Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/30/17
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
828 PM PDT Mon May 29 2017
A trough of low pressure aloft will deepen across California mid
week, before gradually shifting east of the region late in the
week. This pattern will support a cooling trend with overnight to
morning low clouds and patchy drizzle becoming more widespread
through mid week, with a gradual warming trend late in the week.
Satellite imagery showing low clouds and fog moving into many
of the coastal areas this evening. Acars sounding showing marine
layer depth around 1500 feet over the LA basin this evening.
A weak upper level trough of low pressure combined with
strengthening onshore flow and an eddy circulation will help
to deepen the marine layer to around 2000 feet by tomorrow
morning. As a result, looking for low clouds and fog to
fill into most coastal/valley areas overnight into Tuesday
morning, lingering near some of the beaches in the afternoon.
High temperatures on Tuesday are expected to be slightly cooler
across most areas. The Antelope Valley will see some gusty onshore
winds with very warm temperatures above 90 degrees which will
translate into elevated fire danger concerns. The foothills of
the Antelope Valley could see some gusts as high as 45 mph
by late afternoon and evening on Tuesday.
*** From previous discussion ***
At the beaches, a `May Gray` pattern will likely conclude the
month, possibly turning to `June Gloom` to begin the month of
June. Stratus clouds will struggle to clear at the beaches each
over the next couple of days and the beaches will likely remain
As the trough starts to move east on Tuesday, another broader
trough circulation will move in. Instability with the trough will
bring mainly partly to mostly cloudy skies across the area for
Tuesday night through Thursday, along with the possibility of
night through morning drizzle. PoPs have been tweaked a little to
account for measurable drizzle. A slight chance of showers remains
in the forecast for the interior portions of the area as well as
Ridging aloft over the Pacific Ocean builds in for Friday and
Saturday, then another trough will approach the area for next
weekend. Heights do climb a bit, so some warming was introduced;
however, onshore flow should remain and inhibit the air mass
getting too warm for this time of year. Temperatures looks to
remain near normal for the end of the week and into next weekend.
At 2345Z, the marine inversion at KLAX was based at 1400 feet.
The top of the inversion was 4400 feet with a temperature of 22
For tonight, high confidence in return of stratus/fog to all
coastal/valley sites, but only moderate confidence in timing and
flight category. Based on satellite trends, moved up timing of
cigs to coastal areas between 00z-04z and valleys between 06z-
08z. Chance of cigs lingering into afternoon hours on Tuesday at
KOXR, KCMA, KLAX, and KSMO.
KLAX...For tonight, high confidence in return of stratus, but
moderate confidence in timing and flight category (40% chance
CIGs come in at IFR levels).
KBUR...For tonight, high confidence in return of stratus, but
moderate confidence in timing (+/- 2 hours of current 08Z
For the Outer Waters, high confidence in current forecast. Small
Craft Advisory (SCA) level winds will continue through Saturday.
Each afternoon/evening, there will be a 30% chance of Gale force
For the Inner Waters, moderate to high confidence in current
forecast. For the waters north of Point Sal, SCA level winds are
expected each afternoon/evening today through Friday then drop
below SCA levels on Saturday. For the waters south of Point
Conception, conditions are generally expected to remain below SCA
levels through Saturday. However, there is a 30% chance of SCA
level winds across the western half of the Santa Barbara Channel
during the afternoon/evening hours on Wednesday and Thursday.
PZ...Small Craft Advisory in effect until 9 AM PDT Wednesday for
zones 645-670-673-676. (See LAXMWWLOX).
.HAZARD POTENTIAL OUTLOOK...(THU-MON)
No significant hazards expected.