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fxus66 klox 160559 
afdlox 


Area forecast discussion...updated 
National Weather Service Los Angeles/Oxnard California 
1059 PM PDT Mon Oct 15 2018 


Synopsis...15/750 PM. 


Gusty Santa Ana winds will diminish but remain elevated through at 
least Tuesday. Afternoon temperatures will continue to warm 
through the week with some valley locations reaching ninety 
degrees by Friday. Santa Ana winds may redevelop by the weekend. 


&& 


Short term (mon-thu)...15/822 PM. 


The first significant Santa Ana wind event of the season came in 
fast and furious this morning and continued through much of the 
afternoon with impressive wind gusts across the Los Angeles and 
Ventura counties. There were several reports of trees down and 
some boat damage in and around the Avalon Harbor earlier today. 
The strongest wind gusts today occurred across Los Angeles County 
mountains with the highest gust recorded at henniger flats of 73 
mph and several other locations in the 60s range. Most valley and 
coastal areas ranged from the mid 30s to mid 50s. What was unusual 
about this wind event, was the San Gabriel valley and eastern 
part of the San Fernando Valley also received strong winds this 
morning. The best upper level support to help enhance the winds 
today were focused over l.A. County but Orange County and San 
Bernardino counties seemed to have the best upper support which 
would make sense with most of the damage occurring in those areas 
today. Nevertheless, this was a significant event today. 


The offshore gradients will continue through Wednesday, and likely 
into this weekend. However, the upper support will be less of a 
factor tomorrow as the upper trough that dug down over the area 
today has already begun to shift east. Expect winds to taper off 
somewhat tonight, then pick up again late tonight through early 
Tuesday afternoon. Winds should be 10-15 mph weaker than today. 
Wind advisories will remain in effect through at least Tue 
afternoon for the usual Santa Ana wind prone areas of l.A. And 
Ventura counties. 


The warmest temperatures today occurred across the coastal areas 
up to the mid 80s due to the compressional warming through the 
mountain passes to the coast. Meanwhile, highs in the Antelope 
Valley only made it to the upper 60s to lower 70s. All that cold 
air advection is what helps drive the winds. Usually the coast has 
the warmest temps the first day of a significant Santa Ana event. 
However, as we lose some of the cold air advection to the east, 
high temps will moderate and the valleys will start to be the 
warmest locations, while the coast remains relatively warm, until 
the seabreeze kicks in by noon in some locations tomorrow and 
Wednesday. Will be adjusting high temps a bit based on todaya's 
highs. Expect highs along the coast to be around the same or a tad 
cooler, while the valleys increase 4 to 7 degrees. The central 
coast will continue to experience weak offshore winds through the 
morning hours and will experience warmer than normal temps through 
early in the afternoon before the seabreeze kicks in. Overnight 
lows will be quite chilly the next couple nights in wind protected 
locations with 30s expected in the Antelope Valley and interior 
slo County and even lower 40s in the Ojai Valley. 


As mentioned earlier, offshore gradients are expected to continue 
through the week but as we lose the upper level support, winds 
will weaken, especially from Wednesday into the second half the of 
the week where the wind prone areas will see near advisory level 
gusts. The marine layer stratus is expected to remain off the 
coast over the next few days, but if it does come back Wed 
morning, it will be dense along the coast. 


Long term (fri-mon)...15/130 PM. 


A little Rex block sets up over the weekend with the upper low 
portion of The Block centered just south of pt Conception. Light 
to moderate offshore gradients expected to continue through the 
period with a slight uptick in offshore flow Fri/Sat which may 
cause winds to increase enough for some low end wind advisories. 
However upper support is still very minimal so it will be much 
weaker than the current event. Will have to keep an eye on the 
possibility that this upper low could pull in some moisture from 
the southeast late Saturday into Sunday but at this point there's 
not enough to generate rain in our forecast area. Temps will warm 
up some Fri/Sat with the increase in offshore gradients then cool 
a few degrees sun/Mon with the upper low and weakening offshore 
flow. 


