ca discuss
Office: EKA
FXUS66 KEKA 251119
AFDEKA
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
419 AM PDT Thu Apr 25 2024
.SYNOPSIS...A cold front will bring cooler temperatures and periods
of light rain to mainly Del Norte and Humboldt counties today
through Friday. A few showers will make it farther south and
east. For the weekend and into next week mainly dry and cool
conditions are expected. There may be some frost on the colder
mornings. Some light rain is possible on Wednesday.
&&
.DISCUSSION...The satellite shows a cold front approaching the
west coast. Most of the energy is expected to remain north of the
area with only some light rain making it down into northwest
California. Rain in Del Norte county is expected to start around
8 or 9am and an hour or two later around Humboldt Bay. Southern
Humboldt is expected to see a sharp gradient in the precip amounts
and this will increase the uncertainty as a small shift could
easily bring a change to the outcome. Snow levels may drop down
to 5,000 feet at times, but snow accumulations will be fairly
light. A few light showers are possible in northern Mendocino
county and western Trinity county. Southern Mendocino and Lake
counties are generally expected to stay dry with just a few
sprinkles possible. Highs will be in the 50s in most areas
although southern Mendocino and Lake counties may get into the
60s. Tonight with widespread cloud cover around temperatures are
expected to mainly be in the 40s. Friday continued showers are
expected. Mendocino and Lake counties may see a few more showers,
but amounts are still generally expected to be less than a tenth
of an inch. Northerly winds are expected to increase Friday
afternoon and evening in Mendocino and Lake counties. The NBM is
showing a 10 to 20 percent chance of wind gusts over 40 mph in the
mountains of Lake county.
Friday night into Saturday near freezing or freezing temperatures
are possible in most valleys. Mendocino, Lake, and Trinity
counties are the most likely to see frost in the colder valleys as
they are expected to see less rain. This will be dependent on how
much rain falls and how much fog forms. Currently the NBM model
is showing 80 to 100 percent chance of low temperatures dropping
into the low 30s in northern Mendocino and Trinity counties.
Sunday through Tuesday nearly zonal flow is expected to keep
temperatures below normal, although it generally looks dry at this
time. The coastal counties will generally see quite a bit of cloud
cover around and this will limit the potential for frost, but if
skies do manage to clear out it is certainly possible. Areas
farther inland are more likely to remain clear and see freezing
temperatures. The best chances will be in Trinity county, but
eastern Mendocino and Lake county will still have a 20 to 30
percent chance of seeing frost.
Wednesday and Thursday some of the models are showing another
weather system bringing some rain, but at this point there is
still a lot of uncertainty on amounts and timing. Probabilities of
a tenth of an inch rain range from 65 percent near the Oregon
border to 10 percent in southern Lake county. MKK
&&
.AVIATION...Stratus remains in place across much of the area and
CIGS vary from IFR to MVFR at the TAF sites. A cold front
approaching the coast today is expected to help mix out this
stratus and lift CIGS this morning. Late this morning and into the
afternoon rain is expected to move into KACV and KCEC. This is
expected to bring lower CIGS, although the rain looks light and it
make take some time for them to lower. Winds are out of the south
in the north, but are light this morning. These winds will pick
up this afternoon and winds of 10 to 20 kt are possible at KACV
and KCEC. Ukiah will continue to see northerly winds which may
increase to 10 kt. IFR ceilings are expected again tonight with
the zonal flow and periods of light rain. This will start to break
up towards morning and MVFR conditions are more likely on Friday.
