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Office: EKA

FXUS66 KEKA 132214
AFDEKA

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
week.

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
winds.

&&

.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

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
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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Office: HNX FXUS66 KHNX 132349 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 449 PM PDT Sat Aug 13 2022 .UPDATE... 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. && DISCUSSION... 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. && AVIATION... 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. && .CERTAINTY... 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. && .HNX WATCHES/WARNINGS/ADVISORIES... Excessive Heat Watch from Tuesday morning through Friday evening for CAZ300>317-319-321-332. && $$ public...JPK aviation....JPK weather.gov/hanford
Office: LOX FXUS66 KLOX 140016 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 516 PM PDT Sat Aug 13 2022 .SYNOPSIS...13/515 PM. 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 as well. 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 feature. .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. && .AVIATION...14/0013Z. 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. && .MARINE...13/200 PM. 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. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. 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). && $$ PUBLIC...jld AVIATION...Munroe MARINE...Munroe SYNOPSIS...jld/RM weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox
Office: STO FXUS66 KSTO 132115 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 215 PM PDT Sat Aug 13 2022 .Synopsis... 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. && .Discussion... 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 slightly. 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 the mountains. SLL && .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 weekend. && .AVIATION... 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. && .STO WATCHES/WARNINGS/ADVISORIES... 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 Sacramento Valley. && $$
Office: SGX FXUS66 KSGX 132031 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 131 PM PDT Sat Aug 13 2022 .SYNOPSIS... 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 COUNTIES... 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. && .AVIATION... 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. && .MARINE... No hazardous marine weather is expected through Thursday. && .SKYWARN... 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: inws.ncep.noaa.gov/report && .SGX WATCHES/WARNINGS/ADVISORIES... 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. PZ...None. && $$ PUBLIC...MM AVIATION/MARINE...Schenk
Office: MTR FXUS66 KMTR 132323 AFDMTR 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 week. 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 interior CA. 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 week. && .MTR WATCHES/WARNINGS/ADVISORIES... .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 AVIATION: DialH MARINE: Canepa Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea