Marine Weather and Tide Forecast for South Monrovia Island, CA

.SHORT TERM (TDY-WED)...13/935 AM.

***UPDATE***

Offshore gradients continue to increase this morning with moderate upper level support. There is a stronger easterly component today and not as much of a northerly push. This pivots the stronger wind axis more to an east/west axis, which results in stronger winds across the Oxnard/Camarillo plain (including the city of Ventura), as well as the western Santa Monicas, and less wind across the I5 corridor and the eastern Santa Monicas. The models indicate an increasing northerly component tonight into Tuesday, but also an increasing easterly component, so by most accounts the expectation is that winds will be stronger as we move into tonight and Tuesday morning and thus the need for the PDS.

***From Previous Discussion***

There is not 100 percent agreement with the mdls on the wind forecast so confidence in not as strong as would be liked. The current forecast is based on the HRRR and 3km NAM. The forecast calls for advisory level gusts to develop this morning and persist through the day and into the night. Just before dawn the upper flow, cool air advection and offshore sfc flow come together and warning level winds will develop. These warning level gusts will continue through Wednesday late morning will a diurnal gap later Tuesday afternoon and early evening.

Today's winds will be in a more easterly direction and will affect VTA county much more than last weeks winds. On Tue/Wed the winds will tilt more to the NE and this will bring the strongest gusts along the axis from the mtns NE of the Santa Clarita Vly over the Santa Susana mtns, through the western Santa Monica mtns and then over the far western portion of the Malibu coast.

One big change to the forecast was the addition of Wind Warnings to the Santa Clarita Vly, western Santa Monicas and the Malibu Cst (note: the winds will be much stronger across the western portion away from the Palisades Fire) due to this forecast NE tilt of the wind axis. The final addition was to add warning level gusts (and a corresponding high wind warning to the eastern San Gabriel where 70 mph gusts should develop. At this time the conditions do not look likely (fortunately) to produce catastrophic mtn waves/turbulence. There will likely be some mtn waves but they should stay aloft.

As mentioned above there is some mdl disagreement and there are a decent number of solutions that show the strongest winds today with less winds on Wednesday. But the best performing mdls favor the current fcst.

Please the the product LAXNPWLOX for all details and timing about the winds.

Not much change in temps today, then look for two days of warming Tue and Wed. By Wed, temps should be several degrees above normal for many areas with highs in the 60s to around 70 for the cst/vlys.
Overnight lows will be quite cold in sheltered areas.

The winds combined with the very low humidities and tinder dry fuels will lead to a Particularly Dangerous Situation (PDS) Red Flag Warning conditions by late Mon night and continue thru Wed morning. Please see the Fire Weather Discussion below for more details.

.LONG TERM (THU-SUN)...13/326 AM.

Offshore flow remains in place over Srn CA on Thursday both at the sfc and aloft. The amount of offshore flow, however, is about half that of Wednesday's values. Some advisory level gusts are likely but warning level gusts are unlikely. The very low RHs will continue through the day. Max temps will cool 3 to 6 degrees across the csts/vlys due to the weaker offshore flow.

The upper level low is forecast to move E of the area Thu night and Friday. The upper level flow will become northwesterly. Most importantly there will be onshore flow (esp in the afternoon). The slightly cyclonic flow aloft and the onshore flow at the sfc will combine to bring marine layer clouds to the csts/vlys both Fri and Sat mornings. Look for widespread 3 to 6 degree cooling on Friday and 1 to 3 degree cooling on Sat. Saturday's temps will come in on the cool side with cst/vly temps only reaching the upper 50s and lower 60s or 5 to 10 degrees under normal.

Weak offshore flow returns Sunday with less or no marine layer clouds and a few degrees of warming across the csts/vlys.

AVIATION
13/1744Z.

At 18Z at KLAX, there was no marine layer nor inversion.

High confidence in VFR conds with only a 10 percent chc of MVFR conds in smoke for the Los Angeles County coastal terminals. Gusty N to NE winds are expected to affect much of the forecast area, especially sites in Ventura and LA County. There will be areas of LLWS, and moderate to locally strong UDDF and turbulence, especially near the foothills and mtns.

KLAX...High confidence in VFR conds thru the pd. However, there is a 10% chance of 4-5SM FU and/or bkn025 smoke layer at any point. There is a 30-40% chance of an east wind component reaching 8 kt tonight with best chances from 14Z and 20Z.

KBUR...High confidence in the CAVU TAF. Moderate confidence in winds. Maximum wind gusts may be off +/- 10 kts and wind group changes may be off +/- 3 hours. LLWS is likely, especially after 00Z through 18Z. Moderate to locally strong turbulence and UDDF will also impact the terminal during the period.

MARINE
13/839 AM.

In the outer waters, Small Craft Advisory (SCA) level NE winds will persist in the southern zone (PZZ676) and eastern portions of the central zone (PZZ673) thru Wed morning and late tonight, respectively. Seas will be at or above SCA levels thru this evening. Conds will be below SCA levels Wed night thru Fri, with a 40% chance of SCA level NW winds Fri night. Elsewhere in the outer waters, SCA level seas are expected thru this evening, then SCA conds are not expected thru Fri night.

In the inner waters N of Pt. Sal, except for a 20% chance of SCA level NE winds nearshore during the morning hours Tue/Wed.
Otherwise, SCA conds are not expected thru Fri night.

In the Santa Barbara Channel, SCA winds are expected from Ventura to eastern Santa Cruz Island southward this morning. Winds will likely (60% chance) increase to Gale Force within the next few hours. Gale force winds will continue much of the time thru Wed afternoon, though winds may drop below Gale force at times. SCA level NE winds may continue into Wed evening, then are not expected Wed night thru Fri night. Elsewhere, there is a 20% chance of SCA level E winds late tonight thru Wed morning.