MKK
&&
.MARINE...Stronger breezes and square to steep wind waves have
been reported this morning, near Point Arena. Borderline small
craft advisory criteria will ease by day break as winds diminish
to a light to gentle breeze. A pressure diffluence will split the
wind profile, WNW south of Shelter Cove and southerly winds north
of Cape Mendocino. This transition will continue to shift towards
the south as an upper level trough approaches the northern area
waters this evening, bringing tighter pressure gradients and a
series of weak cold fronts. Response to these conditions will
manifest into Small Craft criteria by Friday night and into
Saturday. An SC.Y has been hoisted to cover these conditions in
the southern inner and outer waters. Otherwise, the ongoing WNW
swell at 10 - 11 seconds will gradually ease below 10 seconds with
wave heights around 6 - 7 feet through Saturday. A longer period
W swell will arrive Saturday morning around 14 seconds with
smaller wave heights around 2 - 3 feet. Monday evening looks to
have near Gale gusts south of Cape Mendocino which will last
through Tuesday evening. /EYS
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&
$$
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
Office: HNX
FXUS66 KHNX 250940
AFDHNX
Area Forecast Discussion
National Weather Service Hanford CA
240 AM PDT Thu Apr 25 2024
&&
.KEY MESSAGES...
1. A High Wind Warning continues for the Mojave Desert Slopes
and a Wind Advisory for the Kern County Mountains through 11 pm
on Friday.
2. A cooling trend to jest below seasonal normals lasting
through Friday.
3. The next storm system will impact Central California Friday
with mountain snow, foothills rain, and chance of valley
thunderstorms.
4. A warming trend begins on Sunday and lasts through the week
ahead with dry conditions.
&&
.DISCUSSION...
The upper level wave continues to move off to the east into the
Desert Southwest. On the surface a low pressure center over
south central Nevada and high off the California coast will
maintain a very tight pressure gradient over the Kern County
Mountains. This gradient is expected to tighten up throughout
the day and continue through Friday night. The PoE of 60 mph is
80 to near 100% for the Mojave Slopes focused on Highway 58 and
Highway 14. The probability of exceeding 70 mph is 20-30% near
the intersections of the aforementioned highways. The
surrounding Kern County Mountains PoE of 45 mph remains 80 to
near 100% through the same period as the warning. The current
timing and alignment of the warning and advisory is very
reasonable for the event. Areas of blowing dust are probable for
the Slopes area however the reduction in visibility to less
than 1/2 mile is near zero percent.
On Friday an upper wave in the the northwest flow slides down
through the Golden State. The decrease in upper level heights
and lapse rates along with convective energy increase provides
the probability of thunderstorms for the Sierra and San Joaquin
Valley from early afternoon through the early evening hours. The
probabilities of thunder are as follows:
Tioga Pass 19% Yosemite Valley 20%
Wawona 21% Oakhurst 20%
Merced 11% Madera 11%
Shaver Lake 20% Fresno 12%
Grant Grove 18% Visalia 12%
Hanford 9% Lemoore NAS 8%
Delano 9% Bakersfield 8%
Kernville 12% Tehachapi 7%
Lebec 7% Pine Mountain Club 6%
Saturday northwest flow continues over the area and slowly
transitions to zonal westerly flow by Tuesday. The zonal flow
continues through next Thursday. The long and short of it a
warming trend back into the 80s for Tuesday and Wednesday for
the San Joaquin Valley. Here is a PoE table of 80 degree or
better temperatures this week:
SUN MON TUE WED THU
Merced 16% 21% 61% 46% 16%
Madera 21% 36% 66% 51% 21%
Fresno 51% 66% 86% 71% 36%
Reedley 11% 31% 66% 56% 21%
Lemoore NAS 41% 61% 76% 66% 31%
Hanford 41% 61% 81% 71% 36%
Visalia 41% 66% 86% 71% 36%
Delano 41% 66% 81% 81% 36%
Bakersfield 26% 56% 76% 71% 36%
Edwards AFB 51% 81% 91% 86% 51%
The six to ten day CPC forecast is for normal temperatures and
near normal precipitation for the region. For reference the
normal temperatures and precipitation for the second week of May
are in Fresno: High 81, Low 56, and precipitation 0.01 of an
inch. Bakersfield: High 83, Low 57, and precipitation 0.01 of an
inch.
The eight to 14 day CPC forecast takes the temperatures to below
average levels for Central California and near normal
precipitation, which is near zero for mid May, for the region.
&&
.AVIATION...
