ca discuss
Office: EKA
FXUS66 KEKA 080829
AFDEKA
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
1229 AM PST Mon Dec 8 2025
.SYNOPSIS...Cloudy and misty conditions for Del Norte and Humboldt
counties tonight. Generally dry weather conditions and a warming
trend are expected to prevail across NW CA this coming week, with
periods of light rain/drizzle for the North Coast.
&&
.DISCUSSION...A stubborn high pressure center off the CA/Mexican
coast is keeping the synoptic storm track pointed at the northern
PacNW of CONUS. As these storms impact OR and WA, the moisture will
occasionally clip the North Coast, specifically Del Norte & northern
Humbodlt counties. The increased atmospheric moisture will create
fog and low clouds along the coast and in the inland valleys
overnight. The inland cloud coverage is forecasted to burn off
quickly in the valleys.
A warm frontal passage forced between ~0.1-0.2" of precipitation to
fall in northern Del Norte Co. yesterday. The next frontal passage
is forecasted to be late tonight into Tuesday. The warm front from
yesterday will interact with an incoming cold front creating a
stationary boundary over the CA/OR boarder. Most of the forcing for
this next system will remain to the north with stratiform light
rain/drizzle possible through Tuesday. Del Norte will likely
experience at least a handful of hundredths of an inch of
precipitation through this event, and Even less precipitation is
expected for Humboldt north of the Bay.
The previously mentioned ridge of persistent high pressure
responsible for blocking stronger weather systems will strengthen
and expand eastward through the week. With this synoptic shift,
expect significant warming inland. The current forecast yields high
interior temperatures reaching 10-20 degrees above climatological
normal midweek through the weekend as the warming high pressure
expands overhead. NBM data shows high probabilities of ~70-80% & 80-
90 for the warmer interior valleys to exceed 70F Thursday and
especially Friday, respectively. When looking at NBM probabilities
for 75F, the Ukiah area shows probabilities of ~20% and ~30% for
Thursday and Friday, respectively. This would likely break the high
temperature record of 72F from 1958 for Ukiah on Friday if the
forecast holds.
Some ensembles are indicating a weather pattern change next weekend.
There is still a great deal of variability, due to the uncertainty
in how quick the ridge weakens, but some (~15%) of the ensemble
members show the possibility for >1" of 24 hour rainfall by Sunday/
Monday next week. As of right now, next weekend is still quite far
into the future for any true meaning to be applied to the forecast.
DS
&&
.AVIATION...(06Z TAFS)...General overcast skies will continue for
coastal terminals. In general, MVFR ceilings will continue around
the Del Norte coast with the possibility of IFR/LIFR conditions by
early to mid Monday. Some light drizzle/rain could still be a
possibility for mostly the Del Norte Coast into early Monday, as
well. Coastal terminals in the vicinity of Humboldt Bay are forecast
to remain in the IFR/LIFR range into late Monday morning. Some
interior valleys could see stratus and fog into early Monday
morning, but confidence is low on UKI seeing any. There is a
possibility for general lifting or slight clearing of ceilings for
coastal terminals; however, IFR/LIFR conditions are expected again
by Monday evening. /JLW
&&
.MARINE...Generally light winds are forecast through at least the
middle of this week, with south winds forecast north of Cape
Mendocino and west-northwest winds forecast south of the Cape. A mid
period northwest swell has peaked and continues to decay. Seas
subside into early Monday as this swell decays. Another mid-period
northwest swell will fill in Monday afternoon and evening, peaking
at 7-9 ft at 13 seconds by Tuesday. Combined seas may briefly reach
or exceed 10 ft Tuesday. Additional mid-period northwest swells will
continue to fill in through the week. JB
&&
.BEACH HAZARDS...A low to moderate threat of sneaker waves is
expected for the Del Norte, Humboldt, and Mendocino coastlines
late this week. A mid-period westerly swell generated by a storm
currently ~500mi south of the Aleutian Islands will enter the
coastal waters early Thursday morning. A lack of local wind waves
will allow this swell to dominate the sea state, creating beach
conditions that could look deceivingly calm. Forecast confidence
will grow in time as NDBC data becomes available for observations
closer to NW CA as the swell passes midweek. Remember to never
turn your back to the ocean, and to avoid steep beaches, jetties,
outcroppings, and rocks during these events. DS
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&
$$
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
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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png
Office: HNX
FXUS66 KHNX 072329
AFDHNX
Area Forecast Discussion
National Weather Service Hanford CA
329 PM PST Sun Dec 7 2025
.UPDATE...
