Damaging Wind in Arizona, June 17, 2021

Area Forecast Discussion
National Weather Service Las Vegas NV
146 PM PDT Thu Jun 17 2021

.SYNOPSIS...
Dangerous heat will continue through the weekend as temperatures
continue to approach record values. Early next week temperatures
will begin to decrease but are still expected to remain above
normal. Isolated thunderstorms producing dry lightning and strong
winds will be possible on Friday.

&&

.SHORT TERM...Today through Saturday.

The heat wave continues with another few days of well above
normal temperatures challenging records in many areas through
early next week. A cloud shield this morning helped insulate us
overnight with a morning low at McCarran of 90 degrees. This may
limit us from approaching all-time record highs as we have the
past couple of days. With this being said, it will still be very
hot with triple digit temperatures in many locations. No changes
are needed to the Excessive Heat products which now go through
Sunday.

The clouds will lead us to the other weather topic for today and
tomorrow which is the potential for high based showers and storms
with an influx of mid-level moisture. Currently, there are light
radar returns over much of the area as a weak wave rotates around
the the high which is still centered to the east over the Four
Corners region. Today instability is pretty much limited to Inyo
County and the Sierra but a few moderate updrafts are being
indicated over southern Clark County and central Mohave County
later on today on the last few HRRR runs. Showers and any isolated
storms will be very capable of producing strong outflow winds.
Even light activity this morning has already seen a measured gust
of 50 mph out of a weak shower over Kingman. This is further
supported by DCAPE values of 1000-2000 J/kg and very dry low
levels indicated on this mornings sounding. Activity should
decrease this evening with potential for pre-sunrise showers over
southeast California and Esmeralda and Nye counties. Instability
will be more widespread on Friday across much of southern Nevada
and northeast Arizona which will support potential for convective
development Friday afternoon. Threats remain similar to today in
dry lightning, strong outflow winds, and lofted dust.

By Saturday, the ridge shifts southwestward cutting off our
southeast flow which will limit chances for any shower or storm
activity but continue the very hot temperatures across the
region.

.LONG TERM...Sunday through Wednesday.

Sunday's high temperatures are expected to be a few degrees below
highs on Saturday which should bring an end to record challenges for
the time being. With that said, Sunday morning low temperatures will
still be very warm and provide little relief while the slightly
cooler daytime temperatures on Sunday will remain around 10 degrees
above normal. Since heat risk changes little Sunday and will remain
quite elevated, went ahead and extended all heat products through
Sunday evening.

A cooling trend brings more tolerable temperatures to the area Monday
through Wednesday even though summer officially begins on Monday.
Any moisture that was lingering around the area to begin the
weekend is flushed out Sunday with very dry conditions forecast
through Wednesday. Looking further out, the Climate Prediction
Center forecasts the probability of seeing above normal
temperatures across the NWS Las Vegas CWA in the 8-14 day period
at 40-60 percent.

&&

.FIRE WEATHER...
Heat wave continues through early next week with the addition of
isolated, dry thunderstorms today and tomorrow. These storms will
also be capable of producing strong, erratic wind gusts in and
around the area up to near 50 mph. The higher terrain will see
more favorable chances for this activity both days with Friday
being a slightly more active day than today. As a result, went
ahead and upgraded the Fire Weather Watch to a Red Flag Warning
with the addition of Fire Weather Zone 227 in eastern Inyo County.
RH values will drop below critical values each afternoon through
early next week.

&&

.CLIMATE...Listed below are a few climate locations showing both the
record high maximum and high minimum temperature for each location and
the year the record was last set for this Wednesday, Thursday and Friday.

LOCATION            THU-JUNE 17       FRI-JUNE 18		SAT-JUNE 19
(HIGH MAX)          Record(year)      Record(year)		Record(year)

Las Vegas NV          113(1940)         115(1940)		  114(1940)
Bishop CA             104(2017)         107(1985)		  107(2015)
Barstow CA            110(2017)         112(1985)		  115(2017)
Needles CA            120(1917)         119(2017)		  123(2017)
Kingman AZ            108(1917)         109(2017)		  111(2017)
Desert Rock NV        106(2017)         108(2017)		  110(2017)
Death Valley CA       122(1917)         124(2017)		  125(2017)
Laughlin NV*          113(2017)         117(2015) 		  117(2017)
Lake Havasu City AZ*  115(1985)         115(1985)		  117(2017)

* Not climate sites, but state temperature record holders.

LOCATION             THU-JUNE 17       FRI-JUNE 18		SAT-JUNE 19
(HIGH MIN)           Record(year)      Record(year)		Record(year)

Las Vegas NV           87(2008)         86(2017)     	  88(2017)
Bishop CA              65(2002)         69(2017)		  67(2017)
Barstow CA             78(1971)         79(1971)		  79(2017)
Needles CA             88(2000)         90(1988)		  87(2017)
Kingman AZ             79(1949)         73(2000)          75(1945)

&&

.AVIATION...For McCarran...Persistence wind forecast for the rest of
this afternoon so sticking with an easterly component up to 10 kts.
However, any passing area of virga could bring a sudden shift and
gustiness to the wind. Confidence in any of those scenarios is low
so did not mention in the forecast. Typical down valley wind up to 8
kts will develop overnight, although there is some indication that a
more northwesterly wind may develop after midnight. Looking at an
easterly wind up to 10 kts developing again Friday. Any isolated
shower or thunderstorm over the higher terrain Friday could bring
higher gusts to the valley. No significant clouds expected below 12
kft. Temperatures will remain in the 113 to 115 range over the next
few days with temperatures exceeding 100 by 11 AM.

For the rest of southern Nevada, northwest Arizona and southeast
California...Outside of any convective influence wind at terminal
sites the rest of this afternoon should be light and variable. Any
nearby shower or thunderstorm could bring on a sudden shift and
gustiness. Look for typical downvalley winds to develop overnight
with speeds less than 10 kts. The exception will be around KDAG
where sustained speeds will be 10-15 kts. Typical afternoon winds
expected across the region Friday, but any isolated shower or
thunderstorm over the higher terrain Friday could bring higher gusts
to a terminal. No significant clouds expected below 12 kft.

&&

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

SHORT TERM/FIRE WEATHER...Guillet
LONG TERM...Salmen
AVIATION...Pierce

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