Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 170244

Area Forecast Discussion
National Weather Service Boise ID
844 PM MDT Wed Aug 16 2017

.DISCUSSION...Few clouds from exiting trough have cleared out of
the forecast area. Dry northwest flow should dominate for the next
few days, with virtually clear skies and near-normal temperatures.
Current forecast looks good, and no updates expected.

.AVIATION...VFR. Dry conditions noted under influence of high
pressure. Surface winds: West-Northwest 5-10 kts, weakening to light
and variable after 06z tonight. Another round of gusty wind may be
possible after 18z Thursday, mainly impacting KJER and KTWF. Winds
aloft at 10k ft MSL: West-Northwest at 10-20 kts.

SHORT TERM...Tonight through Friday...A weak upper level trough over
the region this afternoon will move southeast into Utah later this
evening. The trough will bring scattered cu over the higher terrain
of Southwest Idaho. Dry west-northwesterly flow will continue
through Friday for mostly clear skies and near normal

LONG TERM...Friday night through Wednesday...Dry zonal flow on
Saturday will be replaced with a pattern change for Sunday and
Monday. A closed low is expected to develop and be centered over
the Central California Coast by Sunday morning. While both the GFS
and ECMWF agree that this low will draw up moisture from the
south, how far north it comes will be a challenge, as the area
will be in between the low to the south and the stronger flow to
the north. The GFS brings more moisture and the potential for
showers and afternoon thunderstorms to the area on Sunday and
Monday, while the ECMWF keeps the area mostly clear and dry.
However, the latest run of the GFS, as opposed to previous runs,
has the cloud cover and showers/thunderstorms more-so along the
ID/NV border, rather than further north. These differences and
how they progress over the next few days will be closely
monitored. However, as Tuesday and Wednesday arrive, it looks like
the closed low will be absorbed into the southwest flow of a
larger low arriving to the PACNW coast. Expect near normal
temperatures through the period.





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