&&
&&
.KEY MESSAGES...
1. Fog and low clouds will continue each night and morning across
the San Joaquin Valley into this week. Dense fog will also
develop at times in the lower Sierra foothills, coastal ranges,
and the Grapevine.
2. A gradual warming trend will occur in the mountains and
desert until next week, as the high pressure pattern continues
over the region.
&&
.DISCUSSION...
Conditions today remain in a "rinse and repeat" pattern, with
low clouds spanning across the San Joaquin Valley and areas of
fog and reduced visibilities in the foothill areas where these
clouds encounter the local terrain. This pattern comes as the
result of a strong temperature inversion extending to 6000 feet
above ground level which is trapping saturated air between 1000
and 2000 feet. In fact, the warmer temperatures are anomalously
warm for this time of year, running around five degrees celsius
above average. Without warmer temperatures and/or drier
conditions at the surface, or increased winds to mix out the low
clouds, our valley stratus will look to continue at least
through midweek.
As the mid to late week period approaches, the high pressure
ridge over the eastern Pacific driving our stable conditions is
projected to slide eastward, based on current ensemble
forecasts. This pattern change is expected to cause increasingly
anomalous temperatures, especially for the Sierra Nevada and
surrounding foothills, and in the Kern County Desert.
Probabilistic guidance shows areas including Lake Isabella,
Oakhurst, and Yosemite Valley have more than a 90 percent
probability for maximum temperatures to exceed 70 degrees this
coming Friday, when these locations average 50 to 60 degrees. It
will remain to be seen what this system does for the San
Joaquin Valley. Warmer temperatures caused by the ridge will
bring afternoon highs nearer to season averages, which could
lead to clearing conditions during the day, however the
subsidence aloft caused by the high pressure would keep moisture
trapped in the lower levels. These warm and dry conditions are
likely to remain into the extended period, as the Climate
Prediction Center expresses a 70 to 80 percent chance for above
average temperatures and 33 to 50 percent chance for below
average precipitation.
&&
.AVIATION...
IFR to MVFR ceilings and visibilities are expected to prevail
for much of the San Joaquin Valley. These conditions will
continue through 18Z Monday. LIFR conditions will also persist
in the coastal ranges, Sierra foothills, and the Kern County
mountains due to the low stratus deck. Otherwise, VFR conditions
will prevail in the Sierra Nevada and in the Kern County
Mountains and Desert over the next 24 hours.
&&
.AIR QUALITY ISSUES...
ISSUED: 12/07/2025 14:17
EXPIRES: 12/08/2025 23:59
On Monday December 8 2025, Unhealthy for Sensitive Groups in
Fresno, Kern, Madera, and Tulare Counties. Fireplace/Wood Stove
Burning Status is: No Burning For All in Fresno, Kern, and
Madera Counties. No Burning Unless Registered in Kings, Merced,
and Tulare Counties. Burning Discouraged in Kern (Greater
Frazier Park Area) and Sequoia National Park and Forest.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
and/or to provide feedback.
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 11 AM PST Monday for CAZ300-304-308-
313-316>322-334>336.
&&
$$
public...McCoy
aviation....JPK
weather.gov/hanford
Office: LOX
FXUS66 KLOX 080638
AFDLOX
Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1038 PM PST Sun Dec 7 2025
.SYNOPSIS...07/824 PM.
Benign weather will continue through the weekend with a chance of
morning low clouds and fog along the Los Angeles coast. A warming
trend will continue this week with well above normal temperatures
Monday through next Friday, peaking Tuesday through Thursday.
Offshore winds will increase Monday into Tuesday, and are
expected to persist through much of the week.
&&
.SHORT TERM (SUN-WED)...07/821 PM.
Warming trend started today, with most coastal/valley areas
reporting high in the 70s, with few warm spots climbing into the
lower to mid 80s. Current satellite imagery showing some low
clouds and fog near Catalina Island, with a chance for those low
clouds to reach the southern coast of LA county late tonight into
Monday morning. Over the next few days, an upper level ridge of
high pressure, centered over the Eastern Pacific, will gradually
strengthen over the area. At the surface, weak to moderate
offshore gradients will prevail. As of 7 pm this evening, the LAX-
Daggett gradient was -2.4 mb while LAX-Bakersfield was -6 mb.
