Marine Weather and Tide Forecast for La Crescenta-Montrose, CA

.SHORT TERM (TDY-FRI)...30/332 AM.

Today will be a cloudier and cooler day. The marine layer is 1700 ft deep and is capped by a fairly strong inversion. Afternoon onshore gradients will be moderate to strong and these two things will keep most coastal areas cloudy all day long. Max temps will cooler across the vlys, mtns and far interior while the coasts will see little change from ydy's cool temps. Max temps will be 3 to 6 degrees blo normal for most areas with coastal temps in the 60s and vly temps in the 70s. The strong onshore flow will bring gusty but sub advisory winds to the western Antelope Vly and Foothills.

Tonight and Thursday morning will be a repeat of this morning with plenty of low clouds covering the csts, vlys and even the some of the cstl slopes. Clearing, again, will be very slow and likely non-existent at the beaches. The one big change will be the approach of an upper low out of NV. This upper low is now fcst to be a touch wetter and a touch more unstable than it was ydy and now there is a 20 to 30 percent chc of a shower across the mtns of LA and VTA counties as well as the eastern SBA county mtns, the western Antelope Vly and foothills and the Cuyama Vly. Rainfall, if any, will not exceed a quarter inch and likely much less than that. In addition to the chc of showers cumulus build ups over the peaks are likely. Max temps will not change much from todays below normal values.

Sunday will see some warming as a tiny ridge moves into the area.
Onshore flow relaxes as well which should allow for faster and better clearing. Max temps will respond to the higher hgts and greater sunshine by warming 2 to 4 degrees. Despite the warming max temps across the csts/vlys will remain several degrees blo normal.

.LONG TERM (SAT-TUE)...30/330 AM.

Mdls and ensembles are in good agreement for an unusual May weekend weather event. A cold (~550 dam) upper low will sweep into the state on Saturday and over Srn CA on Sunday. A wave of PVA will go over the area and will bring a 20 to 30 percent chc of showers to the mtns in the afternoon. There is not much moisture to work with and any rainfall amounts will be light. In addition to the persistent low clouds there will be partly to mostly cloudy skies from mid and high clouds assoc with the upper low. Strong ~8 mb onshore flow to the east will keep many beaches swaddled in low clouds all day as well as bringing near advisory wind gusts to the Central Coast, mtn tops and the wester Antelope Vly as well as its foothills. Coastal temps will fall 2 to 4 degrees but the rest of the area will 4 to 8 locally up to 12 degrees of cooling. This cooling will bring max temps across the csts down into the 60s with vlys falling into the mid 60s to lower 70s.

The upper low will move over Srn Ca on Sunday. Hgts will fall to ~552 dam. The upper low will bring plenty of cold air aloft for some decent instability but the system is pretty moisture starved and there will only be a 20 to 30 percent chc of mtn showers and a less than 10 percent chc of a TSTM. Skies will be partly to mostly cloudy through the day. Max temps will be the main talking point with 4 to 8 degrees of cooling across the csts and vlys and 8 to 15 degrees across the mtns and far interior. These cold temperatures will allow snow to fall to as low as 5500 ft. It will feel like a colder than normal January day with max temps coming in a few degrees either side of 60 for the csts.

Enough ensemble members swing a secondary impulse across the area Monday as the main upper low exits the state. This is enough for a slight chc of mtn shower, but again without much moisture to work with the shower threat is very minimal. All the cold air should have mixed out the marine inversion so there should be few if any low clouds in the morning. Skies still partly cloudy from some wrap around clouds. 2 to 5 degrees of warming across the csts and vlys will not be enough to bring max temps out of the 60s.

The mdls and ensembles diverge on Tuesday. Whatever the outcome it will be low impact dry day. There will either be slight warming (EC) or substantial warming (GFS)

AVIATION
30/1127Z.

At 1102Z at KLAX, the marine layer was 1700 feet deep. The top of the inversion was at 3800 feet with a temperature of 16 C.

High confidence in TAFs for KWJF and KPMD.

Moderate confidence in TAFs for remaining sites. There is a 20% chance for VLIFR conds at KPRB after 12Z, with a 30% chance of VFR conds persisting. There is a 20 percent chc of SCT conds 21Z-02Z at all coastal sites. Flight Cat changes may be off by +/- 90 minutes.

KLAX...Moderate confidence in TAF. There is a 20 percent chc of SCT015 cond 21Z-02Z. There is a 10% chance of an 8kt east wind component through 16Z Wed.

KBUR...Moderate confidence in TAF. There is a 25 percent chc of SCT conds not arriving until 1930Z.

MARINE
30/250 AM.

In the outer waters, Small Craft Advisory (SCA) level conds may linger into mid-morning, however good confidence that conds will diminish below advisory levels by late morning, so allowed the southern SCAs to expire, with the advisory for the outer waters north of Pt Sal continuing until 9 AM. Then, SCA conds are not expected across the outer waters thru early Fri. SCA winds and seas (with swells up to 15 ft) are likely (>80% chance) Fri afternoon thru Sun night, with a 50% chance of GALE force winds Sat afternoon/night.

In the inner waters N of Pt Sal, SCA conds are not expected thru Fri morning. SCA winds and seas are likely (70% chance) in the afternoon/eve hours Fri through Sun, with a 40% chance GALES Sat afternoon/eve.

In the Santa Barbara Channel, there is a 10-20% chance of SCA level winds in western portions this afternoon into evening.
Otherwise, SCA conds are not expected thru Fri morning. SCA winds and seas are likely (70% chance) during the afternoon thru late night hours Fri through Sun, with a 40% chance of GALES across western sections Sat afternoon/eve.

In the southern inner waters, SCA conds are not expected thru Sat morning, then are likely (70% chance) beginning in the the afternoon Sat and continuing thru Sun.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Beach Hazards Statement in effect through this evening for zones 362-366. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 9 AM PDT this morning for zone 670. (See LAXMWWLOX).