Point Piedras Blancas to Santa Cruz Island CA between 60 and 150 NM Offshore Forecast
|Today...N To Nw Winds 10 To 20 Kt, Becoming Nw 10 To 15 Kt. Seas 5 To 7 Ft.|
|Tonight...Nw Winds 5 To 15 Kt. Seas 5 To 6 Ft.|
|Sun...N To Nw Winds 5 To 15 Kt, Diminishing To Less Than 10 Kt. Seas 5 To 7 Ft.|
|Sun Night...Nw Winds 5 To 15 Kt, Becoming N To Nw 5 To 10 Kt. Seas 5 To 7 Ft.|
|Mon...N To Nw Winds 5 To 15 Kt, Becoming Variable. Seas 5 To 7 Ft.|
|Mon Night...N To Nw Winds Less Than 10 Kt, Becoming Variable. Seas 5 To 7 Ft.|
|Tue...Variable Winds Less Than 5 Kt. Seas 5 To 6 Ft.|
|Tue Night...W To Nw Winds Less Than 10 Kt, Becoming N. Seas 4 To 5 Ft.|
|Wed...W To Nw Winds Less Than 10 Kt. Seas 4 To 5 Ft.|
|Wed Night...W To Nw Winds 5 To 10 Kt. Seas 3 To 5 Ft.|
| Area Forecast Discussion|
National Weather Service Los Angeles/Oxnard CA
155pm PDT Sat July 24 2021
High pressure aloft will weaken through Monday leading to a general cooling trend, but increasing monsoonal moisture will bring muggy conditions. Showers or thunderstorms will be possible Sunday afternoon through Tuesday, especially Monday when any area could see moderate to heavy showers. A small warming trend will follow Tuesday and Wednesday with little change to follow through the rest of the week.
.SHORT TERM (TDY-TUE)...24/152 PM.
A weak but very moist low pressure area aloft, currently centered over Arizona, will continue its drift to the west. It will slide over the California/Mexican border on Sunday, then move about 400 miles southwest of Los Angeles on Monday. This progression will move all the moisture currently over southeast California and Arizona into southwest California through Monday, along with its threat of showers and thunderstorms. Cannot discount some virga or a light shower as early as tonight, especially over the Antelope Valley and nearby mountains as the batch of showers currently over Baker approaches. Chances increase Sunday afternoon and night first over Los Angeles County, then peak on Monday over all areas as deep southerly flow sets up with the low to our southwest. Shower coverage will be hit and miss with some areas not seeing measurable rain, but this rare pattern has the potential to bring some rain to most areas on Monday. Some of those showers could be moderate to heavy at times, with precipitable water (total amount of moisture in the air) projected to be between 1.5 and 2.0 inches (that is a lot). This is especially true over the Los Angeles and Ventura County Mountains, as well as the Antelope Valley, where the moisture and instability are the greatest. As a result, there is a slight risk for isolated flash flooding there with heavy 15 to 30 minute rainfall rates possible. While the instability needed for thunderstorms is fairly minimal, if any thunderstorm forms and taps into that moisture, the flooding threat will increase. Those near recent burn areas in the mountains should stay aware of the weather on Monday, even if the chances for debris flows are small they are above zero.
Temperatures are tricky. Daytime temperatures should lower Sunday and Monday as the low approaches and cloud cover increases. Surface pressure gradients and the flow aloft turns toward offshore however on Monday, which should keep temperatures along the coast and valleys steady if not warmer. This is especially true if the marine layer disappears as it usually does with such a moisture surge. Lots of moving parts and uncertainty as a result.
The low pressure area will stay off the coast on Tuesday, but a large high pressure system centered over the central US will start to build to the west. This should bring some warming over the mountains and valleys and dry things out. There remains however enough moisture at low-levels (850 MB Dewpoints near 10C), as well as increasing instability, to bring a more seasonable threat of afternoon showers and thunderstorms to the Los Angeles and Ventura Mountains and the Antelope Valley.
.LONG TERM (WED-SAT)...24/154 PM.
The moisture continues to decrease on Wednesday, while the high to the east continues to build, but if storms form on Tuesday they could form again on Wednesday. The warming trend will continue from Tuesday to Wednesday over the valleys and mountains, as the marine layer and its low clouds reestablishes itself. Expecting high temperatures to reach about 5 degrees above normal by Wednesday away from the coast, with little change through the end of next week. There is a chance for monsoonal moisture to return by the end of the week.
Not expecting any Small Craft Advisories (SCA) across the coastal waters through at least next Wednesday.
Patchy fog will continue into next week. The poorest visibility and most widely spread conditions will occur in the overnight and morning hours.
.LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE.
.HAZARD POTENTIAL OUTLOOK (TUE-SAT).
Showers and thunderstorms are possible between Tuesday in the mountains and deserts, with dangerous lightning and heavy showers possible.