High Wind in California, October 8, 2017

Area Forecast Discussion
National Weather Service Las Vegas NV
218 PM PDT Sun Oct 8 2017

.SYNOPSIS...An abrupt change in the weather will occur this
afternoon and evening as a cold front sweeps across the region
bringing strong northerly winds and much cooler temperatures to the
area. Winds will diminish late Monday and dry conditions will
continue through the coming week.
&&

.SHORT TERM...Tonight through Monday Night.

The concern through the next 24 hours will continue to revolve
around impacts related to the strong winds late today through
Monday.

Latest 20Z mesoanalysis shows the cold front is likely somewhere
near a Reno to Ely line. Pressure gradients between RNO and LAS are
starting to increase rapidly. Winds in northern NV where the front
has already moved through are currently currently gusting to
around 30MPH. All in all, didnt make too many changes to the wind
forecast through Monday afternoon. Anticipate that this front will
continue to push southward this afternoon and overnight and
strengthen as an upper level trough digs in with it. Winds will
turn north and increase as the front pushes through. Gusty winds
will continue through Monday afternoon, with the strongest winds
through the overnight period. Did need to bump up winds a bit
Monday early afternoon as model guidance has trended upward in
wind speeds, which matches well with the current timing of the
headlines ending Monday afternoon. Still think that the wind
advisory will easily gust to 40- 50MPH, with higher gusts to
60MPH in the high wind warning areas where north winds typically
accelerate. Winds still look like they will fall off from north to
south through Monday afternoon, with lighter winds expected by
Tuesday morning.

Temperatures behind the front will quickly drop, and high
temperatures should run around 15 degrees cooler on Monday compared
to today. Guidance did come in a bit warmer for Mondays highs, so
increased high temperatures a few degrees for tomorrow.

&&

.LONG TERM...Tuesday through Sunday. Not much change to previous
forecast thinking or confidence levels. Flat ridging Tuesday gives
way to southwest flow Wednesday as a trough passes by to the north.
This will push a weak cold front into the northern zones Wednesday
night, but it should wash out Thursday as the parent low swings away
to the northeast. A second, stronger storm is expected to dig into
the northwestern states Friday, but the models still differ quite a
bit with the track and strength of this storm. The GFS is still
farther west and deeper, which would imply stronger winds for much
of the Mojave Desert Friday and Saturday and a sharper cooling trend
on Saturday than the weaker ECMWF. Stuck with a middle of the road
approach again today as there is no compelling reason to favor one
solution over another. Expect dry conditions throughout the period,
with temperatures near normal at least through Friday, and breezy
conditions Wednesday and possibly Friday and/or Saturday.
&&

.FIRE WEATHER...Dry and warm conditions can be expected through much
of the day with humidity values dropping into the teens. Winds will
generally be less than 15 mph over most areas, although gusty
southwest winds 15 to 25 mph will develop this afternoon across
Mohave County. A cold front will move through the region late this
afternoon and evening bringing strong northerly winds to much of the
area with wind speeds likely exceeding 45 mph. Gusty winds will
remain on Monday with the strongest winds likely to remain down the
Colorado River where wind gusts will remain over 40 mph.
&&

.AVIATION...For McCarran...A strong cold front will then
move into the valley after 02z with strong northerly winds
developing behind the front. Wind speeds 15-25 kts with gusts over
35 kts will be likely this evening and much of the overnight hours.
Areas of blowing dust will also be a concern with some lower
visibility possible. Expect gusty winds over 25 kts through Monday
early afternoon before diminishing Monday evening.

For the rest of southern Nevada, northwest Arizona and southeast
California...A cold front is still expected to move through the
region this afternoon and evening bringing strong northerly winds to
much of the area with gusts likely exceeding 35-50kts. Lower
visibilities will also be possible with areas of blowing dust. Gusty
winds will remain overnight and into Monday with the strongest winds
remaining down the Colorado River Valley.
&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&

SHORT TERM...Allen
LONG TERM....Morgan

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