Alert archive / California / High Wind Watches in 2017
High Wind Watch 7, NWS Los Angeles, CA
NWS Los Angeles, CA issued this high wind watch at Oct 7, 2017, 1:17 PM PDT for Los Angeles County, California. It took effect at Oct 9, 2017, 12:00 AM PDT. It was in force for .
The area
The counties it named.
The facts
- Issued
- Oct 7, 2017, 1:17 PM PDT (20:17 UTC)
- In effect from
- Oct 9, 2017, 12:00 AM PDT
- Expired
- Oct 8, 2017, 10:44 AM PDT
- In force
- Issued by
- NWS Los Angeles, CA
County Los Angeles County, CA
The radar
The Santa Ana Mts radar (KSOX), 71 km from the middle of the area, began a volume at 20:16 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
San Diego, CA (KNKX), launched 12:00Z, 8.3 hours before the alert went out and 184 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 4788 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 9 m²/s²
- 0-3 km storm-relative helicity
- 4 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
644 WWUS76 KLOX 072017 NPWLOX URGENT - WEATHER MESSAGE National Weather Service Los Angeles/Oxnard CA 117 PM PDT Sat Oct 7 2017 CAZ046-053-054-080500- /O.NEW.KLOX.HW.A.0007.171009T0700Z-171009T2100Z/ Santa Monica Mountains Recreational Area-Ventura County Mountains- Los Angeles County Mountains excluding the Santa Monica Range- Including the cities of Lockwood Valley, Mount Pinos, Acton, Mount Wilson, and Sandberg 117 PM PDT Sat Oct 7 2017 ...HIGH WIND WATCH IN EFFECT FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON... The National Weather Service in Los Angeles/Oxnard has issued a High Wind Watch for the Los Angeles and Ventura County Mountains including the Santa Monica Mountain Range. This watch is in effect from late Sunday night through Monday afternoon. * TIMING...Gusty and potentially damaging north to northeast winds will likely develop on Sunday night and continue through Monday afternoon. Gusty sub-warning level north to northeast winds will likely linger into Tuesday morning across the mountains. Gusty winds also likely develop across the remaining areas of Los Angeles and Ventura Counties late Sunday night through Tuesday morning. * WINDS...Areas of north to northeast winds will likely increase to 25 to 40 mph with possible damaging gusts to 60 mph on Sunday night and likely linger into Monday afternoon. * IMPACTS...Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers. This includes Highway 33 in Ventura County as well as Interstate 5 and Highway 14 in Los Angeles County. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Wind Watch means that conditions are favorable for potentially damaging winds of 58 mph or greater. Be prepared to secure all loose outdoor furniture in advance of the onset of strong winds. Monitor the latest forecasts on NOAA Weather Radio or your favorite media source. && $$ Hall
3 follow-up statements
864 WWUS76 KLOX 080228 NPWLOX URGENT - WEATHER MESSAGE National Weather Service Los Angeles/Oxnard CA 728 PM PDT Sat Oct 7 2017 ...Potential for damaging winds to affect the mountains of Los Angeles and Ventura Counties including the Santa Monica Range and the Santa Clarita Valley Monday morning... .Confidence is growing that a strong Santa Ana wind event could develop across the usual wind prone Santa Ana wind locations late Sunday night and peaking Monday morning. Winds will begin to trend downward by Monday afternoon and continue into Tuesday morning. CAZ088-081100- /O.EXA.KLOX.HW.A.0007.171009T0700Z-171009T2100Z/ Santa Clarita Valley- Including the cities of Santa Clarita, Newhall, and Valencia 728 PM PDT Sat Oct 7 2017 ...HIGH WIND WATCH IN EFFECT FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON... The National Weather Service in Los Angeles/Oxnard has issued a High Wind Watch, which is in effect from late Sunday night through Monday afternoon. * TIMING...Gusty and potentially damaging northeast winds will likely develop late Sunday night and continue through Monday afternoon. Strongest wind gusts peaking Monday morning through passes and canyons and foothills. Winds will begin to diminish some by late Monday afternoon where wind advisories should handle the duration of the wind event through Tuesday morning. * WINDS...Areas of northeast winds are expected to increase to 25 to 40 mph with possible damaging gusts to 60 mph late Sunday night through Monday morning before diminishing some. Winds should lower to between 15 and 30 mph with gusts to 45 mph late Monday afternoon through Tuesday morning. * IMPACTS...Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers. This includes Highway 14 as well as Interstate 5. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Wind Watch means that conditions are favorable for potentially damaging winds of 58 mph or greater. Be prepared to secure all loose outdoor furniture in advance of the onset of strong winds. Monitor the latest forecasts on NOAA Weather Radio or your favorite media source. && $$ CAZ046-053-054-081100- /O.CON.KLOX.HW.A.0007.171009T0700Z-171009T2100Z/ Santa Monica Mountains Recreational Area-Ventura County Mountains- Los Angeles County Mountains excluding the Santa Monica Range- Including the cities of Lockwood Valley, Mount Pinos, Acton, Mount Wilson, and Sandberg 728 PM PDT Sat Oct 7 2017 ...HIGH WIND WATCH REMAINS IN EFFECT FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON... * TIMING...Gusty and potentially damaging northeast winds will likely develop late Sunday night and continue through Monday afternoon. Strongest wind gusts peaking Monday morning. Winds should begin to diminish some by late Monday afternoon. Wind advisories will likely be able to handle the duration of the wind event through Tuesday afternoon. * WINDS...Areas of north to northeast winds will likely increase to 25 to 40 mph with possible damaging gusts to 60 mph on Sunday night and likely linger into early Monday afternoon before diminishing some. Isolated gusts to 70 mph possible across higher peaks Monday morning. Winds should lower to between 20 and 35 mph with gusts to 50 mph by Monday night into Tuesday morning. * IMPACTS...Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers. This includes Highway 33 in Ventura County as well as Interstate 5 and Highway 14 in Los Angeles County. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Wind Watch means that conditions are favorable for potentially damaging winds of 58 mph or greater. Be prepared to secure all loose outdoor furniture in advance of the onset of strong winds. Monitor the latest forecasts on NOAA Weather Radio or your favorite media source. && $$ Kaplan/Hall
715 WWUS76 KLOX 081042 NPWLOX URGENT - WEATHER MESSAGE National Weather Service Los Angeles/Oxnard CA 342 AM PDT Sun Oct 8 2017 ...Potential for damaging winds to affect the mountains of Los Angeles and Ventura Counties including the Santa Monica Range and the Santa Clarita Valley Monday morning... .A strong Santa Ana wind event could develop late tonight and continue into Tuesday morning. The winds will be strongest Monday morning. CAZ046-053-054-088-081845- /O.CON.KLOX.HW.A.0007.171009T0700Z-171009T2100Z/ Santa Monica Mountains Recreational Area-Ventura County Mountains- Los Angeles County Mountains excluding the Santa Monica Range- Santa Clarita Valley- Including the cities of Lockwood Valley, Mount Pinos, Acton, Mount Wilson, Sandberg, Santa Clarita, Newhall, and Valencia 342 AM PDT Sun Oct 8 2017 ...HIGH WIND WATCH REMAINS IN EFFECT FROM LATE TONIGHT THROUGH MONDAY AFTERNOON... * TIMING...Gusty and potentially damaging northeast winds will likely develop late tonight and continue through Monday afternoon. The strongest wind gusts will occur Monday morning. Warning level gusts will end Monday afternoon but then advisory level gusts will likely continue through Tuesday. * WINDS...Areas of north to northeast winds will likely increase to 25 to 40 mph with possible damaging gusts to 60 mph on tonight and likely linger into early Monday afternoon before diminishing some. Isolated gusts to 70 mph are possible across higher peaks Monday morning. Winds should lower to between 20 and 35 mph with gusts to 50 mph by Monday night and then continue into Tuesday morning. * IMPACTS...Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers. This includes Highway 33 in Ventura County as well as Interstate 5 and Highway 14 in Los Angeles County. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Wind Watch means that conditions are favorable for potentially damaging winds of 58 mph or greater. Be prepared to secure all loose outdoor furniture in advance of the onset of strong winds. Monitor the latest forecasts on NOAA Weather Radio or your favorite media source. && $$ TH/CK/ASR