&& 


Aviation...16/0559z. 


At 0550z at klax there was no marine layer nor any inversion. 


Overall, high confidence in ceiling and visibility unlimited conds for the next 48 hours. 


The winds will be lighter than they were Monday and there will be 
less turbulence and wind sheer. 


Klax...high confidence in ceiling and visibility unlimited taf. The east wind component should 
remain under 8 kt. 


Kbur...high confidence in ceiling and visibility unlimited taf. Lgt - ocnl turbc sfc-090 
11z-18z. 


&& 


Marine...15/136 PM. 


Outer waters...moderate confidence in current forecast. For 
pzz670/673, winds and seas are expected to remain below Small 
Craft Advisory (sca) levels through Friday although there is a 30% 
chance of Small Craft Advisory level winds Tuesday afternoon/evening. For pzz676, 
high confidence in Small Craft Advisory level northeast winds today with a 20% 
chance of Small Craft Advisory level northeast winds tonight and Tuesday. 


Inner waters north of Point Sal...high confidence in current 
forecast. Winds and seas are expected to remain below Small Craft Advisory levels 
through Friday. 


Inner waters south of Point Conception...high confidence in 
forecast. Small Craft Advisory level northeast winds are expected today from 
Ventura southward with a 40% chance of gale force gusts. Tonight 
and Tuesday, there is a 60% chance for another round of Small Craft Advisory level 
northeast winds that will be a little weaker than today's winds. 
Boaters should be aware of rough seas especially in and around 
east facing harbors (including avalon). Avalon Harbor will likely 
see northeast winds gusting to between 20 and 25 knots today with 
2 to 4 feet wind waves. 


&& 


Fire weather...15/237 PM. 


Continued strong Santa Ana winds this afternoon will slowly back 
off early this evening, then regenerate some overnight into 
Tuesday morning. Gusts of 45-55 mph in the Ventura and Los Angeles 
County mountains and 35-45 mph for valleys/coasts will occur 
during this time frame. Widespread single digit humidities will 
not improve much overnight, especially in the windier corridors. 
10-hour fuel moisture values were dropping into single digit 
categories after shedding recent rainfall from last week. Critical 
fire weather conditions remain in place through 8pm Tuesday. As 
winds decrease Tuesday evening, humidities will recover slightly 
overnight but remain between 15-30 percent. There is a very small 
probability that an extension of the red flag will be needed in a 
few locations, but if humidities rise above 15 percent as 
planned the winds do not look high enough to continue the 
warning. 


There will continue to be marginal red flag conditions in the 
north country of Santa Barbara County and across the eastern San 
Luis Obispo County mountains due to single digit humidity and 
locally gusty northeast winds through Tuesday. 


Continued dry offshore flow will persist through the remainder of 
the week, but there appears to be enough humidity to remain above 
criteria and better overnight recoveries are expected. Another 
Santa Ana may be possible Friday through Sunday morning, but wind 
speeds will not be as strong. 


Critical fire weather will persist through Tuesday evening. The 
public needs to use extreme caution with any potential fire 
ignition sources. Winds of this magnitude may cause tree damage 
and knock down power lines. Be prepared for power outages and be 
ready to evacuate if you live in the urban-wildland interface. 


&& 


Lox watches/warnings/advisories... 
California...Wind Advisory in effect until 3 PM PDT Tuesday for zones 
44>46-53-54-88-547. (See laxnpwlox). 
Red flag warning in effect until 8 PM PDT Tuesday for zones 
238-240-241-244>246-251>254-288-547-548. (See laxrfwlox). 
Pz...Small Craft Advisory in effect from 3 am to noon PDT Tuesday 
for zone 655. (See laxmwwlox). 


&& 


Hazard potential outlook (thu-mon). 


Elevated fire weather conditions expected through the period with 
locally gusty offshore winds, low humidities, warm temperatures, 
and dry fuels. 


&& 


$$ 


Public...Kaplan/mw 
aviation...rorke 
marine...Sweet 



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