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Office: LKN

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 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.

Sensible Weather/Impacts:

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.





Office: VEF FXUS65 KVEF 171029 AFDVEF 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 highs threatened. 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 Morongo Basin. 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 northwest Arizona. .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 procedures. && $$ SHORT TERM/AVIATION...Pierce LONG TERM.............Kryston For more forecast information...see us on our webpage: or follow us on Facebook and Twitter
Office: REV FXUS65 KREV 171031 AFDREV Area Forecast Discussion National Weather Service Reno NV 331 AM PDT Tue Jul 17 2018 .SYNOPSIS... 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. && .SHORT TERM... 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 related illness. 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 && .AVIATION... 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 && .REV Watches/Warnings/Advisories... 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. && $$ For more information from the National Weather Service visit...