364 WWUS76 KLOX 081744 NPWLOX URGENT - WEATHER MESSAGE National Weather Service Los Angeles/Oxnard CA 1044 AM PDT Sun Oct 8 2017 ...Gusty and potentially damaging winds to develop tonight across portions of Southwest California... .A strong Santa Ana wind event will develop tonight and continue into Tuesday morning. Gusty north to northeast winds will develop across portions of Southwest California tonight and continue through at least Monday evening, or as late as Tuesday morning for some areas. The strongest winds will be focused in the mountains and across Northwestern Los Angeles and Eastern Ventura Counties. CAZ053-054-090145- /O.UPG.KLOX.HW.A.0007.171009T0700Z-171009T2100Z/ /O.NEW.KLOX.HW.W.0011.171009T0500Z-171009T2300Z/ Ventura County Mountains- Los Angeles County Mountains excluding the Santa Monica Range- Including the cities of Lockwood Valley, Mount Pinos, Acton, Mount Wilson, and Sandberg 1044 AM PDT Sun Oct 8 2017 ...HIGH WIND WARNING IN EFFECT FROM 10 PM THIS EVENING TO 4 PM PDT MONDAY... The National Weather Service in Los Angeles/Oxnard has issued a High Wind Warning for the Los Angeles and Ventura County Mountains. This warning is in effect from 10 PM this evening to 4 PM PDT Monday. The High Wind Watch is no longer in effect. * TIMING...Areas of north to northeast winds with damaging wind gusts will develop late tonight and continue through Monday afternoon. The strongest wind gusts will occur Monday morning. Warning level gusts will end Monday afternoon but then advisory level gusts will likely continue through Tuesday. * WINDS...Areas of north to northeast winds will increase to 30 to 45 mph with damaging gusts to 65 to 70 mph tonight and likely linger into Monday afternoon before decreasing. Isolated gusts to 75 mph are possible across higher peaks Monday morning. Winds should lower to between 20 and 35 mph with gusts to 50 mph by Monday night and then continue into Tuesday morning. * IMPACTS...Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers. This includes Highway 33 in Ventura County as well as Interstate 5 and Highway 14 in Los Angeles County. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Wind Warning means that damaging high winds of 58 mph or greater are likely or imminent. Secure all loose outdoor furniture in advance of the onset of strong winds. Monitor the latest forecasts on NOAA Weather Radio or your favorite media source. && $$ CAZ046-088-090145- /O.UPG.KLOX.HW.A.0007.171009T0700Z-171009T2100Z/ /O.NEW.KLOX.HW.W.0011.171009T0500Z-171009T2300Z/ Santa Monica Mountains Recreational Area-Santa Clarita Valley- Including the cities of Santa Clarita, Newhall, and Valencia 1044 AM PDT Sun Oct 8 2017 ...HIGH WIND WARNING IN EFFECT FROM 10 PM THIS EVENING TO 4 PM PDT MONDAY... The National Weather Service in Los Angeles/Oxnard has issued a High Wind Warning for the Santa Monica Mountains and Santa Clarita Valley. This warning is in effect from 10 PM this evening to 4 PM PDT Monday. The High Wind Watch is no longer in effect. * TIMING...Areas of north to northeast winds with damaging wind gusts will develop late tonight and continue through Monday afternoon. The strongest wind gusts will occur Monday morning. Warning level gusts will end Monday afternoon but then advisory level gusts will likely continue through Tuesday. * WINDS...Areas of north to northeast winds will increase to 25 to 40 mph with damaging gusts to 60 mph tonight and linger into Monday afternoon before decreasing. Isolated gusts to 70 mph are possible across higher peaks Monday morning. Winds should lower to between 20 and 35 mph with gusts to 50 mph by Monday night and then continue into Tuesday morning. * IMPACTS...Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers. This includes Interstate 5 and Highways 14 and 126. