244
FXUS66 KEKA 032157
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
257 PM PDT Fri May 3 2024

.SYNOPSIS...A cold front will move across the area this evening
through early Saturday morning bringing a period of heavy rain.
Brief heavy wet snow is also expected above 2500 feet early
Saturday morning. Colder air will settle over the area for Sunday
and persist through the middle of next week bringing near freezing
and freezing temperatures expected for the interior valleys
during early morning hours.

&&

.DISCUSSION...Satellite shows the unseasonably strong cold front
off the coast this afternoon. Rain is expected to start in
Crescent City between 3 and 4 pm and move south with it expected
to make it to Eureka around 7 pm or so. Moderate to heavy rain is
expected with this front with widespread 1 to 3 inches across the
area. The mounts of Humboldt and Del Norte counties show up to 4
inches while the valleys of southern Lake and eastern Trinity
counties may only see around a half inch. Snow levels are expected
to fall rapidly as this front moves in and are expected to be
around 2,500 to 3,500 feet by Saturday morning. The lowest levels
are expected to be in Humboldt and Del Norte counties. This will
likely bring several inches of snow above the snow level. With the
warm ground temperatures and high sun angle this is expected to
melt fairly quickly on Saturday. The winter weather advisory
remains on track. Saturday afternoon showers and possibly
thunderstorms are expected. There is a lot of cold air aloft with
500 mb temperatures dropping to -32. This has the potential for
some instability to develop if skies clear, but this is uncertain.
There is still around a 15 percent chance for thunder.

Saturday night the precip comes to an end and it has the potential
to be a cold night. The temperatures at 850MB are only around -3C.
This could bring freezing temperatures as low as 2,000 feet even
if skies remain cloudy and there isn`t any radiational cooling.
Any valleys that do clear out could see temperatures drop below
freezing. Sunday afternoon temperatures will remain well below
seasonal normals with highs likely remaining in the 50s in the
most areas. A freeze watch may be needed in Trinity, but there is
currently a winter weather advisory in place in many of the areas
that will potentially see freezing temperatures so have held off.

Sunday night and Monday a short wave and associated cold front is
expected to bring more light rain and additional clouds,
especially in the north. Rainfall amounts have increased with this
system in Del Norte county amounts are now close to a half inch.
This will likely leave lingering moisture that develops into low
clouds or fog in the north. This is expected to keep the northern
the northern areas from getting as cold, although Mendocino and
Lake counties could see freezing temperatures. Tuesday and
Wednesday will likely see more clearing skies allow more
radiational cooling, however warm advection will be warming
temperatures aloft each day. Frost or freezing temperatures are
possible both nights, although there is still uncertainty on the
locations. Thursday and Friday the models show high pressure
building back into the area with Ukiah, Lakeport, and surrounding
areas getting back into the 80s. Friday Lakeport has a 35 percent
chance of exceeding 85 degrees. MKK

&&

.AVIATION...A brief period of IFR level stratus moved over ACV
this morning. Otherwise, prevailing cloud/visibilities into mid-
afternoon have been VFR low-mid Cigs. Prefrontal conditions are
forecasted to slowly dip down to MVFR, then IFR this evening. The
cold front will arrive this evening preceded and accompanied by
periods of moderate to heavy rain...which will definitely impact
ACV and CEC`s flight operations. Just ahead of the front, there is
a minimal threat of LLWS at CEC, but the main concern will be
increased surface wind gusts this evening along the coast. Rain
should taper Saturday morning and become more shower; Cig/Vis will
be on the rise also. Note: Flight hazard: snow could impact air
operations across the interior higher terrain. /TAA

&&

.MARINE...Winds will continue to become southerly and increase
ahead of an approaching frontal passage. Gusts 15-20KT will
develop first in the northern waters along the frontal boundary
late this evening into early Saturday morning, quickly turning
W/NW behind the front. Gusty NW winds will become confined to the
southern waters amidst scattered convective showers Saturday
evening. Steep wind wave response expected late Saturday through
Sunday as lingering showers dissipate. Combined seas are forecast
to be 6-7 feet with 7-9 second periods through the weekend before
a long period NW swell fills in early next week. Strong
northerlies combined with another steep NW swell mid week may
produce combined seas exceeding 10 feet.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Winter Weather Advisory from 4 AM to 11 AM PDT Saturday for
     CAZ102-105>108-111.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 9 PM this evening to 3 AM PDT
     Saturday for PZZ450.

     Small Craft Advisory from 9 PM this evening to 9 AM PDT
     Saturday for PZZ470.

     Small Craft Advisory from 3 AM to 9 PM PDT Saturday for
     PZZ475.

&&

$$

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