FXUS65 KVEF 171624 AAA
Area Forecast Discussion
National Weather Service Las Vegas NV
924 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.
.UPDATE...9 am satellite imagery shows a mix of high and mid
level clouds east of line from Twentynine Palms to Las Vegas up to
Mesquite with mostly clear conditions elsewhere. An Excessive Heat
Warning will go into effect later this morning for the Owens Valley
in SE CA and Esmeralda County in southcentral NV. Elsewhere across
the area, expect another day of hot and humid conditions. The best
chance of developing convention today will be in Mohave County and
parts of southcentral NV with isolated storms possible over the
Spring Mountains and Sheep Range this afternoon. The operational
HRRR model has been consistent in forecasting t-storm activity
developing over Lincoln County this evening moving south into Clark
County. Currently, we are not calling for any thunderstorms in the
Las Vegas Valley however, this could change as we head into the
evening hours. -Salmen-
.PREVIOUS DISCUSSION...329 AM PDT...
.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
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