Forecast-wise, two main issues will be offshore winds and
temperatures. With respect to offshore winds, the offshore
pressure gradients will help generate some weak to locally
moderate north to northeast winds across typical wind prone areas
of Ventura/LA counties, as well as gusty offshore winds across
wind prone foothills and canyons of San Luis Obispo and Santa
Barbara counties. Offshore gradients to the north and east are
expected to peak on Tuesday morning, but throughout the short term
period, the upper level support remains rather weak. So, do not
anticipate any widespread advisory level winds through Tuesday but
a 30-40% chance of some advisories being needed for the Santa
Susana mountains.
As for temperatures, the combination of the upper level ridge
strengthening and the offshore surface pressure gradients, a nice
warming trend will continue. By Tuesday and Wednesday, most areas
will be 10-15 degrees above normal with widespread 80+ degree
temperatures across the valleys and inland coastal plain. No
record-breaking temperatures are expected, but it will be rather
warm. As for overnight lows, it will be chilly in wind sheltered
areas.
.LONG TERM (THU-SUN)...07/1258 PM.
Overall, the 12Z models have the same broad idea, but differ in
the details. However, the differences will have minimal impact on
the overall sensible weather.
Through the period, the upper level ridge is forecast to weaken.
At the surface, the offshore flow will weaken with weak diurnal
flow expected by the weekend. So, will anticipate a slight and
gradual cool down through the period with a decrease in
northeasterly winds. By the weekend, there is a decent chance
that the marine layer stratus/fog will return to the coastal
plain. Overall, just rather benign weather through next week.
&&
.AVIATION...08/0637Z.
At 0525Z at KLAX, the marine layer was 500 feet deep. The top of
the inversion was 1800 feet with a temperature of 20 C.
High confidence in TAFs for KPRB, KSBP, KSMX, KCMA, KBUR, KVNY,
KPMD and KWJF.
Fair confidence in TAFs for KSBA, KOXR with a 15 percent chc of
LIFR conds 10Z-16Z.
Moderate confidence in TAFs for KSMO, KLGB (30 percent chc of
LIFR conds 10Z-16Z) and KLAX (25 percent chc of no low clouds)
KLAX...Moderate confidence in TAF. There is a 25 percent chance
of VFR conds persisting through the period. If low clouds do
arrive they could arrive any time between 08Z-12Z. Any easterly
winds will be less than 7 knots.
KBUR...High confidence in CAVU TAF.
&&
.MARINE...07/839 PM.
For the outer waters, there is a 40-60% chance of low-end Small
Craft Advisory (SCA) conditions through the week, especially
across the western portions of the waters north of Santa Cruz
Island during the afternoon and evening hours.
For the inner waters including the southern California bight and
the nearshore waters along the Central Coast, there is a 30-50%
of local northeast SCA level wind gusts from Ventura to Santa
Monica as well as from Pismo Beach to Point Piedras Blancas each
night and morning through Tuesday, and a 30% chance of reoccurring
on Wednesday. Otherwise, winds and seas should remain below SCA
levels.
There is a moderate chance of dense fog over the coastal waters
through Monday morning. Confidence remains low on timing and
coverage.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PST Tuesday for
zones 670-673. (See LAXMWWLOX).
&&
$$
PUBLIC...Gomberg/Thompson
AVIATION...Rorke
MARINE...Lund/Schoenfeld
SYNOPSIS...Gomberg
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox
Office: STO
FXUS66 KSTO 072153
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
153 PM PST Sun Dec 7 2025
.KEY MESSAGES...
- Periods of low clouds, mist, or fog continue in the Central
Valley for the next few mornings
- Seasonable temperatures and light winds are forecast over the
next several days
&&
.DISCUSSION...
...Today...
Stratus/Low clouds continued today across the Central Valley and
lower foothills with heights below 1000 feet. As of 12 PM this
afternoon, height have begun to rise although still present
across swaths of the Valley and will continue through the evening
before reforming and repeating tomorrow morning.
Dry weather and seasonable temperatures are forecasted for the
region, with upper 40s to around 60 in the Valley and foothills,
and 40s to 50s in the mountains for the daytime highs. Highs are
trending several degrees cooler than initially forecasted due to
the persistence of the fog/low clouds, keeping max temperatures
from being fully actualized again.
...Next Week...
High pressure builds across the region next week, allowing for a
gradual warming trend with high temperatures warming to the 50s
to near 70 (mainly for areas outside of stratus/fog
development). Dry conditions will continue through next week.
