. Expect IFR at KACV with periods of LIFR in the early morning
hours. Gusty northerlies are likely at KUKI by Monday afternoon,
lasting into the evening hours with VFR prevailing. /EYS


&&

.MARINE...Winds are forecasts to ease from the northern outer
waters, reducing small craft advisories to inner and outer waters
south of Cape Mendocino. The sea state will be largely dominated by
steep short period wind waves. Winds are forecast to gradually
decrease and retreat to the southern waters early in the week. As
the winds die down, a small mid-period NW swell enters the area
waters early Tuesday morning.


&&

.FIRE WEATHER...An additional shortwave moving through the area
today will bring a low chance for showers in NE Trinity county. The
thunderstorm setup does not look great in Trinity, as instability
remains meager, but probabilities hover around 5%.

Northerly winds are forecast to increase today, with the strongest
winds in southern Mendocino and Lake Counties. These mainly
diurnally driven afternoon winds will trend slightly lower Tuesday,
but will increase again late next week behind a stronger trough and
front. Minimum RH values will trend lower early to mid next week,
with some values in the mid to upper teens Wednesday. Locally
elevated to some brief critical fire weather conditions will develop
with these afternoon wind pulses and lowering RH. JJW/JB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 10 PM PDT this evening for
     PZZ455-475.

&&

$$

NOTE: The full forecast discussion is now regularly issued between
10 am/pm and 1 pm/am. Additional updates will be issued as needed.

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