A low VFR ceiling will continue UNTL 16Z-21Z clearing from
north to south in the SJV. Then VFR and unlimited after 21Z. The
Sierra and Kern County Mountains may have localized mountain
obscurations. The Kern County and Mojave Desert has a high
probability of surface wind sustaining above 30 KTS through the
TAF period.
&&
.AIR QUALITY ISSUES...
ISSUED: 04/24/2024 14:25
EXPIRES: 04/25/2024 23:59
None.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is high.
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...
High Wind Warning until 11 PM PDT Friday for CAZ338.
Wind Advisory until 11 PM PDT Friday for CAZ331-333-334-337-
339.
&&
$$
public/aviation/fire weather...Proton
DSS/PIO....SM
weather.gov/hanford
Office: LOX
FXUS66 KLOX 251555
AFDLOX
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
855 AM PDT Thu Apr 25 2024
.SYNOPSIS...25/240 AM.
Strong onshore flow and a deep marine layer will keep temperatures
much cooler than normal across much of Southwest California
through Friday. Warmer weather is expected by the weekend into
early next week.
&&
.SHORT TERM (TDY-SAT)...25/853 AM.
***UPDATE***
A deep moist layer around 5000 ft thick covered the forecast area
this morning. Low clouds shrouded much of the region with only
parts of the SBA County S coast, the higher mtns and Antelope Vly
free of clouds. The clouds are expected to thin and scatter out
for much of the coast and a few adjacent vlys into the afternoon,
but overall should linger for much of the coastal slopes and
inland vlys.
During the afternoon, gusty mainly sub-Advisory level NW to N
winds are expected to affect the Central Coast, the southwestern
SBA County mtns and coast, he Antelope Vly including foothills,
and the L.A. County mtns along the I-5 Corridor. Otherwise, breezy
onshore winds can be expected this afternoon.
A cool air mass from a departing upper level trof will result in
afternoon temps today about 6-12 deg below seasonal norms.
Highs should only be in the 60s for much of the coast, vlys and
deserts.
***From Previous Discussion***
The north winds will increase today and advisory levels gusts
will develop in the early evening across the SW portion of SBA
county where a wind advisory is in effect from 6pm to 6am. Strong
winds will develop more slowly across the mtns and Antelope Vly
and wind advisories will likely be issued later in the day these
areas. The north flow will also bring upslope clouds and a slight
chc of showers to north slopes near the Kern County line. Low
confidence in the stratus forecast which may well be mixed out.
Right now betting on the the north winds to clear out most of VTA
county and the SBA south coast with cloudy conds across LA county
and the Central Coast.
Friday will be a breezy day as the NW flow reaches its maximum.
These winds will scour out the low clouds and will be a sunny day.
Advisory level gusts are likely for the Santa Ynez Mountains, VTA
mtns, northern I-5 corridor, and Antelope Valley. Look for 3 to 6
degrees of warming which will only make a small dent in the below
normal max temps.
A little inside slider will move down the CA/NV border Friday
night and will again bring a slight chc of N slopes showers to the
N slopes near the Kern county line. It will also reinforce the N
winds and advisory level northerly winds will likely continue
through dawn in the mtns and Antelope Vly with the strongest winds
focused through the I-5 corridor.
Saturday will see sunny skies and decreasing winds. 3 to 6 degrees
of warming will result from the offshore flow from the north, the
lack of marine layer, sunny skies and rising hgts.
.LONG TERM (SUN-WED)...25/326 AM.
Sunday and Monday will be very nice days with plenty of sunshine
and warming temps. All brought about by a weak ridge moving
overhead, weaker onshore flow to the east and continued offshore
flow from the north. Monday will likely be the warmest day of the
next 7 with highs in the 70s and lower 80s in the valleys and
upper 60s and 70s near the coast. These max temps will end up a
degree or 2 either side of normals.
Tuesday may have similar temps to Monday or it will cool some. It
all depends on how quickly the ridge breaks down and onshore flow
increases.
Troffing and increased onshore flow and a likely return of coastal
low clouds will ensure that Wednesday ends up about 4 degrees
cooler than Tuesday.
