High Surf Advisory 9, NWS Los Angeles, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1118 AM PDT Mon Mar 27 2017

.SYNOPSIS...
A mostly dry cold front will bring some rain showers and snow
showers to the mountains today, mainly to northern slopes. Behind
the front, widespread strong west to north winds will affect the
region later today through Tuesday morning. High pressure will
bring a warming trend Tuesday and Wednesday. An upper trough
moving to our north will bring cooling again for Thursday and
Friday, with warmer weather once again over the weekend.

&&

.SHORT TERM...(TDY-WED)

The long-awaited arrival of strong northwest flow is almost at
hand. Already seeing some gusts to around 40 mph in the Antelope
Valley and in some of the mountain areas near the I5 corridor. As
the day goes on winds will become stronger and more widespread.
Few places will escape the gusty winds though not everywhere will
reach advisory or warning levels. Current set of advisories and
warnings seems to cover it pretty well, the Ventura and even the
LA Coast could see some gusts into the 30s this afternoon. The
remaining high wind watches for srn SB County and the Santa
Clarita Valley will be looked at closer, though first instinct
based on 12z models is to go with wind advisories for both these
areas. Only other issue is the ending time of the hazards. Models
show winds shifting to northeast Tuesday morning and decent upper
level support, and while not likely warning level anywhere it
could easily stay in the advisory category across the favored
parts of LA/Ventura counties through early afternoon. So will
consider extending some of the hazards a few more hours Tuesday.

***From previous discussion***

An upper ridge will amplify off the West Coast on Tue. Skies
should be mostly sunny. Rising heights and thickness values should
lead to several degrees of warming, especially west of the
mountains where low level flow will shift to a more nely
direction. Max temps should reach 80 degrees in warmer coastal and
valley areas on Tue.

The ridge will continue to build Tue night and Wed and heights and
thicknesses will continue to rise. Low level flow will be
offshore, enough for some gusty ne winds across L.A. and VTU
Counties, but probably below advisory levels. Max temps will jump
again on Wed, possibly getting close to 90 degrees in some valley
areas.

.LONG TERM...(THU-SUN)

An upper level trough will move through the Pac NW and into the
Great Basin on Thu, then southeastward to the Four Corners area on
Fri. This should bring cooling to the region Thu and Fri, but it
appears that any rainfall will remain to the north and east of the
forecast area. An upper level ridge and offshore flow will bring
significant warming to the area on Saturday, with temps back up
into the 80s in the valleys and possible some coastal areas. Above
normal temps will likely continuing on Sunday.

&&

.AVIATION...27/1800Z.

At 1718Z at KLAX...There was no marine inversion.

Low level wind shear is possible just about anywhere today due to
very strong winds and turbulence. All TAF locations are expected
to have VFR conditions through Tuesday.

KLAX...Good confidence in the 18z TAF. There is a 30 percent
chance of north cross winds near 10 knots between 03-09z.
Otherwise, VFR conditions and possible low level wind shear. East
winds, if any, will stay below 7 knots.

KBUR...Good confidence in the 18z TAF. VFR conditions will
prevail with possible low level wind shear.

&&

.MARINE...27/900 AM.

Winds are already at the criteria for Small Craft Advisory and
they will quickly increase to Gale Warning criteria in the next
few hours. Gale Warnings are in effect for all coastal waters
through tonight. The inner waters will experience very steep
choppy waves today and tonight. Widespread Small Craft Advisories
will be needed for Tuesday through Wednesday for at least most of
the zones. By Thursday and Friday, Gale Warnings may again be
needed for the outer waters and Small Craft Advisory strength
winds will affect the inner waters.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 9 PM PDT this evening for zones
      34-35. (See LAXNPWLOX).
     Beach Hazards Statement in effect through late tonight for
      zones 34-35. (See LAXCFWLOX).
     Wind Advisory in effect until 6 PM PDT this evening for zones
      39-88. (See LAXNPWLOX).
     High Wind Watch in effect from 6 PM PDT this evening through
      late tonight for zone 39. (See LAXNPWLOX).
     Wind Advisory in effect from 3 PM this afternoon to 9 AM PDT
      Tuesday for zones 41-44>46-87-547. (See LAXNPWLOX).
     Wind Advisory in effect until 3 PM PDT this afternoon for
      zones 52>54-59. (See LAXNPWLOX).
     High Wind Warning in effect from 3 PM this afternoon to 3 AM
      PDT Tuesday for zones 52-59. (See LAXNPWLOX).
     High Wind Warning in effect from 3 PM this afternoon to 9 AM
      PDT Tuesday for zones 53-54. (See LAXNPWLOX).
     High Wind Watch in effect from 6 PM PDT this evening through
      Tuesday morning for zone 88. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until noon PDT today for zones
      645-650-655-670-673-676. (See LAXMWWLOX).
     Gale Warning in effect until 5 AM PDT Tuesday for zones
      645-650-655. (See LAXMWWLOX).
     Gale Warning in effect until 11 AM PDT Tuesday for zones
      670-673-676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK...(WED-SUN)
Another round of strong and gusty northwest to north winds will
be possible Thu night in the mountains and along the Santa Barbara
County south coast, with travel being affected by the winds.

&&

PUBLIC...MW/DB
AVIATION...Sweet
MARINE...Sweet
SYNOPSIS...DB

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