467 
FXUS65 KBOI 090241
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
841 PM MDT Sun Apr 8 2018

.DISCUSSION...Showers continue across the area this evening. Some
activity lingered across the Treasure Valley a few hours longer 
than expected. Main update for this evening was to extend mention 
of showers across southwestern Idaho. The West Central and Boise 
Mountains look to continue their activity into the overnight 
hours, though dry conditions are expected by Monday morning. Dry 
conditions then anticipated through Tuesday morning, ahead of the 
next disturbance. No further updates planned.

&&

.AVIATION...VFR except for areas of MVFR conditions in snow in the 
west central Idaho and Boise Mountains through 06z. Isolated rain 
showers will continue in the Snake River Valley until 05z. Surface 
winds west-northwest 5-15 kts. Winds aloft near 10k ft MSL west to 
northwest 20-30 kts.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Tuesday...A weak upper level wave
embedded in northwest flow is moving through the area this
afternoon, aiding shower development. These showers may bring 
wind gusts to 40 mph and brief moderate rain. This system will 
move rapidly south and east of the area this evening, allowing dry
conditions Monday into Monday night. The next upper level system 
will move in Tue, spreading showers mainly into southeast Oregon 
in the morning, and much of southwest Idaho in the afternoon. At 
this time, it appears the western Magic Valley will stay dry 
through the afternoon hours on Tuesday. Temps will be seasonable 
each day, meaning within 5 degrees of normal. Lows Tue morning 
will be relatively mild, owing to increasing clouds and winds.

LONG TERM...Tuesday night through Friday...Models are in good 
agreement. Showers will continue over the west central Idaho and 
Boise Mountains, but decrease to isolated elsewhere by Wednesday 
morning. The next round of precipitation will spread across our 
northern zones on Wednesday ahead of a deep upper level low pressure 
trough. As it moves inland, the trough will bring widespread 
precipitation Wednesday night and Thursday, breezy west winds, and 
much cooler temperatures, with highs 10 to 15 degrees below normal. 
Snow levels will lower to between 3000 and 4000 feet on Thursday, 
and even the lower valleys could see some snow mixed with the rain. 
A weak high pressure ridge will end the showers at lower elevations 
by Friday morning, and temperatures will start a slow recovery. 

Friday evening through Monday morning...A break in the active 
weather pattern is upcoming as west upper level flow and ridging 
briefly take control allowing for drier, sunnier conditions to 
temporarily prevail. Models agree that some moisture will spill over 
the ridge (axis slightly stronger in GFS) mostly affecting the 
northern portions of the CWA during the earlier periods. Expect 
higher probabilities for cloudy skies and occasional precipitation 
in those areas. Models also suggest that another moderate low 
pressure system is building/strengthening upstream. Increasing 
clouds and precipitation along with breezy southwest winds will 
begin entering the west section of CWA by Monday morning. The 
latest EC is heavier on the moisture amounts and lighter on the 
wind speeds. Precipitation will fall as rain along most low 
valleys with snow in the higher mountains. However, the areas of 
rain should gradually increase and the areas of snow should 
decrease as snow level gradually rise in advance of this next 
system. Temperatures are expected to hover within a few degrees of
normal.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

$$

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DISCUSSION...KB
AVIATION.....JS
PREV SHORT TERM...SP
PREV LONG TERM....JT/WH