&&
.AVIATION...25/1310Z.
At 12Z at KLAX, there was no true marine layer, but a moist layer
up to about 7000 feet.
Widespread clouds were affecting the forecast area except for the
Antelope Valley and the highest mtns. Conds were mostly low VFR
to high MVFR, except IFR to VLIFR in the foothills/mtns. Skies
should become partly cloudy in most areas by late morning. Even
where it stays cloudy, cigs should be in the VFR category, except
in the foothills and mtns, where IFR conds may persist. Expect
widespread clouds again tonight, but with a weakening inversion,
clouds may be less solid in nature. Expect high MVFR to VFR cigs
tonight, except IFR to VLIFR conds in the foothills/mtns. Gusty NW
winds will affect southern SBA County and the I-5 Corridor, with
gusty W winds in the Antelope Valley. There will be some LLWS and
turbulence, with mdt UDDF near the mtns.
KLAX...Moderate confidence in TAF. Conds are expected to improve
to VFR by mid morning. There is a 20% chance that MVFR cigs will
persist until 19Z-20Z. There is a 20% chance that cigs will scatter
out from 21Z today to 03Z Fri. There is a 20% chance that conds
will remain VFR tonight, with cigs above 3000 ft. No east wind
component expected.
KBUR...Moderate confidence in TAF. Conds are expected to improve
to VFR by noon. There is a 20% chance that cigs will rise into
the VFR category as early as 17Z. There is a 20% chance that cigs
will scatter out from 21Z today to 03Z Fri. There is a 20% chance
that conds will remain VFR tonight, with cigs above 3000 ft.
&&
.MARINE...25/611 AM.
In the Outer Waters, good confidence that winds will reach Small
Craft Advisory (SCA) levels this morning, or at least by early
afternoon. SCA level winds and seas will likely continue thru Mon.
There is a 20% chance of gales in the southern 2 zones (PZZ673/676)
this evening thru late tonight. There is a 60-70% chance of gales
across all of the outer waters Fri morning or early Fri afternoon
thru late Fri night, best chances in the southern 2 zones. There
is a 50% chance that gales will occur again Sat afternoon into Sat
night or possibly Sun, especially in the southern zones.
For the Inner Waters N of Pt. Sal, good confidence that winds will
reach SCA levels this morning or early this afternoon. SCA level
winds/seas will likely continue much of the time thru Mon. There
is a 50% chance of gales Fri afternoon/evening, with a 30% chance
of gales into Sat evening, with a brief respite Sat morning.
In the Inner Waters S Pt Conception, SCA conds are likely in western
portions of the SBA Channel by noon, spreading across the rest of
the Channel and into western portions of the southern inner waters
this afternoon. Winds may occasionally drop below SCA levels late
tonight or early Fri near the coast, then SCA level winds and seas
are expected from late Fri morning thru Sat night, and most likely
thru Mon. There is a 60-70% chance of gales Fri afternoon into Fri
night, with a 40-50% chance of gales Sat afternoon into Sat night.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 6 PM this evening to 6 AM PDT
Friday for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT Friday for
zones 645-670. (See LAXMWWLOX).
Gale Watch in effect from Friday afternoon through Friday
evening for zones 645-670. (See LAXMWWLOX).
Small Craft Advisory in effect from noon today to 9 AM PDT
Friday for zone 650. (See LAXMWWLOX).
Gale Watch in effect from Friday morning through late Friday
night for zones 650-673-676. (See LAXMWWLOX).
Small Craft Advisory in effect from 3 PM this afternoon to 3
PM PDT Friday for zone 655. (See LAXMWWLOX).
Gale Watch in effect from Friday afternoon through late
Friday night for zone 655. (See LAXMWWLOX).
Small Craft Advisory in effect until 9 AM PDT Friday for
zones 673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...Rorke/Sirard
AVIATION...DB
MARINE...DB
SYNOPSIS...JLD
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox
Office: STO
FXUS66 KSTO 250955
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
255 AM PDT Thu Apr 25 2024
.Synopsis...
