Home > Products > Valid Products > AFD

000
FXUS66 KLOX 291150
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
450 AM PDT SUN MAY 29 2016

.SYNOPSIS...
The cut-off low pressure system currently overhead will once
again support the chance for afternoon thunderstorms today in
the mountains and Antelope Valley. High pressure aloft will build
into the area by the middle of next week... supporting much warmer
conditions that will likely persist into next weekend.

&&

.SHORT TERM...(TDY-TUE)

The marine layer is 2500 feet deep and capped by a fairly strong
inversion. Marine layer stratus covers almost all of the coasts
and vlys. Good offshore trends are forecast today as an upper low
moves directly over the area. The offshore trends will allow for
slightly better and slightly faster clearing today compared to
yesterday. There is some uncertainty with this line of thinking
as there are currently onshore trends. If the pressure gradient
fcst is wrong then there will be slow to no clearing across the
coasts again.

The other big issue of the day is the thunderstorm chances. The
upper low and its associated destabilizing cool pool of air aloft
will be overhead this afternoon right at peak heating. This will
make today more unstable than yesterday...but there will be less
PVA today then ydy when the low was just to the west. Without the
PVA there may not be trigger to start the initial lift that will
allow the atmosphere to exploit the instability. Still there is
likely enough differential mtn slope heating in the mtns to kick
off some development. If TSTMs do get started then their outflows
will trigger more TSTMs in sort of an atmospheric chain reaction.
Any TSTMs that do form will be slow moving so the greatest threat
today will be flash flooding but there is not that much water to
work with and the TSTMs should be pretty short lived so the flash
flood threat is on the lower side of things.

The deep marine layer and the falling hgts caused by the upper low
will combine to produce cooler temps than normal...again.

There is a non zero chance that the outflows from the afternoon`s
and evening`s convection will mix the marine layer up a bit...but
its more likely that that will not happen and that there will be
a solid marine layer again tonight.

There should be good onshore trends on Monday and this will result
in another cloudy and cool day across most of the coasts with much
slower than normal clearing in the vlys. The upper low will be too
far away to create any shower threat but partly cloudy skies will
likely develop over the mtns in the afternoon due to sunshine and
some residual low level moisture.

A ridge builds in on Tuesday and hgts climb up to 582 DM. This
kind of warming aloft will really strengthen and squash the
inversion. The lower marine layer depth will not allow as many
clouds into the vlys as previous mornings but the very strong
inversion will be hard to bust up and again many beaches may stay
cloudy. Max temps will leap to above normal readings while coastal
and esp beach temperatures will hardly change at all.

.LONG TERM...(WED-SAT)

The ridge will persist over the area Wed and Thu. Both days will
resemble Tuesday with a shallow marine layer capped by a strong
inversion. The beaches will have a tough time clearing. Above
normal temps will continue inland with much cooling readings near
to the beaches.

Something rather interesting is currently forecast by both the EC
and the GFS for next Friday and Saturday. An upper low moves into
the area to the WSW of Pt Conception. It will bring plenty of
south flow into the area. Not going to anything more than bring in
partly cloudy skies to the fcst now but will have to keep a wary
eye on this time period.

&&

.AVIATION... 29/12Z...

AT 08Z AT KLAX... THE INVERSION WAS ABOUT 1250 FEET DEEP. THE TOP
WAS NEAR 3900 FEET WITH A TEMPERATURE OF 16 DEGREES CELSIUS.

OVERALL... MODERATE TO HIGH CONFIDENCE IN THE 12Z TAFS. THE
SLIGHTLY REDUCED CONFIDENCE IS DUE TO THE GENERAL UNCERTAINTY IN
MARINE INCURSION BEHAVIOR AND BECAUSE THE CATEGORY CHANGES AND
CLEARING TIMES MAY BE OFF BY +/- 1 HOUR. SOME LOCALES MAY NOT
FULLY CLEAR PRIOR TO THE MARINE INCURSION RETURNING THIS EVENING.
ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THE MOUNTAINS AFTER 22Z.
OTHERWISE AND ELSEWHERE VFR CONDITIONS ARE EXPECTED.