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Wind Warning means that damaging high winds of 58 mph or greater are likely or imminent. Secure all loose outdoor furniture in advance of the onset of strong winds. Monitor the latest forecasts on NOAA Weather Radio or your favorite media source. && $$ CAZ045-090145- /O.NEW.KLOX.HW.W.0011.171009T0500Z-171009T2300Z/ Ventura County Coastal Valleys- Including the cities of Thousand Oaks, Simi Valley, Moorpark, and Newbury Park 1044 AM PDT Sun Oct 8 2017 ...HIGH WIND WARNING IN EFFECT FROM 10 PM THIS EVENING TO 4 PM PDT MONDAY... The National Weather Service in Los Angeles/Oxnard has issued a High Wind Warning for the Ventura County Coastal Valleys. This warning is in effect from 10 PM this evening to 4 PM PDT Monday. * TIMING...Areas of north to northeast winds with damaging wind gusts will develop late tonight and continue through Monday afternoon. The strongest wind gusts will occur Monday morning. Warning level gusts will end Monday afternoon but then advisory level gusts will likely continue through Tuesday. * WINDS...Areas of north to northeast winds will increase to 25 to 40 mph with damaging gusts to 60 mph tonight and linger into Monday afternoon before decreasing. Isolated gusts to 70 mph are possible across higher peaks Monday morning. Winds should lower to between 20 and 35 mph with gusts to 50 mph by Monday night and then continue into Tuesday morning. * IMPACTS...Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers. This includes the 23, 101, and 118 freeways. PRECAUTIONARY/PREPAREDNESS ACTIONS... A High Wind Warning means that damaging high winds of 58 mph or greater are likely or imminent. Secure all loose outdoor furniture in advance of the onset of strong winds. Monitor the latest forecasts on NOAA Weather Radio or your favorite media source. && $$ CAZ059-090145- /O.NEW.KLOX.WI.Y.0063.171009T0500Z-171010T0300Z/ Antelope Valley- Including the cities of Lancaster and Palmdale 1044 AM PDT Sun Oct 8 2017 ...WIND ADVISORY IN EFFECT FROM 10 PM THIS EVENING TO 8 PM PDT MONDAY... The National Weather Service in Los Angeles/Oxnard has issued a Wind Advisory for the Antelope Valley. This advisory is in effect from 10 PM this evening to 8 PM PDT Monday. * TIMING...Gusty north to northeast winds will develop late tonight and continue through Monday evening. The strongest wind gusts will occur in the foothills. * WINDS...Areas of northeast winds will increase to 15 to 30 mph with gusts to 45 mph tonight and linger into Monday evening. Isolated gusts in excess of 55 mph are possible in the foothills on Monday morning. * IMPACTS...Gusty winds will make driving difficult, especially for high profile vehicles. Areas of blowing dust can suddenly and dangerously reduce visibilities to near zero. This includes Highways 14 and 138, especially near the foothills. PRECAUTIONARY/PREPAREDNESS ACTIONS... When driving, use extra caution. Be prepared for sudden gusty cross winds. && $$ CAZ044-547-090145- /O.NEW.KLOX.WI.Y.0063.171009T0500Z-171010T1700Z/ Ventura County Interior Valleys- Los Angeles County San Fernando Valley- Including the cities of Santa Paula, Fillmore, Ojai, Piru, Woodland Hills, Northridge, Burbank, and Universal City 1044 AM PDT Sun Oct 8 2017 ...WIND ADVISORY IN EFFECT FROM 10 PM THIS EVENING TO 10 AM PDT TUESDAY... The National Weather Service in Los Angeles/Oxnard has issued a Wind Advisory for the San Fernando and Ventura County Interior Valleys. This advisory is in effect from 10 PM this evening to 10 AM PDT Tuesday. * TIMING...Gusty north to northeast winds will develop late tonight and continue through Tuesday morning. * WINDS...Areas of northeast winds will increase to 20 to 35 mph with gusts to 50 to 55 mph tonight and linger into Tuesday morning. Isolated gusts up to 65 mph are possible on Monday morning. * IMPACTS...Gusty winds will make driving difficult, especially for high profile vehicles. This includes Highways 33 and 126. PRECAUTIONARY/PREPAREDNESS ACTIONS... When driving, use extra caution. Be prepared for sudden gusty cross winds. && $$ CAZ040-090145- /O.NEW.KLOX.WI.Y.0063.171009T0800Z-171010T1700Z/ Ventura County Coast- Including the cities of Ventura, Oxnard, and Camarillo 1044 AM PDT Sun Oct 8 2017 ...WIND ADVISORY IN EFFECT FROM 1 AM MONDAY TO 10 AM PDT TUESDAY... The National Weather