Scientific Forecaster Discussion
fxus66 klox 282202
Area forecast discussion
National Weather Service Los Angeles/Oxnard California
302 PM PDT sun may 28 2017
A weak ridge aloft in place will be replaced by a weak trough
aloft early next week. A cooling trend with more widespread night
to morning low clouds will develop over the next several days.
There is also a slight chance of thunderstorms across the
The latest water vapor imagery indicates a ridge of high pressure
over the state this afternoon. Weakening onshore flow across the
area has brought some warming this afternoon. A weak marine
inversion the last couple of days should strengthen and allow for
better marine layer stratus formation tonight and into Memorial
Day. Despite weaker onshore flow, the marine layer depth near 700
feet deep currently should deepen to around 1500 feet deep by
A trough of low pressure near 34n and 130w will approach the area
through Monday as the ridge of high pressure nudges east. This
trough in phase with a broader trough over the eastern Pacific
Ocean will become a staple of the weather pattern through the
middle of next week. After near similar day for Memorial Day in
comparison to today, a cooling trend should develop into midweek
along with a deepening marine layer.
Model solutions are introducing the possibility of some
instability developing over the mountains for tomorrow and there
is some concern about convective storms developing over the
mountains for the Memorial Day Holiday. Models solutions look to
introduce some cumulus formation in moisture fields. There is some
Omega and cape values over the moutains, especially the Ventura
County portion. While this is a rather new wrinkle in the
forecast, some clouds have been added to the package. Pops have
also been nudged higher, but remain below mentionable thresholds.
The next shift will be briefed about the possibility of
A trough of low pressure will likely linger along the West Coast
into Thursday. Increased onshore flow and a deeper marine layer
will likely continue cooling into Thursday. Patchy night through
morning drizzle or light showers cannot be ruled out between late
Tuesday night through Thursday morning, especially in the
foothills and mountains. A mention of a slight chance of showers
and thunderstorms has been left in place for the mountains on
Wednesday afternoon and evening, but the possibility of night
through morning drizzle will likely need to be addressed.
A brief warm-up should develop for Friday, but model solutions are
handling a developing trough of low pressure to the southwest of
the area poorly for next weekend. The forecast takes a cooler
stance for now as higher confidence exists in a continued strong
onshore flow pattern.
At 1530z, the marine inversion at klax was based at 1100 feet.
The top of the inversion was 1700 feet with a temperature of 16
Overall, moderate confidence in 18z taf package. VFR conditions
are anticipated through this afternoon. For tonight, high
confidence in return of stratus/fog to all coastal and coastal
valley sites, but low confidence in timing and flight category.
Klax...moderate confidence in 18z taf. High confidence in VFR
conditions through this evening. High confidence in return of
stratus tonight, but low confidence in timing (+/- 3 hours of
07z forecast) and flight category (50% chance of IFR cigs).
Kbur...moderate confidence in 18z taf. Moderate confidence in
return of stratus tonight, but low confidence in timing
(+/- 3 hours of current 09z forecast).
For the outer waters, high confidence in current forecast. Small
Craft Advisory (sca) level winds will continue through Friday.
There is a 20% chance of gale force conditions developing in the
afternoon/evening hours Tuesday and Wednesday.
For the inner waters, moderate confidence in current forecast. For
the waters north of Point Sal, Small Craft Advisory level winds are likely each
afternoon/evening today through Friday. For the waters south of
Point Conception, winds and seas are expected to remain below Small Craft Advisory
levels through Friday.
Pz...Small Craft Advisory in effect until 9 am PDT Tuesday for
zones 645-670-673-676. (See laxmwwlox).
Hazard potential outlook...(wed-sun)
no significant hazards expected.