KLAX... MODERATE TO HIGH CONFIDENCE IN THE 12Z TAF. THE SLIGHTLY
REDUCED CONFIDENCE IS DUE TO THE GENERAL UNCERTAINTY IN MARINE
INCURSION BEHAVIOR AND BECAUSE THE CATEGORY CHANGES AND CLEARING
TIMES MAY BE OFF BY +/- 1 HOUR. THERE IS A TWENTY PERCENT CHANCE
THAT MVFR CONDITIONS WILL NOT CLEAR TODAY.

KBUR... MODERATE TO HIGH CONFIDENCE IN THE 12Z TAF. THE SLIGHTLY
REDUCED CONFIDENCE IS DUE TO THE GENERAL UNCERTAINTY IN MARINE
INCURSION BEHAVIOR AND BECAUSE THE CATEGORY CHANGES AND CLEARING
TIMES MAY BE OFF BY +/- 1 HOUR. THERE IS A FIFTEEN PERCENT CHANCE
THAT MVFR CONDITIONS WILL NOT CLEAR TODAY.

&&

.MARINE... 29/230 AM...

Conditions will remain below advisory levels through at least
Thursday.  The northwest swell across the coastal waters will
diminish through the middle of the week. A long period south swell
is expected to reach the coastal waters by Tuesday then peak on
Wednesday before gradually diminishing.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&
$$

PUBLIC...Rorke
AVIATION...KJ
MARINE...KJ
SYNOPSIS...Munroe

weather.gov/losangeles





000
FXUS66 KLOX 291035
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
335 AM PDT SUN MAY 29 2016

.SYNOPSIS...
The cut-off low pressure system currently overhead will once
again support the chance for afternoon thunderstorms across
the mountains and pushing into the Antelope Valley on Sunday.
High pressure aloft will build in behind into the area by the
middle of next week, supporting much warmer conditions that
will likely persist into next weekend.

&&

.SHORT TERM...(TDY-TUE)

The marine layer is 2500 feet deep and capped by a fairly strong
inversion. Marine layer stratus covers almost all of the coasts
and vlys. Good offshore trends are forecast today as an upper low
moves directly over the area. The offshore trends will allow for
slightly better and slightly faster clearing today compared to
yesterday. There is some uncertainty with this line of thinking
as there are currently onshore trends. If the pressure gradient
fcst is wrong then there will be slow to no clearing across the
coasts again.

The other big issue of the day is the thunderstorm chances. The
upper low and its associated destabilizing cool pool of air aloft
will be overhead this afternoon right at peak heating. This will
make today more unstable than yesterday...but there will be less
PVA today then ydy when the low was just to the west. Without the
PVA there may not be trigger to start the initial lift that will
allow the atmosphere to exploit the instability. Still there is
likely enough differential mtn slope heating in the mtns to kick
off some development. If TSTMs do get started then their outflows
will trigger more TSTMs in sort of an atmospheric chain reaction.
Any TSTMs that do form will be slow moving so the greatest threat
today will be flash flooding but there is not that much water to
work with and the TSTMs should be pretty short lived so the flash
flood threat is on the lower side of things.

The deep marine layer and the falling hgts caused by the upper low
will combine to produce cooler temps than normal...again.

There is a non zero chance that the outflows from the afternoon`s
and evening`s convection will mix the marine layer up a bit...but
its more likely that that will not happen and that there will be
a solid marine layer again tonight.

There should be good onshore trends on Monday and this will result
in another cloudy and cool day across most of the coasts with much
slower than normal clearing in the vlys. The upper low will be too
far away to create any shower threat but partly cloudy skies will
likely develop over the mtns in the afternoon due to sunshine and
some residual low level moisture.

