FXUS66 KEKA 132214
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
314 PM PDT Sat Aug 13 2022
.SYNOPSIS...Seasonable temperatures and dry weather will continue
this weekend with areas of morning coastal clouds and persistent
smoke around the Trinity River Valley. Inland temperatures will
heat up through next week, with a chance for thunderstorms around
Trinity County on Wednesday.
.DISCUSSION...As upper troughing extending southeastward from the
Gulf of Alaska toward the Pacific Northwest gradually lifts out,
an upper-level ridge will gradually retrograde toward our region
from the southern Rockies. That will result in a hotter week ahead
for inland northwest California, and temperatures this afternoon
are already running 4 to 8 degrees warmer than this time
yesterday. Areas of locally dense smoke are persisting mainly
around portions of the Trinity River Valley, from the Six Rivers
Lightning Complex fires. Air quality is particularly poor this
afternoon between Willow Creek and Burnt Ranch, and the smoke will
likely continue to linger there much of the week ahead. Periods
of thicker smoke will slosh back and fourth through other nearby
valleys as fairly light, terrain-driven winds shift around
diurnally. Low-level winds will trend a bit more northerly through
early next week, which may allow some smoke to drift southward
into portions of Mendocino and Lake County. Meanwhile, the marine
layer will help keep most coastal areas smoke-free with good air
quality. A bit more mixing with northerly breezes there should at
least allow for a good amount of sunshine the next couple of days.
A stronger inversion and shallow, persistent marine layer will
likely mean more stubborn clouds and fog heading through next
With the increase in temperatures this week, the risk of heat-
related illness may become a concern for portions of our forecast
area, particularly around portions of Lake County Wednesday
through Friday. After adjusting high temperatures down from the
NBM in Trinity County due to smoke limiting daytime heating (and
still allowing for good radiational cooling at night), the risk
appears lower there. A Heat Advisory may need to be hoisted at
some point in the next couple days for around Lake County.
Perhaps the greatest forecast concern and certainly the biggest
challenge will be the threat of thunderstorms around Wednesday.
The best shot looks to be around northern and eastern Trinity
County that day, so added a 'slight chance' to our forecast grids.
However, there has been quite a bit of inconsistency both between
models and run to run, so it is possible that the threat could
end up a bit more widespread, or not materialize in our area at
all. An upper-level low developing offshore and heading toward
California late in the week will aid in drawing monsoonal moisture
back toward our region. However, the details of how much
moisture, instability, and forcing is not clear. There has been
some solutions pointing toward a rather thin layer of elevated
moisture and instability as early as Tuesday afternoon and night
drifting into our area as the left-front quad of a jet streak
approaches from the south. However, all of the guidance at the
moment has been trending even more limited as far as the degree of
that moisture and instability, so even virga showers might be a
stretch. The better shot continues to look like Wednesday
afternoon, with some better potential for a bit deeper moisture
and some surface instability to get involved over the mountains
around Trinity County. At this point any storms look rather
isolated. Would not rule out some thunder on Thursday, but have
not included any in the forecast yet, as forcing will likely be
more limited that day even if enough moisture lingers around. /AAD
.AVIATION...A bit of stratus briefly got into KACV this morning,
otherwise the majority of the region has become stratus free and VFR
today. The stratus will attempt to make a comeback overnight,
expanding north along the immediate coast. Ceilings will lower
overnight and especially into the early morning hours. IFR to LIFR
conditions may develop, but confidence is not high as the marine
layer should undergo deepening with some weak shortwave energy
moving through. Overnight coverage is also in question given the
previous 24 behavior. KUKI will remain VFR with lighter surface
.MARINE...Advisory level northerly winds 15 to 20 kt will continue
to expand north across the waters today. Stronger winds exceeding 25
kt will be focused in the southern waters lee of the cape, with
higher gusts. Northerly winds will further strengthen on Sunday and
again Monday when some isolated portions of the waters will see gale
force gusts through Tuesday. Short-period seas will continue to
build in response to the increasing winds. Otherwise, a small, long-
period southerly swell will linger throughout portions of the waters
through the weekend.
.FIRE WEATHER...Have continued a headline in the FWF advertising
the threat for thunderstorms around mid-week, mainly around
Trinity County. As discussed in the main discussion, there is a
very outside chance at elevated convection as early as later
Tuesday and into Wednesday morning, but at this point am not
forecasting that, as moisture and instability appears too limited.
later Wednesday should bring the best chance for at least isolated
thunderstorms. Hotter and drier weather will also be a concern
this week even while winds remain light and terrain-driven.
