Heavy showers and thunderstorms generated flash flooding as well as mud and debris flows near the community of Duarte. Up to 6 inches of mud and debris was reported across Brookridge and Melcanyon roads.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LOX wrote it up.
Heavy showers and thunderstorms generated flash flooding as well as mud and debris flows near the community of Duarte. Up to 6 inches of mud and debris was reported across Brookridge and Melcanyon roads.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Los Angeles, CA wrote its last area forecast discussion before the first event at Dec 16, 3:38 AM PST, 45 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
338 AM PST Fri Dec 16 2016
.SYNOPSIS...
A Pacific storm system will bring widespread rain, high elevation
mountain snow and gusty winds to the region this evening through
Friday morning. Showers will occur behind the front and linger
across the mountains through early Saturday morning. Dry and cool
conditions will prevail on Sunday. For early next, Santa Ana winds
will bring continued dry conditions and seasonable temperatures.
&&
.SHORT TERM...(TDY-SUN)
The back edge of the cold front is currently over NW SLO county.
Warm frontal overrunning rain covers the rest of the area. Steady
rain has added up to about an inch in most areas with a little
more on the coastal slopes and a little less across the interior.
As is so often the case Rocky Butte in the NW tip of SLO county
was the big rainfall winner coming in at 5.16 inches of rain. The
rain will spoil the L.A. morning commute and then diminish. There
are still pockets rainfall capable of producing debris flows in
the recent burn areas so the Flash Flood watch will continue. There
will be a chance of showers over the mtns and L.A. county this
afternoon but otherwise skies will be partly cloudy this
afternoon.
Snow levels remain over 8000 feet but will come down this
afternoon in the wake of the front. The snow level will fall to
5000 feet but there will not be that much shower activity left
over to produce much in the way of snowfall.
A low level jet provided ample energy for the south winds in the
mtns and all of the mtn zones saw gusts approaching 60 mph. The
SLO interior Vly and the Antelope Vly also had warning level winds
as mountain waves touched down in a few places. West to Northwest
winds will develop behind the front as cold air pours in behind
it. There will likely be a need for some wind advisories across
the mtns...the Antelope Vly and the Central Coast later this
morning.
Cold north flow will push up lots of clouds against the north
slopes and will generate some snow showers. The moisture will also
work its way into the Cuyama vly producing clouds and snow
showers. There will be plenty of wind and cold and some snow. A
winter weather advisory in in effect from later this afternoon to
Saturday morning to cover the snow wind cold and wind chills. This
advisory does include the Grapevine area of Interstate 5 travelers
planning to drive through the mtns this evening through Sat
morning should check the mtn weather conditions before departing.
The big deal for the weekend will be the overnight low temps each
night as the clear skies and dry air will allow good cooling in
an already cold airmass. There will be hard freezes across the
interior and min temps at or near freezing for most of the vlys.
The Central Coast will likely see freezing temps for almost all of
the non beach areas.
Aside from those Saturday morning showers on the north slopes
skies will be partly cloudy at worst. Max temps Will be 4 to 8
degrees blo normal. There will be some light NE flow on Sunday but
right now it looks sub advisory.
.LONG TERM...(MON-THU)
Some warming will start Monday as weak ridging begins to move into
the area. This will also be the time of maximum offshore Santa Ana
flow. There will probably be a need for several low end advisories
in the morning. Max temps will warm but will likely remain a
degree or two blo normals. Min temps in wind sheltered locations
and esp the interior will continue well below normal with freezing
temps likely in many areas.
One Tue and Wed...the mdls disagree with each and from run to run
on the exact solution for a cut off low that will develop to the
SW of LA county. But right now it looks like the exact location of
the upper low will not affect the forecast too much. There will be
slight ridging over the area and light offshore flow and rising
hgts. Add sunny skies into the mix and max temps will rise to
above normal for both days.
A little trof will begin to move into the area on Thursday. It
will likely produce partly cloudy skies over SLO and SBA counties.
hgts will lower and the weak offshore flow will turn weakly
onshore. Max temps will fall but will likely still be above
normal.
&&
.AVIATION...
16/1035Z
At 1030Z, there was no marine inversion at KLAX, just a deep
moist layer.
