053
FXUS66 KEKA 081325 CCA
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
544 AM PDT Mon Jul 8 2024

.SYNOPSIS...Very hot and dry weather will continue in the
interior all week. A shallow marine layer will result in cooling
and periods of fog for coastal areas today through Wednesday.

&&

.DISCUSSION...Extreme to major heat risk is forecast to continue
across most of Trinity, eastern/southeastern Mendocino,
northeast/eastern Humboldt, eastern Del Norte and northern Lake
counties today. Otherwise, heat risk is forecast to remain low to
moderate. Upper level ridging will continue to weaken and shift
eastward today through Tuesday as a shortwave trough approaches from
the west. Interior temperatures will trend down on Tuesday, but it
will remain hot for much of the interior with 850mb temperatures
well above normal; 25 to 30C. Excessive heat warnings and heat
advisories remain in effect for today. Another record high
temperature at Ukiah Municipal Airport is not forecast today. The
record for Ukiah today is 110F and we are forecasting 106F. Also,
with a shallow marine layer, expect considerably cooler coastal
temperatures with fog potentially hugging the coastline through the
day.

Upper ridging and offshore flow will return on Wed and interior
temperatures will once again be on an upward trend through Thu.
Extreme to major heat risk will once expand and another warning
or advisory may be necessary, especially for Trinity, Lake and
interior Mendocino. Depending the strength of the offshore flow
Wed and Thu, coastal areas may also warm back up. Confidence is
not high with the NBM forecast for coastal areas.

The heat will last into Friday and Saturday before abating on
Sunday. The relief is not forecast to be very dramatic with highs
in the mid 90`s to around 100F forecast on Sunday. A trough or
semi-closed low will approach over the weekend. National Blend of
Models (NBM) indicates interior temperatures remaining above
normal Sat and Sun; generally in the 90`s except 100-105F in
Trinity and NE Humboldt. The trough should induce a deeper marine
layer as well as stronger diurnally driven winds in the interior.
NBM mean indicates gusts from 15-20 mph with 90th percentile
gusts up to 30 mph. And minimum RH`s will probably remain critically
low; 10-20%. Potential for thunderstorms during the weekend
remains very low with ensemble mean PWATS below normal across NW
California forecast area. NBM 12 hour probabilities are also quite
low (no more than 9%) across the mountains of NE Trinity Sat and
Sun. This will need to monitored. Main impact from this trough
over the weekend appears to be "cooling" and gustier diurnally
driven winds in the interior. DB

&&

.AVIATION...A narrow band of stratus along the coast is bringing
flight categories to LIFT/IFR this morning as conditions favor fog
development but mostly it is advecting marine stratus that will keep
KCEC and KACV socked in at the coast until after sunrise. Light to
calm winds along with a near shore wind reversal, has further
enhanced the low cloud and fog development at KACV and more recently
at KCEC. Low level moisture appears to be persistent in the model
soundings with a bit of relief this afternoon but returning this
evening and deepening overnight into Tuesday. KUKI has a much drier
profile and will have prevailing VFR conditions. Northerlies will
build in the afternoon at KUKI. /EYS

&&

.MARINE...Northerly winds and waves expected to continue with SC.Y
conditions in the outer waters downwind of Port Orford and Cape
Mendocino, stronger gusts 25-30 knots possible within the inner
waters in the lee of the Cape. Square 6-7 foot wave response
expected through Tuesday in the southern outer zone PZZ475 with
conditions in the northern outer zone PZZ470, diminishing this
morning. Expect Gale force conditions to develop Wednesday for both
northern and southern outer waters as gusts build to 40 knots and
steep square waves developing in response to wind and wave action.
/EYS

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Heat Advisory until 8 PM PDT this evening for CAZ102-104-
     106-112.

     Excessive Heat Warning until 8 PM PDT this evening for
     CAZ105-107-108-110-111-113>115.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT this morning for PZZ470.

     Small Craft Advisory until noon PDT Tuesday for PZZ475.

&&

$$

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