237
FXUS66 KEKA 062021
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
121 PM PDT Fri Jun 6 2025

.SYNOPSIS...Warmer temperatures inland this weekend. A slight
chance of thunderstorms over the Klamath Mountains and the Yolla
Bollas on Sunday, Monday, and Tuesday afternoons. Windy afternoons
return to NW California by the middle of next week.


&&

.DISCUSSION...An upper level High pressure pattern continues to
develop over the CWA, with a very distinct ridge forming over the
PACNW and Canada by Saturday. This will usher in a transition
to a much warmer regime with 850mb showing a broader expanse of
heat into the four corners on Sunday and expanding to the Great
Basin into late Sunday afternoon, repeating this diurnal trend
Monday and into mid week. Inland valleys are expected to crest
above 100F with Big Bar off CA299 having a 30% probability of over
110F on Monday afternoon. Marine air intrusion via the Russian
river valley due to southerly winds will probably keep southern
Mendocino County from getting above 100F this weekend. However, it
will still be hot, and we will continue to message heat and river
safety rips in weather story graphics.

A semi-closed low aloft (700-500mb) is forecast to bring an increase
in mid level humidity and E-SE flow Sat-Sun. GFS has trend with
higher CAPE and instability over NE Trinity mountains as early as
Sat, however the soundings look super dry in the lower atmosphere.
Convective parameters for storms increase on Sunday and more so on
Monday per the GFS model. It will still be really dry in the lower
atmosphere and with 100F degree heat bubbling up in afternoon a few
updrafts could break through the mid level stable layer. Once
convection begins the storms may spread NW into Del Norte County
Sunday night into Monday morning. Forecast confidence remains low
for this event due to the minimal forcing for the potential storms.

Mid level cyclonic circulation is forecast to slowly meander across
the area early to mid next week. Moisture does not look to be in
abundant supply. Main impacts appear to be CG strikes and gusty
outflow winds given inverted-V profiles indicated by the GFS model.
NBM 12hr thunderstorm probabilities are sitting around 10-20% for
this weekend into early next week.

The potential for more storms on Tue. diminishes, however models
continue to struggle with the rate of progression of a semi-closed
low and another upstream shortwave trough in the westerly flow. Thus
storm chances seem on the fringe of possibilities in far NE Trinity
on Tue. Brief ridging on Tue may be followed by a deeper trough Wed
and Thu next week. This trough looks quite dry and main impacts
appear to be a return of stronger gusty winds.



&&

.AVIATION...Stratus remains persistent at the coastal terminals
early this afternoon. Conditions have largely remained LIFR, but
some lifting to IFR and partial clearing is possible late afternoon.
Stratus will likely fill back in later this afternoon and overnight.
LIFR ceilings and visibilities are once again possible at the
coastal terminals. Skies clearing on Saturday is uncertain: NBM is
showing around a 50% chance for CEC and ACV to be cloudy all day
Saturday. Ukiah also saw stratus advect northward this morning,
which is possible again tonight. Southerly winds and a deeper marine
layer do suggest MVFR or IFR ceilings are possible at UKI, but these
will once again lift and clear by late morning. JB


&&

.MARINE...Northerly winds have largely eased outside 40-60 nm into
the coastal waters. Nearshore, winds are largely southerly as eddies
spin offshore. Seas remain steep and hazardous to small crafts, but
these gradually ease as winds remain light this weekend. Sunday both
winds and seas are forecast to be mild, though stratus will likely
create foggy conditions in the morning and evening. Northerly winds
gradually pick up again next week, with winds of 20-25 kts possible
by Tuesday, and gales possible by Wednesday. JB


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PDT this afternoon for
     PZZ450.

     Small Craft Advisory until 3 PM PDT Saturday for PZZ470-475.

&&

$$

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