Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 230927

Area Forecast Discussion
National Weather Service Boise ID
327 AM MDT Thu Mar 23 2017

.SHORT TERM...Pacific frontal system along 130W at 2 AM MDT will
reach the coast late today, and move across Oregon tonight and
Friday morning, and into our CWA Friday. System will bring
widespread rain with 0.25" to 0.50" expected in Baker County,
northern parts of Harney and Malheur Counties, and Idaho north of
the Snake Basin.  Lesser amounts are expected to the south, with
least amounts along the Nevada border.  Relatively tight west-east
surface pressure gradient across southern Idaho today will produce
west winds 20 to 30 mph in and near the Magic Valley.  Winds will
become east or southeast in all areas tonight ahead of the
approaching Pacific frontal system.  Winds Friday will continue
light to moderate southeast, but will shift to southwest in eastern
Oregon behind the front.  No thunderstorms are expected as models
keep lifted index above +2 through Friday.  Thermal contrast across
the front looks weak with only 2-5 degrees cooling behind it.

.LONG TERM...Friday night through Thursday...Active storm track will
remain focused on the Pac NW through next week. This will bring a
weather system through the region every couple of days with brief
breaks in between. Friday night and Saturday will see an upper
trough exiting eastward with precipitation tapering off in valleys
on Saturday and across the mountains by Saturday night. The next
trough arrives late Sunday, exiting eastward Monday night. This is
followed by a third storm for late Wed/Thur. Each system will bring
moderate liquid/snow accumulations across higher terrain, while
lower elevations will see lighter amounts and less continuous
precipitation. Snow levels will fluctuate between 4500 and 6500 feet
MSL with passage of each system. Temperatures will be at or slightly
below normal through the period.


.AVIATION...VFR with mid-level ceilings across the east-central
Oregon and west-central Idaho mountains today. Northwest winds to 25
kts surface through 10k feet.


.HYDROLOGY...Rivers will generally lower through Friday then
rise slightly again Saturday after Friday`s rain.  Rivers should
then resume a downward trend into next week.  But the Snake River
at Weiser is forecast to continue a few inches above flood stage
through next Wednesday, while the Boise River at Glenwood Bridge
will continue about a half-foot above flood stage for at least
another week.  An areal flood warning continues for northern Harney
County, OR, through this morning.  Flood warnings were cancelled
last evening for the Payette River near Emmett, and the Weiser River
near Weiser.





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