Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 060951

Area Forecast Discussion
National Weather Service Boise ID
250 AM MST Tue Dec 6 2016

.SHORT TERM...Today through Wednesday...A very cold upper level
trough with limited moisture has been generating light snow early
this morning across northern and western portions of our CWA. So far
the only reporting points observing precipitation have been Burns,
Baker, and McCall. Radar shows 20-30 dbz returns moving east over
the lower Treasure Valley, but no snow has been reported at Ontario
or Caldwell, and none has been seen on webcams. Possibly flakes have
been sublimating in the dry air before reaching the ground. It
appears doubtful that there will be enough snow in the valleys to
enhance radiational cooling tonight, and several models have raised
tonight`s mins a few degrees. Highs on Wednesday are still expected
to remain below freezing despite abundant sunshine.

.LONG TERM...Wednesday night through Monday...Northwest flow aloft
Wed night becomes zonal Thu as a moderate-strength and wet trough
moves east toward the PacNW. Moisture ahead of and accompanying this
trough will bring snow to even the lowest elevations, starting in
southeast Oregon late Wed night and spreading into southwest Idaho
Thu morning. This trough will take its time moving through, and
precipitation is expected to last through Saturday. A warm front
associated with this system Thu into Thu night, turning snow to rain
over the southern portion of the CWA below around 5000 feet. After
the trough axis moves through Fri night, a cold front will bring
snow levels back down so that snow would occur at even the lowest
elevations by Saturday night. However, by that time, moisture will
be quite limited and any snowfall is expected to be light. During
the height of the event, heavy snow is forecast for the mountains,
with snow totals from Thu through Sat ranging from around 9 inches
near McCall to over 20 inches at the highest elevations. The
Treasure Valley will see 1 to 3 inches with the western Magic Valley
getting 3 to 5 inches, on average. Showers remain in the forecast
even for Sunday, and the potential exists for another relatively
cold and wet storm for Mon through Wed of next week. At this time,
model agreement is not sufficient to attempt to choose a day upon
which this is most likely to happen, but the potential is certainly

After Thu, high temperatures through the extended will not vary
much. We will see a continuation of the very cold weather for Thu,
with highs near freezing in the lower elevations, followed by a
warmup to near normal for Fri into the middle of next week.
Low temperatures will start out cold Thu morning, then moderate
significantly behind Thu`s warm front and remaining above normal Fri
and Sat. From Sunday into the middle of next week, lows will most
likely be near normal.


.AVIATION...Conditions are still mostly VFR, but scattered snow
showers generated by an passing upper level trough will likely bring
areas of MVFR and isolated IFR to the area today. Mtns obscured at
times. Surface winds: 10 kts or less today, with a directional
change from generally south or east this morning to northwest this
afternoon as the upper trough moves through. Winds aloft through
10kft will change from southwest 15-25 kts this morning to northwest
10-20 kts late this afternoon and tonight.





SHORT TERM...JT LONG TERM AND AVIATION....SP is the U.S. government's official web portal to all federal, state and local government web resources and services.