Excessive Heat in Nevada, May 30 to 31, 2025

Area Forecast Discussion
National Weather Service Las Vegas NV
452 AM PDT Fri May 30 2025

.SYNOPSIS...Above average temperatures persist and an Extreme Heat
Warning will be in effect today and tomorrow for sections of the
Mojave Desert. Tropical moisture brings increased cloud cover,
precipitation potential, and cooler temperatures early next week.
The greatest precipitation amounts appear to be in northwestern
Arizona on Sunday.

&&

.SHORT TERM...Through Saturday.

The main concern in the short term is heat. An upper level ridge
builds over the southwestern United States while a low remains
entrenched to the south over Baja California. Rising heights aloft
will help drive up temperatures at the surface with highs between 5
and 10 degrees above average today and tomorrow. Warm overnight
temperatures can also be expected, particularly on Saturday night as
cloud cover prevents overnight radiative cooling. Both daily maximum
temperature records and warm minimum temperature records are
threatened each day. See the CLIMATE section below for more
information on potential broken daily temperature records.

Moderate (Level 2) to Major (Level 3) HeatRisk is widespread across
the Mojave Desert, a level of heat that is dangerous to those
without effective cooling or adequate hydration. An Extreme Heat
Warning is in effect for areas including Las Vegas, Pahrump, Lake
Mead, Death Valley, and Barstow today and tomorrow.

.LONG TERM...Sunday through Friday.

A cut off area of low pressure off the Baja California coast will
continue to meander around that vicinity over the next few days,
allowing it to pick up substantial moisture before pushing inland
this weekend. Meanwhile, Tropical Depression One-E has been upgraded
to Tropical Storm Alvin and will slowly push northward along the
western Mexico coast before weakening back into a Tropical
Depression and pushing into the Gulf of California.

In general, forcing associated with this tropical system should have
minimal impact to our forecast area, but mid-and-upper level
moisture associated with its remnants will get wrapped into the Baja
low as it moves inland late this weekend into the start of next
week. The combined moisture surge from these two systems will result
in PWATs across the eastern half of our forecast area to 250-300
percent of normal. Expect widespread slight-to-moderate chances of
precipitation on Sunday, with moderate-to-high chances focused south
and east of Interstate 15. There remains a bit of uncertainty
regarding how convective this precipitation will be, as remnant mid-
to-upper level moisture from Tropical Storm Alvin could result in
widespread thick cloud cover, inhibiting convective potential. This
moisture will help drop temperatures out of the 100s for desert
valleys and into the low-to-mid 90s (below-normal).

What originally was thought to be a deep digging trough along the
western CONUS Monday and Tuesday has trended substantially weaker
over the last 48 hours. Models are in better consensus now that a
trough will drop down the west coast before closing off in the
southeastern Pacific. This area of low pressure will then move
inland with a similar trajectory as the Baja low. This low will
provide additional moisture and lift to the region while also
tapping into the left over moisture from its predecessor. As such,
precipitation chances for our eastern zones now linger later into
the week, with slight PoPs persisting as late as Wednesday. This
change has resulted in a continued weaker trend in forecast wind
speeds through the week due to the ease in forecast pressure
gradients. Additionally, the drop in heights that was anticipated
from the deep digging trough will no longer occur, so expect only a
modest drop in temperatures early-to-mid week from the increase of
moisture to the region.

&&

.AVIATION...For Harry Reid...For the 12Z Forecast Package...Light
and variable winds this morning are expected to settle out of the
southeast similar to previous days. While sustained wind speeds
through early this evening are expected to remain under 8KT,
intermittent gusts to around 10-15KT are possible during peak
heating this afternoon. However, confidence in precise timing and
direction is low. After sunset, winds follow typical diurnal
patterns, becoming light overnight. Temperatures are expected to
be 100 degrees or greater between 21Z to 03Z, with a maximum of
103 degrees around 23Z. Otherwise, VFR conditions prevail with
passing mid and high clouds with bases at or above 15kft.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...Winds across the
region will largely follow diurnal patterns the next 24 hours,
with some variability during the afternoon. Sustained speeds are
expected to be 10KT or less, though this evening, KHND could see
an uptick in southwesterly winds after sunset. VFR conditions will
prevail, with passing mid and high clouds with bases at or above
12kft.

&&

.CLIMATE...Numerous climate locations have a forecast high
temperature and/or forecast warm low temperature within 3 degrees of
the daily record.

The table below shows the daily record maximum temperature and the
year the record was last set. An asterisk (*) denotes which records
are in jeopardy (within 3 degrees of the forecast).

MAX           FRI, MAY 30  SAT, MAY 31
               Record(Yr)   Record(Yr)

Las Vegas      106(2002)*   104(2024)*
Bishop         100(1986)*    99(1950)*
Needles        114(1910)    116(1910)
Daggett        106(1997)    106(2001)*
Kingman        102(1984)    100(1938)*
Desert Rock    102(2002)*   100(2012)*
Death Valley   122(2000)    118(2002)*

The table below shows the daily record warm minimum temperature and
the year the record was last set. An asterisk (*) denotes which
records are in jeopardy (within 3 degrees of the forecast).

WARM MIN      FRI, MAY 30  SAT, MAY 31
               Record(Yr)   Record(Yr)

Las Vegas      83(2003)     82(1997)*
Bishop         60(2001)     60(2013)*
Needles        90(1984)     84(2004)
Daggett        83(1984)     78(1972)
Kingman        76(1984)     71(1997)*
Desert Rock    79(2003)     77(1997)
Death Valley   94(2003)     91(2001)*

&&

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

&&

SHORT TERM...Meltzer
LONG TERM...Soulat
AVIATION...Phillipson

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