Light rain and mountain snow this afternoon through Friday with
thunderstorm chances today and tomorrow, and best chances over
the foothills and mountains.
&&
.Discussion...
Another quiet night across Northern California outside of some
scattered cloud cover and breezy Delta winds. As of midnight,
observations show gusts 15 to 25 MPH in the Delta area, slowly
trickling down as the morning continues and returning in the
afternoon. Ensembles show a trough dropping down from the
northwest, moving into the Great Basin, that will bring
precipitation across our forecast area today into Friday, highest
over the mountains. Light sprinkles are possible across the
Sierra and Southern Cascades with a heavier precipitation
expected Thursday afternoon through Friday morning. Latest WPC QPF
totals are 0.25-1.00" over the mountains, 0.10-0.50" over the
foothills and 0.01-0.15" in the Valley, albeit dry over the Delta
and portions of the Northern San Joaquin Valley. Thunderstorms
will be possible this afternoon and evening (10-20% chance),
primarily north of I-80 through the northeast foothills. Friday
shows a better chance of thunderstorm development (15-30% chance),
highest over the I-80 and Hwy.50 corridor over the Sierra.
Lightning, brief heavy rain, gusty winds, and small hail will be
possible with any thunderstorms that develop.
Today's weak system will bring snowfall to the Sierra, but no
moderate travel impacts are expected. Snow levels will be 7000 to
8000 feet initially, lowering to 5500 to 6500 feet by Friday late
morning. Totals will only amount to a few inches, up to 8-10
inches along mountain peaks above 7000 feet. NBM probabilities
point to a lower snow totals with probabilities of 4 inches or
more only being 10-25% south of Hwy. 50 and less than 10%
elsewhere. Heaviest snowfall will be late Friday morning before
tapering off throughout the afternoon.
By Saturday, weak ridging develops over NorCal that will quiet any
lingering precipitation and warm afternoon Valley highs to the
mid to upper 70s and upper 40s to 60s across the mountains and
foothills respectively.
&&
.EXTENDED DISCUSSION (Monday THROUGH Thursday)...
Progs suggesting enough ridging in place over interior NorCal
Monday and Tuesday to keep short wave troughs north of the CWA.
Cluster analysis showing broader divergence in solutions beyond
Tuesday leading to increased forecast uncertainty midweek. EC now
maintaining more ridging in place resulting in continued dry
conditions, while GFS supports deeper troughing with potential for
mountain precip Wednesday night into Thursday. NBM leans toward
the GFS with POPs and forecasts above normal high temperatures
Monday into Wednesday, then below normal Thursday.
&&
.AVIATION...
Pac storm will bring a threat of showers, higher elevation mtn
snow showers and slight chance of thunderstorms next 24 hrs.
Mainly VFR conditions thru 12z Fri except areas MVFR/IFR
conditions possible over the mtns in precip. Snow levels above
7000 ft lowering to 5000-6000 ft Fri AM. In Central Vly, sfc wind
mainly below 12 kts til 21z Thu, then areas Sly sfc wind 15-20
kts. Vcnty Delta, SWly sfc wind 15-25 kts. Over mtns, areas Wly
sfc wind gusts up to 30 kts possible aft 18z Thu.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Office: SGX
FXUS66 KSGX 251422
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
722 AM PDT Thu Apr 25 2024
.SYNOPSIS...
Gusty southwest to west winds; areas of night and morning drizzle or
light rain; and cooler conditions are expected through Friday. A
deep marine layer will result in night and morning low clouds
throughout much of the coastal basin for the next couple of days. A
gradual warming is expected over the weekend into early next week.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Visible satellite at 7 AM was showing widespread cloud coverage
in the coastal basin, with mostly clear skies in the deserts.
Showers developed overnight, and are currently (as of 7 AM) moving
southeast across San Diego County. Rain has been light, with
0.01-0.05 inches of accumulation over the past 12-hours for the
coast and valleys. In the mountains accumulations have been a
little bit higher with 0.06- 0.08 inches of accumulation. Showers
are expected to taper off by mid-morning. The upper level pattern
stays relatively unsettled into Friday with periods of drizzle or
light rain expected each night and morning through Friday night.
