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Area forecast discussion 
National Weather Service Las Vegas Nevada
910 PM PDT Sat Oct 25 2014

Synopsis...a weak cold front will pass through the region tonight
and Sunday...with gusty southwest winds ending overnight and
temperatures coming down about ten degrees by Monday. Temperatures
will rebound to slightly above normal by the middle of the week.

Update...winds across the area are beginning to settle down but are
still gusting 20-30 miles per hour over a relatively widespread area with
localized gusts to around 35 miles per hour in portions of Inyo...central and
southern Nye counties. The only advisory currently in effect is for
the Sierra, Owens Valley and Spring Mountain zones through 5 am
Sunday. A hires model cross section over the Sierra indicates maybe
an hour or two of downslope wind potential left while one over the
Spring Mountains would indicate a peak downslope wind period from
about 11 PM this evening through 3 am Sunday. The far western
sections of the Las Vegas Valley could see some increase in wind
overnight as the downslope winds develop on the east/NE side of the
Spring Mountains and spread into the valley. Other than wind, a few middle
clouds have formed over parts of the area but precipitation anywhere
within the County Warning Area is unlikely. Plan to let the current forecast ride
for now but will monitor weather conditions for possible later
updates. -Salmen-

Aviation...for McCarran...winds at the Airport have generally
settled into a typical diurnal surface flow this evening with speeds
up to 10 kts and this should continue to be the case overnight.
Hi-res models continue to indicate a period of north winds moving
through the terminal Sunday morning around 15-16z and continuing
through noon before becoming light northeast in the afternoon. This
will be evaluated for the 06z taf package. A few middle level clouds
were noted on satellite over northwest Clark County but will remain
operationally insignificant.

For the rest of southern Nevada...northwest Arizona...and southeast
California...south to southwest winds will diminish overnight as a
weak cold front moves through. Winds will shift to northerly Sunday
over the southern Great Basin and northern Mojave Desert...but
remain southwest to west across the southern Mojave Desert. Winds
will be northerly areawide on Monday with the strongest gusts around
30 knots down the Colorado River valley. No operationally
significant clouds are expected through the period.

Previous discussion...240 PM PDT...

Short term...through Monday night...south to southwest winds were
gusting 40 to 50 miles per hour in much of the advisory area this afternoon so
left it in place. The gusty winds will subside in the northern zones
early this evening...with a late night peak possible on the east
slopes of the Spring Mountains before the event ends around sunrise.
Looking upstream...the cold front passed through Reno between noon
and 1 PM...with temperatures falling from 66 to 51 in two hours and
winds gusting over 50 miles per hour from the northwest. The front will work
into the northern County Warning Area tonight but will be weakening as it
winds behind it should not be nearly as strong in our County Warning Area as in the
Reno area. High resolution models bring a weak wind shift into Las
Vegas as early as noon Sunday...spreading down the Colorado River
Sunday night. The best chance for strong north winds will be in the
favored areas of the Colorado River valley on Monday...but advisory
level winds look unlikely as the forecast surface pressure gradient
is unimpressive /11 mb Ely-eed/ and upper support is weak to
nonexistent. Moisture associated with the front is expected to be
intercepted by the Sierra...leaving our area dry. Temperatures will
come down about ten degrees areawide from today to Monday.

Long term...Tuesday through Friday...high pressure is expected to
build over the area during the middle part of the week with
temperatures increasing slightly each day. Outside of some high
clouds from time to time skies will remain generally clear. Models
are coming into better agreement toward the end of the week as a
trough starts to dig off the West Coast. Changes will start being
seen by Friday as we increase the southwest flow and cool
temperatures slightly. All models are showing the trough moving into
California Saturday with winds increasing significantly across the
area. Moisture is also expected to increase...but how much makes it
over the Sierra is still in question. However it looks like some
showers will at least be possible for the Sierra...White Mountains
and portions of Esmeralda County by Saturday afternoon and evening.

Spotter information statement...spotter reports of wind will be
needed through tonight. Spotter activation is not expected Sunday
through Thursday.



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