Area Forecast Discussion
Issued by NWS Las Vegas, NV
FXUS65 KVEF 240930
Area Forecast Discussion
National Weather Service Las Vegas NV
230 AM PDT SUN JUL 24 2016
.SYNOPSIS...Hot and dry weather will continue for most of the area.
Moisture and thunderstorm chances begin to return to southern
portions of the area through early week...mainly confined to San
Bernardino and Mohave counties.
.SHORT TERM...Through Tuesday Night.
A few features of interest on satellite overnight include a
circulation over Baja California and an MCS in Sonora. The
circulation does not seem to be doing too much, but when combined
with the MCS, may aide in slinging moisture into southern portions
of the area today. Dewpoints in the 50s have spread up the Colorado
River Valley and even up into the Las Vegas Valley. Most high res
guidance that has this moisture quickly mixes most of it out during
the morning and afternoon. There is little support for any
precipitation for any of the CWA today, however, have kept slight
chances in eastern Mohave county...on the periphery of the one inch
Moisture will continue to seep into southern portions of the area
Monday and Tuesday, especially Mohave and eastern San Bernardino
counties. Some high res models even pick up on moisture sneaking up
into the Morongo basin, possibly as far north and west as Barstow.
Generally, areas south of I-40 will have afternoon thunderstorm
chances both days, but coverage and specific areas will be highly
dependent on any features such as MCS or currently unresolved
shortwaves. Temperatures will remain about the same through the
period, as guidance has nudged slightly upward. Daytime highs will
be around 110 for the deserts, and 110 to 115 for the Colorado River
.LONG TERM...Wednesday through Saturday.
Operational models and ensemble spreads are similar to yesterday,
which leads to a little better confidence today. For Wednesday
through Friday, moisture is expected to remain confined south of Las
Vegas, with strong mid level high pressure over the Great Basin
producing a substantial cap near and north of Las Vegas. This
pattern will lead to two concerns: thunderstorms in the southern
zones, and heat in the central and northern zones. Made only minimal
changes to the previous forecast through Friday. Saturday is when
things could get more interesting. There has been good model to
model and run to run agreement for two days showing a tropical
wave/depression passing west across the mouth of the Gulf of
California on Thursday. This is a well known setup to produce a Gulf
Surge which typically reaches Las Vegas in about 48 hours (Saturday
in this case). Raised PoPs and lowered temperatures a bit for
Saturday. Models are notoriously fickle with tropical systems, so
did not want to bite too hard yet. However, if future runs remain
locked onto this feature`s placement and timing, PoPs will need to
be raised further and temperatures perhaps lowered a bit more. &&
.FIRE WEATHER...Dry conditions today will be tempered somewhat through
the week as moisture begins to work into southern portions of Mohave
and San Bernardino counties early this week. This will lead to
chances of isolated thunderstorms across Mohave county Monday,
spreading west into San Bernardino county Tuesday.
.AVIATION...For McCarran...Continued hot and dry weather. Mostly
typical diurnal trends expected for winds..with southerly winds
becoming briefly easterly or variable in the morning before
southwest afternoon gusts kick in.
For the rest of southern Nevada...northwest Arizona...and southeast
California...Another hot and dry day expected, with afternoon west
to south gusts expected for all terminals except KBIH.
.SPOTTER INFORMATION STATEMENT...Spotter activation is not expected
today although spotters are encouraged to report any significant
weather...including smoke near the surface/visibility reductions
using standard operating procedures. Spotter activation may be
necessary later this week.
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