A ridge builds in on Tuesday and hgts climb up to 582 DM. This
kind of warming aloft will really strengthen and squash the
inversion. The lower marine layer depth will not allow as many
clouds into the vlys as previous mornings but the very strong
inversion will be hard to bust up and again many beaches may stay
cloudy. Max temps will leap to above normal readings while coastal
and esp beach temperatures will hardly change at all.

.LONG TERM...(WED-SAT)

The ridge will persist over the area Wed and Thu. Both days will
resemble Tuesday with a shallow marine layer capped by a strong
inversion. The beaches will have a tough time clearing. Above
normal temps will continue inland with much cooling readings near
to the beaches.

Something rather interesting is currently forecast by both the EC
and the GFS for next Friday and Saturday. An upper low moves into
the area to the WSW of Pt Conception. It will bring plenty of
south flow into the area. Not going to anything more than bring in
partly cloudy skies to the fcst now but will have to keep a wary
eye on this time period.

&&

.AVIATION...

29/0600Z

At 0535Z at KLAX the marine layer was 1500 feet deep. The
inversion top was at 2600 feet with a temp of 17 degrees C.

Good confidence in TAFs. Cat changes and clearing times may be
off by +/- 1 hour. There will be isolated TSTMs over the mtns aft
22Z.

KLAX...Good confidence in TAF. There is a 20 percent chc of VFR
conds aft 21Z.

KBUR...Good confidence in TAF. IFR/MVFR transitions and clearing
could occur +/- 1 hour from fcst time.

&&

.MARINE...

29/230 AM

Conditions will remain below advisory levels through at least
Thursday.  The northwest swell across the coastal waters will
diminish through the middle of the week. A long period south swell
is expected to reach the coastal waters by Tuesday then peak on
Wednesday before gradually diminishing.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...Rorke
AVIATION...Rorke
MARINE...KJ
SYNOPSIS...Munroe

weather.gov/losangeles





000
FXUS66 KLOX 290603
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1100 PM PDT SAT MAY 28 2016

Updated Aviation Discussion

.SYNOPSIS...
The cut-off low pressure system currently overhead will once
again support the slight chance for afternoon thunderstorms
across the mountains and pushing into the Antelope Valley on
Sunday. High pressure aloft will build into the area by the
middle of next week, supporting much warmer conditions that
will likely persist into next weekend.

&&

.UPDATE...

A weak upper low just to the west of Point Conception was in a
good position to rotate a weak lobe of PVA into SBA county this
afternoon. The lift from the PVA interacted with weak instability
over the interior sections to spawn about a half dozen TSTMs. The
TSTMs were short lived pulse storms that likely produced brief
heavy downpours and perhaps some small hail.

The marine layer was slow to clear today and there was no clearing
across the south facing beaches of LA and VTA counties as well as
the central coast. The Marine layer stratus deck will slowly
reform overnight and by dawn low clouds will again cover the
coastal and vly areas.

Moderate onshore flow and the late clearing kept max temps several
degrees blo normal across the coasts and vlys but 574 DM hgts and
plenty of sunshine allowed the interior to warm to near normal
temps.

Forecast is in good shape and no updates are planned. The big
question mark is tomorrow afternoon`s convection. The upper low
will sit right atop of the area. This will mean better instability
but less in the way of low level dynamics. Given the very steep
sun angle think that there will be enough differential heating to
kick of some storms.

&&

.SHORT TERM...(SAT-TUE)

The weak upper level low will drift se across the forecast area
tomorrow morning, then into sern CA for Sun afternoon. An e-w
oriented upper level trof will linger over srn ca Sun night and
Mon, while at the same time upper level ridging builds into
central and nrn CA. The upper ridge will expand into swrn ca Mon
night and Tue.

