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fxus65 kboi 141725 

Area forecast discussion
National Weather Service Boise Idaho
1025 am MST Thu Nov 14 2019

Discussion...high clouds are overspreading the region this
morning ahead of an approaching shortwave trough. Surface winds
will increase across the middle snake as this feature approaches.
Have updated forecast for winds today to reflect the increasing


Aviation...patchy IFR/MVFR fog in the lower valleys in Baker and
valley counties this morning. Otherwise, VFR with broken high
clouds today. Surface winds south to southeast 10 kts or less,
becoming southwest to southeast aft 15/06z. Winds aloft at 10kft
mean sea level west to southwest 10 to 20 kts.

Weekend outlook...MVFR/IFR conditions in showers Friday night into
Saturday across the west central mountains of Idaho with passage
of a weak trough. More showers in the west central mountains
expected Sunday afternoon as another weak trough moves across the
northern Rocky Mountains.


Air stagnation...passing upper trough will bring enough wind and
cooling to improve conditions over portions of the snake plain
today and Friday. Lower elevations will remain inverted with
little wind.


Previous discussion...
short through upper level ridge axis
will pass over the area today, ushering in a period of southwest
flow aloft and slowly increasing moisture. A shortwave trough will
bring precipitation to the region Friday and Friday night, with
the majority of the activity across the northern two-thirds of the
County Warning Area (generally north of a Burns to Boise to Fairfield line). This
system will push a cold front through and significantly increase
winds. This will end the air stagnation we have been experiencing
(see discussion below). Temps will remain above 8 to 12 degrees
above normal today and Friday, then cool around 5 degrees Saturday
and Sunday.

Long term...Sunday night through Wednesday...good model
agreement through the first part of the extended as the upper
ridge that has been off the coast the last few weeks slides into
the Great Basin early Tuesday which pushes a warm front over the
northern zones. This brings a slight chance of showers across
Baker and valley counties for the Monday time period. Otherwise,
pleasant weather in the form of sunny skies and well above normal
temperatures Monday can be expected. Tuesday could be a near
repeat of Monday for at least southwest Idaho as the next front
begins to push into central Oregon. Models then begin to diverge,
but the main theme is that showers push into eastern Oregon midday
Tuesday and then eastward by Wednesday morning. Snow levels lower
to around 4500-5000 feet by Wednesday. This is not expected to be
a significant precipitation maker at this time. The GFS continues
to be more progressive with the front by kicking it eastward
Wednesday afternoon, whereas the ecm/Canadian continue to close
the low off over California/Nevada region then drop it into
Southern California. At best, this would bring a slight threat of
showers to the Nevada border region the flow wraps back around
that closed low.


Boi watches/warnings/advisories...
Idaho...air stagnation advisory until 11 am MST Friday idz012-014-033.
Or...air stagnation advisory until 11 am MST /10 am PST/ Friday





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