Current forecasts show very low chances (5-15%) for light showers
across Shasta County on Tuesday but little to no impacts expected
even if precipitation occurs. In the extended, models show chances
for the ridge to weaken next weekend but still too far out in the
future for any definitive forecast updates.
&&
.AVIATION...
Lingering low cigs and mist across the Central Valley continue
into this evening with IFR/LIFR conditions, although some sites
may very briefly see MVFR/VFR visibility around 22-24Z, mainly for
TAF sites north of Sacramento. Another round of BF/FG and low
stratus returns once again tonight with areas of IFR/LIFR ceilings
once again expected to persist through the day. Light and
variable surface winds less than 12kts.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Office: SGX
FXUS66 KSGX 080510
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
910 PM PST Sun Dec 7 2025
.SYNOPSIS...
Warm and dry conditions with periods of Santa Ana winds expected
this week. The peak of the heat is expected to be mid-week. Patchy
low clouds could develop overnight into Monday morning near the
coast.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.Evening Update...
A few areas of low clouds and fog continue to drift over parts of
the coastal waters this evening. Very isolated spots of fog may
occur near the coast through the early morning, but most areas
are expected to stay clear overnight.
Though the weekend has ended, the warm weather has not! The
forecast remains on track to see high temperatures 10 to 20
degrees above normal for the upcoming week. Tuesday will be the
warmest day for valleys west of the mountains with chances near
20% to 60% to see highs at or above 85 degrees. The ridge has a
good chance to break down some by next weekend, leading to a slow
cooling trend.
.Previous Discussion (141 PM Sunday)...
For tonight into Monday morning there is a 10 to 20 percent
chance of patchy low clouds and dense fog developing along the
coast, with slightly higher chances of dense fog developing over
the coastal waters. Mostly clear skies will prevail from Monday
afternoon through the middle of the week due to periods of weak to
moderate Santa Ana winds.
A persistent surface high pressure over the Great Basin will remain
in place through Saturday. This will bring weak to locally moderate
Santa Ana winds to the area. With no upper level support, the
strongest winds will remain confined to coastal mountain slopes,
foothills, and below passes. The strongest winds are expected on
Tuesday with gusts 25 to 45 mph. A secondary peak in winds is
expected on Friday. The airmass getting pushed into Southern
California from the Great Basin will be on the drier side, with
minimum afternoon relative humidity for inland areas falling to 10
to 20% each afternoon through Friday, bringing periods of elevated
fire weather conditions.
An upper level ridge over the East Pacific will strengthen over the
US West Coast through Tuesday, bringing an uptick in high
temperatures. High temperatures on Tuesday will be 15 to 20 degrees
above average. Widespread highs in the low to mid 80s are forecast
across the inland coastal areas into the valleys as well as the low
deserts. Weaker Santa Ana winds and a weakening in the upper level
ridge will allow for minor cooling on Wednesday and Thursday mainly
for coastal areas. The secondary uptick in Santa Ana winds on Friday
is expected to bring additional warming to areas west of the
mountains with high temperatures expected to run up to 20 degrees
above average for inland areas. Nights and mornings will remain
cool, especially in the wind-sheltered areas, minimizing any heat
impacts. A few degrees of cooling is expected into next weekend as
weak onshore flow returns, but temperatures will continue to run
above average.
&&
.AVIATION...
072100Z...Clear skies and VFR prevail region-wide through Monday.
10-20% chance for very patchy fog/vis reductions developing
within 5 miles of the coast overnight. Offshore E/NE winds
gusting 25-35 kts to pick up through mountain passes and Santa Ana
mountain coastal slopes after 13z Mon, clearing out any leftover
fog near the coast.
&&
.MARINE...
Patchy dense fog this evening will continue to be isolated through
early Monday morning. Visibility in fog 1 nautical mile or less.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
UPDATE...APR
PUBLIC...CO
AVIATION/MARINE...APR
Office: MTR
FXUS66 KMTR 080926
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
126 AM PST Mon Dec 8 2025
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 117 AM PST Mon Dec 8 2025
- Another round of fog this morning in the valleys across the Bay
Area.
- Fairly consistent weather pattern continues this week.
- Next chance of rain around the 15th.
&&
.SHORT TERM...
Issued at 117 AM PST Mon Dec 8 2025
(Today and tonight)
Tule Fog remains in the Central Valley and there is slightly more
low stratus coverage across the Bay Area than this time last
night. There is a good chance for these clouds to expand down to
the surface as the the wind continues to calm through the morning.
