Area Forecast Discussion
Issued by NWS Boise, ID
FXUS65 KBOI 270240
Area Forecast Discussion
National Weather Service Boise ID
840 PM MDT Sun Mar 26 2017
.DISCUSSION...Showers were moving east across much of southeast
Oregon as of 830 pm MDT, and have recently crossed into the
mountains of southwest Idaho. Additional showers are expected
overnight as a strong cold front and upper level system approach
from the west. The cold front was just west of the CWA as of 830
pm MDT, and will move into southeast Oregon this evening and
southwest Idaho late tonight. It will clear the western Magic
Valley around 8 am MDT. Northwest winds behind the front will gust
above 30 mph tomorrow afternoon in the Upper Treasure Valley near
and east of Mountain Home, and over the western Magic Valley. All
this is handled well by the current forecast and no update is
planned this evening.
Several rivers continue in minor flood, including the Boise in
Ada and Canyon counties and the Silvies in northern Harney County.
The Snake River near Weiser is temporarily below flood stage, but
is forecast to rise back into minor flood tomorrow afternoon.
Finally, flooding from snowmelt continues to impact the Camas
Prairie and some surrounding areas.
.AVIATION...Scattered IFR/MVFR conditions with rain and snow
continuing through Monday. Precipitation coverage will increase
beginning late tonight with cold frontal passage. Snow levels around
5000 feet will bring a rain/snow mix to KMYL overnight. Front exits
the region late Monday morning. Scattered showers will continue in
the higher terrain through Monday evening. Surface winds, southeast
to south 10-20 kts with locally higher gusts ahead of the front
shifting to the west or northwest after 27/0900z. Winds at 10kft
west-northwest 20-30 kts.
SHORT TERM...Warm front with light rain on the Idaho side
this evening. Rain and mountain snow in all areas again late
tonight and Monday morning as Pacific cold front moves through.
Showers continuing Monday under upper trough. Air mass
destabilizing Monday with a slight chance of thunderstorms on
the Idaho side Monday afternoon. Post-frontal west/northwest
winds will increase to near advisory speeds in the Upper Treasure
Valley and Western Magic Valley Monday afternoon. Clearing west
to east in all areas Monday night, and colder under northerly
flow aloft. Tuesday morning will average 10 degrees colder
than Monday morning. Upper ridge Tuesday will bring mostly
sunny skies and rapid warming in the afternoon. Minor
flooding to continue on the Snake River near Weiser and on the
Boise River at Glenwood bridge. Colder air Monday night should
LONG TERM...Tuesday night through Sunday...
Unsettled weather through the extended period as an active pattern
continues through most of the upcoming week. A brief upper ridge
will be over the region early Wednesday before another strong
trough moves into the Pacific Northwest in the afternoon. Precip
water values soar into the 90-95th percentile...so should see a
potent rain/snow event across the region with snow levels 5500-6500
feet in the north to over 7000 feet along the NV border area. Precip
values over the higher terrain generally 0.75-1.00 inches and above
for Wed/Thur time period. The upper low dives southward across the
Great Basin into Friday morning which should bring brisk northwest
winds across all zones. Another brief upper ridge expected by the
weekend bringing a drying trend to the region...but models for next
weekend are showing some disagreement with the timing of troughs
potentially pushing through the upper ridge.
PREV SHORT TERM...LC
PREV LONG TERM.....CR/DD