FXUS65 KLKN 170838
Area Forecast Discussion
National Weather Service Elko NV
138 AM PDT Tue Jul 17 2018
.SYNOPSIS...Hot. Mostly dry with a few thunderstorms in central
Nevada mid week and beyond. Some of the storms will produce some
rain, briefly heavy in spots. Northern Nevada is going to stay hot
and dry. Expect highs around or just over 100 in many valleys
around the Great Basin.
.SHORT TERM...Today through Thursday.
Flat Four Corners ridge keeping deeper moisture out of the bulk of
the state, allowing only our extreme southern sections, that is,
parts of central and far eastern Nevada to participate in a
limitedmonsoonal flow. Storms will generally be dry lightning
producers. Biggest two issues will be smoky skies and the heat.
Many higher valleys will approach 100, with lower valleys hitting
it, or topping it.
.LONG TERM...Thursday night through next Tuesday
Main Concern or Impact: Thunderstorms..mainly central NV
Brief synoptic overview:
Four Corners High which was parked overhead in central Nevada
begins to rotate back to east and southeast, allowing
southeasterlyflow to pull monsoonal moisture into central Nevada
on Thursday. This trend continues on Fridays as the central of the
500mb high is now over the four corners region. Also on Friday, a
wave off the CA southern CA pulls northward, which drags a weak
sub- tropical jet over western and eventually northern areas,
aiding to destabilize the atmosphere for most of the area. By the
weekend, the four corners position allows any waves to rotate
around and impact the area from the south until it shifts
southward into southern AZ by late Sunday.
Changes to Previous Forecast: Adjustment on POPs to highlight
some possible waves rotating around the four corners high into
the area from the south, in particular Friday and Sunday.
Forecast Confidence: Above average for the overall synoptic
pattern...no doubt we'll deal with day after day of wet and dry
t-storms for mainly central and eastern Nevada as all models are
pushing PW values near or above .75 inches. Low confidence on
forcing each day as there is no strong trof impacting the area.
Thunderstorms...mainly in central Nevada and occasionally pulling
northward into northeastern Nevada. As always gusty outflow winds
and possible flash flooding with these. Also, can't rule hazy or
smoky skies due to weak flow aloft.
Other than winds from thunderstorms, no concerns given the synoptic
Above average high temps before falling to near average Friday and
beyond, in particular central and eastern Nevada. Overnight lows
will stay above average, especially towards the weekend due to
increase moisture and cloud cover.
.AVIATION...Hot. Dry. Only KELY will have visible TS in the
distance. However, KELY...KTPH...and KEKO could have towering
cumulus with virga, creating localized dry downbursts. Smoky skies
over most areas at TAF sites and en-route could hinder slant
visibility but not surface visibility at actual airfields.
Please note: extreme heat with highs reaching upper 90s into the
low 100s will drive density altitudes way high.
.FIRE WEATHER...Strong upper ridge of high pressure will make most
zones hot and dry. Early this week a few dry storms will form over
central and eastern Nevada mostly south of US Highway 50. Min Rh's
in the singles and teens most areas. Recoveries will be in the 50s
and 60s in central Nevada with only 20s and 30s north.
Outlook for remainder of week: increasing thunderstorm coverage
toward the north, with storms transitioning to more wet. Some
storms in central and eastern Nevada will become wet enough to
cause local flooding, but storms over northern Nevada, although
"wet" by definition, will only be barely so.
FXUS65 KVEF 171029
Area Forecast Discussion
National Weather Service Las Vegas NV
329 AM PDT Tue Jul 17 2018
.SYNOPSIS...Hot temperatures and humid conditions will
continue across the region through mid week. Isolated thunderstorm
chances will continue Tuesday across the higher terrain of
southern Nevada and southeast California. A better chance exists
across at least the southern half of Mohave County.
.SHORT TERM...through Thursday night.
Now...radar detecting rain showers, stray thunderstorm approaching
the southeast Mohave County line. Elsewhere, skies clear/mostly
clear as cloudiness associated with storms over south central
Nevada have dissipated. These showers/thunderstorms will move
southwest through Wikieup and Lake Havasu City early this morning.
Main change for today and Wednesday was to issue an Excessive Heat
Warning for the Owens Valley, Esmeralda and central Nye Counties, as
well as a Heat Advisory for the White Mtns. So far this year,
Bishop's hottest temperature has been 104 degrees, hit on several
days. Bishop will likely exceed 104 today and Wednesday with record
As for storms. The setup is very similar to yesterday.
East/northeast flow sandwiched between strong ridge over the Great
Basin and inverted trough over southern Arizona will steer storms off
the higher terrain of central Arizona southwestward into southern
Mohave County/lower Colorado River this afternoon and evening. HREF
pinpointing southern Mohave County as the area that would be
impacted by gusty winds and heavy rain between 3 pm and 10 pm this
evening. As inverted trough skirts our southern forecast boundary
tonight it should continue to support storms westward into the
On Wednesday and Thursday, inverted trough will continue moving
westward into the Pacific around the periphery of strong ridge. With
dynamics moving away, but no lack of moisture diurnal, terrain
driven thunderstorms will be favored across the Great Basin and
.LONG TERM....Friday through Tuesday.
