04/416 PM.
Mostly clear skies, dry conditions, a general warming trend and periods of offshore winds are likely through the week. The warmest and windiest conditions are likely on Friday and Sunday.
(Wed-Sat), 04/746 PM.
***UPDATE***
Light offshore flow will pick up late tonight into tomorrow morning focused across the mountains, keeping most clouds at bay across the coasts and valleys. Temperatures will warm by several degrees tomorrow compared to today, as a result of the increasing offshore flow. Expect highs in the upper 70s to low 80s for much of the area.
***From Previous Discussion***
Overall, 12Z models in good synoptic agreement through the short term period. At upper levels, trough moves over the area tonight and Thursday, then into the Great Basin on Friday and Saturday as a ridge builds over the area. At the surface, offshore flow gradually increases through the period.
Forecast-wise, main issues in the short term will be winds and temperatures. With respect to winds, the area can expect a gradual increase in northeasterly winds through Saturday. Through Thursday, the upper level support looks minimal, so any offshore winds are expected to remain below advisory levels. However by Friday and Saturday, the upper level support looks to increase along with the surface pressure gradients. So, the chances for low-end advisory level winds look to increase across the Santa Ana wind corridor of Ventura/LA counties as well as the Santa Lucia Range in San Luis Obispo county. Looking at the ensembles, the chances for gusts in the 35-50 MPH range look to be in the 30-50% range for Friday and Saturday. So, would not be surprised to see some wind advisories be issued by future shifts for this Friday and Saturday time period.
The secondary concern through the short term period will be temperatures. The combination of increasing offshore pressure gradients and building upper level ridge will bring an noticeable warming trend to the area. At this time, Saturday looks to be the warmest day in the short term with widespread upper 70s and 80s across the coasts and coastal valleys. Looking at Heat Risk forecasts, widespread MODERATE HEAT RISK is likely by Saturday across the coastal plain and coastal valleys with even some isolated MAJOR HEAT RISK. So, later shifts may need to consider heat products for some areas.
Given the gusty offshore winds, warming temperatures and dry conditions, there will be elevated to locally critical fire weather conditions across the area by Friday and Saturday. Recent rainfall has helped mitigate the fire threat a bit, but live fuel moistures are still in the 65-80% range which means the area is not "out of the woods" with respect to the fire threat. There is a 30% chance of "targeted" Red Flag Warnings on Friday and Saturday.
(Sun-Wed), 04/107 PM.
For the extended, models are on the same synoptic page. At upper levels, ridge will be a bit "undercut" by a weak upper low, resulting in some lowering of the H5 heights. At the surface, the offshore flow will gradually weaken with weak diurnal flow prevailing by Tuesday/Wednesday.
Forecast-wise, the above synoptic pattern will result in dry and benign weather fore the area. Overall, skies should remain mostly clear through the period, but some stratus/fog could possibly return to the coastal plain by Tuesday or Wednesday. As for temperatures, Sunday will be the warmest day with a gradual cooling trend Monday through Wednesday as ridge weakens and offshore flow weakens and eventually turns weakly onshore. Finally for winds, any offshore winds should remain below advisory levels on Sunday with no wind issues expected Monday through Wednesday.
A bit further out into the following weekend (November 13-16), models are still indicating a wet and unsettled pattern across the area. At this time, there is relatively high confidence in widespread measurable rainfall, but low confidence in timing and amounts. AI ensembles indicate at least a 40-60% chance of rain totals greater than one inch and a 20-40% chance of totals greater than two inches. Obviously, the details of this potential wet weekend will change over the coming days, but everyone should be aware of the potential. Stay tuned.
05/0015z.
At 2327Z at LAX, there was no inversion and no marine layer.
Overall, high confidence in the 00Z TAF package as CAVU conditions are expected through the period. However, there is a 10-20% chance of VLIFR conditions at KPRB between 10Z-17Z Thu.
KLAX, High confidence in the 00Z TAF as CAVU conditions are expected through the period. No significant easterly wind component is expected.
KBUR, High confidence in the 00Z TAF as CAVU conditions are expected through the period.
04/748 PM.
For the Outer Waters, high confidence in current forecast. Through Friday, a combination of Small Craft Advisory (SCA) level winds and seas will prevail. For Saturday and Sunday, SCA level seas are expected to continue with winds dropping below SCA levels.
For the Inner Waters north of Point Sal, moderate confidence in current forecast. SCA winds may persist through late tonight, and there is a 30-40% chance of SCA level winds Thursday afternoon and evening. For Friday through Sunday, there is a 20% chance of SCA level north to northeast winds, mainly in the overnight and morning hours, and seas will approach SCA levels.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. High confidence in winds and seas remaining below SCA levels through Thursday, except for SCA winds in the western Santa Barbara Channel in the late afternoon and evening hours. For Friday through Saturday, there is a 20-30% chance of SCA level northeast winds from Ventura south to Santa Monica in the night and morning hours. On Sunday, winds and seas are expected to remain below SCA levels.
Through Friday, the gusty winds will likely result in choppy, short- period, seas.
Ca, High Surf Advisory in effect until 7 AM PST Thursday for zones 340-346. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 9 PM PST this evening for zones 645-650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PST Friday for zones 670-673-676. (See LAXMWWLOX).
