Trinity Center, California Weather Forecast Discussion

345
FXUS66 KEKA 092014
AFDEKA
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
114 PM PDT Tue Sep 9 2025
.SYNOPSIS...Periods of rain and thunderstorms are forecast to
continue today through Wednesday. Locally heavy rain will be
possible with storms in the interior each day. Drier weather will
be possible toward the end of the week, followed by another
chance of rain during the weekend.
&&
.DISCUSSION...A nearly vertically stacked area of low pressure
remains off the coast this afternoon. Over the next 24 hours this
is expected to move gradually to the south and east. This will
keep the clouds around as well as showers and a few thunderstorms.
The question will be how much sunshine and afternoon heating there
will be before the showers and thunderstorms get started. Today
these showers are expected to be the strongest and most widespread
in Trinity and eastern Del Norte and eastern Humboldt counties.
There is still some uncertainty on how much lightning there will
be with these storms. The lapse rates aloft are under 6C/KM and
this may limit the convection despite having around 400 j/kg of
CAPE. These showers and thunderstorms are expected to produce
locally heavy rain. The HREF is showing over a 70 percent chance
of 1 inch in 3 hours in N. Trinity county.  Today it looks like
the shower and thunderstorm may be limited in Mendocino and Lake
counties.
Tonight there may be a few showers along the coast, but these may
be fairly limited. Wednesday the showers are expected to be mainly
over the inland areas. The models are showing around 500 j/kg and
lapse rates remain under 6c/km in the upper levels. This makes the
CAPE fairly skinny and may limit the thunderstorm potential.
Locally heavy rainfall is expected again with these showers. The
HREF probabilities of over 1 inch in 3 hours moves farther south
into NE Mendocino county and northern Lake county. Temperatures
are expected to be fairly similar to today.
Thursday high pressure starts to build into the area and this will
limit the potential for convection. A few showers are possible in
the far eastern mountains from Trinity county down to Lake county.
There may be fairly widespread fog Thursday night into Friday
morning. Dry weather and clearing skies are expected Friday.
For the weekend it looks like there will be another weather
system bring some more rain to the area. There is still quite a
bit of uncertainty on how quickly this will occurs. The GFS keeps
Saturday dry and brings the rain in on Sunday. The ECMWF is
slightly faster and brings in precip Saturday night. The NBM puts
pops in starting Saturday afternoon, but only a fairly low chance
with higher chances early Sunday. This may also bring some chances
for thunder as well. MKK
&&
.AVIATION....A closed, low-pressure, cyclonic circulation is
spinning about 100 miles off the coast of Cape Mendocino. The low
has brought bouts of showers and multiple cloud levels creating
mostly IFR/MVFR categories and calm, variable winds. For coastal
sites, model guidance shows around a 40% probability of IFR
conditions (ceilings 

NWS EKA Office Area Forecast Discussion