Overnight recoveries will trend poorer, particularly over the
near-coastal ridges as the marine layer become shallower. /AAD
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 9 PM PDT Monday for PZZ455-475.
Small Craft Advisory until 9 PM PDT Monday for PZZ470.
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FXUS66 KHNX 132349
Area Forecast Discussion
National Weather Service Hanford CA
449 PM PDT Sat Aug 13 2022
Updated AIR QUALITY ISSUES section.
SYNOPSIS...The major story is the return of the triple digits for
much of the San Joaquin Valley. The probability of temperatures
reaching 105 will be higher Tuesday through Friday resulting in
the issuance of an Excessive Heat Watch. Thunderstorms will return
to the Sierra Nevada on Monday afternoon.
A ridge currently over the Rockies will build up over the next week
and move west. This building of the ridge and movement west will
help increase temperatures in the Central Valley. The building ridge
will also bring a slight monsoon flow into the Sierra Nevada which
would lead to thunderstorms to start back up on Monday. The GEFS and
European model are in agreement that the ridge will be increasing
in strength and will be very strong by the middle of the week.
The probability of triple digits will increase to at least 67
percent for the entire San Joaquin Valley by Monday. The probability
for the entire valley increases to above 75 percent Tuesday through
Friday. Temperatures are expected to start to cool next Saturday.
However, the real story is the probability of exceeding 105 degrees.
Tuesday through Friday will have the highest chances of exceeding
105. Hanford, Fresno, and Lemoore will have probabilities of at
least 50 percent and Bakersfield around 40 percent of 105 or higher
in that span. An Excessive Heat Watch has been issued due to the
probability of 105 degrees or higher for Tuesday through Friday.
VFR conditions will prevail across Central California through at
least the next 24 hours.
.AIR QUALITY ISSUES...
On Sunday August 14 2022... Unhealthy for Sensitive Groups in
Kern and Tulare Counties... and Sequoia National Park and Forest.
The level of certainty for days 1 and 2 is high.
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
an/or to provide feedback.
Excessive Heat Watch from Tuesday morning through Friday evening
FXUS66 KLOX 140016
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
516 PM PDT Sat Aug 13 2022
Above normal temperatures and low humidity will continue through
the weekend with night to morning low clouds and fog along the
Central Coast. Monsoonal showers or thunderstorms may return to
some eastern areas mid week.
.SHORT TERM (SAT-TUE)...13/149 PM.
Synoptically, the area is remains under the influence of a
persistent 595 dam upper-level high currently centered over the
Great Basin. The orientation of this system continues to bring
anomalously high moisture into the southwest and monsoonal
showers are active east of our area again today. We may see shower
activity in the Big Pines Area and are seeing clouds develop
there now. An upper level trough / low will drop down the
California coast to about the San Francisco Bay latitude by
Tuesday but this shouldn't affect our weather. European models
don't make much of it while the global ensemble system keeps it
hanging on until later in the week. The NBM is picking up on the
idea of the trough and our decreasing temps next weekend are a
reflection of that solution. By mid-week the high should move just
enough westward to bring a slight chance of monsoonal activity
back to eastern LA County.
Moderate onshore flow will continue to the east with weakening
northerly offshore gradients. The onshore gradient weakened in the
LA area today and morning temperature were 2-5 degrees warmer than
yesterday. Raised the resulting afternoon temperature a few
degrees accordingly. Southern SBA Co will see northwesterly winds
return again this evening, but they should remain just below
advisory level. Night to morning marine layer stratus/fog will
likely remain confined to areas north of Point Conception tonight,
but some models were suggesting a chance in the Long Beach area
For the monsoon activity this afternoon, high resolution models
show negative LIs and moderate CAPE, with PWAT around 1 inch across
the eastern San Gabriel Mountains.
Models indicate that the northerly gradients will continue to
weaken Sunday so no wind impacts are expected. They also indicate
less instability and PWATs, so PoPs over eastern LA county will
be 10% or less. Marine layer stratus/fog will likely remain
confined to areas north of Point Conception. Temperatures will
remain a few degrees above seasonal normals.
