Scientific Forecaster Discussion
fxus65 kboi 180926
Area forecast discussion
National Weather Service Boise Idaho
326 am MDT Wed Sep 18 2019
Short term...today through Saturday...a stalled band of showers
continues west of a McCall-Ontario-Rome line early this morning.
The band is expected to remain nearly stationary until mid-
morning, then slowly drift eastward and weaken late this morning.
Showers and isolated thunderstorms will accompany an upper low as
it slowly moves into the pacnw this afternoon and evening,
including southeast Oregon and southwest Idaho. The upper low will
be centered over our area on Thursday for more showers and a
slight chance of afternoon thunderstorms. Snow levels will lower
to around 7500 feet by Thursday night with light snow
accumulations possible on the peaks. The low will finally start to
move to our northeast on Friday, although there is a chance for
showers to continue in southwest Idaho. Drier air will accompany a
weak upper ridge Friday night and Saturday. Temperatures will be
around 10 to 15 degrees below normal through Friday and 5 to 10
degrees below normal on Saturday.
Long term...Saturday night through Wednesday...models are in
good agreement. The next upper level trough from the Gulf of
Alaska is scheduled to arrive on Sunday, spreading showers across
our area by Sunday night. Showers are expected to end on Monday as
the trough exits to the south and stalls over Southern
California. Temperatures will be a few degrees below normal Sunday
and Monday and near normal Tuesday and Wednesday.
Aviation...widespread showers over eastern Oregon and the west
central Idaho mountains spreading across southwest Idaho after 12z
and the Magic Valley by 19/00z. Showers continuing all areas
through Thursday. Isolated afternoon and evening thunderstorms.
Expect mountain obscuration and areas of MVFR/local IFR
conditions. Snow levels 8k-9k feet mean sea level today lowering to 7k-8k
feet mean sea level Thursday. Surface winds variable 10 kts or less. Winds
aloft at 10k feet mean sea level southwest 20-30 kts.