The marine layer pattern will continue over the next few days, with
the inversion forecast to gradually strengthen and lower each day,
most pronounced Mon night and Tue as the upper ridge builds in and
boundary layer temps warm up. Extensive night and morning low clouds
and fog can be expected to affect the coast and adjacent vlys
tonight thru Tue morning, altho the inland extent of the low clouds
will diminish considerably Mon night due to the shrinking marine
inversion. There will be the possibility of afternoon cu buildups in
the mtns Sun thru Mon, but for Sun there should continue to be
enough moisture and instability for the formation of isolated
showers or thunderstorms in far sern SLO County, Cuyama Vly, the
mtns of SBA/VTU/L.A. Counties and in the Antelope Vly. Any
thunderstorms that develop could drift s into the adjacent vlys over
VTU/L.A. Counties as well by late Sun afternoon or early evening.
The 12Z NAM does indicate the best chance of thunderstorms Sun
afternoon to be over eastern San Gabriel Mtns, but even so a slight
chance of showers and thunderstorms is in the forecast for all of
the above mentioned areas. Otherwise, mostly clear skies are
expected over the forecast area for the most part Sun thru Tue. A
typical onshore flow pattern is expected each afternoon and evening,
with locally gusty sw to nw winds for the foothills, mtns and
Antelope Vly.

Temps for Sun are forecast to be generally 3 to 6 deg below normal
for the cst and adjacent vlys, while inland vlys, mtns and deserts
will be near normal to slightly above seasonal norms. For Mon, temps
will warm a few degrees, especially in the interior areas, mtns and
deserts, where highs should be 4 to 10 deg above normal. For the
coastal plain, Santa Ynez Vly, and vlys of VTU/L.A. Counties, highs
on Mon will be 2 to 6 deg below normal overall. It`ll be warmer
still for Tue with many areas away from the coastal plain warming to
4 to 12 deg above normal. Highs in the warmest vlys on Tue should
reach the upper 80s to mid 90s.


.LONG TERM...(WED-SAT)

The EC and GFS are in decent agreement Wed and Thu with upper
ridging over the area. For Fri and Sat, the EC keeps the fcst area
on the w side of a large upper ridge, while the GFS brings a broad
upper trof to the CA cst Fri, then upper troffiness moves over the
area thru Sat while a weak upper low swings into nrn Baja from the e
Pac. Either solution will keep dry and warm conditions over swrn CA
thru the extended period. Night and morning marine layer clouds will
continue to affect mainly coastal areas Wed, then be confined to the
L.A. County coast Thu thru Sat. Otherwise, mostly clear skies will
prevail across the region Wed thru Sat. There will continue to be
typical onshore flow afternoon and evening hours, with locally gusty
sw to nw winds in the foothills, mtns and deserts.

Temps will warm to about 5 to 12 deg above normal for many areas
away from the coastal plain Wed thru Fri, with slight cooling
expected on Sat. The warmest days should be Thu and Fri, with highs
in the warmest vlys and foothills reaching the upper 80s to mid 90s,
except mid to upper 90s in the Antelope Vly.

&&

.AVIATION...

29/0600Z

At 0535Z at KLAX the marine layer was 1500 feet deep. The inversion
top was at 2600 feet with a temp of 17 degrees C.

Good confidence in TAFs. Cat changes and clearing times may be off
by +/- 1 hour. There will be isolated TSTMs over the mtns aft 22Z.

KLAX...Good confidence in TAF. There is a 20 percent chc of VFR
conds aft 21Z.

KBUR...Good confidence in TAF. IFR/MVFR transitions and clearing
could occur +/- 1 hour from fcst time.

&&

.MARINE...

28/900 PM PDT

Sub small craft advisory level short period waves currently across
portions of the outer waters will gradually diminish overnight.
Small craft conditions for winds or seas are not currently
expected through at least Thursday. The northwest swell currently
across the coastal waters is expected to gradually diminish
through the middle of next week. A long period south swell is
expected to reach the coastal waters by Tuesday, peaking
Wednesday, before gradually diminishing.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...JS/Rorke
AVIATION...Rorke
MARINE...Munroe/30
SYNOPSIS...Munroe

weather.gov/losangeles





000
FXUS66 KLOX 281249
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
549 AM PDT SAT MAY 28 2016

.SYNOPSIS...
Weak low pressure will linger over the area keeping temperatures
a little below normal through Sunday. There is a slight chance of
thunderstorms across mountains and some interior valleys on
Saturday afternoon and evening. Next week, high pressure will
build in causing a gradual warming trend across inland areas
while the coastal temperatures will remain steady.

