Area Forecast Discussion
Issued by NWS Boise, ID

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000
FXUS65 KBOI 202201
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
301 PM MST Mon Feb 20 2017

.SHORT TERM...Tonight through Wednesday...Moist southwest flow
will continue to feed precipitation into the mountains of
southeast Oregon and southwest Idaho tonight and Tuesday. Lower
elevations will see a period of rain tonight as an upper wave
lifts north across the region. Strong winds aloft will focus
precipitation in the mountains on Tuesday, while valleys are
mostly dry. Snow levels are 6-7k feet through Tuesday morning,
dropping to around 5k feet by Tuesday afternoon. Sites at or above
7k feet could see an additional 6-10 inches of snow through
Tuesday afternoon as qpf in the higher terrain approaches an inch
of liquid. Windy conditions will prevail through Tuesday with the
strongest winds across southeast Oregon and highlands of
southwest Idaho. The wind advisory for these areas remains well
supported, though the strongest winds aloft (700 mb) are during
the early morning, before the surface inversion breaks. A deeper
trough moves into the Pac NW on Wednesday, pinching off the feed
of Pacific moisture and refocusing precipitation over far
southeast Oregon. Snow levels drop to valley floors, but
temperatures will remain too warm at lowest elevations to see any
accumulations. Temperatures are about 10 degrees above normal
Tuesday, dropping to around 5 degrees below normal on Wednesday.


.LONG TERM...Wednesday night through Monday...A deep trough along
the Pacific Northwest coastline through the period helps push
feature after feature through the CWA. Snow levels are at the valley
floors throughout the extended. Most of the precipitation with the
waves passing through look to be convectively driven, meaning they
will be most active during the afternoon periods. Snow showers
expected to occur during the afternoon periods throughout the
extended period, however with the daytime high temperatures forecast
to go above freezing for most valley locations, accumulations are
not expected to be of much impact. Temperatures stay below normal
the entire period.

&&

.AVIATION...Mostly VFR. MVFR within showers. Showers currently in SE
OR and SW ID pushing northeast this morning. A second wave of
precipitation will move in from the south pushing northward by late
Monday evening into Tuesday. Isolated thunderstorms Monday afternoon
into late evening with graupel. Surface winds, southerly 10-30 kts
with gusts 25-35 kts in valleys and 30-45 kts in higher elevations.
Winds aloft to 10k feet MSL, southwest 30-60 kts.

&&

.HYDROLOGY...Mild and breezy conditions will accelerate snowmelt
across lower elevations over the next 24-36 hours. Coupled with
overnight precipitation, expect to see an increase in runoff
through Tuesday afternoon. Those in lowland areas with remaining
snow cover or located along small streams and rivers should
continue to monitor the weather conditions closely. Flood
warnings remain in effect for the Malheur River near Vale and the
Weiser River near Weiser, both of which are expected to rise above
flood stage on Tuesday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory from 11 AM to 8 PM MST Tuesday IDZ029.
OR...Wind Advisory from 11 AM MST /10 AM PST/ to 8 PM MST /7 PM PST/
     Tuesday ORZ061-063.

&&

$$

www.weather.gov/Boise
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SHORT TERM...DG
LONG TERM....JC
AVIATION.....JC
HYDROLOGY....DG



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