Alton, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

898
FXUS66 KEKA 270650
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1150 PM PDT Thu Jun 26 2025

.SYNOPSIS...Hot and dry weather will peak this weekend with highs
near 100 for the interior. Warm and Sunny weather will even approach
the coast by Sunday. There is a chance for scattered thunderstorms
over the interior early next week.


&&

.DISCUSSION...In the short term, high pressure will
continue to build across the area into the weekend. High
temperatures will march upward each day, peaking on Sunday with
highs around 100 across most interior valleys. At least on Sunday,
the potential for highs above 100 is very high (over 90%), but
probabilities drop quickly for higher temperatures with less than 10
to 20% chance of highs hitting 105 for most valleys. This level of
heat correlates to a minor or moderate risk of heat related illness.
Everyone is encouraged to limit their outdoor activity during the
heat of the day. For the coast, a marine layer (already evident all
along the coast early this morning) will keep conditions cool at
least on Friday. But offshore flow will gradually build this
weekend, promoting unusually warm and clear daytime conditions along
the coast. Saturday and especially Sunday, NBM places a 70 to 90%
chance of highs over 70 in Arcata and McKinleyville.

High pressure will gradually break early next week as low pressure
skirts just south of the area into the Central California Coast.
Breaking high pressure will help to decrease highs back into the 90s
and pull more marine influence back along the coast, though offshore
wind will most likely keep marine influence shallow and sporadic
Monday and Tuesday. Global ensembles show a strong and consistent
signal that the low will also help enhance midlevel instability and
pull in some moisture from the south, likely helping to produce
isolated to scattered thunderstorms. Early convection models show a
very weak signal (10% chance) of isolated nocturnal thunderstorms
early Monday morning. Any storms that form overnight would likely
push to the coast form the east. There is much higher confidence
(30% chance) of isolated to scattered thunderstorms over the
interior Monday and Tuesday, mostly concentrated over high terrain
during the peak heat of the afternoon. Meager moisture and dry low
level conditions would likely encourage storms to be mostly dry.
Beyond storms, there is high confidence that the general pattern
next week will remain warm, dry, and benign. /JHW


&&

.AVIATION...06Z TAFs...Nighttime satellite imagery depicts the
marine layer and stratus pushing onshore as a weak shortwave trough
moves through. Mainly MVFR conditions is expected along the coastal
terminals overnight. High-res model guidance suggest low clouds
eroding back to the coast Friday morning with the diurnal heating.
For the coastal terminals, expect VFR conidtions after 16Z with low
clouds mixing out by late morning and afternoon as a high pressure
begin to builds in and promote increasing NNW winds along the coast.
Meanwhile, VFR conditions will prevail in the interior and UKI.
Surface winds light and variable, after 16Z becoming NNW at 10-15
kts with gusts ranging from 20-25 mph. /ZVS


&&

.MARINE...Northerly winds will accelerate by late morning and
afternoon, with strongest winds south of Cape Mendocino as a high
pressure begin to builds in and a thermal trough develop near the
coast. These will favor moderate to strong pressure gradient. Winds
will steadily increase into Saturday, with widespread sustained
strong to near gale force winds and steep seas. Gusty northerly
winds up to around 40 kt across the southern waters. A Gale Warning
is in effect this afternoon through late tonight for the zones 455
and 475. This gales will propagate in a burst of very steep seas
into the northern inner waters Tuesday evening through late
Wednesday afternoon. Have to hoisted a Hazardous Seas Warning for
zone 450 as result.

This weekend, gale conditions will spread into the northern outer
waters Saturday afternoon through Sunday. Steep seas are expected to
propagate into the northern inner waters Saturday afternoon. A Gale
Watch remain in place for the northern outer waters on Saturday
afternoon through Sunday. With a tightening pressure gradient early
next week, conditions will remain hazardous with strong to gale
force northerly wind gusts and steep to very steep seas across the
coastal waters through much of the upcoming week. /ZVS


&&

.FIRE WEATHER...Hot and dry conditions will build into the weekend
with highs near 100 and minimum RH in the mid teens. RH recovery is
currently very good around 80% or more at low elevations, but it
will gradually worsen to closer to 50% and subsidence inversions
strengthen and lower through the weekend. Thankfully, winds are
mostly diurnal and terrain driven with only short lived gusty
conditions each afternoon.

Low pressure skirting the area will help slightly ease temperature
and RH early next week but will also bring as chance of scattered,
mostly dry, thunderstorms. There is a very weak indication of
isolated storms forming overnight early Monday morning, most likely
over the interior and then moving east towards the coast. There is a
much stronger signal of thunderstorms forming over high terrain
during the afternoon on Monday and Tuesday (30% chance). Any storms
would be mostly try posing a risk of new fire starts. /JHW


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 2 PM PDT Friday for PZZ455.

     Gale Warning from 2 PM to 11 PM PDT Friday for PZZ455.

     Small Craft Advisory from 11 PM Friday to 2 PM PDT Saturday
     for PZZ470.

     Gale Watch from Saturday afternoon through Sunday morning
     for PZZ470.

     Small Craft Advisory until 1 PM PDT Friday for PZZ475.

     Gale Warning from 1 PM Friday to 3 AM 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