Area Forecast Discussion
Issued by NWS Boise, ID
FXUS65 KBOI 252146
Area Forecast Discussion
National Weather Service Boise ID
246 PM MST Sat Feb 25 2017
.SHORT TERM...Tonight through Tuesday...Generally quiet conditions
seen today across the forecast area as the area of low pressure off
the California coast continues to have little impact. The next
Alaskan system, however, promises to have different results. The
system will move over the Pacific Northwest by Sunday morning, with
snowfall beginning to impact the west central mountains of Idaho
late Sunday morning. As the system dives southeast, it is expected
to bring significant moisture over the northern portion of the
forecast area. Related snowfall will continue through Monday as the
trough axis moves through central Idaho, with significant snowfall
accumulations expected. The west central mountains can expect 3 to 6
inches of snowfall with this system by Monday afternoon, with
locally higher amounts over the higher peaks. A Winter Weather
Advisory has been issued for this time frame to account for the
related impacts, especially to travel across the area. Baker county
of Oregon and the Upper Weiser River areas could also see some
decent snowfall out of this system, though currently are not
anticipated to meet impact thresholds for any highlights. This will
continue to be monitored.
Snowfall relating to this Alaskan trough will continue through
Tuesday, though its greatest impacts are anticipated to be felt
through Monday evening. Numerical models are in decent agreement
with the severity of this upcoming trough. Additionally, models are
again promoting instability across the area for Monday afternoon as
the trough axis progresses. For now, left out mention of thunder,
though it certainly remains possible to see some thunderstorm
activity, or at least graupel producing showers.
.LONG TERM...Tuesday night through Saturday...The trough will
quickly exit the region and a cool northwesterly flow aloft will set
in in its wake. Some moisture will continue to ride within the flow,
so looking for chances of snow showers mainly over the central Idaho
mountains and the higher elevations in Baker County through
Thursday. Temperatures will have climbed slowly to within 5 degrees
of normal at this point. Friday will offer a brief dry period as the
upper level flow turns west, then southwest ahead of the next
system. Precipitation will spread into the region from northwest to
southeast throughout the day Saturday, bringing snow above about
5000 ft MSL. Temperatures in the lowest valleys will be in the mid
to upper 40s and mountain valleys in the mid to upper 30s.
.AVIATION...VFR under mostly clear skies, except isolated midlevel
clouds and MVFR snow showers mainly over the West Central and Boise
Mountains through the day. Surface winds: variable 10 kts or less.
Winds aloft at 10K ft MSL: WNW 15-15 kts.
Sunday outlook: Deteriorating conditions with incoming system as
snow spreads across the area through the course of the day.
Expecting scattered MVFR snow showers over the mountains north of a
KBNO-KBOI-KSUN line during the morning hours, spreading south across
the area in the afternoon and evening. Widespread snow showers over
the mountains. IFR/LIFR conditions in the heavier showers and
mountain obscuration possible. Surface winds will increase and
become breezy in the afternoon.
ID...Winter Weather Advisory from 11 AM Sunday to 11 AM MST Monday