Overall, low confidence in 12Z TAF package through 20Z as
CIGs/VSBYs fluctuate between LIFR and MVFR levels. After 20Z,
moderate to high confidence in TAF package as VFR conditions will
prevail along with gusty west to northwest winds.
KLAX...low confidence in 12Z TAF through 20Z as CIGs/VSBYs will
fluctuate between LIFR and MVFR levels. High confidence in VFR
conditions after 20Z as strong west winds develop. East to
southeast winds near 10 knots will continue until 15Z this
morning.
KBUR...low confidence in 12Z TAF through 20Z as CIGs/VSBYs will
fluctuate between LIFR and MVFR levels. Moderate confidence in
VFR conditions after 20Z with gusty northwest winds developing
after 02Z.
&&
.MARINE...
16/200 AM
For the Outer Waters, moderate to high confidence in current
forecast. Strong northwest winds, behind a cold front, are
expected to reach Gale Force levels today/tonight across
PZZ673/676 and strong Small Craft Advisory (SCA) levels across
PZZ670. On Saturday, the winds will diminish a bit, but still
widespread SCA level winds are likely. For Sunday through Tuesday,
winds will remain gusty with a decent chance of SCA level winds
developing at times.
For the Inner Waters, moderate to high confidence in current
forecast. For the waters north of Point Sal, SCA level winds are
expected through tonight with winds dropping below SCA levels
Saturday through Tuesday. For the waters south of Point
Conception, Gale Force winds are expected to develop today and
continue through tonight, before diminishing on Saturday. For
Sunday through Tuesday, northeast winds will prevail across the
waters with a chance of SCA level winds developing.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 4 AM PST early this morning for
zones 34>36-38-39. (See LAXNPWLOX).
Flash Flood Watch in effect until 6 AM PST early this morning
for zones 34>37-39-52. (See LAXFFALOX).
High Wind Warning in effect until 4 AM PST early this morning
for zones 37-51-52. (See LAXNPWLOX).
Winter Weather Advisory in effect from 2 PM this afternoon to
10 AM PST Saturday for zones 38-52>54. (See LAXWSWLOX).
Flash Flood Watch in effect until noon PST today for zones
40-44>46-53-54-88-547. (See LAXFFALOX).
High Surf Advisory in effect from noon today to 2 AM PST
Saturday for zones 40-41-87. (See LAXCFWLOX).
High Wind Warning in effect until 10 AM PST this morning for
zones 53-54-59. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PST Saturday for
zones 645-670. (See LAXMWWLOX).
Gale Warning in effect from 10 AM this morning to 3 AM PST
Saturday for zones 650-655. (See LAXMWWLOX).
Gale Warning in effect until 3 AM PST Saturday for zones
673-676. (See LAXMWWLOX).
&&
.HAZARD POTENTIAL OUTLOOK...(SUN-THU)
Gusty advisory level Santa Ana winds possible Sunday through
Tuesday. Many areas will see freezing temps Sunday morning.
&&
PUBLIC...Rorke
AVIATION...RAT
MARINE...RAT
SYNOPSIS...RAT
weather.gov/losangelesPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1224 AM PST FRI DEC 16 2016
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0955 PM NON-TSTM WND GST 5 NNE SAN FERNANDO 34.35N 118.42W
12/15/2016 M59 MPH LOS ANGELES CA MESONET
CAMP 9 RAWS AT 4000 FT. SE GUST 59 MPH. .
&&
CKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1227 AM PST FRI DEC 16 2016
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1213 AM NON-TSTM WND GST CALIFORNIA VALLEY 35.32N 120.00W
12/16/2016 M60 MPH SAN LUIS OBISPO CA PUBLIC
CALIFORNIA VALLEY RAWS ELEVATION 3280 FT. SW
GUST 60 MPH. .
&&
CKThe Santa Ana Mts radar (KSOX), 47 km away, was scanning. The volume nearest the first event began at 12:21 UTC.
1 flash flood. Local standard time, as filed.
Heavy rain over the Fish burn area generated flash flooding as well as mud and debris flows in the city of Duarte. At the intersection of Brookridge Road and Melcanyon Road, over 6 inches of mud and debris was reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2016Every state in 2016This day in weather historyWarnings in California, December 2016
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 668955.