Scientific Forecaster Discussion
fxus65 kboi 251600
Area forecast discussion
National Weather Service Boise Idaho
1000 am MDT Thu may 25 2017
Discussion...weak upper trough will strengthen as a short wave in
eastern Washington moves south into the northern portion of our
forecast area this afternoon. As it does, scattered showers and
isolated thunderstorms will develop from far northern Harney
County and Baker County, east into the west central and Boise
Mountains. Temperatures will remain below normal, with highs
mainly in the 60s. No updates.
Aviation...VFR through 20z, then isolated MVFR in showers and
thunderstorms over northern Harney and Malheur counties, Baker
County, and the central Idaho mountains. Thunderstorms end by 06z
Friday, but showers will continue and spread south to the Nevada
border by 12z Friday. Surface winds: northwest 5-10 kts. Winds
aloft near 10k ft msl: northwest 10-15 kts.
short term...cool upper trough over our area currently extends from
a low in Saskatchewan. Trough will be reinforced later today by a
short wave trough moving south from British Columbia. This will keep temps below
normal while increasing pops in northern areas this afternoon.
Air mass will be unstable enough for a slight chance of
thunderstorms in northern areas this afternoon. An upper low will
form in central Idaho tonight, then weaken Friday as it moves east
into Wyoming. Cyclonic flow around the low will maintain showers
through Friday especially in the Idaho mountains north of the snake
basin. Slight chance of thunderstorms in central and south-
central Idaho Friday afternoon. Oregon will dry out Friday as
big coastal upper ridge begins to come inland. Light west or
northwest winds through Friday, except locally moderate wind
speeds in the upper Treasure valley and western Magic Valley.
Long term...Friday night through Wednesday...the upper level trough
will depart Friday night, but enough moisture and instability will
remain over our area for isolated showers and thunderstorms over the
central Idaho mountains and the higher terrain along the Idaho-
Nevada border. On Saturday an upper level ridge building in from the
west will bring dry weather, and a warming trend which will continue
through Wednesday. Temperatures will be near normal on Saturday, and
rise to 10-15 degrees above normal by Wednesday.