Service in Los Angeles/Oxnard has issued a Wind Advisory for the Ventura County Coast. This advisory is in effect from 1 AM Monday to 10 AM PDT Tuesday. * TIMING...Gusty north to northeast winds will develop late tonight and continue through Tuesday morning. * WINDS...Areas of northeast winds will increase to 20 to 35 mph with gusts up to 50 mph tonight and linger into Tuesday morning. Isolated gusts up to 60 mph are possible on Monday morning. * IMPACTS...Gusty winds will make driving difficult, especially for high profile vehicles. This includes Highway 101 and Pacific Coast Highway. PRECAUTIONARY/PREPAREDNESS ACTIONS... When driving, use extra caution. Be prepared for sudden gusty cross winds. && $$ CAZ041-090145- /O.NEW.KLOX.WI.Y.0063.171009T0800Z-171010T0300Z/ Los Angeles County Coast including Downtown Los Angeles- Including the cities of Malibu, Santa Monica, Beverly Hills, Hollywood, and Long Beach 1044 AM PDT Sun Oct 8 2017 ...WIND ADVISORY IN EFFECT FROM 1 AM TO 8 PM PDT MONDAY... The National Weather Service in Los Angeles/Oxnard has issued a Wind Advisory for the Los Angeles County Coast. This advisory is in effect from 1 AM to 8 PM PDT Monday and is mainly for the portion from Malibu to the Hollywood Hills. * TIMING...Gusty north to northeast winds will develop late tonight and continue through Monday evening. The strongest winds will occur from Malibu to the Hollywood Hills. * WINDS...From Malibu to the Hollywood Hills, areas of north to northeast winds will increase to 15 to 30 mph with gusts up to 45 mph tonight and linger into Monday evening. * IMPACTS...Gusty winds will make driving difficult, especially for high profile vehicles. This includes Pacific Coast Highway and the 10 and 405 freeways. PRECAUTIONARY/PREPAREDNESS ACTIONS... When driving, use extra caution. Be prepared for sudden gusty cross winds. && $$ CAZ037-038-051-090145- /O.NEW.KLOX.WI.Y.0063.171009T0800Z-171010T0300Z/ San Luis Obispo County Interior Valleys-Cuyama Valley- San Luis Obispo County Mountains- Including the cities of Paso Robles, Atascadero, Cuyama, and Black Mountain 1044 AM PDT Sun Oct 8 2017 ...WIND ADVISORY IN EFFECT FROM 1 AM TO 8 PM PDT MONDAY... The National Weather Service in Los Angeles/Oxnard has issued a Wind Advisory for the interior portions of San Luis Obispo County and Cuyama Valley. This advisory is in effect from 1 AM to 8 PM PDT Monday. * TIMING...Gusty north to northeast winds will develop late tonight and continue through Monday evening. * WINDS...Areas of east to southeast winds will increase to 15 to 25 mph with gusts to 35 mph tonight and linger through Monday evening. Local stronger winds 20 to 30 mph with gusts up to 45 mph across the higher terrain. * IMPACTS...Gusty winds will make driving difficult, especially for high profile vehicles. PRECAUTIONARY/PREPAREDNESS ACTIONS... When driving, use extra caution. Be prepared for sudden gusty cross winds. && $$ CAZ548-090145- /O.NEW.KLOX.WI.Y.0063.171009T1200Z-171010T0300Z/ Los Angeles County San Gabriel Valley- Including the cities of Pasadena, San Gabriel, and Pomona 1044 AM PDT Sun Oct 8 2017 ...WIND ADVISORY IN EFFECT FROM 5 AM TO 8 PM PDT MONDAY... The National Weather Service in Los Angeles/Oxnard has issued a Wind Advisory for the San Gabriel Valley. This advisory is in effect from 5 AM to 8 PM PDT Monday and is mainly for the foothill portions. * TIMING...Gusty north to northeast winds will develop late tonight and continue through Monday evening. The strongest wind gusts will occur in the foothills. * WINDS...In the foothills, areas of north to northeast winds will increase to 15 to 30 mph with gusts up to 45 mph on Monday morning and continue into Monday evening. * IMPACTS...Gusty winds will make driving difficult, especially for high profile vehicles. This includes the 10, 57, 60, 210, 605, and 710 freeways. PRECAUTIONARY/PREPAREDNESS ACTIONS... When driving, use extra caution. Be prepared for sudden gusty cross winds. && $$ Hall/Kj
What forecasters said that day
The local office's own words before this high wind watch went out, 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 this high wind watch went out at Oct 7, 10:48 AM PDT, 2 hours 29 minutes earlier.
