Area Forecast Discussion
Issued by NWS Las Vegas, NV
FXUS65 KVEF 282122
Area Forecast Discussion
National Weather Service Las Vegas NV
220 PM PDT WED SEP 28 2016
.SYNOPSIS...Scattered shower and isolated thunderstorm chances
continue through Thursday before gradually dwindling on Friday.
Temperatures will average near normal. Over the weekend a trough
moving in from the west will bring widespread breezy to windy
conditions to the region along with cooler temperatures next week.
.SHORT TERM...through Saturday night.
Scattered showers and isolated thunderstorms have developed this
afternoon under a weak upper low over the region. So far, activity
is primarily occurring over the terrain of Mohave County, southern
Clark County as well as northeast and northwest San Bernardino
County. Any thunderstorms that develop will be weak and short-lived
due to the lack of dynamics and limited CAPE.
As we go through the evening models indicate the weak convection
will dissipate primarily from the loss of daytime heating. Upper low
progged to weaken and start shearing out to the northeast late
tonight/Thursday as additional shortwave energy off northern Baja
Peninsula lift northeast across the lower Colorado River
Valley/Mohave County Thursday afternoon-Friday. The weak dynamics
and limited CAPE will produce similar convection to what we have
seen today mainly over southeast Nevada/Mohave Count Thursday and
only Mohave County Friday. A trough of low pressure approaching the
coast on Friday night-Saturday will initiate a drier/stronger
southwest flow across much of the area. The strongest band of gusty
southwest winds will be across the western Mojave Desert and up into
Death Valley and southern Nye County where gusts of 30 to 40 mph
Temperatures Thursday will be similar today then will warm
a few degrees Friday and Saturday.
.LONG TERM...Sunday through Wednesday.
The main issue for the period will be winds over the weekend. On
Sunday, the trough axis will begin to move inland and winds should
be enhanced in comparison to Saturday and some areas may see winds
strong enough to warrant a wind advisory. There is still some
difference in the timing, but main low will drop into northern
Nevada on Monday and push a cold front through southern Nevada on
Monday or Monday night. Relatively dry west-northwesterly flow will
then be the rule on Tuesday and Wednesday. Temperatures will
steadily decline through the period from slightly above normal on
Saturday to around 10 degrees below normal by Monday and Tuesday
with slight warming on Wednesday. The main change to the forecast
was to low temperatures a few degrees on Monday and Tuesday.
.FIRE WEATHER...Scattered showers and isolated thunderstorms will
dissipate this evening with a few showers lingering overnight in
Lincoln County. Scattered showers and isolated thunderstorms will
develop Thursday mainly over the terrain of Clark and Mohave
Counties. Any storms by Friday will be over Mohave County as drier
air starts working in from the west. The main fire weather issue
will begin over the weekend with southwest flow across the area on
both Saturday and Sunday. RH values will be less than 15 percent
across much of the Mojave Desert and southern Nevada on Saturday
afternoon and will be less than 15 percent area wide on Sunday
afternoon. There may be a need for a Fire Weather Watch across
portions of the area on both days will be assessing over the next
couple of shifts. A cold front will provide a shift to gusty
northwest winds on Sunday night into Monday.
.AVIATION...For McCarran...Just a few showers/isolated thunderstorms
in the approach corridors this afternoon. A shower at the terminal
cannot be completely ruled out through this evening. CIGs will
generally remain above 10k feet, except in shower activity where
they could dip to 8k feet. Light winds favoring typical diurnal
trends are expected through the period.
For the rest of southern Nevada...northwest Arizona...and southeast
California...Scattered showers and isolated thunderstorms will
continue into this evening, with gusty winds near any shower
activity. Outside of showers, light east to southeast winds will
continue into this evening and develop once again Thursday afternoon.
.SPOTTER INFORMATION STATEMENT...Shower and thunderstorm
will overspread much of the area today and begin decreasing the rest
of the week. Spotters are encouraged to report rainfall amounts and
any other significant weather.
Short Term/Fire Weather...Pierce
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