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

.SHORT TERM (TDY-THU)...20/308 AM.

Three very warm days on tap esp away from the beaches. At the upper levels a ridge will build in today and then peak tomorrow.
On Thursday the ridge will flatten some as a trof rolls through the PACNW. Hgts will reach 584 dam today, 585 dam Wed and then fall to about 582 dam later Thursday. Currently there is about a mb of onshore flow to the east and a mb of offshore flow from the north. Just after dawn the E/W gradient will be close to zero while the offshore push from the N will reach 2 mb. Similar gradients are fcst for Wed with weak onshore trends slated for Thursday.

Look for 4 to 8 degrees of warming today, followed by 1 to 3 degrees of additional warming on Wednesday. Today's temps will come in just under advisory levels, but people working or playing outside in the vlys today should take heat related precautions.
The lows tonight will be above normal in many vly locations which will exacerbate the heat danger. This combined with the extra warming will push many locations away form the nearshore area into advisory levels - please see the product LAXNPWLOX for details and precautions about these heat dangers. Highs Wednesday will be in the 70s at the beaches, the 80s across the inland coastal areas and in the 90s for the vlys. There is a 40 percent chc that the warmest vly locations will end up at 100 or 101 degrees. These max temps are mostly 12 to 18 degrees above normal.

Some shallow marine layer clouds are forecast to develop under the low and strong inversion Thursday morning and low clouds are likely across the LA/VTA county beaches. Because the marine layer will be so smooshed dense fog will likely accompany the clouds.
Max temps will cool some across LA and VTA counties but not enough to end the heat advisories. A stronger onshore gradient later in the afternoon may bring some late afternoon cooling relief.

.LONG TERM (FRI-MON)...20/1214 AM.

EC and the GFS still in good agreement for the Fri/Sat forecast. A small trof will push through the state on Friday and hgts will lower to 580 dam. Onshore flow to the east will increase slightly while offshore flow from the N will continue. Marine layer stratus will likely affect most of the coasts (save for the SBA south coast) and the Santa Ynez Vly. The lower hgts and slight lift from the trof will raise the marine layer enough to allow some cooler marine air into some of the vlys. This cooler air along with the stronger sea breeze will combine to bring 4 to 8 degrees of cooling to the csts and vlys. Lowering hgts will cool the interior a few degrees as well.

Bigger cooling is on tap on Saturday. The onshore push to the east will not change much but the offshore flow from the north will switch to onshore and this will enhance the cooling across the csts/vlys. Cooler air ushered in behind Friday's trof will cool the interior. The csts will cool 2 to 4 degrees but the vlys will see 5 to 10 degrees of additional cooling. While the mtns and interior cool 3 to 6 degrees. All of this cooling will bring max temps across the csts/vlys down into the 70s with just a few 80 or 81 degree readings in the warmest vly locations. These max temps are within a degree or 2 of normal.

A little ridge pops up over the area on Sunday. The morning low clouds will likely cover the LA csts and the Central Coast.
Pressure grads are similar to Saturday's (at least in the morning)
and max temps will bump up a couple of degrees due to hgts rises.
The afternoon onshore push will increase to near 9 mb to the east and this will bring gusty winds to the Central Coast and the western Antelope Vly.

The ridge pushes off to the east on Monday as a large east Pac trof begins to approach the west coast. Max temps will not change much but the strong onshore flow to the east will continue as will the gusty afternoon winds.

AVIATION
20/0603Z.

At 0505Z at KLAX, the marine layer was 700 feet deep. The top of the inversion was 1600 feet with a temperature of 26 C.

Good confidence in TAFs. There is a 15% chance of MVFR vsbys at KLAX, KSMO, KOXR, KSBA and KSMX from 12Z-17Z.

KLAX...Good confidence in TAF. There is a 15% chance of 5SM HZ 12Z-17Z. No significant east wind component is expected.

KBUR...High confidence in TAF.

MARINE
19/731 PM.

Moderate to high confidence in the current forecast. Higher confidence exists in the forecast for seas relative to the forecast for winds.

For the Outer Waters and the nearshore waters along the Central Coast, conditions will be at least Small Craft Advisory (SCA)
levels through Tuesday night, except for lulls nearshore along the Central Coast during late night and early morning hours. There is a 60-90 percent chance for GALE Force winds late this afternoon through this evening, decreasing to a 60-80 percent chance of Gales Tuesday through Tuesday night. The highest chances for Gale Force winds will be for the majority of the Outer Waters, while the lowest chances will be for the nearshore waters along the Central Coast and the for southern Outer Waters. There remains a moderate to high chance for GALE Force winds through the work week, but low confidence in timing and max wind speeds beyond Tuesday.

Across the Santa Barbara Channel, there is a 40-60 percent chance of SCA level winds tonight across the western portion, followed by a 40-60 percent chance on Tuesday afternoon and night. There are lesser chances for Wednesday and Thursday afternoons and evenings.

South of Point Mugu, into the Santa Monica Bay, and the San Pedro Channel, winds and seas are expected to remain below SCA levels through at least Thursday.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Heat Advisory remains in effect from 11 AM Wednesday to 9 PM PDT Thursday for zones 88-343-348-351>353-356>358-368-374-375-548. (See LAXNPWLOX).
Heat Advisory remains in effect from 11 AM this morning to 9 PM PDT Thursday for zones 369>373. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for zone 645. (See LAXMWWLOX).
Gale Warning in effect until 3 AM PDT Wednesday for zones 670-673-676. (See LAXMWWLOX).