The most likely locations to develop fog are the North Bay
Valleys, Interior East Bay Valleys, and the Santa Clara Valley.
There's more uncertainty along the Bay side of San Mateo County.
Typically this area is less prone to fog than the cooler valleys,
but is the best set-up for it. Light NNE winds over the Bay don't
suffer from the downslope drying of winds with a westerly
component. For example, historically the visibility at SFO drops
below 3 miles 8% of the time in December between 5AM and 10AM. If
we add a NNE wind direction constraint to these variables, the
probability increases to 17%. On the other hand, NW winds bring
this low visibility only 4% of the time. The otherwise clear
skies and long December nights also help with the radiative
cooling to generate this fog, and cloud top radiation helps to
sustain it. The complicating factor is the relatively warm water
in the Bay (55F) compared to the air temp (45F). This induces some
instability that will work to lift fog into a low cloud deck if
the low level winds don't calm this morning. In the end, I'll give
a 30% chance for fog in Eastern San Mateo, 50% for the Santa
Clara Valley, and 80% across the North and East Bay Valleys.
Otherwise the weather will be quite similar to the last couple
days as the fog and low clouds gradually clear through the day and
temperatures under the morning stratus struggle to get into the
60s in the afternoon.
&&
.LONG TERM...
Issued at 117 AM PST Mon Dec 8 2025
(Tuesday through Sunday)
The long term forecast is mostly boring. There is a hint of rain at
the end of the 7-day window, but let's spend a minute discussing
this dry spell first. If you've read any of our AFDs in the last
week, you know it's caused by a "ridiculously resilient ridge" over
California that is keeping the storm track well to our North. It's
now been 17 days since San Francisco recorded any rain, and that
streak will very likely extend into the mid 20s. How unusual is
that? Well it turns out a long dry spell in the middle of the
rainy season is actually pretty common. There have been 54
instances of a dry spell lasting 24 days or more between November
and March since 1849. In other words, there is a 31% (54/176)
chance of getting a dry spell at least this long any given Winter.
The longest such streak was 60 days from November 17, 1876 to
January 15, 1877. We're not expected to get anywhere near that
record as it looks like a pattern change is finally on the
horizon. More and more ensemble members are agreeing that the
ridge will finally break down with more a more active zonal
pattern bringing the jet stream and chances for rain back to the
Bay Area. 40/50 ECMWF ensemble members bring some rain to the Bay
Area next week, with an outside chance for heavier rain the
following weekend. We'll wait and see for now, but our official
forecast finally has a decent probability of precipitation
starting on the 15th.
&&
.AVIATION...
(06Z TAFS)
Issued at 948 PM PST Sun Dec 7 2025
Low clouds and fog are building in the North Bay and interior East
Bay, but have cleared over STS and LVK while APC remains IFR. Expect
cloud cover to lower further into the night while the fog to becomes
thicker. The OAK and SJC see CIGs arrive overnight with some
reductions in visibilities. Winds stay mostly light to moderate
through the morning, with wind directions determined by more
localized affects. Cloud cover and fog will be slow to erode into
Monday, but conditions look to improve into the afternoon. However,
the North and East Bay will continue to struggle with low clouds and
fog, causing some doubt for clearing at STS and LVK, while APC
doesn't clear. As cloud cover erodes, pockets of haze will affect
much of the region. CIGs and fog reform for STS and APC into the
evening.
Vicinity of SFO...VFR through the TAF period. Winds become lighter
into the night with scattered low clouds building into the area,
along with some slight reduction in visibilities. Cloud cover thins
into the afternoon and winds become slightly more moderate and
northwesterly.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR through the TAF period. Winds stay
light for MRY through the TAF period, while SNS sees moderate
northwest winds become light into the night. North to northwest
winds return Monday afternoon with the potential for haze.
&&
.MARINE...
(Tonight through next Saturday)
Issued at 948 PM PST Sun Dec 7 2025
Moderate to fresh north to northwest winds continue for the
southern waters. Moderate seas with wave heights 6 to 8 feet
across the outer waters will subside to around 4 to 6 feet for
Monday. Winds and swell increase Monday night, with strong gusts
possible across the waters. A new, long period northwesterly
swell is anticipated by Wednesday and looks to exit late Friday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 AM PST Tuesday for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Small Craft Advisory from 3 PM this afternoon to 3 AM PST
Tuesday for Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 3 PM this afternoon to 9 AM PST
Tuesday for Pigeon Pt to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Murdock
MARINE...Murdock
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