16/1228 PM.
Generally quiet weather expected with cooler than normal temperatures and a robust marine layer through Thursday. Slight warming and shrinking marine layer Friday into the weekend.
(tdy-Sat), 16/1248 PM.
Thanks to the influence of the upper level low to our north and the persistent onshore flow, an extremely deep marine layer brought a June Gloom day to us here in Southwest California in mid-September. We're expecting another night of a fairly robust marine layer which will bring another gray morning to most folks, likely with better clearing tomorrow compared to today.
Only minor changes for tomorrow's temperatures, then a slight warming trend will occur Friday into the weekend as onshore flow weakens quite a bit and a short-lived pop up ridge moves into the area on Saturday. We'll likely see some light to locally moderate northerly winds across the interior mountains, and northeast winds across the Santa Lucias. This combo should dramatically reduce the coverage and extent of the marine layer cloud coverage each night through morning starting Friday morning. Otherwise moslty clear skies are expected Friday and much of Saturday.
(Sun-Wed), 16/1228 PM.
Quiet weather continues Sunday and most likely through the extended period. A weak upper level low will swing into the area Sunday, most likely remaining overhead through Monday and potentially Tuesday. While the most likely outcome is generally slightly cooler temps with a deeper and more expansive marine layer and the potential for morning drizzle, there is a very small chance for isolated shower or thunderstorm activity (likely focused over the interior mountains). Most European ensemble members show increasing PWATs as the upper low's cyclonic flow attempts to pull in some moisture from the fetch to our south and east, but PWAT values are not very substantial with a mean just over 1". Additionally most members also show some increasing CAPE over the area. However QPF output is very limited to nil, so it appears that the still limited moisture and the weakness of the trough will limit any sort of convective initiation. We will continue to monitor this very low chance for some "exciting" weather in an otherwise quiet pattern.
For Tuesday-Wednesday the most likely outcome is for that upper low to be replaced by weak ridging with slightly increasing 500 mb heights and weakening onshore flow, resulting in region-wide warming. There does remain a very low chance for that mountain focused convective activity continues.
16/1802z.
At 1714Z at KLAX, the marine layer was 4800 feet deep. The top of the inversion was at 6000 feet with a temperature of 16 C.
High confidence in TAFs for KPMD and KWJF.
Moderate confidence in remaining TAFs. Timing of flight cat changes could be off by +/- 3 hours. Cst and vly airfields of L.A. County will likely not scatter out this afternoon with VFR cigs.
KLAX, Moderate confidence in TAF. There is a 70% chance for no afternoon clearing. There is a 30 percent chc of an 8 kt east wind component thru 19Z.
KBUR, Moderate confidence in TAF. There is a 70% chance for no afternoon clearing.
16/105 PM.
For the outer waters, generally high confidence in the current forecast. Winds and seas will remain below Small Craft Advisory (SCA) levels through Thursday. Winds are likely to increase to SCA levels Thursday night and continue through Monday night, most prevalent and long-lasting for the waters west and south of Point Conception. Expect steep, choppy seas with the SCA conditions.
For the inner waters N of Point Sal, generally high confidence in the current forecast. Conds are expected to be below SCA levels through Friday morning, then SCA wind gusts are likely during the afternoons and evenings from Friday through Monday.
For the inner waters S of Point Conception, moderate to high confidence in the current forecast. Conds are expected to be below SCA levels for the most part through Monday night. However, for the western Santa Barbara Channel, there is a 60% chance of SCA wind gusts Friday evening, a 50% chance of these gusts Monday evening, and a 30% chance of these gusts Saturday evening and Sunday evening.
Ca, NONE. PZ, NONE.
