Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 261615
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
315 AM PDT Fri May 26 2017

.SYNOPSIS...A general warming trend is on tap through the weekend
along with locally breezy conditions. Most areas will remain dry,
but a slight chance of showers will remain over the highest peaks of
the Sierra and portions of northeast Lincoln County.
&&

.UPDATE...Forecast, for the most part, is holding up well. Winds on
Lake Mead expected to be breezy through the day. Boulder Island has
been gusty this morning, with the latest gust of 35 mph. Winds along
Lake Mead should steadily pick up this afternoon with gusts expected
to be 25-35 mph. Lincoln County may see some shower activity similar
to yesterday with showers and a few thunderstorms developing late
this afternoon and evening.

&&

.SHORT TERM...through Sunday night.

A weak upper low will dig southeast out of Idaho and across
northeast Nevada and northern Utah today and tonight. This will drag
a weak cold front through mainly our far northern zones this evening
along with some enhanced dynamics across northern Lincoln County.
There could be enough energy to help produce a few showers for
mainly northern Lincoln County this evening, but overall they should
be rather isolated. We could see some brief gusty north to northeast
winds over mainly Lincoln and central Nye Counties overnight, but
they are expected to remain below any advisory levels and will
weaken during the morning hours Saturday.

We will continue to see some gusty southwest winds this afternoon
over most of the southern half of the area with the higher winds
over Mohave County. It looks like the winds will generally remain in
the 30-40 mph range with only a few isolated locations seeing any
gusts over 40 mph. At this time will not issue any wind products as
most of the area will remain below any advisory levels. Another
concern is for fire weather as winds will be right around the
threshold for Red Flag Warnings over Mohave County. Humidity values
should bottom out around 10-15% during the afternoon and winds are
likely to gust around 35 mph for at least three hours. SPC has
already placed northeast Arizona in the Elevated Risk for fire
concerns. Although it will likely marginal, feel that conditions
should warrant a Red Flag Warning for Mohave County.

The trough will weaken Saturday and push east with weak high
pressure building in through Sunday. This will bring warming
temperatures along with lighter winds. There will still be enough
moisture of the Sierra to continue the threat of afternoon showers,
but those should remain rather isolated.

.LONG TERM....Monday through Thursday.

Model agreement is decent on Monday but deteriorates rapidly by mid
week as high pressure weakens and is pushed east by a trough
approaching the west coast.

On Monday, models forecast a eastern Pacific trough with an area of
low pressure developing near the central/southern California coast.
As a shortwave embedded in the parent trough moves towards the west
coast on Tuesday, this area of low pressure drifts over northern
Baja and model differences begin to unfold. The area of low pressure
separates from the parent trough according to the ECMWF and CMC
solutions while the GFS hangs onto a connection between the two. The
GFS solution allows a coupling of the trough and weak low...allowing
strong shortwave energy to develop a closed low over the forecast
area by Thursday morning. In the ECMWF solution, the trough lifts
harmlessly into the Pacific NW with the area of low pressure over
Baja moving well away from the area. The CMC solution plays the
cutoff low card and lingers a weak low pressure system over northern
Mexico/southern Arizona. The different solutions would result in
different weather scenarios for our region. Thus, this forecaster`s
confidence is very low beyond Tuesday and details will be withheld
until models show better agreement and run-to-run consistency.

Hot temperatures are expected Monday and Tuesday running 6-8 degrees
above normal putting Las Vegas highs back around 100. The latest EC
guidance maintains these well above normal temperatures through
Thursday while the MEX guidance conversely suggests temperatures
falling back to several degrees below normal due to a low developing
over the area. My temperature forecast generally follows the above
normal trends of the EC but nods to the GFS by lowering the
Wednesday and Thursday temps a tad.
&&

FIRE WEATHER...Gusty winds along with low humidity values will
remain over Mohave County again today. Conditions are expected to be
marginal, but we could see at least three hours of winds gusting to
35 mph or greater during the afternoon along with humidity values in
the 10-15% range. Will go ahead and issue a Red Flag Warning for
Fire Zone 102 from 1pm until 8pm this evening.
&&

.AVIATION...For McCarran...Southwest winds around 12-16 kts with
gusts around 35 kts are expected to continue through much of today.
Although we could see a break with lighter winds between 14z-19z
before gusty winds return for the remainder of the afternoon. Skies
will remain generally clear.

For the rest of southern Nevada, northwest Arizona and southeast
California...South to southwest winds will be seem over much of the
area today with strongest winds expected across Mohave County where
gusts will approach 30-35 kts. Other area will generally see winds
gusting to 25-30 kts. A weak cold front is expected to move into
northern Lincoln and central Nye this evening with winds shifting to
the northwest with wind speeds around 10-20 mph. Slight chances for
showers are possible in northeast Lincoln County. Elsewhere clear
skies expected through the period.
&&

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

$$

SHORT TERM/AVIATION/FIRE WEATHER...Gorelow
LONG TERM..........................Salmen

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