Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 270317

Area Forecast Discussion
National Weather Service Boise ID
917 PM MDT Wed Apr 26 2017

.DISCUSSION...Main area of shower development is shifting into
s-central Idaho this evening as an upper level feature tracks
through Idaho. Thunderstorm threat is diminishing with loss of
heating but stronger showers will continue to drop brief heavy
rain. Shower activity will retreat to the mountains overnight as
upper dynamics exits eastward. Have updated forecast to cover
shower activity in s-central Idaho this evening and expected
decrease in activity after midnight. Northwest winds tonight will
strengthen Thursday morning, with core of strongest winds focused
over the Western Magic Valley.


.AVIATION...VFR. Showers are currently pushing southeastward through
SW Idaho and will die off for most locations after sunset. Chances
linger for shower activity up around KMYL and the West Central
Mountains through Thursday evening. Surface winds, westerly 10-15
kts. Winds aloft to 10k feet MSL, northwest 30-45 kts.


SHORT TERM...Tonight through Friday...Widespread precipitation
continuing through this evening as the upper level trough and cold
front move across the region. Satellite showing the upper level
trough over Central Oregon at 20z. Surface cold front is roughly
over the Cascades at 20z and is expected to reach Burns/Baker City
around 00z and Boise/McCall around 03z tonight. Precipitation will
diminish with the frontal passage though showers will continue
mainly in the mountains though Thursday. Northwesterly flow
follows the upper level trough passage Thursday through Friday
bring cold and breezier conditions along with a chance for
showers. Tight pressure gradient over south-central Idaho along
with strong (35-45 kts) mid level jet following the cold front
early Thursday will bring gusty winds to the Western Magic Valley
and Southern Twin Falls County. Have issued a wind advisory for
this area on Thursday. A reinforcing trough Friday morning will
bring a snow showers to the mountains. Temperatures will remain
at least 15 degrees below normal through period. Friday morning
temperatures will be close to freezing (33-36 F).

LONG TERM...Friday night through Wednesday...An upper trough will
exit to the east Friday night. An upper ridge will translate across
the area on Saturday for dry weather and slightly warmer
temperatures. A couple of fast-moving short wave troughs residing
within a northwest flow aloft will bring a chance of showers (mainly
across the north) Sunday and Monday. Temperatures will be around 5
degrees below normal. An upper ridge off the west coast will move
inland for dry weather and a warming trend Tuesday through


ID...Wind Advisory from 9 AM to 6 PM MDT Thursday IDZ016-030.



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