Area forecast discussion, Oct 7, 10:48 AM PDT, 2 hours 29 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1048 AM PDT Sat Oct 7 2017
Updated Aviation and Fire Sections
.SYNOPSIS...
A return to onshore flow with low clouds to many coastal areas
will bring significant cooling to most areas Sunday. The first
significant Santa Ana event of the season will bring widespread
offshore wind with warming and drying to the west of the mountains
through Tuesday. A trough of low pressure building over the West
Coast will likely bring cooling for the middle of next week.
&&
.SHORT TERM...(TDY-MON)
With the exception of high cloudiness and a patch of stratus off
the Los Angeles County coast, the latest satellite imagery shows
clear skies prevailing across the region this morning as offshore
flow remains in place beneath high pressure aloft. A warm and dry
air mass will remain over the area today, then offshore flow will
breakdown giving away to onshore flow tonight. A broad trough of
low pressure over the Pacific Northwest this morning will sag
south into the Great Basin through Sunday afternoon and evening.
With the trough's influence and the low-level flow pattern shift,
a cooling trend should develop on Sunday. An eddy circulation
developing across the coastal waters should promote a bit more
stratus formation tonight through Sunday night.
*** FROM PREVIOUS DISCUSSION ***
The WRF indicates low clouds moving northward into at least
coastal sections of L.A. County and probably Ventura County late
tonight and Sunday morning, and it is not out of the question that
clouds could push into some valley areas. Clouds could linger at
the beaches of L.A. and VTU Counties well into the afternoon on
Sunday. There will be significant cooling on Sunday, with max
temps down as much as 12 to 18 degrees in some valley areas and
across far interior portions of the coastal plain.
The upper trough in the Great Basin will move eastward Sunday
night and Mon, and a strong surface high will settle into Nevada.
Pressure gradients will rapidly reverse, and are forecast to be
nearly 8 mb offshore between KLAX and KDAG Mon morning. There
could be some low clouds across coastal sections of L.A. County
Sunday night, but those should be whisked off the coast by the
developing offshore flow. Strong offshore gradients, cold air
advection, and fairly good upper level support with strong winds
at 850 mb should result in some decent Santa Ana winds across much
of L.A. and VTU Counties Monday. At this point, it looks almost
certain that Wind Advisories will be needed across most of L.A.
and VTU Counties, and High Wind Warning level winds are certainly
possible. Max temps will likely rise several degrees west of the
mountains on Mon, but will likely fall significantly in the mtns
and deserts.
.LONG TERM...(TUE-FRI)
Broad upper ridge will become zonal flow across Southwestern CA on
Tue, and heights will rise slightly or change little. Gradients
will still be offshore, in the morning, then will flip onshore.
There should be several degrees of warming on Tue in the mtns and
deserts, little change or slight warming in the valleys, and some
cooling across the coastal plain, mainly near the beaches. A
trough will move into the West Coast on Wed, causing
heights/thicknesses to fall. Low level flow will be increasingly
onshore. This should bring a few degrees of cooling to most
areas Wed. The upper trough across the West Coast will sharpen and
dig some Thu, so expect some additional cooling. Then, expect
little change in temps on Fri as the trough remains in place.
Night through morning low clouds will probably return to coastal
areas Wed night and Thu, and become more widespread Thu night and
Fri. There is a chance that low clouds could return as early
as Tue night, but that appears unlikely at this time.
&&
.AVIATION...07/1740Z.
At 17Z at KLAX...there was no marine layer with a surface-based
inversion up to 2300 ft at 28 degrees Celsius.
High confidence in VFR through this evening and winds generally
below 12 KT. Shallow marine layer likely to reform tonight, but
confidence is low as to where and when CIG might occur. 70 percent
chance of forming at KSMX KLAX KLGB KSMO, 40 percent chance at
KSBP KOXR KCMA, 20 percent chance at KSBA. Wherever it forms,
moderately confident that LIFR cats will prevail at onset, lifting
to IFR before dissipating Sunday morning.
KLAX...High confidence in VFR and onshore flow through this
evening. Marine layer likely to reform late tonight, 70 percent
chance of CIG/VIS restrictions after 09Z. LIFR FG possible
especially early. SE winds expected Sunday morning, likely below
8 KT.
KBUR...High confidence in VFR with light onshore winds.