&&

.SHORT TERM...(TDY-MON)

Latest fog product imagery indicated low clouds filling in
across all coastal areas and into the LA county valleys. For areas
S of Point Conception...expect all coastal valleys to be affected
with low clouds and patchy fog by sunrise this morning. Latest
AMDAR sounding around LAX indicated a strong inversion at
2000 ft this morning. Low clouds should scour out from the valleys
by mid morning...then across coastal areas to near the beaches by
early to mid afternoon. There will be a better chance that several
beaches could only see partial clearing or no clearing at all this
afternoon due to the stronger inversion and a southerly low level
wind push that could keep low clouds lingering across the
beaches...especially Santa Barbara south coast and Ventura
Counties. Some of the low clouds could move north around Point
Conception into the local beaches of the Santa Barbara South Coast
into the early afternoon hours.

Synoptically, a weak upper trough will become cutoff over the
forecast area this afternoon and meander a bit southeast still
remaining over the area into Sunday. There will be enough cooling
aloft and warming at the surface to help steep lapse rates to
cause the atmosphere to become marginally unstable over the
mountains and interior areas today and once again on Sunday. There
will be the possibility of isolated thunderstorms across the
mountains and interior valleys including the Antelope Valley this
afternoon and early evening. There is plenty of instability over
the mountains with CAPE over 1,000 j/kg and Lifted Index values
ranging from -3 to -5. The best chance for storms to initiate
today will be over the Ventura County Mountains. There continues
to be limited moisture over the area so not anticipating any flash
flooding. One of the frustrations in forecasting convection over
the mountains in recent days has been the soundings looking a bit
overdone. However both the GFS and NAM are in agreement that 850
mb dew point temps are forecasted to be between 8-10 degrees
celsius which should help juice up the mid levels a bit. Have
added the Antelope Valley with slight chance POPS as the steering
winds of storms that initiate over the mountains could drift to the
north. Isolated showers or thunderstorms will diminish by early
this evening...if they do develop. Remember only 20% chance.

Expect a similar weather pattern tonight into Sunday with the
return of night through morning low clouds across coast and
valleys. There could be some low clouds lingering across the coast
once again in the afternoon hours. Also, a similar convective
pattern as mentioned earlier for the mountains and interior
locations...best chance of the LA county mountains. Any storms
that do develop will now drift to the south and a bit slower
moving. Have added slight chance POPS to the LA/VTU county
adjacent valley foothills in case a rogue shower moves to the
south off the mountains. The shower chances will diminish on
Monday...but there will continue to be the usual May Gray night
through morning low clouds over the coast and valleys.

Temps are forecast to change little from yesterday thru Sun.
Highs will be generally 3 to 6 deg below normal for the cst and
adjacent vlys, while inland vlys, mtns and deserts will be near
normal to slightly above seasonal norms. For mon, temps will warm
a few degrees, especially in the interior areas, mtns and deserts,
where highs should be 4 to 10 deg above normal. For the coastal
plain, Santa Ynez Vly, and vlys of VTU/L.A. Counties, highs on Mon
will be 2 to 6 deg below normal overall. The warmest day will be
on Mon, with highs expected to reach the 80s to around 90 in the
warmest vlys and foothills, except lower 90s in the Antelope Vly.

.LONG TERM...(TUE-FRI)

The EC and GFS remain in fairly good agreement Tue thru Wed with
upper level ridging moving into CA. The models continue to diverge
greatly by Thursday into Friday with the GFS more bullish on
bringing another upper broad trough over the region while the EC
is under a strengthening ridge. For now, will continue to lean
toward the GFS solution as the Canadian mdl falls more in line
with solution.

