Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 272045 CCA

Area Forecast Discussion
National Weather Service Boise ID
245 PM MDT Mon Mar 27 2017

.SHORT TERM...Scattered light rain and snow showers in the higher
terrain will end by sunset.  Clearing and colder tonight.  Patchy
valley fog late tonight and Tuesday morning.  High pressure
surface and aloft will bring dry, mild weather Tuesday through
Wednesday morning.  On Wednesday a Pacific frontal system will begin
rain in Baker County, spreading southeastward during the day.
By late afternoon the leading edge will be Challis, ID - Ontario,
OR - Steens Mountain, OR.  Low temps tonight will be 30 to 35 in
the lower valleys, 20s in the mountains.  Highs Tuesday in the
lower to mid 50s in the valleys, 40s to lower 50s in the mountains.
Tuesday night will be slightly warmer as clouds increase especially
in Baker County.  Wednesday will be about 10 degrees warmer than
Tuesday in southern areas, but about the same as Tuesday in the
cloudy north.  Light to moderate west winds Tuesday, light southeast
winds Wednesday.

.LONG TERM...Wednesday night through Monday...A very moist
Southwesterly flow aloft will take aim on the region Wednesday night
through Thursday ahead of an approaching PacNW trough. Snow levels
during the period of heaviest precip (Wednesday night through
Thursday morning) will average 8500 feet, thus snowfall will be
limited to the mountain peaks. QPF amounts look impressive, with
total amounts of up to 0.50 inches in the valleys and up to an inch
in the mountains. Locally higher amounts are possible. The PacNW
trough will become a closed upper low in Nevada on Thursday, or near
the ID/OR/NV triple point depending on model solution. The track of
the low will determine the amount and extent of wrap-around QPF
Thursday night through Friday. Snow levels will fall to around 4000
feet MSL Thursday night with accumulating snows likely at higher
elevations along the ID/NV border. Windy conditions will develop
Thursday afternoon which will persist into Friday. The upper low
will shift well to our East as an upper ridge builds into the area
on Saturday for dry weather, mild temperatures, and light winds.
Next Pacific system brings a chance of showers and cooler
temperatures Sunday and Monday.


.AVIATION...Widespread VFR. MVFR conditions in scattered showers
will dissipate by 03Z. Snow levels near 5000 feet MSL. IFR/LIFR
clouds may develop near KJER after 09Z. Patchy IFR fog in the
northern mountain valleys (including KMYL) after 06Z. Surface
winds: Northwest 15-25 kts will diminish to 5-15 kts by 06Z. Winds
aloft at 10k feet MSL: Northwest 10-20 kts.


.HYDROLOGY...Flood warning was cancelled for the Silvies River area
in northern Harney Co this morning as flow has decreased.  Flood
advisory continues until Tuesday afternoon in Camas and northern
Elmore Counties with flow still high on the Camas Creek. The Boise
River at Glenwood Bridge in Boise will remain in minor flood at
least several more days.  The Snake River at Weiser dipped
slightly below flood stage this afternoon but was beginning to
rise again at 2 PM MDT.  It will continue a few inches either side
of flood stage through Thursday, then rise more significantly Friday
and especially Saturday.  We are therefore continuing the flood
warning there.





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