Freeze Warning 2, NWS Elko, NV

Area Forecast Discussion
National Weather Service Elko NV
233 PM PDT Fri Jun 7 2019

.SYNOPSIS...An upper low pressure trough with cold air will cross
the Great Basin Friday and then move east for the weekend. Windy
conditions will follow it Friday, and then cold air will drop
morning temperatures below freezing in many places Saturday and
Sunday mornings. A few rain or even snow showers will fall across
northern Nevada and then drier air moves in.

&&

.SHORT TERM...Tonight through Sunday.

A large-ish short wave trough was crossing the Great Basin Friday
afternoon, with the trough axis extending roughly from south
central Idaho into northern Nevada, then southwestward. Cold air
aloft is producing short topped towering cu and even a few small
cb's as it moves east. Light rain showers, virga, and even some
higher elevation snow showers or "snirga" are falling across
mostly northeast Nevada.

A wind advisory is in effect for eastern Nevada as the post-cold
front thermal gradient is tight. Winds gusting to over 50 mph in
valleys, likely higher in mountains. This will slacken after
sunset and diminish overnight.

Colder air advects in as the upper trajectory turns northwest with
passage of trough axis and a freeze warning is in effect for
Saturday morning for the entire forecast area. Best chances for
cold temps will be in northern Nevada, but even central highlands
will be in the 20s to near freezing in the higher valleys Saturday
morning.

Pops drop to near zero Saturday and Sunday with dry advection, but
temps Sunday morning again will push freezing but have not issued
freeze/frost products as sunshine, dewpoints, and some breezes
will tend to keep most places above freezing. That said, there are
higher valleys in all counties that have almost no growing season
and will not rule out them hitting freezing or below Sunday
morning, but this will not be widespread.

.LONG TERM...Sunday night through next Friday.

Sunday night through Wednesday...high confident forecast with no
impacts/challenges.

500mb ridge expands northeast over the area on Monday and
Tuesday, rising 500mb heights to 588 to 590dm, which is climbing
slightly above average for this time of year. Thus, above avg
temperatures Monday and Tuesday (80s to low 90s). By
Wednesday,500mb ridge axis is directly overhead, meaning high
temperatures should peak. As the axis passes, mid and high level
moisture increases a tad as the upper level flow turns more
southwesterly ahead of a weakening system in the Pacific.

Thursday and Friday...moderate confidence due to potential
convection, although no impacts anticipated.

A broad trof pushes into the area Thursday with a weak frontal
boundary/sharper 500mb trof just to the northwest of the area over
the Pacific NW. Instability remains favorable for convection
although unfavorable for most of the rainfall to reach the surface
(very typical for mid June). PW, Ks, and Integrated WV numbers
are there for convection, along with an area of lower PV 1.5
heights...but nothing alarming. The best chances are in northern
Elko county as well as over the high peaks of the Toiyabe Mtns.
By Friday, the trof to the northwest digs southeast, along with
what's left of the weak frontal boundary, advecting a drier and
more stable airmass by late afternoon. With moisture already in
place, and cooling more aloft, precip chances increase slightly
Friday ahead of the boundary in eastern NV. Overall, a slight drop
in high temperatures Friday compared to Thursday (more 80s and
less 90s).

&&

.AVIATION...Cold air stratocumulus covers the northern sites
through this evening under strong northerly flow...still expect
VFR Cigs for the most of the time. Vertical and horizontal
visibility at KEKO likely reduce to due to dust or haze (blowing
in from the Martin Fire burn scar) through this evening as well.
Less cloud cover in the central valley airports (KTPH and KELY).
Wind gusts up to 30kts likely at all sites through the evening.
Expect clouds to scattered out and wind gust to diminish after
midnight. Tomorrow, clear skies and lighter winds.

&&

.FIRE WEATHER...Breezy today and tonight over especially eastern
Nevada. A few rain showers will fall over mostly northern parts of
zones 468, 469, 470, tapering off to the south. Snow showers could
fall above about 7500 feet but will not stick. Most rain showers
will not produce wetting conditions but will produce gusty
erratic winds. Saturday morning min temps will fall below
freezing over large areas of every zone, but will be more likely
further north. Sunday morning temps will be warmer but still cold.
The next chance for precip looks to be closer to Thursday.

&&

.HYDROLOGY...Flooding continues on the Mary's and Humboldt Rivers.
Much colder temps coming up will reduce snow melt and lower levels
on Lamoille Creek and other smaller streams.

&&

.LKN WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 2 AM to 9 AM PDT Saturday for Humboldt
County-Northeastern Nye County-Northern Elko County-Northern
Lander County and Northern Eureka County-Northwestern Nye County-
Ruby Mountains/East Humboldt Range-South Central Elko County-
Southeastern Elko County-Southern Lander County and Southern
Eureka County-Southwestern Elko County-White Pine County.

Wind Advisory until 8 PM PDT this evening for Northern Elko
County-Ruby Mountains/East Humboldt Range-South Central Elko
County-Southeastern Elko County-Southwestern Elko County-White
Pine County.

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