Monday and Tuesday will be quite similar to Sunday, with the
wildcard being the upper level low that will drop down the coast,
but still not seeing any impactful weather associated with that
.LONG TERM (WED-SAT)...13/201 PM.
For the extended forecast, the main feature will continue to be
the upper level high centered over the four corners region
on Wednesday and then building over CA Thursday and Friday.
The main impact will continue to be monsoonal showers and
thunderstorms. Ensembles continue to keep the area on the
periphery of any monsoonal push, with nothing more than a slight
chance until Saturday over the far eastern San Gabriel Mountains
and associated desert foothills.
The forecast will remain otherwise typical for August, with
temperatures a bit above normal and high pressure dominating the
forecast. The areal coverage of marine layer stratus/fog will
likely remain north of Point Conception, with only patchy
conditions south of Point Conception. Skies should remain clear to
partly cloudy. Low confidence in the cooling trend for next
weekend as many ensemble solutions build the 500mb heights to
above 590 dam by Saturday.
At 00Z at KLAX, the marine layer was about 500 ft deep. The top
of the inversion was at 1800 ft with a temperature of 30 deg C.
Good confidence in VFR conds away from coast. Wind shift may be
off by 2 hours and strength by 3-5 kts.
Moderate confidence in coastal TAFs, except low confidence at KSMX
where there is a 50-70 percent chance of LIFR cigs/vsbys. There is
a 20-40 percent chance of IFR/LIFR cigs/vsbys at other coastal
sites, highest for KLGB and KSBP.
.KLAX...Good confidence in TAF. There is a 20-30 chance of
IFR/LIFR cigs between 09Z and 15Z. There is a 20-30 percent chance
that east wind component briefly reaches 5 kts around 12Z due to a
weak eddy, but will remain below 8 kts.
KBUR...High confidence in VFR conditions thru the period.
A strong coastal jet will support prevailing Small Craft Advisory
(SCA) conds or stronger through at least early for the outer
waters north of the Channel Islands. Gale conditions will likely
(60-80 percent chance) prevail this afternoon through tonight, and
may (20-30 percent chance) return late Sunday into Sunday night.
For the inner waters north of Point Sal: SCA conditions likely
(60-80 percent chance) through this evening, and may (30-50
percent chance) return Sunday or Monday evening.
For the inner waters south of Point Conception: local SCA
conditions far western portions, with a 20-30 percent chance of
reaching SCA conditions western SBA channel this evening.
Patchy dense fog (1 SM or less) may develop tonight, especially
northwest of the Channel Islands to Central Coast. Although an
eddy tonight and again possibly Monday night may spin up low
clouds and fog in portions of the southern waters as well.
PZ...Small Craft Advisory in effect until 9 PM PDT this evening
for zone 645. (See LAXMWWLOX).
Gale Warning in effect until 3 AM PDT Sunday for zones
670-673. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PDT Monday for zone
676. (See LAXMWWLOX).
Experimental Graphical Hazardous Weather Outlook at:
FXUS66 KSTO 132115
Area Forecast Discussion
National Weather Service Sacramento CA
215 PM PDT Sat Aug 13 2022
Hot temperatures return this week with widespread triple digit
high temperatures in the Valley. Smoke from area wildfires will
continue to impact portions of interior Northern California.
Monsoonal showers will be possible around mid-week with best
chances over the Sierra.
Visible satellite imagery shows clear skis over Northern
California this afternoon other than an area of smoke in the
northern Coastal Range. Winds are also generally light with gusts
only to 15 mph for the breeziest locations. Similar conditions
are expected tomorrow with temperatures starting to trend up
By Monday, ensembles are in agreement high pressure building into
the region will lead to increasing high temperatures early next
week. An Excessive Heat Watch has been issued for the entire
Central Valley in coordination with the Hanford weather forecast
office starting late morning on Tuesday and continuing into the
later part of the week. Moderate to high heat risk is forecast for
much of the Valley and foothills with highs ranging from 95 to
around 109 and lows in the mid 60s to upper 70s. The warmest
overnight lows will be along the thermal belts in the foothills.
The hottest high temperatures for interior Northern California
are expected in the northern Sacramento Valley.
With high pressure building west this week, monsoonal moisture is
also forecast to return to the Sierra, possibly extending into
the southern Cascades by mid-week. Thunderstorm chances have
trended lower with recent model updates, however by Tuesday
afternoon and evening the potential for isolated showers and
thunderstorms over the Sierra can not be ruled out. The best
chances will generally be to the east of the Sierra Crest.
