Area Forecast Discussion
Issued by NWS Elko, NV

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FXUS65 KLKN 222118

Area Forecast Discussion
National Weather Service Elko NV
218 PM PDT Sat Jul 22 2017

.SYNOPSIS...Monsoonal moisture will continue to stream into the
region through the weekend into early next week. Showers and
thunderstorms across the central and east this afternoon and
evening with scattered thunderstorms statewide tomorrow. An
approaching trough from the west will increase coverage and
intensity of storms on Monday and Tuesday before drier air begins
to work back into the state mid-week, diminishing thunderstorm
coverage through the end of the work week.


.SHORT TERM...Slow-moving mix of wet and showers and storms
expected to continue across east-central NV this afternoon and
expand north and west this evening. PW values increase through the
overnight tonight and expect thunderstorms to transition to
mainly wet.

Tomorrow, the slug of monsoonal moisture continues to be pulled
north in between the Four Corners ridge and the upper-level low
sitting off the Cali coast. Thunderstorm coverage will expand
tomorrow with widespread PW values of 0.75-1.00 inches. Expecting
mostly wet thunderstorms with some dry thunderstorms on the
leading edge of the moisture push north of I80 before
transitioning to wet tomorrow evening. On Monday, showers and
thunderstorm coverage and intensity increases as the upper-level
low encroaches on the region. Ensemble mean PW values expected to
be in the 90th percentile or higher over an inch and CAPE values
of 800-1500 J/kg will provide ample fuel for widespread showers
and storms. With the upper-level jet spreading over the state,
some of this activity could be better organized and strong.
Another issue will be possible flash flooding due to moderate to
heavy rain and overall slow storm motions, particularly over
recent burn scars. Expect warms temps to continue with highs in
the upper 80s to mid 90s on Sunday, dropping a few degrees on
Monday with the increased moisture and cloud cover.

.LONG TERM...Monday night through next Saturday. The long-term
period begins with a cut-off low parked along the northern
California coast and a broad ridge over the desert southwest. The
result of which is increased moisture and instability over
northern and central Nevada. Moderate jet energy associated with
the cut-off low will persist Monday night through Wednesday across
most of northern NV and portions of central NV. At the same time
increased moisture will push up from the south into Nevada, guided
by the cyclonic flow of the cut-off low to the west, and the
anticyclonic flow to our southeast. Increasing moisture, lift,
instability and shear will result in some moderate and possibly
heavy rainfalls next week. Heaviest rains will likely be on
Tuesday afternoon and evening over and near Elko County. Moderate
to strong thunderstorms are possible both Tuesday and Wednesday,
which may also result in some flash flooding. In the wake of some
recent wildfire activity, burn scar areas near roadways will be
of particular concern if heavy rains and flash flooding do
develop, as debris flows onto roadways will be possible.

By Wednesday the northern CA cut-off low weakens and ejects
northeastward. At the same time, the ridge to the southeast
retrogrades westward building into southern NV and CA with overall
ridging across NV later this week on through the weekend. Drier
and more stable air will gradually push in from the west Wednesday
night onward. By Saturday most of the remaining shower and
thunderstorms activity should be limited to northeastern and east-
central NV, generally eastern Elko and White Pine Counties.


.AVIATION...Increasing cumulus cloud build-ups this afternoon
through early evening across east-central NV, with isolated
thunderstorms possible at KELY through the mid to late evening
hours. Clouds will spread west and north into this evening,
however thunderstorms are not expected to reach KTPH or KEKO.
Mid and high level clouds will build in from the southeast
tonight, with more widespread thunderstorms activity on Sunday
likely reaching KWMC, KEKO, KTPH and KELY.


.FIRE WEATHER...A mix of slow-moving dry and wet storms across
White Pine county will expand this afternoon and tonight and
transition to all wet. Storm activity is expected to expand north
and west tomorrow. North of I80 expect a chance of isolated dry
storms before before transitioning over to scattered wet. Western
and Central Humboldt are expected to stay mainly dry storms and a
Red Flag has been issued for Sunday afternoon and evening. South
of I80 expect scattered showers and thunderstorms, with moderate
to possibly heavy rains possible as PWAT values jump to around an
inch, surface dew points increase to around 50 degrees and overall
storm motion will be slow to the north. Overnight RH recoveries
will begin to have decent improvements over Central NV tonight.
Recoveries continue to improve tomorrow night and Monday night
across most of central and northern NV as mid and surface moisture
increases. Expect scattered wet showers and thunderstorms Monday
and Tuesday before drier air works in from the west mid to late
week, diminishing overage thunderstorm coverage.


Red Flag Warning from 2 PM to 11 PM PDT Sunday for Central and
Western Humboldt County.



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