735
FXUS65 KLKN 182121
AFDLKN

Area Forecast Discussion
National Weather Service Elko NV
221 PM PDT Thu Jul 18 2024

.SYNOPSIS...Robust upper ridge remains anchored over the western
U.S. thru early next week and adequate subtropical moisture under
the ridge will allow for afternoon showers and thunderstorms to
be present across much of the forecast area each afternoon. A
gradual warming trend will also be present with daytime highs
creeping into the mid 90s to low 100s by this weekend.

&&

.SHORT TERM...Tonight through Friday Night

Robust upper ridge remains situated across the western U.S. and
Canada with high pressure centered over the four corners area.
Meanwhile, a deep closed upper low builds over the Gulf of Alaska
with south-southwesterly flow situated over the forecast area.
Showers and thunderstorms present across much of central and
northeastern Nevada this afternoon will weaken and dissipate thru
this evening with fair weather under clearing skies expected for
tonight. Overnight low temperatures will be mostly in the 50s.

Aforementioned upper ridge gradually begins to drift west on
Friday, positioned over southern California/Nevada and western
Arizona by sunrise Saturday. Adequate moisture lingering under the
ridge will allow for afternoon isolated to scattered showers and
thunderstorms to again be present across the forecast area with
the exception again being Humboldt County where dry and generally
fair weather will persist. With the high pressure shifting west,
upper flow will be very weak. This will result in slow storm
motions of around 10 mph. This will allow better opportunity for
wetting rains (rain totals greater than 0.10) under showers and
storms, especially with the latest progs indicating PWAT values
generally between 0.75 and 0.85, and as high as 1.00 in some
locales. Biggest threats will be lightning and gusty and erratic
thunderstorm outflow winds with gusts 45+ mph possible. Strong
storms may also create localized minor flooding. Otherwise winds
will again be generally light though some gusts around 20 mph in
the afternoon are likely. Look for activity to again weaken and
dissipate thru the evening and skies to clear overnight. Daytime
high temperatures will be in the upper 80s to upper 90s with
overnight lows in the low 50s to low 60s.

&&

.LONG TERM...Saturday through next Thursday

The bulk of the forecast period is dominated by the persistent
high pressure system that amplifies and is entrenched across the
Inter-mountain West region of the western CONUS on Saturday.
Monsoonal moisture from the southeast over AZ continues to filter
into mainly the central and eastern portions of the CWA and acts
as the catalyst for afternoon convective chances in the region.
The ridge amplifying well into western Canada keeps the meridional
upper level flow well to the north of Nevada.

For western portions of the CWA the ridge will create hot high
temperatures through the weekend into the early portions of next
week prompting an Excessive Heat Watch for Humboldt county in
northeastern Nevada Saturday through Tuesday. Those susceptible to
heat related health issues should plan to reduce time outdoors,
drink plenty of water, and remain in air-conditioned buildings.
Heat-sensitive groups, such as the elderly, young children, and
those with chronic ailments may need assistance to avoid heat-
related illnesses.

Convective chances of 10 to 30% for central and eastern portions
of the CWA will be an afternoon staple of the forecast period as a
result of daytime heating effects and the aforementioned available
monsoonal moisture infiltrating the region from the south. PWAT
values ranging 0.75 to nearly 1 inch over the central and eastern
CWA will present a mix of wet and dry afternoon storm potential
through Monday. A large upper level trough will begin to push its
way slowly to the southeast from western Canada into the Pacific
NW Tuesday morning. This will begin to shunt moisture away from
the region to the east as the trough forces the ridge to begin
its trek eastward over the course of Tuesday and Wednesday. This
will limit convective chances to mainly southern portions of the
CWA by mid- week, but also begin to abate hot high temperatures
across the region as the trough sets up a change in the recent
weather pattern over the western CONUS.

&&

.AVIATION...VFR conditions are expected this evening and tonight.
Moisture will allow for a 10% to 30% chance for showers and
thunderstorms this afternoon at KEKO, KELY, and KTPH with a lesser
chance for KBAM. Gusty outflow winds up to 40+ knots, blowing
dust, lightning, and brief heavy rainfall will be the primary
threats. Storms are expected to weaken by the late evening hours.
Outside of storms, breezy winds from the W-SW at 10-15 knots with
gusts up to 20 knots possible. Storm chances will reduce after
sunset and winds will become light and variable overnight and into
the morning hours of Friday. Clouds will also decrease overnight
and then begin to increase from south to north as the morning
progresses on Friday.

&&

.FIRE WEATHER...Robust upper ridge remains planted across the western
U.S. with a high pressure center situated over the four-corners
region. Modest south to southwest flow continues over the region
with isolated to scattered showers and thunderstorms forecast each
afternoon across much of the forecast area with zone 437 being
the exception as mostly storm free condtions look to prevail. That
said, adequate moisture and instability look to creep into zone
437 early next week with increased thunderstorm potential within
the zone. As such, isolated thunderstorms have been expanded in
areal coverage to include portions of zone 437 beginning Sunday
afternoon. Storm modes will continue to be a mix of dry and wet
with dry storms more prevalent mid day while wet storms become
more notable later in the afternoon and evening. Overall winds
will be mostly light with modest afternoon breezes though
convective outflows of 45+ mph are expected under any thunderstorm
activity. Do not believe critical fire weather conditions will be
met over the next few days, though elevated risk primarily due to
lightning and gusty thunderstorm outflows will certainly be in
place. A warming trend will also continue as the upper level ridge
persists over the western U.S. Daytime high temperatures
widespread in the mid 90s or hotter will be present by this
weekend with some locales reaching into the low 100s, particularly
across zone 437 where an excessive heat watch has been issued,
valid Saturday thru Tuesday.

&&

.LKN Watches/Warnings/Advisories...
Excessive Heat Watch from Saturday morning through Tuesday
evening Humboldt County.

&&

$$

92/99/99/92