Rainfall amounts are also not expected to be high as indicated by
forecast PWAT values that are expected to remain below 1 inch over
.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
EFI continues to highlight a strong signature for anomalously high
daytime and overnight temperatures for much of the extended.
Ensembles indicate high pressure will linger over interior NorCal
through mid to late week, contributing to widespread moderate
heat risk with areas of high heat risk in the Valley and
foothills. The Excessive Heat Watch is in effect through Thursday
night at 10 pm PDT.
In addition to the hot temperatures, monsoonal moisture will also
be able to surge northward during this time. As a result,
isolated shower and thunderstorm chances will linger over the high
elevation Sierra on Wednesday afternoon and evening. Those
chances are trending much lower over our CWA later in the week.
Looking at the weekend, some clusters are favoring an upper level
trough off the PacNW coast that may help shift the ridge
eastward. This could bring some relief in temperatures over the
VFR conditions are forecast to prevail throughout interior
northern California over the next 24 hours. Surface wind gusts
generally below 12 kts, except southwest 20-30 kts gusts in the
vicinity of the Delta.
Excessive Heat Watch from Tuesday morning through Thursday
evening for Carquinez Strait and Delta-Central Sacramento Valley-
Motherlode-Mountains Southwestern Shasta County to Western
Colusa County-Northeast Foothills/Sacramento Valley-Northern
Sacramento Valley-Northern San Joaquin Valley-Southern
FXUS66 KSGX 132031
Area Forecast Discussion
National Weather Service San Diego CA
131 PM PDT Sat Aug 13 2022
A monsoonal weather pattern will continue through next week,
leading to a daily risk of thunderstorms, mainly during the
afternoons over the mountains and deserts. Moisture levels will
be highest today with flash flooding possible over the mountains
and deserts. Little day to day temperature changes will occur
while humidity remains high.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Several powerful thunderstorms have erupted over the mountains so
far today. These will probably drift into adjacent deserts late
this afternoon. Individual thunderstorms are capable of dropping 1
to 2 inches per hour. The Flood Watch remains through 8 pm. If
you have any reports of flash flooding or other damage from
storms, please report it via Twitter @NWSSanDiego. Skywarn
activation continues for San Diego, Riverside and San Bernardino
Counties through 8 pm. Hot weather with temps exceeding 100
degrees will continue in the Inland Empire this afternoon,
supporting the heat advisory that expires at 8 pm. Temps will be
trimmed by only a couple degrees Sunday and for the coming week.
Moisture decreases for Sunday and Monday for fewer thunderstorms
during the afternoons in mountains and deserts. This looks to be
the pattern with little change through about Thursday, making for
a rather persistent forecast Sunday through Thursday. However,
we'll watch for a wildcard thunderstorm complex or some such
nocturnal thing that could materialize far out in the desert and
move into our region, such as last night's feature. These
adjustments may be needed on a day-to-day basis. On Friday and
Saturday, some guidance increases the moisture, and some of that
guidance increases it a lot. Other guidance maintains the status
quo. It's possible the precip chances edge westward to the coast
Friday and Saturday and the forecast precip amounts get larger.
The current forecast reflects a slight trend wetter and slightly
farther west of the mountains toward week's end. We've seen
guidance show a deep moisture surge by day 6 or 7 this pasts week,
and somehow subsequent model runs keep delaying it. We just have
to wait and see. In the meantime, we'll have similar weather,
though not quite as hot, for the next five days or so. Stay tuned
for any variations on this theme as they could be important.
132030Z...Coast/Valleys...Multiple cloud layers with SCT 6000-8000
FT MSL and SCT-BKN 15,000-20,000 FT MSL are occurring across San
Diego County, and may spread into Orange County later this
afternoon. Low clouds may return to coastal areas after 03z Sun,
with bases near 1000 FT MSL. Any low clouds near the coast will
scatter out 15-17z Sun.
Mountains/Deserts...Widespread TSRA activity will continue through
01z Sun. Bases near 6,000-9,000 FT MSL and tops to 40,000 FT MSL.
Gusty and erratic winds with severe up/downdrafts, frequent
lightning and reduced vis of 2-4 SM, locally below 1 SM, in +RA and
BLDU. Otherwise, SCT-BKN AOA 20,000 FT MSL through tonight.
No hazardous marine weather is expected through Thursday.