Periods of gusty southwest to west winds will continue over the
mountains and into the deserts through Friday night. Over the past
24-hours, the top wind gusts have been recorded through and below
the San Gorgonio Pass into portions of the northern Coachella
Valley. The top gust so far occurred at Whitewater RAWS just
before 1 AM with a gust of 69 mph. Winds are expected to weaken
into this morning, before strengthening again this afternoon and
overnight. Peak gusts for this afternoon into early Friday morning
will be mostly 50 to 60 mph on the desert mountain slopes,
locally into the deserts. Local gusts up to 70 mph possible
through the San Gorgonio Pass near Whitewater. Gusty winds will
continue for Friday afternoon into early Saturday. There is a
potential for more widespread coverage of stronger wind gusts on
Friday as a low pressure system moves into the Great Basin and
east into the Four Corners region through early Saturday morning.
Gusts of 50 to 65 mph are expected. There will also be the
potential for gusts 70 to 75 mph in wind prone locations like
through the San Gorgonio Pass.
High temperatures today are expected to be a degree or two cooler
than yesterday near the coast and valleys, with highs 5 to 10
degrees cooler than yesterday in the mountains and deserts.
Widespread below average high temperatures are expected into
Saturday. By Sunday, highs will warm to near average, with some
locations still a degree or two cooler than average for this time of
year. Further warming is expected into early next week. By the
middle of next week, some uncertainty develops in the upper level
pattern. This introduces uncertainty into the temperature forecast,
with the potential for a few degrees of cooling. This uncertainty
also impacts the depth of the marine layer. Current forecast
reflects a shallower marine layer for early next week, slowly
deepening into the middle to end of next week.
&&
.AVIATION...
251445Z...Coast/Valleys/Foothills...OVC low clouds based from 2500-
3500 feet MSL and tops to 6000 feet will continue, along with
scattered -DZ or -SHRA dropping cigs to 2000 feet and vis to 3-5SM
with higher terrain obscured through 18Z. BKN briefly SCT low clouds
will prevail thereafter with bases 3000-5000 feet through 03Z. BKN-
OVC low clouds based around 2500-3500 feet MSL along with some
obscuration of higher terrain overnight into Friday.
Mountain Ridges/Deserts...Areas of west winds with surface gusts 25-
55 kt today and tonight. Occasional LLWS and rotors near lee slopes
and adjacent deserts, such as vcnty KPSP, along with MOD
up/downdrafts. Areas of reduced vis 2-5SM in BLDU in deserts.
&&
.MARINE...
Stronger winds and higher seas will generate hazardous boating
conditions Friday through early Saturday, especially beyond 15 NM
offshore. A few gales are possible Friday night near San Clemente
Island. The Small Craft Advisory contains the details. Otherwise, no
hazardous marine conditions are expected.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 11 PM PDT Friday 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...Small Craft Advisory from 1 PM Friday to 7 AM PDT Saturday for
Coastal Waters from San Mateo Point to the Mexican Border
and out to 30 nm.
Small Craft Advisory from 3 AM Friday to 11 AM PDT Saturday for
Waters from San Mateo Point to the Mexican Border Extending
30 to 60 nm out including San Clemente Island.
&&
$$
PUBLIC...CO
AVIATION/MARINE...Small
Office: MTR
FXUS66 KMTR 251756
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1056 AM PDT Thu Apr 25 2024
...New AVIATION, MARINE...
.SYNOPSIS...
Issued at 1201 AM PDT Thu Apr 25 2024
Cool temperatures will continue today. A cold front will bring
a chance for light rain beginning tonight, with strong winds
Friday night. Increasing sunshine will kick off a warming trend
Sat-Tue.
&&
.SHORT TERM...
