Resighini Rancheria, California Weather Forecast Discussion

914
FXUS66 KEKA 292121 CCA
AFDEKA
AREA FORECAST DISCUSSION...CORRECTED
National Weather Service Eureka CA
221 PM PDT Mon Sep 29 2025
.SYNOPSIS...Widespread rain is forecast to end by late evening. A
few showers will remain possible overnight. Another front will bring
additional rain and strong gusty southerly winds Tuesday afternoon
through Tuesday night. Lingering showers on Wednesday will
diminish on Thursday. Dry weather is expected Friday through the
weekend.
&&
.DISCUSSION...A cold front has been moving across Northwest
California today. Heaviest rain so far has been in coastal Del
Norte where automated gages recorded 1.27 to 1.41 inches in the
last 12 hours. Meanwhile, for southern Mendocino and Lake, no rain
or only a few hundredths has occurred thus far. The frontal
boundary is forecast to steadily track east and south this
afternoon and evening, providing greater amounts of rain for
Mendocino. Lake and Trinity. For estimated storm total rainfall
with this first round and second round of rain, see the rainfall
graphic we posted on facebook and on our web page.
Lightning detection network indicated a few strikes offshore SW
of our coastal waters this morning. HREF probabilistic guidance
continues to show the highest chance for elevated convection
this afternoon and evening across southern Humboldt, Mendocino,
Lake and Trinity Counties. Otherwise, satellite imagery showed a
"clear slot" offshore the North Coast behind the frontal boundary
this afternoon. A few convective cells were still evident behind
this "clear slot" as well. Thus precipitation intensity and
coverage will wind down this afternoon and evening for Del Norte
and Humboldt Counties, but continue into mid to late evening for
Trinity, Mendocino and Lake.
Previous discussion, Tuesday the next cold front is expected to
move onshore bringing more wind and rain. The rain is generally
expected to hold off until the afternoon. Overall this second
system is expected to have less rain and more wind as it moves
onshore. The strongest winds are expected to move onshore in the
evening. The NAM is showing 850 MB winds of 30 to 40 kt over
Humboldt and Del Norte counties. This will likely bring some 40
mph gusts to higher terrain of these areas. The low levels remain
fairly dry and unstable along the coast so these areas could see a
few gusts to 40 mph or even 45 mph in Crescent City. So have
decided to issue a wind advisory, for now have confined it to Del
Norte county, but it may need to be expanded. Rainfall amounts are
expected to be fairly light with this second front. This will be
especially true in areas in the lee of the mountains, notably the
Humboldt Bay area. Most areas are expected to see less than a half
inch with the exception of a few mountainous areas of Humboldt
and Del Norte counties.
Wednesday may see some lingering showers around the area, but in
general not much rain is expected. Winds are also expected to
diminish. There is still the potential for a thunderstorm or two,
but confidence is low on this with poor lapse rates aloft.
Wednesday night if there is some clearing aloft many of the
valleys are expected to see widespread low clouds and fog.
Thursday there may be a few lingering showers in the morning, but
generally dry weather is expected.
Friday and into the weekend high pressure is expected to start
building into the area. This will bring a return of high
temperatures in the 80s in the warmer inland valleys. Some of the
colder valleys of Trinity could see their first frost of the
season. This will depend on which nights manage to stay clear and
dry. Hayfork dropped to 40 degrees Saturday morning so with a
slightly cooler and drier airmass it could easily drop into the
low 30s. Sunny weather is possible along the coast with offshore
flow returning as well. MKK
&&
.AVIATION...A frontal passage this morning is creating oscillating
categories. IFR is expected through early afternoon with low clouds,
variable rain strengths, and degraded visibilities. Strong winds
aloft will be present  Conditions to improve this afternoon with
models showing only a 30% probability for IFR this evening (06Z-12Z)
along the North Coast and a 10-20% probability for MVFR this evening
inland. Strong winds aloft forecasted for 1.5-2 kft AGL beginning in
the morning (~15Z) before another cold frontal passage later in the
day tomorrow. Strong winds at coastal headlands and in terrain are
expected, leading to the potential for low level turbulence
tomorrow.
&&
.MARINE...Southerly winds across the area waters will diminish this
afternoon in the wake of a cold front passing overhead. Wind waves
have increased slightly, yet the quick moving nature of this front
has kept any substantial growth of occurring. This leaves a mixed
sea state with steep, short-period, southerly wind waves mixing with
a mid-period NW swell.
This afternoon, the winds are expected to diminish quickly behind
the frontal passage. This lull will be brief, only about 18-24 hours
or so, before another cold front swings down to our area Tuesday
morning. The cold front will follow the usual pattern of southerlies
ahead of the front, a NW swell, and southerly wind waves. Winds for
this second system are expected to peak around 30-35kts, especially
in the northern waters near Cape Mendocino. A Gale Warning has been
issued for the northern waters from midday Tuesday until around dawn
on Wednesday. More hazards are possible as increased high resolution
data becomes available this afternoon.
Southerly winds are expected to continue on Wednesday and Thursday
with models still confirming a large NW swell entering the coastal
the waters. GlobalWaveWatch shows this swell building into a large
steep "square wave" of 12-13 feet around 12-13 seconds. If this
materializes, this would be the first large swell of the fall. The
beaches generally still have their shallower summer slopes allowing
larger than expected breakers with it. Breakers may exceed 16 feet
Wednesday night into Thursday morning. DS
&&
.FIRE WEATHER...Widespread wetting rain is expected to end this
overnight. Strong and gusty southerlies in advance of a second
frontal system will build during the day on Tuesday before the
bulk of rain with the next frontal wave arrives during the
afternoon and evening hours. Confidence in thunderstorms remain
low at this time, however highest chance this evening will be
across southern Humboldt, Mendocino, Lake and Trinity Counties.
Drier conditions and northerlies are expected to return Friday
through the weekend. There is still variability and uncertainty
with the trajectory and depth of a cold upper level trough expected
to plunge southward over the weekend. This trough will most likely
induce brisk offshore flow and drying over the weekend.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Wind Advisory from 11 AM Tuesday to 1 AM PDT Wednesday for
     CAZ101-102-104>106.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Gale Warning from 11 AM to 11 PM PDT Tuesday for PZZ450.
Gale Warning from 11 AM Tuesday to 3 AM PDT Wednesday for
     PZZ470.
&&
$$
NOTE: The full forecast discussion is now regularly issued between
10 am/pm and 1 pm/am. Additional updates will be issued as needed.
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

NWS EKA Office Area Forecast Discussion