Area Forecast Discussion
Issued by NWS Boise, ID
FXUS65 KBOI 251633
Area Forecast Discussion
National Weather Service Boise ID
933 AM MST Sat Feb 25 2017
.DISCUSSION...No updates planned for current forecast. Fairly
quiet day as low off Pacific coast continues to move west. This
movement is anticipated to pull moisture along with it, with
limited activity anticipated today. The next Pacific trough is
expected to arrive Sunday, spreading moisture across much of the
.AVIATION...Mostly VFR today and tonight under mostly clear skies.
Isolated midlevel clouds and MVFR snow showers 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.
SHORT TERM...Today through Sunday...Fast moving trough dropping
through the Pac NW this morning continues southward today. The
main dynamics with this system are well offshore, which will its
impact to isolated snow showers across far southeast Oregon and
the west-central mountains in Idaho for today. Otherwise will see
partly cloudy and cold conditions across the area. Weak warm
advection keeps slight chance of showers in the central ID
mountains overnight. This is ahead of a second cold upper level
trough tracking from the Gulf of Alaska into the Pac NW for
Sunday. Showers increase in coverage Sunday afternoon with
increased instability ahead of the low center. Snow will fall to
valley floors but accumulations will be limited to elevations
above 4k feet MSL. Winds will also increase on Sunday with breezy
conditions developing by afternoon. Temperatures are around 10
degrees below normal through Sunday.
LONG TERM...Sunday night through Friday...The cold upper level
trough will exit the Intermountain Region on Tuesday, leaving our
area under northwest flow aloft. Temperatures will be around 10
degrees below normal Monday and Tuesday, but slowly moderate to
around 5 degrees below normal on Friday as the upper level flow
shifts to more westerly. Snow showers will be widespread Sunday
night and Monday, then decrease to scattered Monday night and
Tuesday. Precipitation will be mainly confined to the mountains of
central Idaho and Baker County Oregon Tuesday night through Friday.
PREV SHORT TERM...DG
PREV LONG TERM....JT