Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

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 



National Weather Service Glossary of Abbreviations