15/208 PM.
Scattered showers can be expected through Sunday. There is also a slight chance of thunderstorms through early this evening. This coming Wednesday looks to be dry and milder. Otherwise, the stormy pattern will continue with periods of rain possible through late next week. Below normal daytime temperatures can be expected for much of the time as well.
(tdy-Tue), 15/311 PM.
***MODERATE TO HIGH RISK OF DANGEROUS FLASH FLOODING AND DEBRIS FLOWS INTO EARLY THIS EVENING***
The main rain bands with the current storm system will move off to the N by late today as the upper level low center approaches the coast. The rain pattern will turn to showers and persist into tonight as the upper level low center passes thru the region.
Plenty of lingering moisture and increased instability will lead to a chance to slight chance of thunderstorms this afternoon and early evening especially over southern parts of the forecast area. Any thunderstorms that develop will be capable of producing heavy rain, gusty winds and small hail.
While there is enough twist in the lower atmosphere to allow any TSTM that forms to produce severe weather or even a weak tornado, the real threat from any convection will be the rainfall rates which could still be close to 0.50 inch to 1 inch per hour at times. These rainfall rates on top of the already saturated grounds will could well produce flash flooding anywhere. The recent burn areas will be most vulnerable to flash flooding and debris flows. A flash flood watch is in effect for much of the area through 8 PM this evening.
The chance of showers will continue Sun but there could see some peeks of sunshine at times. Mostly cloudy skies with just a slight chance of showers can be expected Sun night.
The models are in pretty good agreement that an upper level low/trof and surface frontal system will move down the CA coast and into the fcst area on Mon and Mon night. The main frontal band with light to moderate rain should move thru the area from NW to SE thru the day Mon then as the upper level low center moves in Mon night into Tue there will be lingering showers. A few thunderstorms cannot be ruled out as well.
Preliminary rainfall amounts tonight through Sun is expected to be in the 0.50 inch to 1.50 inch range for the coast and vlys, and in the 1 to 2.5 inch range in the mtns. For Sun nigh thru Tue, the entire area should see about 0.50 to 1.00 inch, with locally higher amounts up to 2 inches in the mtns.
Snow levels will remain pretty high thru Mon then lower to 5500 to 6000 feet by Tue, with any snow of a few inches possible at higher elevations.
As with almost all rain events this late in the year max temps across the csts and vlys will be in upper 50s to mid 60s all three days or 6 to 12 degrees blo normal.
(Wed-Sat), 15/202 PM.
The models are in generally good agreement that a dry NW flow aloft will prevail Wed with clear to partly cloudy skies and milder temperatures.
Another system is slated to affect the state on Thursday and Friday. Since the storm is so far out in time, there is considerable disagreement on the exact timing and intensity of this system. Best to wait a little bit before talking about specifics and just realize that it could be wet couple of days.
Next Sat is trending dry and milder. However, the models are still not in complete agreement on that as the GFS shows some lingering pcpn while the EC is dry.
15/2306z.
At 2300Z at KLAX, there was no marine layer. There was a deep moist layer up to at least 10000 feet.
Overall, low confidence in 00Z TAF package. Light to locally moderate showers can be expected overnight. CIGs and VSBYS will bounce around between IFR and VFR levels overnight with low confidence in timing of category changes.
KLAX, Low confidence in 00Z TAF. CIGs and VSBYs will likely settle into MVFR levels this evening and overnight, but there is a 50% chance of periods of VFR conditions. East to southeast winds around 7 knots are expected through 08Z.
KBUR, Low confidence in 00Z TAF. CIGs and VSBYs will likely settle into MVFR levels this evening and overnight, but there is a 50% chance of periods of VFR conditions.
15/150 PM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Sunday night, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. For Monday through Tuesday, high confidence in combination of SCA level winds and seas. For Wednesday, high confidence in winds and seas remaining below SCA levels. On Thursday, there is a 30-40% chance of a combination of SCA level winds and seas.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Sunday night, high confidence in winds and seas remaining below SCA levels. For Monday through Tuesday, there is a 50-60% chance of a combination of SCA level winds and seas. For Wednesday through Thursday, high confidence in winds and seas remaining below SCA levels.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through Sunday night, high confidence in winds and seas remaining below SCA levels. For Monday through Tuesday, there is a 30-50% chance of SCA level winds with the highest chances across the Santa Barbara Channel. For Wednesday through Thursday, high confidence in winds and seas remaining below SCA levels.
There is a 20-30% chance of thunderstorms across the coastal waters south of Point Conception through tonight. Any thunderstorms that develop will be capable of producing brief heavy rain, small hail, dangerous cloud to surface lightning, gusty and erratic winds, locally rough seas, and possible waterspouts.
Ca, Flood Watch now in effect until 8 PM PST this evening for zones 87-88-346>358-362-366>383-548>550. (See LAXFFALOX). PZ, NONE.