In the southern inner waters. SCA winds are being observed from Malibu to Point Mugu and out to Anacapa this morning. Winds will likely (70% chance) increase to Gale Force by late morning. Gale force winds will continue much of the time thru Wed afternoon, though winds may drop below Gale force at times. SCA level NE winds will likely continue into Wed evening, then are not expected Wed night thru Fri night. Elsewhere, SCA level NE winds are likely at times from this afternoon thru Wed afternoon. This is especially likely (70% chance) thru the San Pedro Channel out to Avalon and Two Harbors on Catalina Island this afternoon, and again during the late night thru morning hours tonight thru Wed.
There is a 30% chance of Gale Force winds thru the San Pedro Channel to Catalina Island at times thru Wed afternoon, with best chances Wednesday morning. SCA conds are not expected Wed night thru Fri night.

FIRE WEATHER
12/802 PM.

...PARTICULARLY DANGEROUS SITUATION (PDS) RED FLAG WARNING IN EFFECT 4 AM TUESDAY UNTIL NOON WEDNESDAY DUE TO DAMAGING NORTHEAST TO EAST WINDS AND LOW HUMIDITIES FOR THE FOLLOWING AREAS: WESTERN SAN GABRIEL MOUNTAINS/ I5 CORRIDOR/ SOUTHERN VENTURA COUNTY MOUNTAINS/ SANTA SUSANA MOUNTAINS/ VENTURA VALLEYS (MAINLY NEAR SIMI VALLEY/MOORPARK/ SANTA PAULA/SOUTH MOUNTAIN)/ WESTERN SANTA MONICAS/ NORTHERN SAN FERNANDO VALLEY (MAINLY HIGHWAYS 118/210 CORRIDORS FROM PORTER RANCH TO SAN FERNANDO)/ VENTURA COUNTY COASTAL PLAIN (MAINLY HILLS ABOVE CAMARILLO/OXNARD WESTWARD TO VENTURA) -- THIS WILL BE A TIME PERIOD OF LOCALLY DAMAGING WINDS WITH EXTREMELY CRITICAL FIRE WEATHER CONDITIONS...

...RED FLAG WARNINGS IN EFFECT FOR MUCH OF LOS ANGELES AND VENTURA COUNTIES THROUGH WEDNESDAY DUE TO GUSTY NORTHEAST TO EAST WINDS AND LOW HUMIDITIES...

...RED FLAG WARNINGS IN EFFECT FOR THE SANTA BARBARA AND SAN LUIS OBISPO COUNTY MOUNTAINS AS WELL AS LAKE CASITAS AND OJAI VALLEY FROM 10 PM MONDAY UNTIL NOON WEDNESDAY DUE TO GUSTY EASTERLY WINDS AND LOW HUMIDITIES...

Quick update to add Santa Ynez Mountains Eastern Range, Lake Casitas, and Ojai Valley to Red Flag Warning (not PDS), no other changes.

A long duration Red Flag Warning remains in effect through much of Los Angeles and Ventura counties through Wednesday, expanding into the mountains of San Luis Obispo and Santa Barbara counties by Monday night. THERE WILL LIKELY BE DAMAGING WINDS GUSTING BETWEEN 55 AND 70 MPH ACROSS PORTIONS OF THE RED FLAG WARNING AREA FROM EARLY TUESDAY MORNING THROUGH WEDNESDAY MORNING, LEADING TO THE PDS RED FLAG WARNING UPGRADE. AREAS IN THE RED FLAG WARNING (ESPECIALLY DURING THE PDS TIME FRAME) WILL HAVE A HIGH RISK FOR LARGE FIRES WITH VERY RAPID FIRE SPREAD, EXTREME FIRE BEHAVIOR, AND LONG RANGE SPOTTING. WHILE DANGEROUS PDS RED FLAG FIRE WEATHER CONDITIONS ARE LIKELY WITH THIS EVENT EARLY TUESDAY MORNING INTO WEDNESDAY MORNING, THIS WIND EVENT IS NOT EXPECTED TO BE AS STRONG AND DESTRUCTIVE AS LAST WEEK'S WINDSTORM. Due to the more easterly component of the wind, much of Ventura County will likely have stronger winds than the offshore wind events this past week.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Wind Advisory now in effect until 4 AM PST Tuesday for zones 88-362-371-380. (See LAXNPWLOX).
High Wind Warning in effect from 4 AM Tuesday to noon PST Wednesday for zones 88-362-371-380. (See LAXNPWLOX).
Wind Advisory remains in effect until 4 AM PST Tuesday for zones 354-355-358-369-372-374>376-378-379. (See LAXNPWLOX).
High Wind Warning remains in effect from 4 AM Tuesday to noon PST Wednesday for zones 354-355-358-369-372-374>376-378-379. (See LAXNPWLOX).
Wind Advisory remains in effect until noon PST Wednesday for zones 370-373-377. (See LAXNPWLOX).
Red Flag Warning in effect until 6 PM PST Wednesday for zones 288-354-355-358-362-369>376-378>380. (See LAXRFWLOX).
Red Flag Warning in effect from 10 PM this evening to noon PST Wednesday for zones 345-352-353-356-357. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 10 AM PST this morning for zones 650-655. (See LAXMWWLOX).
Gale Warning in effect until 3 PM PST Wednesday for zones 650-655. (See LAXMWWLOX).
Small Craft Advisory in effect until 9 PM PST this evening for zone 670. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PST Tuesday for zone 673. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 PM PST Wednesday for zone 676. (See LAXMWWLOX).