There will continue to be night through morning low clouds...but
with the upper ridge overhead during much of the extended period,
the inversion will be more shallow and should allow a quicker
clearing along inland areas or remain clear across valleys
altogether. Some limited clearing and patchy dense fog will be
possible as well along coastal areas late night into early morning
hours.

Temps will rise significantly inland from Tue-Thu with only a
slight cool off on Friday. It looks like temps will warm several more
degrees for Tue with highs about 4 to 10 deg above normal away
from the coastal plain. By Thu, highs will warm further to about 5
to 12 deg above normal for many areas away from the immediate
coast, with similar temps expected on Fri. The warmest day overall
in the extended period should be Thu with highs reaching the upper
70s to lower 80s for the inland coastal plain, the 80s to low 90s
in the vlys and foothills, and mid 90s to near 100 in the Antelope
Vly.

&&

.AVIATION...28/12Z.

At 1100Z the marine layer at LAX was 2000 feet deep. The top of
the inversion was at 3000 feet with a temp of 18 degrees C.

Widespread low clouds in all coastal and valley areas, except the
interior valleys of SLO and SBA counties and the Santa Clarita
Valley. Conds were generally IFR north and MVFR south. Expect
clearing in most areas by afternoon, except low clouds may linger
near the beaches, especially s of Pt Conception. There is a slight
chance of Tstms across interior sern SLO County, the Cuyama
Valley, the mtns, and the Antelope Valley this afternoon and
evening. Expect widespread low MVFR to high IFR cigs in all
coastal and valley areas tonight/Sunday morning.

KLAX...Low to moderate confidence in the 12z TAF. There is a 30
to 40 percent chance that cigs will not scatter out this
afternoon.

KBUR....Moderate confidence in the 12z TAF. There is a 20 to 30
percent chance that cigs will scatter out as early as 17z.

&&

.MARINE...28/300 AM PDT.

Winds have dropped below SCA levels across the outer waters, and
all advisories have been allowed to expire. There is a 30 percent
chance of SCA level winds across the outer waters, mainly the
northern two thirds Monday afternoon through Tuesday evening.
Otherwise, SCA conds are not expected through Wednesday.

Long period south swell arrive late Monday and build through
Tuesday. The swells will remain below small craft advisory for
hazardous seas but there will be extra surging and currents along
exposed south facing shores.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...CK
AVIATION...DB
MARINE...DB
SYNOPSIS...CK

weather.gov/losangeles





000
FXUS66 KLOX 271153
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
453 AM PDT FRI MAY 27 2016

.SYNOPSIS...

Weak low pressure will linger over the area through the weekend.
This system will keep afternoon temperatures a little below normal
through Sunday and generate a slight chance of mountain
thunderstorms Saturday afternoon. For next week, high pressure
will build in from the west. For inland areas, a gradual warming
trend is expected while a continued marine influence will keep
coastal temperatures nearly persistent.
&&

.SHORT TERM...(TDY-SUN)

Latest fog product imagery indicated a late surge of stratus
filling across the southern portion of the SoCal Bight and should
fill in across LA County Coast and coastal valleys and into
Ventura County coast and southern valleys by dawn. There was
plenty of stratus across much of the Central Coast and Santa Ynez
Valley as well. Latest AMDAR sounding showed the marine layer only
around 1600 ft this morning with a modestly stronger inversion in
place. This will help the low clouds become more organized through
this morning. Expect low clouds to scour out from the valleys
first, then to the coast by early afternoon.

