Area Forecast Discussion
Issued by NWS Boise, ID

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
FXUS65 KBOI 210920

Area Forecast Discussion
National Weather Service Boise ID
320 AM MDT Wed Mar 21 2018

.SHORT TERM...Today through Thursday...Showers are expanding in
coverage to the south and west of the CWA this morning, associated
with a warm front that will move northeast through the area today.
These showers will enter the area this morning, and additional
showers will develop behind the warm front this afternoon and
evening. Southwest flow aloft will transport high PW air into the
region through the short term, and upslope into the mountains will
enhance precipitation there. Snow levels will increase to a range
of 6500 north to 8000 south this evening and remain about that
high through Thu afternoon. Therefore, significant snows will be
confined to the highest peaks. On Thursday, a cold front will move
toward the region from the west, and convection will once again
develop in the warm sector. The front may just enter our western
fringes (Harney and western Baker counties) by late afternoon.
There should be sufficient instability for thunderstorms Thu
afternoon, initially in southeast Oregon, but eventually spreading
into southwest Idaho late in the afternoon. Temps will be 5 to 10
degrees above normal through the short term period. Winds will
increase Thu afternoon, coming out of the southwest in southeast
Oregon and mainly out of the southeast in southwest Idaho and
Baker County Oregon. Windspeeds will average 20 to 30 mph in
southeast Oregon, and 15 to 20 mph in southwest Idaho. This is not
high enough for a wind advisory, but is certainly well above

.LONG TERM...Thursday night through Tuesday...Exiting cold front
Thursday night into Friday pushes precipitation to our east. The
upper Low off the British Columbia coastline begins to drop south
swinging another boundary onshore first thing Friday morning. Snow
levels at this time are still hovering right around 4000 feet
MSL. As the second boundary begins to press through our CWA early
Saturday morning, snow levels drop down to the valley floors. The
main low drops just to our south leaving snow showers in our
forecast for much of the area through late Sunday. An upper level
ridge offshore helps push much of the moisture up and well north
of our area leaving just slight chance of precipitation for our
northern mountains for the remainder of our forecast period. Snow
levels begin climbing back above 3000 feet MSL by Tuesday and end
the forecast period around 6000 feet MSL.


.AVIATION...Mostly VFR. Increase in rain throughout the morning
and into the afternoon as a warm front pushes up from the
southwest. Snow levels sit between 6000-7000 feet MSL. Isolated
MVFR within heavier rain bands. Surface winds, mostly southwest
10-20kts with afternoon gusts 25-35kts through southern Harney and
Malheur counties and the Southwest Highlands. Winds aloft to 10k
feet MSL, southwest 20-35kts through 00z then 40-50kts.





AVIATION.....JC is the U.S. government's official web portal to all federal, state and local government web resources and services.