Skywarn activation is requested through 8 pm today for San Diego,
Riverside, and San Bernardino Counties. Please use Twitter
@NWSSanDiego or the online spotter report form:
CA...Heat Advisory until 8 PM PDT this evening for San Bernardino and
Riverside County Valleys-The Inland Empire.
Flood Watch until 8 PM PDT this evening for Apple and Lucerne
Valleys-Coachella Valley-Riverside County Mountains-San
Bernardino County Mountains-San Diego County Deserts-San
Diego County Mountains-San Gorgonio Pass Near Banning.
FXUS66 KMTR 132323
Area Forecast Discussion
National Weather Service San Francisco Bay Area
423 PM PDT Sat Aug 13 2022
.SYNOPSIS...Gradual warming and drying for this weekend into next
week as high pressure builds into the area from the east.
.DISCUSSION...as of 01:30 PM PDT Saturday...The core of the
closed low that has been lingering off of Cape Mendocino for most
of the month of August departed the region over the previous 24
hours, leaving behind a weaker open trough along the Pacific
coast. At the same time, a broad high pressure ridge cover a
slight majority of the CONUS is slowly backbuilding westward into
California as the coastal trough eases. For today, the coastal
trough remains the predominate feature across the San Francisco
Bay Area and Central Coast but expect the strengthening ridge to
gradually become the dominate feature over the area by early next
As such, today is running slightly warmer and drier versus 24
hours ago. This trend of gradually warming and drying conditions
will continue into early next week. Tuesday will likely be the
warmest day with the interior pushing the mid 90s to the low 100s
while nearshore locales increase only a few degrees warmer than
today due to the influence of the marine layer. Tuesday's
max afternoon temperatures will peak at 8 to 12 degrees above
normal across the interior, while coastal and nearshore areas are
generally forecast to rise just 2 to 6 degrees above normal. For
now, looks sub criteria for a heat advisory given limited extent
of the heat (primarily Tuesday for the interior) and values not
too far beyond the typical climatology. Furthermore, HREF and WRF
data indicate a high probability of the return of the marine layer
(albeit compressed) beginning tonight. The marine layer will keep
the coast and nearshore areas relatively much cooler than
Otherwise, mid level monsoonal moisture will wrap clockwise
around the western periphery of the expanding ridge through the
coming days, allowing for an increase in mid level clouds to the
east, but with little to no risk of high based convection due to
unfavorable instability and moisture profiles. At this time,
Tuesday afternoon to evening presents one limited opportunity for
localized monsoonal convection to arrive from the south, so will
monitor this moving forward over the coming days.
.AVIATION... As of 4:20 PM Saturday... For the 00Z TAFs. VFR prevails
across the region with breezy to gusty winds generally from the west
for the rest of the day. A shallow marine layer will limit inland
stratus intrusion overnight, but stratus impacts will likely take
hold for longer than last night. Moderate to high confidence of IFR
filling in over the northern San Francisco Bay and the East Bay, and
moderate to high confidence of LIFR ceilings over the Monterey Bay
terminals. Stratus should dissipate by around 17-18z with breezy
onshore winds developing in the afternoon.
Vicinity of KSFO... VFR for the rest of the day. Have opted to
adjust gusts downward to account for observed gusts lower than
forecast. Overnight stratus impacts should be intermittent with
possible IFR ceilings. Any stratus cover dissipates by 18z with west
winds with gusts at or slightly below those observed so far today.
KSFO Bridge Approach... Similar to SFO.
Monterey Bay... VFR for the rest of the day, winds breezy from the
northwest. Stratus comes in tonight with periods of LIFR ceilings
possible with moderate confidence at MRY and low to moderate
confidence at SNS. Stratus should clear around 17-18z with breezy
west winds returning Sunday afternoon.
.MARINE...as of 04:21 PM PDT Saturday...Strong and gusty northwest
winds across the coastal waters through the weekend and early next
week. Gale force winds along the Big Sur coast through today.
Gusty afternoon and evening west winds also developing today
across the San Francisco Bay mainly north of the Bay Bridge.
Light southwest swell from 15 to 19 seconds continuing into next
.Tngt...SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
GLW...Pt Pinos to Pt Piedras Blancas 0-10 nm until 8 PM
SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...SF Bay until 9 PM
SCA...Mry Bay until 9 PM
PUBLIC FORECAST: DRP
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