&&
.MARINE...07/900 AM.
High confidence that northwest winds will increase today and
continue through Sunday evening from the Central Coast to San
Nicolas Island, peaking tonight. Moderate confidence in Gale
Force winds beyond 20 miles from the Central Coast...which may or
may not reach the buoys. These winds will generate a short-period
swell, especially near the coast. Light winds are expected in that
area after that from Monday through at least Wednesday.
For the Santa Barbara Channel and the Santa Monica Basin, winds
should remain below Small Craft Advisory (SCA) through Sunday
evening. A potentially strong offshore event is expected for
Monday...with 20-30KT NE winds likely from Ventura to Santa
Monica...out to the Channel Islands. This does not look like the
type of event that affects Avalon, but there is a 20 percent
chance that 10-20 KT winds reach the harbor.
Dense fog will affect the San Pedro Channel this morning, and
could affect more areas tonight.
A long period south swell is peaking now, which will create
hazardous breaking waves near the coast...especially for small
boats.
&&
.FIRE WEATHER...07/1000 AM.
Offshore winds are weakening today, however very warm and dry
conditions will continue to bring widespread elevated fire
weather danger across the area through the day.
A stronger offshore wind event is expected for late Sunday night
into Monday when offshore pressure gradients are expected to
strengthen and there is some fairly strong wind support up to the
850 mb level. There is still some differences in strength with
this event, with the 12z NAM advertising a LAX-Daggett gradient
around -8 mb and the 12z GFS showing a gradient peaking around -5
mb. Either way, it appears there will be sufficiently strong
offshore winds coupled with low humidities to bring a high
potential for critical fire weather conditions. Current Fire
Weather Watches Monday into early Tuesday look on track.
Peak offshore winds are expected on Monday, especially across
western Los Angeles and eastern Ventura counties, where gusts
between 50 and 60 mph will be possible across the mountains,
and gusts between 40 and 50 mph will be possible across the
coastal and valley areas (with locally stronger gusts possible
in the Santa Clarita Valley). This surge of offshore winds will
bring considerable drying to the region, first across the
mountains late Sunday night then descending into coastal and
valley areas during the day Monday. Widespread humidities into the
single digits and teens will be likely during this period. During
this period of potential critical fire weather conditions, there
will be an increased risk of fire ignitions and large fire
growth, including rapid fire spread and long range spotting
potential due to the gusty offshore winds and very dry fuels.
Offshore winds are expected to diminish rapidly Tuesday morning,
with a transition to onshore winds by the afternoon with continued
very low humidities.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement in effect through Sunday evening for
zones 34-35-40-41-87. (See LAXCFWLOX).
Fire Weather Watch in effect from late Sunday night through
Monday evening for zones 237-238-251. (See LAXRFWLOX).
Fire Weather Watch in effect from late Sunday night through
Tuesday morning for zones
240-241-244>246-253-254-288-547-548. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 11
PM PDT this evening for zone 645. (See LAXMWWLOX).
Small Craft Advisory in effect until 6 PM PDT this evening
for zones 670-673. (See LAXMWWLOX).
Gale Warning in effect from 6 PM this evening to 9 AM PDT
Sunday for zones 670-673. (See LAXMWWLOX).
Small Craft Advisory in effect from 6 PM this evening to 9 PM
PDT Sunday for zone 676. (See LAXMWWLOX).
&&
.HAZARD POTENTIAL OUTLOOK...(MON-FRI)
Gusty Santa Ana winds and critical fire weather conditions are
possible on Monday.
&&
PUBLIC...Hall/DB
AVIATION...Kittell
MARINE...Kittell
FIRE...Gomberg
SYNOPSIS...Munroe
weather.gov/losangelesThe office that day
Everything else NWS Los Angeles, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 7, 3:44 AM PDT | Small Craft Advisory | LOX | 5 hr | |
| Oct 7, 9:10 AM PDT | Gale Warning | LOX | 24 hr | |
| Oct 7, 9:10 AM PDT | Small Craft Advisory | LOX | 42 hr | |
| Oct 7, 4:03 PM PDT | Red Flag Warning | LOX | Los Angeles, Santa Barbara | 66 hr |
Nearby
High Wind Watches in California, 2017Every high wind watch in 2017
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.