439
FXUS66 KEKA 042018
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
118 PM PDT Fri Jul 4 2025

.SYNOPSIS...Temperatures will generally trend warmer through
Monday. A trough will bring slightly cooler temperatures Tuesday
and Wednesday with many areas warming over 100 late in the week.

&&

.DISCUSSION...AN upper level trough moving through the area has
brought some changes to the weather. The most noticeable is likely
the cooler temperatures. Highs are only in the upper 70s to low
80s in the warmest areas with cooler temperatures closer to the
coast. The deep marine layer has allowed clouds to linger into the
afternoon in areas well inland from the coast in Humboldt and Del
Norte counties. At the immediate coast there has been some
clearing from the west. Tonight the valley and coastal clouds are
expected to be widespread again across much of Humboldt and Del
Norte counties even stretching into southern Trinity and northern
Mendocino counties. With the deep marine layer fog is not expected
at the coast this evening. Winds are breezy this afternoon,
especially across Lake county.

For the weekend high pressure is expected to build back into the
area for the weekend and into Monday. Temperatures will quickly
return to seasonal normals normals Saturday with highs around 90
in the warmer inland areas. The deep marine layer will keep the
near coastal areas cooler, but not as cool as today. Additional
warming is expected Sunday with highs in the 90s in most areas.
This will likely be the warmest day near the coast and the
sunniest. Monday additional warming is expected, but the marine
layer may start to return and be more persistent along the coast
as an upper level low starts to approach the area.

Late Monday or Tuesday the upper level low approaching the coast
has the potential to bring some thunderstorms to the area, but
there is still a lot of uncertainty on the location of this low
and the potential for thunderstorms. This potential could
continue into Wednesday For now have left the thunderstorms out of
the forecast as it looks like the better chance will be north of
the area. This will definitely need to be watched as it gets
closer.

Thursday and Friday high pressure strengthens over the area and
most inland valleys are expected to see high temperatures near or
slightly above the 100 degree marks. This will increase the heat
risk. MKK

&&

.AVIATION...Overcast MVFR ceilings have remained lifted 2000 to 3000
feet along the north coast after weak upper shortwave deepened the
marine layer. HREF probabilities suggest that cloud cover will
struggle to scatter out this afternoon as winds diminish along the
coast. Otherwise, WNW flow will continue through the evening with
gusts 10 to 15 knots possible at the coastal terminals. UKI expected
to more breezy conditions with afternoon with gusts 15 to 25 knots
possible around 00Z. Stratus expected to redevelop along the coast
with IFR to LIFR ceilings and viz overnight. Hi-res models indicate
potential for light mist or drizzle around Humboldt Bay by sunrise
Saturday (20 to 50%).

&&

.MARINE...Moderate to fresh breezes will continue in the outer waters
through Friday as a long period southwesterly swell fills into the
waters, with locally stronger gusts nearshore and downwind of the
Cape. Northerlies are expected to strengthen again late Saturday
into early next week as high pressure builds back into the region,
with gusts 20 to 30 knots developing in the outer waters late
Saturday night into Sunday morning. Models have consistently shown
winds strengthening to near gale with gale gusts Sunday afternoon
into Monday (NBM 50 to 70% chance) in the northern outer waters.
There still exists some model spread in potential coverage spreading
further south into Z475. Steep and hazardous wind waves 9 to 12 feet
are forecast to develop in response to these winds, potentially
propagating into the northern inner waters briefly.

&&

Fire Weather...High temperatures are forecast to warm over the
weekend into early next week while minimum RH`s become drier.
Overnight recoveries are generally expected to remain good except
for a few exposed ridges where low RH`s may persist through the
night.

An upper level low is expected to approach the area Monday and
this poses a low risk for convection. At this point it looks like
the better chances for thunderstorms will be north of the area,
but this will need to be watched as it gets closer.

The upper level low is forecast to finally eject N-NE by mid next
week as a massive ridge over the four corners region expands over
the area. Much hotter temperatures and drier humidity are highly
probable (80% chance) in the interior late next week.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until noon PDT today for PZZ455.

     Small Craft Advisory until 10 PM PDT Saturday for PZZ475.

&&

$$

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