Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 210913

Area Forecast Discussion
National Weather Service Las Vegas NV
213 AM PDT FRI OCT 21 2016

.SYNOPSIS...Pleasant conditions will persist through Saturday. The
next storm system will impact the region Sunday and Monday, bringing
breezy winds and chances for rain to portions of the area.
Conditions will then improve during the middle of the week.

.SHORT TERM...Today through Monday Night.

Dry and quiet conditions are expected to persist through Saturday as
high pressure remains in place leading into the weekend. This will
result in an uptick in temperatures both Friday and Saturday, with
highs topping out around 10 degrees above normal on Saturday.

Things are expected to change Sunday and Monday as the next Pacific
trough moves into the west coast. South winds will begin to increase
late Saturday and increase through Sunday. However, winds do not
appear to reach advisory levels through short term, gusting to 20-
30mph across most of the region, and upwards of 35mph across central
Nevada. Will be keeping an eye on this however, as this could easily
change. Instead, rain may be the bigger impact with this system. The
latest guidance suggest a modest tap of moisture developing late
Sunday through Monday courtesy of the strong high pressure system
that currently resides over the area. Moisture values with this
system are similar to that of a low-grade monsoon day (850-500
Mixing Ratios of 4-6 g/kg). This combined with weak dynamic support
on Sunday, increasing to moderate support on Monday should lead to a
fairly decent shot at widespread precipitation east of a Barstow-
Pahrump-Rachel line. Weak instability is most likely to develop on
Monday, and a slight chance of thunderstorms will accompany the
chances of rain, mainly in areas east of Las Vegas.

As far as a timeline is concerned, precipitation is most likely to
begin over southern San Bernardino County early Sunday, with chances
spreading to areas south of I-15 by mid-day. One or more bands of
precipitation are likely to develop by Sunday evening as dynamic
forcing increases. This trend continues into Monday morning when the
most widespread chances of rain exist across the region. As the
trough axis moves east across the region through Monday/Monday Night
chances for rain will end from west to east.

When all is said and done, the high terrain of Mohave County is
expected to see the most precipitation from this system. Current
estimates place up to a third of an inch there, with 0.05-0.20
inches over the rest of the county. Elsewhere, 0.00-0.10 inches
appears the most likely outcome at this time. Stay tuned as this
forecast is likely to evolve.

.LONG TERM...Tuesday through Thursday.

Weak system which affected the region in the short term should be
exiting to the east Tuesday morning. Ridging then builds well to the
south over the Baja, but there will probably be quite a bit of high
clouds spilling in from the moisture plume pointing into Oregon and
northern California. As the ridge strengthens on Wednesday and
pushes the moisture plume farther north and west, cloud cover should
diminish and temperatures climb several degrees above normal. By
Thursday, models agree on the existence of a strong low along 130W
with moisture coming into California, but there are strength and
timing differences. Any impacts for our area would likely occur
after Thursday, and will continue to monitor model trends.

.AVIATION...For McCarran...No significant weather is expected
through Saturday. Winds will be light and follow typical diurnal
trends. The next storm system will move through Sunday and Monday
bringing enhanced southwest winds and chances of rain/lower CIGS to
the area.

For the rest of southern Nevada...northwest Arizona...and southeast
California...Outside of 10-15kt southerly winds across central
Nevada, mainly light winds favoring typical diurnal trends across
the region today. South winds will increase slightly on Saturday.
The next storm system will bring further increases in wind speeds as
well as chances for rain and lower CIGS to portions of the area
Sunday and Monday.

.SPOTTER INFORMATION STATEMENT...Spotter activation will not be
needed through Saturday. Chances for rain and perhaps isolated
storms will increase on Sunday and Monday. Spotters should report
significant weather according to standard operating procedures.


Short Term/Aviation...Wolcott
Long Term.............Morgan

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