11/304 AM.
It will be mostly dry Saturday with cooler than normal temperatures. Moderate rain and a chance of thunderstorms will likely sweep through the area Saturday night into Sunday morning. Scattered shower activity is possible Sunday afternoon into Monday morning. Dry and warmer weather is expected the rest of next week.
(tdy-Mon), 11/831 AM.
***UPDATE***
Latest satellite and surface observations indicate partly to mostly cloudy skies across the area this morning. Based on radar and gauge data, some scattered light showers are falling across the Central Coast. No significant winds are currently observed.
Forecast-wise for the immediate short term, no significant issues are expected. Partly to mostly cloudy skies will continue through the afternoon. Precipitation will continue north of Point Conception through this evening with totals by this evening generally around 0.25 inches or less, although northwest San Luis Obispo county will get up to around 1.00 inches. South of Point Conception, only isolated light showers or sprinkles are expected through this evening.
Overall, current forecast has good handle on the immediate short term. So, no significant updates are expected. For the afternoon forecast suite, potent cold front, primed to sweep across the area, will continue to be the main focus.
***From Previous Discussion***
The first front moved through the area with little affect. Leaving only a mishmash of low clouds in its wake. The latest hi rez mdls indicate that this morning and afternoon should be dry save for a slight chc of afternoon showers across the Central Coast and even then mostly just SLO county. Skies today will be partly cloudy. Max temps will cool 1 to 3 degrees due to the cool air funneling in behind ydy's front. Max temps across the csts/vlys will mostly be in the mid to upper 60s.
All eyes still on tonight when the much more cohesive and vigorous front will pass through the area. The latest RRFS run shows little change to the previous thinking. With rain starting in SLO county in the evening and then reaching LA county after midnight. The good dynamics and increasing instability will bring a 3-5 hour period of steady rain and possible thunderstorms to the entire forecast area. CAPE values of around 500j/kg will provide the necessary lift for convective activity, including brief heavy downpours, gusty winds, and possible lightning. There is enough helicity in the lower layers to spin up a small tornado or waterspout in any TSTM that forms.
Rain amounts expected to generally be a half to one inch, except locally higher in the mountains and along the Central Coast. Due to the convective nature of this storm, rain amounts could vary quite a bit, even over very short distances. Rain rates expected to top out around a quarter to half inch per hour, except very brief and isolated rates as high as 0.75" in the strongest storms.
Strong southerly winds will develop ahead of the front and 35 to 45 mph gusts are likely across the mtns.
A Winter Weather Advisory is in effect starting at 900 pm for the higher mountains, above 5000 feet. Snow levels will be around 7000 feet through Sunday morning, then lowering to around 5000 feet Sunday afternoon into Monday morning. Snow accumulations of up to 6 inches are possible above 7000 feet, and 1-3 inches as low as 5000 feet. Not expecting any snow accumulations on the Grapevine over I-5, though there could be a mix of rain and snow early Monday morning.
Rain will taper off pretty quickly behind the front and by afternoon there will only be a 20 to 30 percent chc of showers across the area with the greatest chc over eastern LA county and there will only a the mtns.
2 to 4 locally 6 degrees of cooling due to all of the cold air advection behind the front will bring max temps down to a January like lower to mid 60s.
Earlier mdl runs were showing another impulse moving through Monday with additional rain chcs. This is no longer shown and Monday should be partly cloudy and dry with a 2 to 4 degree warming trend. Max temps will still end up 4 to 8 degrees blo normals.
(Tue-Fri), 11/256 AM.
Dry and warmer conditions will persist through the rest of the week. There will be weak ridging on Tuesday followed by dry NW flow on Wednesday. A dry trof moves through the state on Thursday. There is a bit of disagreement on the Friday upper level pattern with a troffier EC solution and a flatter GFS fcst. At the sfc there will be weak offshore flow from the N and weak to moderate onshore flow to the east. Can't rule out some night through morning low clouds esp Thu and Fri.
After the chilly start to the week there will be 3 to 6 degrees of warming on Tue, followed by and additional 1 to 3 degrees on Wed. Looking for little change in temps on Thu. The current forecast calls for more warming on Friday, but this really depends on what mdl solution verifies best.
11/1003z.
At 0822Z at KLAX, the marine layer was 1500 ft deep. The top of the inversion was at 2200 ft with a temperature of 15 C.
Good confidence in TAFs for KPMD and KWJF.
Moderate confidence in the remainder of the TAFs. SCT-BKN conds with layers around 015, 025 and 035 will likely continue through the morning. Better confidence in mostly VFR conds in the afternoon KSBA and points south.
A cold front will affect all terminals this evening and overnight. There is good confidence in rain timing. Low confidence in cig/vis fcst when the rain is occuring.
KLAX, Moderate confidence in TAF. SCT-BKN conds with layers around 015, 025 and 035 are likely through 18Z. Good confidence in CIGS AOA 100 18Z-02Z. Lower confidence after 02Z with lower cigs possible. Good confidence in -RA after 09Z. The rain will bring variable cig/vis along with east winds. There will be a 25 percent chc of a TSTM 11Z-16Z. No significant east wind component expected through 08Z then increasing chances of at least a 10 kt east wind component.
KBUR, Moderate confidence in TAF. SCT-BKN conds with layers around 015, 025 and 035 are likely through 18Z. Good confidence in CIGS AOA 100 18Z-02Z. Lower confidence after 07Z with lower cigs possible. Good confidence in -RA after 09Z. The rain will bring variable cig/vis. There will be a 25 percent chc of a TSTM 11Z-16Z.
11/304 AM.
A weak cold front will move across the coastal waters through this morning bringing showers and a slight chance for a thunderstorm north of Point Conception.
A second system will arrive late this afternoon into Sunday. This front will be stronger, bring Small Craft level southerly winds, showers and a chance for thunderstorms across all waters. Potential hazards include: heavy downpours, dangerous cloud to ocean lightning, small hail, and erratic gusty winds. Boaters, especially those with small vessels should avoid these conditions.
Seas will build on Sunday to near 10 feet across the Outer Waters and to 5-7 feet across the Inner Waters. Additionally Small Craft level west to northwest winds are likely for all the waters Monday afternoon and night. Then northwest SCA winds are possible each afternoon and evening Tuesday through Friday across the outer waters.
Ca, Winter Weather Advisory remains in effect from 9 PM this evening to 11 AM PDT Monday for zones 353-376-377. (See LAXWSWLOX). Winter Weather Advisory remains in effect from 3 AM Sunday to 11 AM PDT Monday for zones 378>380. (See LAXWSWLOX). PZ, Small Craft Advisory in effect from noon today to 3 AM PDT Sunday for zones 645-670-673. (See LAXMWWLOX).
