321 
FXUS65 KPIH 201005
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
305 AM MST Sun Jan 20 2019

.SHORT TERM...Today through Tuesday night.  
Upper trof in the Pacific will move east today and extensive
Pacific moisture will continue to stream into southeast Idaho 
with snow and rain. Snow levels will range between 5 and 6 
thousand feet through midnight tonight so precipitation expected 
to be rain in Snake River Plain. Winter Weather Advisories are in 
effect for the central mountains and upper snake highlands through
tonight and in the southern highlands this evening through Monday
morning. Travel over mountain passes especially is expected to be
hazardous for the next 24 hours. Snow levels will drop to valley 
floors early Monday morning after the cold front with the system 
pushes east and there is still the possibility of 1 to 3 inches of
snow in the Snake River Plain on Monday. Models are differing 
significantly on the effect in the Pocatello to Idaho Falls 
interstate corridor however. Precipitation will linger Monday in 
the southern highlands then taper off Monday night with Tuesday 
expected to be dry and snow showers moving back into the mountains
Tuesday night with very light accumulations. Temperatures will be
very warm today with significant cooling down Monday and Tuesday 
to seasonal normals and even below normal by Tuesday. 
GK

.LONG TERM...Wednesday through next Sunday
Highlights:
- Mountain snow for middle of next week
- High pressure leads to a calmer weather pattern late next week
- Temperatures at or slightly above seasonal averages

The broad trough of low pressure set up to our southeast by the 
digging early week system will act to steer a new disturbance 
through our area beginning Wednesday. This British Columbia Clipper 
will be quickly pulled through the area from northwest to southeast. 
This looks to set up a precipitation shadow effect over the Snake 
Plain, while focusing the much of the snow through the central 
mountains and especially along the eastern highlands. It is over the 
eastern highlands that snow will then remain focused through at 
least Thursday as the moisture stream continues to hold. From about 
I-15 and west will begin to dry out heading towards the weekend.

Models are trending a little less towards a big ridge directly 
overhead, as we have seen with previous model runs, but there is 
still some potential. For now will keep the end of the week and 
weekend dry, but look for possible changes to this if we stay in the 
northwesterly flowing moisture stream.
TAX

&&

.AVIATION...The primary moisture stream, fueling much of the 
remaining rain and snow showers is beginning to shift to the north. 
This means that SUN/IDA/DIJ still have the best chance at 
precipitation this morning, but with temperatures warming it may 
switch over to rain. 

Recent satellite images show that beneath the obscuring cirrus, we 
can discern a stratus layer primarily over southeastern Idaho. While 
not currently impacting PIH or BYI, we cannot rule out a brief 
ceiling reduction. Otherwise, current VFR conditions are expected to 
hold until the next wave pushes moisture and precipitation back to 
the area later tonight. This will initially fall as rain, but as 
colder air moves back in late tonight into Monday, a transition to 
snow should occur. This will bring areawide restrictions stretching 
through the day Monday.
TAX

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 PM this afternoon to 11 AM MST 
Monday for IDZ056>063.

Winter Weather Advisory until 5 AM MST Monday for IDZ064>066-
071>074.

&&

$$