12/111 PM.
A large storm system will move into the Central Coast Thursday afternoon and Friday farther south. The storm will generate periods of moderate to heavy rain Thursday through Saturday, and possibly into early next week. Quite a bit of uncertainty in the progression of the storm exists, however, flooding of roadways and burn scars is possible, especially Friday and Saturday.
(tdy-Sat), 12/201 PM.
, POTENTIAL FOR SEVERAL INCHES OF RAIN ACROSS THE AREA WITH MAJOR IMPACTS MAINLY FRIDAY AND SATURDAY,
A large storm system has moved into the eastern Pacific and this will be the primary weather concern for the next several days. There remains a lot of uncertainty with how this will play out because the low is expected to cut off and once that happens the predictability of the storm decreases dramatically. Based on the model projections today, the upper low is expected to move into a position that will generate widespread 2-4 inches of rain, starting Thursday afternoon along the Central Coast, then Friday and Saturday elsewhere, highest south of Pt Conception and especially in upslope areas. Could even see some amounts in the 5-6 inch range in the foothills and mountains. Hourly rates of a half inch would be common in this scenario with isolated rates up to an inch. Thunderstorms are possible as well, best chances from Santa Barbara north but can't rule out a storm or two down south as well.
With this in mind, residents, especially those in vulnerable areas, should start taking precautions immediately to prepare for the storm and protect their interests. This scenario would potentially create many significant impacts area-wide, including possible debris flows in the burn areas, significant ponding of roads and highways, mudslides through the canyons, fallen trees, etc.
However, there are some solutions that place the upper low in a much less favorable location that results in quite a bit less rain. This is a less likely scenario than the one above but still possible. By Thursday there should be more clarity on the track of the low and at that point consideration will be given to any possible Flood watches.
(Sun-Wed), 12/212 PM.
Most of the latest model solutions indicate little or no rain Sunday, especially after dawn, but small rain chances linger due to the cutoff low and the uncertainties associated with that.
If the upper low moves as models are indicating the storm door will be open for another upper low to come through on Monday, creating another chance of rain, though all indications now are that this next system would be quite weak with any rain totals under a half inch. Then dry weather the rest of the week with no indications of any Santa Ana wind events or additional storms.
12/1942z.
Around 1850Z, the marine layer depth was around 1000 feet deep at KLAX. The top of the inversion was near 2200 feet with a temperature around 20 degrees Celsius.
Moderate confidence in the current forecast for terminals from KSBA north. Moderate to high confidence in the current forecast for terminals from KSBA south.
High MVFR to VFR conditions will continue through 20Z, then VFR conditions will develop after 20Z and continue through at least 03Z Thursday. There is a moderate chance of MVFR conditions after 03Z at coastal terminals. Otherwise, ceilings at or below 6000 feet will likely become prevalent after 06Z Thursday for terminals north of Point Conception with MVFR conditions in rain showers developing after 12Z Thursday.
Periods of moderate to strong low-level wind shear and turbulence are possible at terminals north of Point Conception after 14Z Thursday.
KLAX, There is a 30 percent chance of periodic MVFR conditions through 07Z Thursday, otherwise VFR conditions will likely persist. MVFR conditions should develop by 09Z at the latest with chances increasing to above 60 percent. No wind impacts are expected at this time.
KBUR, VFR conditions are expected through the period, but there is a 10 percent chance of MVFR visibilities after 08Z Thursday. No wind impacts are expected at this time.
12/142 PM.
High confidence in the current forecast for impacts. Moderate confidence in the current forecast for timing. A storm system will bring gusty winds, steep short period seas, and a slight chance of thunderstorms across the entire waters through at least Saturday morning. Any thunderstorms that develop will be capable of producing frequent lightning, gusty and erratic winds, locally rough seas and even waterspouts.
There is an imminent (80-100 percent) chance of widespread Small Craft Advisory (SCA) conditions as soon as this afternoon or tonight moving from northwest to southeast across the waters west through northwest of Point Conception. There is a 50-90 percent chance for Gale Force winds for the waters west through northwest of Channel Islands from late tonight through Thursday afternoon or evening. Steep short period seas will build to hazardous levels throughout the day on Thursday, then likely decrease to below 10 feet after Saturday morning.
Inside the California bight, winds and seas will remain below SCA levels through at least early Thursday morning, then winds will begin to increase through Thursday night. SCA level south- southeast winds (20-30 knots) will be common through at least early Friday morning, but there is a high chance that SCA conditions (winds and seas) may linger into Friday evening.
Ca, Wind Advisory in effect from 8 AM to 6 PM PST Thursday for zones 340>348. (See LAXNPWLOX). High Surf Advisory in effect from 2 AM Friday to 10 AM PST Saturday for zones 340-346. (See LAXCFWLOX). PZ, Small Craft Advisory in effect from 9 PM this evening to 8 AM PST Thursday for zones 645-673. (See LAXMWWLOX). Gale Warning in effect from 8 AM to 4 PM PST Thursday for zones 645-673. (See LAXMWWLOX). Small Craft Advisory in effect from 4 PM Thursday to 4 AM PST Friday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 4 AM PST Thursday for zone 670. (See LAXMWWLOX). Gale Warning in effect from 4 AM to 4 PM PST Thursday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect from 3 AM Thursday to 3 AM PST Saturday for zone 676. (See LAXMWWLOX).
