Marine Weather and Tide Forecast for South Monrovia Island, CA

.SHORT TERM (MON-THU)...19/824 PM.

***UPDATE***

Offshore gradients this evening are stronger than yesterday at this time, with the LAX to Daggett gradient now at -3.9 mb compared to -2.3 mb yesterday evening. Rising pressure over the Great Basin will cause the gradient to increase additionally overnight, producing offshore wind gusts of 25 to 40 mph in the typical Santa Ana wind corridors of Ventura and LA Counties.
Isolated gusts up to 45 mph may affect portions of the western San Gabriels and the Santa Susana Mountains. Low humidity will continue with temperatures in the low 70s to low 80s. Portions of the coastal plain will warm a few degrees as today's onshore flow is replaced by offshore.

***From Previous Discussion***

Offshore flow continues today, though at only -1.8mb this morning this was the closest to onshore we have been since January 8. This has allowed a notable sea breeze to develop and bring cool maritime air to coastal areas. But while temps there are down 6-12 degrees from yesterday, just a little farther inland and up a few hundred feet in elevation temperatures are in the upper 70s to mid 80s.

As models have been projecting, gradients are trending back offshore again due to pressure rises across the Great Basin so Tuesday will likely see warming temps across parts of the coastal plain and similar or possibly even slightly warmer temperatures elsewhere. Some high res models are indicating at least a small chance of some morning stratus but given the current trend this seems unlikely. If that happens the best chance would be along the Central Coast and southern LA County.

The rest of the forecast is more or less on track. Onshore flow is expected to return later Wednesday beginning a significant cooling trend. A weak upper level low will split off from a system in the Gulf of Alaska and travel south off the California coast. There's not a ton of moisture with it but there is a little bit of moisture being tapped from a disorganized band of moisture off the coast of Mexico. Models have been struggling with this one but most of the ensemble solutions now do show at least some sprinkles or very light showers Thursday with amounts topping out around a tenth of an inch. Official rain chances are low because many areas may get sprinkles but not enough to measure 0.01.

.LONG TERM (FRI-MON)...19/216 PM.

After Thursday high pressure will rebuild over the West Coast for dry conditions and a slow warming trend through early the following week. There are some indications that offshore flow could return as soon as Saturday or Sunday with some models indicating a return to moderate offshore flow and Santa Ana winds, but the upper pattern suggests minimal upper level support so most likely any offshore winds would be below advisory levels with minimal impacts.

As far as rain chances go, ensembles are still picking up on some signals somewhere around the 28th-30th, though more recent solutions are pushing that back to early Feb. And the vast majority of the solutions favor light to at most moderate rain with again minimal impacts.

AVIATION
20/0624Z.

At 06Z at KLAX, there was no marine layer. There was a weak sfc- based inversion with a top at 2400 ft with a temperature of 20 C.

Overall, high confidence in 06Z TAFs. 10-20% chance of LIFR/VLIFR conditions at coastal sites and KPRB through 17Z Tue.

KLAX...High confidence in TAF. Less than 10% chc for BKN002-004 and 1/4SM-1/2SM between 14Z and 17Z. East wind component is expected to remain below 7 kt.

KBUR...High confidence in TAF. Light LLWS possible through 00Z Wed.

MARINE
19/837 PM.

Localized northeast Santa Ana wind gusts of 15-20 knots may occur at times late tonight through Tuesday morning nearshore between Channel Islands harbor and Mailbu.

Elsewhere, winds and seas are expected to remain below Small Craft Advisory (SCA) through Wednesday, with a low chance (30%) of SCA winds across the Outer Waters beyond 40 NM from shore - Thursday into the weekend.

Patchy dense fog with visibilities less than 1 NM may impact the coastal waters at times into next week, but low confidence in timing and location.

LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.