Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 280933

Area Forecast Discussion
National Weather Service Pocatello ID
333 AM MDT Sun May 28 2017

.SHORT TERM...Today through Tue night. Upper level ridge firmly
in place, but the question is how far east will it shove the
instability and moisture that will generate weak showers and
thunderstorms on the eastern side of the high--especially the
first two days. The NAM has the moisture and instability much
farther east and much less of it. The GFS keeps fairly decent
moisture along the ID-WY border. By Tue the upper level ridge is
pushed far enough south where some instablity and moisture enter
the ridge and spread across the central Idaho mountains and the
northern and eastern highlands for afternoon and evening showers
and thunderstorms. Temperatures continue with a strong warming
trend today, up 2 to 7 from today to Mon, then another 1 to 5 from
Mon to Tue. Only serious forecast issues are snow melt and
flooding. Messick

.LONG TERM...Wednesday through Sunday. Models push the dominant
upper ridge off to the east as an upper trof moves into the Pac NW.
The upper trof evolves into a split flow pattern with a more
energetic northern stream. This results in more tstm coverage Thu
aftn/eve...but mainly in the mtns. Models become more chaotic by the
weekend...with the ECMWF more progressive with another upper trof
moving into the Pac NW on Fri. The GFS has a ridge...but both are
trending dry.  The GFS does not bring the trof in until Sun. The
ECMWF tends to keep precip limited with this will go drier
thru the weekend...with a small increase in tstms Sun aftn/eve over
the mtns. Hedges


.AVIATION...Upper ridging will result in VFR conditions thru tonight.



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