(Today and tonight)
Issued at 1201 AM PDT Thu Apr 25 2024
A coastal surface trough will continue to weaken and move inland,
allowing a low-amplitude ridge to build. This will cause the
marine layer to compress to about 1,500 ft. Compared to the 4,000
ft deep marine layer observed Wednesday, the low overcast today
will be more limited to the coast and adjacent low valleys. The
standard NW flow will also return as the trough weakens. The cool
temperatures will continue, with highs generally in the 60s. This
ridge pattern will be short lived as a cold front moves through on
Friday.
&&
.LONG TERM...
(Friday through Wednesday)
Issued at 1201 AM PDT Thu Apr 25 2024
Some light rain is possible starting ahead of the cold front
Thursday night, with low PoPs lasting though the day Friday.
22/26 members of the SREF have some precipitation falling at SFO
between Thursday night and Friday, but only 4 of them are above
0.05" of accumulation, and none of those are above 0.1". Similar
results are found throughout the Bay Area, with slightly more
bullish results along the Central Coast. As such, I have
increased the NBM PoPs to at least 15% to ensure a slight chance
of rain is mentioned, but did not increase the QPF from the WPC
guidance, which is near zero. There's a decent chance some rain
falls late Thursday-Friday, but it will be light.
The bigger impact will be from strong NW winds behind the cold
front. 24 hours ago, it looked like a slam dunk wind advisory
along the coast, but the models have backed off since then. NBM is
on the high side of the guidance, but only shows a slight chance
of exceeding 40 mph gusts along the coast on Friday night. The
timing of the strongest winds has also shifted from Friday
afternoon to overnight Friday. Based on this, and the fact that
other deterministic models are even less aggressive, we are not
hoisting a wind advisory at this time. That being said, there will
be plenty of gusts above 30 mph on Friday and Saturday with some
minor impacts expected.
The weekend will feature clearing skies and slightly warmer
temperatures, although Saturday will still be breezy. The gradual
warm-up will continue through early next week, as the region
returns to seasonal temperatures under mostly clear skies. The
next threat of rain arrives late next week.
&&
.AVIATION...
(18Z TAFS)
Issued at 1056 AM PDT Thu Apr 25 2024
Satellite shows low ceilings shuffling through the region
causing MVFR conditions over most of the terminals. Onshore winds
will continue to build to breezy and gusty through the afternoon
with some terminals seeing relief overnight to moderate winds. SF
Bay terminals are expected to remain gusty and breezy through the
TAF period. Stratus may lift to VFR for brief moments this afternoon
before lower ceilings will return tonight bringing a mix of VFR/MVFR
conditions overnight. VFR is expected to return by Friday morning.
Vicinity of SFO...MVFR with W/NW breezy and gusty winds. Models
suggest a short brief moment of VFR near the afternoon but had low
confidence to include in TAFs. If lifting does occur, expect MVFR
conditions to linger near by the terminals. Winds will remain breezy
and gusty through the TAF period.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...MVFR through most of the TAF period for
KMRY but KSNS may see a temporary lift to VFR this afternoon. Winds
will become breezy and gusty this afternoon, before transitions to
moderate overnight. VFR expected to prevail after 12Z.
&&
.MARINE...
Issued at 1056 AM PDT Thu Apr 25 2024
Moderate northwesterly winds persist through Friday morning with
occasional fresh to strong gusts through various portions of the
coastal waters, mostly in the southern waters. Winds strengthen
to become strong and gusty into Friday afternoon with gale-force
gusts likely near the Big Sur coast. These strong and gusty
northwesterly winds last through the weekend and into at least the
early portion of next week, bringing hazardous conditions for
small craft vessels. Moderate period northwest swell will
continue to move through the waters this weekend, with a new
longer period northwest swell train entering the waters Sunday.
Light, long period southerly swell continues through end of
forecast period.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay.
Small Craft Advisory from 9 AM to 3 PM PDT Friday for Mry Bay-
Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60
NM.
Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt
to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos
to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
evening for Pigeon Pt to Pt Pinos 0-10 nm.
Gale Warning from 3 PM this afternoon to 9 PM PDT this evening
for Pt Pinos to Pt Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...SO
MARINE...SO
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