Synoptically, a weak upper trough will sit over much of California
today through saturday. The weak upper low associated with the
trough will cutoff over southern california by Sunday morning.
This will keep high temps near or just below normal for this time
of year. The marine layer inversion should be a bit stronger and
more shallow than recent weeks, which should translate into a
more traditional night through morning low cloud regime, where
clouds will scour out from the valleys first, then to the coast by
late morning to early afternoon hours. Some immediate coastal
areas could see only partial afternoon clearing both Saturday and
Sunday afternoons. Some limited mid level moisture and instability
will likely generate some afternoon cloud buildups over the local
mountains this afternoon. On Saturday, there was a slight chance
of thunderstorms in the forecast for the Ventura/LA county mtns.
Although the instability looks decent, there will continue to be
limited mid level moisture and any storms that do develop will be
high based above 700 mb, so changed to slight chance of showers as
opposed to thunderstorms. it seems as though the NAM has been
overdone with convective parameters, as there has been no real
vertical cumulus cloud growth over the last few days, so not
terribly confident with showers developing. Models also show a
chance for afternoon showers over the same mountainous areas of
LA/VTU on Sunday but will hold off for now and let later shifts
look at it. The May Gray pattern will continue into next week.

.LONG TERM...(MON-THU)

Both the ECMWF and GFS are in pretty good agreement during the
extended period. The upper low will will shift east as an upper
ridge will build in from the eastern Pacific and persist through
at least next Wed before weakening as a broad upper level trof
over the e Pac approaches. The models start to diverge on
Wednesday as the ECMWF holds onto the upper ridging more so than
the GFS by Thu. Overall, it looks like a typical June gloom marine
layer pattern will prevail during the extended period with night
and morning low clouds and fog for the coast and coastal vlys.

The marine layer could be disturbed a bit across the central coast
Monday night/Tue Morning, and again the following night and
morning due to some weak offshore winds, but expect some patchy
low clouds to develop. Sundowner winds should also keep the SBA
south coast mostly clear with little chance of low clouds during
the same time period mentioned.

Temps are forecast to become increasingly warm and several degrees
above normal over interior areas, while the coast and adjacent vlys
will be near normal to a few degrees below normal thru the week. The
warmest day next week is expected to be on Wed with highs from the
upper 60s and 70s at the coast to upper 70s and 80s for the vlys and
foothills, except warming into the lower to mid 90s in the Antelope
vly.


&&

.AVIATION...27/1145Z.

At 11Z at KLAX...The marine layer was 2000 feet deep. The top of
inversion was 4500 ft with a temperature of 15 degrees Celsius.

N of Pt Conception, low clouds were widespread on the Central Coast
and in the Santa Ynez Valley, and were spilling into the Salinas
Valley. S of Pt Conception, clouds were beginning to push into
south coastal sections of L.A. County, and will become widespread
across coastal sections by daybreak. Clouds will likely push into
the San Gabriel Valley. Conditions were mostly low MVFR S of Pt
Conception, and IFR north. Expect skies to clear in most areas by
mid to late morning, except maybe early afternoon near the beaches.
More widespread low clouds are expected tonight/Sat morning, with
clouds expected in all coastal and most valley areas. Conds
should be mainly low MVFR or high IFR tonight.

KLAX...Moderate confidence in the 12z TAF. There is a 30 percent
chance that cigs will scatter out as early as 17z. There is
a 30 percent chance that cigs tonight will not arrive until
06z or later.

KBUR...Moderate confidence in the 12z TAF. There is a 30 percent
chance of MVFR cigs between 13z and 17z this morning. There is a
20 to 30 percent chance that cigs will arrive as early as 07z
tonight, and could be at IFR levels.

&&

.MARINE...27/300 AM

Across the outer waters, winds may drop below Small Craft
Advisory levels for a few hours this morning, but will likely
reach SCA levels again this afternoon through late tonight.

There is a 20 to 30 percent chance of SCA level winds
across the northern portions of the outer waters each
afternoon and evening Saturday through Monday.

Fairly high confidence that conds will remain below SCA levels
across the inner waters and the SBA Channel through Monday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Saturday For
      zones 670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...CK
AVIATION...DB
MARINE...DB
SYNOPSIS...CK

weather.gov/losangeles





    US Dept of Commerce
    National Oceanic and Atmospheric Administration
    National Weather Service
    1325 East West Highway
    Silver Spring, MD 20910
    Page Author: NWS Internet Services Team
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities