794
FXUS66 KEKA 171221
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
521 AM PDT Tue Sep 17 2024

.SYNOPSIS...Another round of light rain showers is expected
to spread across the area from north to south starting this
afternoon in Del Norte county and working south tonight and
Wednesday. A drying and warming trend is expected late in the
week.

&&

.DISCUSSION...This morning the water vapor shows on upper level
low moving out of the area and the next one approaching the area.
The models are now in fairly good agreement on this low dropping
down just off the west coast. It looks to pass by the area
Wednesday morning. With the low remaining off the coast this will
keep the threat for thunderstorms off the coast until Wednesday
afternoon in Mendocino and Lake counties. The low will be passing
by near or shortly before peak heating bringing a slight chance
for thunderstorms across Mendocino and Lake counties. PWATS are
nearly an inch so any storms that do form will likely has some
rain with them. CAPE in the NBM is around 100 to 300 j/kg which
would be enough to generate a few thunderstorms. The models have
continued to trend lower on the rainfall amounts.

Rainfall amounts in Humboldt and Del norte counties are expected
to range from close to a half inch in the mountains of Del Norte
county to less than a tenth of inch in southeastern Humboldt
county. Farther south and east most areas will see a trace to a
tenth of an inch, although locally higher amounts are possible if
any thunderstorms develop. There is still quite a bit of
uncertainty on this with the rainfall amounts with the 75th
percentile peaking near 1.5 inches in Del Norte county. The 25th
percentile shows less than a tenth of an inch in any location.
Models are also in fairly good agreement that in most areas this
rain will hold off until very late in the afternoon Tuesday,
although Del Norte county could see rain as soon as early
afternoon. This low will also bring cooler temperatures in the
inland areas with highs mainly in the low to mid 70s.

Wednesday night the low moves south and out of the area fairly
quickly. This is expected to bring offshore flow that may keep
the coastal areas clear. Inland areas could see some frost in the
coldest spots, especially if there is little to no rainfall to
help generate low clouds. Thursday highs are expected to rebound
into the mid 80s with upper 80s to low 90s for the weekend. The
current NBM shows these temperatures continuing into early next
week. MKK

&&

.AVIATION...A variety of clouds have formed along the coast ahead
of an incoming moist cold front. Degraded conditions (mostly IFR,
possibly becoming LIFR this evening) are expected along the coast
for the next 24hrs due to low ceilings, reduced visibilities, and
occasional rain/drizzle. The threat of precipitation is currently
forecasted to maximize from 01Z-04Z this evening at both KCEC and
KACV. Winds are not expected to be stronger than slight breezes
(<10kt) due to minimal atmospheric forcing at the surface, and it
seems southerlies/south-westerlies will prevail for most of the
forecast period along the coast. Inland, mid-level clouds (~5kft
AGL) are forecast to cover the KUKI area, yet conditions should
remain VFR.

&&

.MARINE...Hazardous conditions for small craft across the coastal
waters are expected through this morning. Northerly winds and
seas will continue to gradually diminish and subside through today
due to weaker winds over the waters. These winds are expected to
become light westerlies to northwesterlies through the morning as
a cold front approaches and arrives this afternoon. Wet,
unfavorable weather conditions are expected this early evening
through Wednesday afternoon. Isolated thunderstorm activity and
erratic gusty winds are forecasted to accompany this incoming cold
front. After this systems passes through our area, northerly
winds are expected to return and increase into Thursday,
especially across the outer waters. Gust up to 30 kts are
forecasted from Thursday into Friday. These winds will generate
steep, potentially hazardous seas Thursday through Saturday.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 9 AM PDT this morning for PZZ450-
     455-470-475.

&&

$$

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

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