Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 300317
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
817 PM PDT Wed Mar 29 2017

.SYNOPSIS...A vigorous cold front moving down from the northwest
will bring a significant wind storm to the region late Thursday
morning through the evening. Widespread gusts of 45 to 65 MPH can be
expected along with scattered showers and isolated thunderstorms to
the north and east of Las Vegas. Strong north winds will linger into
Friday for many areas. Another storm may move across the region late
Sunday into Monday.
&&

.UPDATE...
Forecast seems to be on track overnight into early Tuesday with calm
and mostly dry conditions across the region under high pressure
aloft. Dramatic changes in the weather are expected on Thursday as
trough digs down across the southwest creating hazardous winds and
scattered showers and isolated storms across the southern Great
Basin and northwest Arizona. High Wind Warning remains in effect for
most of the area Tuesday morning through late Tuesday night.

&&

.PREV DISCUSSION...240 PM PDT Wed Mar 29 2017

.SHORT TERM...tonight through Friday.

A cold trough digging off the Pacific Northwest coast still has our
area directly in its sights by Thursday afternoon according to the
latest models. This system is forecast to dive into northwest Nevada
by Thursday morning then rush toward southern Nevada Thursday
afternoon and evening. In addition to the momentum that will be
carried by the fast moving cold front, the forecast surface pressure
and 700 mb thermal gradients between Reno and Las Vegas at 18Z
Thursday are respectively 16 mb and 16 degrees C, similar to past
high wind events where northwest winds gusting over 60 mph occurred
in the Las Vegas Valley. This system will pack a one-two punch
across San Bernardino, Clark and Mohave counties...first by the belt
of southwest-west winds ahead of the front, then by the northwest
blast behind the front when the highest winds will likely occur for
southern Nevada and nearby zones. This scenario will produce
widespread areas of blowing dust from the San Bernardino County dry
lake beds followed by the dust moving down between Tonopah and Las
Vegas. The cold front is forecast to sweep across the Las Vegas
Valley between 4 PM and 6 PM Thursday afternoon. High north winds
will likely persist for an hour or two behind the front then settle
into gusts of 35 to 45 mph. Scattered showers and isolated
thunderstorms should be confined primarily to central Nye and
Lincoln counties, but brief showers with the front may be
intercepted by the Spring Mountains and Sheep Range Thursday
afternoon.

The high res models still indicate high winds over southern
Esmeralda County and central Nye County Friday with Advisory level
winds (gusts over 40 mph) for the Owens Valley, Death Valley and
southern Nye/Lincoln counties through early Friday evening. Stiff
north winds will persist Friday night, but gusts should generally be
less than 40 mph. Also, a few showers will linger over Lincoln and
northern Mohave counties Friday on the back side of closed low which
will be centered near Lake Powell by then.

.LONG TERM...Saturday through Wednesday.

A dry northerly flow will be over the area Saturday as a large upper
low moves east into New Mexico. There will be some showers wrapping
around the back side of the low but at this time I am going with the
model solutions keeping those just east of Mohave County.
Temperatures will be warming compared to Friday but breezy north
winds will be lingering over much of the area. A shortwave ridge
will quickly traverse the forecast area Saturday night into Sunday
with dry and warm conditions. A shortwave trough will move across
northern Nevada into Utah Sunday night and Monday bringing a chance
of showers to mainly Esmeralda County and northern portions of
Lincoln and central Nye Counties. Breezy to windy conditions will
develop by Monday as north winds overspread the area. This will also
cool temperatures down again Monday by roughly 5 degrees compared to
Sunday. It looks like a good chance we will have ridging move over
the area Tuesday through Wednesday with dry conditions and slightly
above normal temperatures.
&&

.AVIATION...For McCarran...East winds generally less than 10
kts will become southerly this evening. Winds are expected to be
light into Thursday morning before increasing rapidly as a powerful
storm system impacts the region mid-day Thursday into Friday. Gusty
southwest winds early Thursday afternoon will turn to the northwest
behind a strong cold front on Thursday afternoon between 22Z and
01Z. Northwest gusts of 40-50 KTS are expected Thursday afternoon
and evening. Northwest winds of 20-30 KTS will continue on Friday
with gusts of 35-45 KTS.

For the rest of southern Nevada, northwest Arizona and southeast
California...Light winds generally less than 10 KTS tonight. Winds
will increase during the morning ahead of a powerful storm system
that will impact the area through Friday. Gusty west to southwest
winds will occur along and south of the I-15 corridor with the
strongest wind gusts of 40-50 KTS across the western portions of San
Bernardino County. A strong cold front will push south across the
region from mid-day Thursday into Thursday evening. North to
northwest gusts of 40-50 KTS are expected with this cold front.
North winds will linger Friday into Saturday.
&&

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

$$

Short Term/Aviation...Adair
Long Term.............Harrison
Update................Guillet

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