By FRI, an upper level trough over NW Canada and the NW Pacific will
help nudge the ridge overhead eastward, eventually moving it over
New Mexico and Texas by Saturday. The eastward propagation of the
high should result in some mid-level dry air off the SoCal coast to
filter in across southwestern portions of our CWA FRI-SAT. However,
lingering low level moisture combined with daytime heating will
still allow for thunderstorms to develop mainly along higher terrain
through the weekend. By SUN-MON, models are now shifting the high
pressure back across the southwest and over Arizona. This westward
propagation will increase temps and continue to keep thunderstorms
chances mainly focused over the higher terrain through TUE. Main
threats with any thunderstorm development will be localized
flooding, small hail, and strong to severe outflows capable of
producing damaging winds and blowing dust.
Besides storm chances, expect light winds less than 10-15 mph,
temperatures to increase a degree or two each day and partly sunny
to partly cloudy skies.
.AVIATION...For McCarran...Outside of convective influence, light,
variable winds below 10 knots will continue across the terminal
through the afternoon. Probability of outflow affecting the terminal
this evening is low. CIGs should remain above 10k feet.
For the rest of southern Nevada, northwest Arizona and southeast
California...Scattered to isolated thunderstorms across the region
today. Storms will likely persist through the night along and south
of Interstate 40 through southern California and southwest Arizona.
Outside of thunderstorm influences, winds will follow diurnal trends
with speeds of 5-15 knots. CIGs at or above 10k feet; CIGs may drop
to 5-7 k feet with convection developing near terminals.
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
For more forecast information...see us on our webpage:
http://weather.gov/lasvegas or follow us on Facebook and Twitter
FXUS65 KREV 171031
Area Forecast Discussion
National Weather Service Reno NV
331 AM PDT Tue Jul 17 2018
Heat advisories remain in effect today through Thursday due to
well above normal temperatures. Conditions will be much drier than
previous days with only isolated thunderstorms for southern Mono
and Mineral Counties. High pressure will begin to shift eastward
on Thursday with thunderstorm chances increasing into the weekend
as temperatures gradually cool.
No major changes were made to the existing forecast; high
temperatures continue to be the main concern through Thursday.
Heat Advisories are in effect starting around noon today as
temperatures aloft warm 16-19C. These temperatures correlate to
afternoon highs in the 100-106 range with Wednesday being the
hottest day. The duration of these hot temperatures coupled with
overnight minimums 65-75 are the driving factors for the
advisories. Sensitive populations and those working or recreating
outdoors should consume extra water and know the signs of heat
Otherwise, areas of smoke from the Ferguson Fire and
isolated/scattered thunderstorms outline the remaining weather
concerns. Air quality may be an issue for locations closer to
the source; smoke transport models favor higher terrain in
central/northern Mono County as the area where smoke will be
thickest and air quality poorest. Some higher trails northward to
around Lake Tahoe may also have air quality impacts. Elsewhere, it
will be mainly hazy with some degradation to air quality which
should improve with mixing in the afternoon.
Thunderstorm chances increase for southern zones in Mono/Mineral
Counties Wednesday afternoon and spread northward to Interstate 80
by Thursday afternoon. Even though the ridge axis will suppress
convection around Reno early Thursday afternoon, models do project
some height falls which should be sufficient to kick off late
afternoon storms given high temperatures in excess of 100 degrees
and increasing atmospheric moisture. Any storms and showers moving
over valley locations would cause gusty outflow due to very high
density perturbations feeding into large momentum transfer down
valleys of western Nevada. Boyd
.LONG TERM...Friday and beyond...
There were no large scale changes for late week into the weekend as
monsoon moisture deepens and brings an increasing threat for locally
heavy rains and flash floods near burn scars, steep terrain and
urban areas. While upper level disturbances could enhance
convection, extensive clouds could also limit storm coverage and
strength as PWATs approach 1". Both the GFS/ECMWF continue to
indicate a possible wave Friday which could favor that day for
thunderstorms. The best coverage of storms will be south of I-80
with decreasing coverage toward the Oregon border.
Temperatures will cool as a result of the increasing moisture and
cloud cover although overnight lows will remain rather muggy. There
are some indications the upper ridge will shift west into the Desert
Southwest next week as a trough develops over the eastern portion of
the U.S. This would suppress convection a bit and limit it mainly to
Mono-Mineral Counties. Hohmann
VFR conditions will prevail through midweek although areas of haze
and smoke aloft from the Ferguson Fire will likely continue. Late
afternoon-evening wind gusts around 20 KT are expected along the
US-395 corridor with lighter winds elsewhere. A drier westerly
flow aloft will limit isolated thunderstorms to Mono-Mineral
Counties today then edging northward to near US-50 by Wednesday. For
the main terminals, only KMMH is at risk of being affected by
thunder--less than 10% probability today, increasing to near 20%
Wednesday. Storm coverage will increase and expand northward later
this week. MJD/Hohmann
NV...Heat Advisory from noon today to 9 PM PDT Thursday NVZ003-004.
Heat Advisory from noon Wednesday to 9 PM PDT Thursday NVZ005.
Heat Advisory from noon today to 9 PM PDT Wednesday NVZ001.
CA...Heat Advisory from noon Wednesday to 9 PM PDT Thursday CAZ070.
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