19/315 AM.
A weak upper level trough will move over the area this weekend into Monday, cooling temperatures slightly and increasing marine layer stratus. A warming trend will begin Tuesday and peak on Thursday, with highs 5 to 10 degrees above normal.
(tdy-Mon), 19/858 AM.
***UPDATE***
Another quiet weather day with no impactful conditions other that some patchy marine layer stratus along the Central Coast and in parts of LA County that could create some minor impacts to aviation interests. Still expecting a minor cooling trend this weekend as a weak upper low approaches from the west and moves through the area Sunday and Monday. Still can't rule out a stray shower during that time but chances are less than 10 percent as moisture is lacking. Not expecting any major deviations to the current forecast today.
***From Previous Discussion***
Calm weather and near to below normal temperatures will last through Tuesday. A weak low pressure system will move across the region Sunday and Monday, brining a cooling trend. Monday will be the coolest day of the week, when temperatures will be largely in the 70s across the region and gusty onshore flow will occur across the beaches and interior during the afternoon and evening. The low is favored to be relatively dry, however the low will bring some instability and moisture to the area. Thus there is a 5-15 percent chance of a shower or thunderstorms occuring over San Luis Obispo and Santa Barbara Counties, as well as the interior mountains of LA and Ventura Counties Sunday and Monday. Marine layer clouds are expected each day across the coasts and some valleys, with the highest inland coverage likely on Monday and Tuesday.
(Tue-Fri), 19/404 AM.
Behind the trough, weak high pressure is favored to build over the area with 500 mb heights peaking mid and late this upcoming week. In addition, surface pressure gradients have the potential to switch to light offshore Wednesday and Thursday, which will contribute to a warming trend (though minor compared to the heat event earlier this month). Highs have the potential to rise to 80-90 degrees at the beaches and inland coasts, and 90-100 degrees for the valleys (around 10 degrees above normal). At this point, there is a small (15 percent) chance that some Heat Advisories will be issued next week for Wednesday and Thursday.
19/1810z.
At 1735Z at KLAX, the marine layer was 2300 ft deep. The top of the inversion was at 5200 ft with a temperature of 18 C.
High confidence in VFR conds for KPMD & KWJF.
Low to moderate confidence in the remaining sites. The timing of CIG and any VSBY restrictions tonight into Sun morning may be off +/- 2 hrs and flight minimums by one category.
KLAX, Low to moderate confidence in TAF. Return and dissipation of MVFR CIGs 015-020 may differ by +/- 2 hrs from forecast times, and cigs may scatter and reform due to high clouds after 08Z Sun. Any east wind component is expected remain less than 6kt.
KBUR, Moderate to high confidence in TAF. Cigs OVC007-010 will likely occur between 09-17Z Sun with timing possibly off +/- 2 hrs from forecast times.
19/846 AM.
For the outer waters, generally high confidence in the current forecast. Small Craft Advisory (SCA) level winds are likely across all the waters through Sunday night, then for the waters west and south of Point Conception Sunday night through Monday night. There is a 40%-50% chance of SCA wind gusts again in these areas Tuesday night, otherwise conds will be below SCA levels Tuesday through Wednesday night. Expect steep, choppy seas with the SCA conditions.
For the inner waters N of Point Sal, moderate to high confidence in the current forecast. SCA wind gusts are likely during the afternoons and evenings through Sunday. Conds are then expected to be below SCA levels late Sunday night through Wednesday night, although there will still be a 20%-30% chance of occasional SCA level wind gusts each afternoon and evening.
For the inner waters S of Point Conception, moderate to high confidence in the current forecast. Conds are expected to be below SCA levels for the most part through Wednesday night. However, for the western Santa Barbara Channel, there is a 50-60% chance of SCA wind gusts this afternoon/evening and again Monday afternoon/evening. There is also a 30%-40% chance of these gusts Tuesday evening.
Ca, NONE. PZ, Small Craft Advisory in effect until 3 AM PDT Sunday for zones 645-676. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PDT this evening for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Monday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 5 AM PDT Tuesday for zone 673. (See LAXMWWLOX).
