Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 192015

Area Forecast Discussion
National Weather Service Pocatello ID
215 PM MDT Thu Apr 19 2018

.SHORT TERM...Tonight through Sunday. Upper low centered in
southern Nevada this afternoon. Best moisture remains south of the
state line but have kept showers in place this evening weak radar
returns are indicating potential for development of weak
convection. Moisture quite limited, so scant QPF values at best.
Northern gradient strengthens overnight into Friday with breezy to
windy conditions throughout much of Snake Plain. Any weak
convection that survives past sunset will shift focus toward the
highlands along the UT border tonight, and then gradually
dissipate through the morning Friday. Upper ridge in place for
most of the weekend, though weak shortwave tries to flatten ridge
Sunday. Moisture even more limited with this fast moving feature,
so it looks to be just enough for some additional cloud cover and
a nudge upwards in winds. Otherwise expect warm conditions with
portions of the Snake Plain reaching near or above 70 degrees,
which is eagerly anticipated by many.

.LONG TERM...Monday through next Thursday night. Sunday night into
Monday models continue their agreement on a system moving through
bringing light to moderate showers. Snow levels will be around 8000
to 9000 feet before dropping to 6500 feet particularly in the
Central mountains. Look for 0.01 to 0.10 in the valleys with around
0.15 to .30 inch, likely higher for our northern areas,
precipitation for the mountains. Look for 1 to 3 inches of snow
above 7000 feet particularly for our northern areas. Weak high
pressure builds back in on Tuesday bringing drier conditions.
Wednesday and Thursday models become in better agreement though
still off on timing and placement. However, overall trend is
increase in cloudiness and a slight chance of showers particularly
for our southern border as a system moves through Utah. Temperatures
will be around normal early in the period becoming 10 to 15 degrees
above normal by the end of the period. Wyatt


.AVIATION...Expect VFR conditions through the period. Look for
cloudy conditions and maybe some vicinity showers as a weak trough
moves through the area tonight.   Look for breezy northeast winds
this evening as high pressure fills in. Winds become slightly
breezier as well as westerly by mid to late tomorrow morning. Wyatt


.HYDROLOGY...Palisades Reservoir releases remain high, so the
Snake River remains the region of concern. Gages at Lorenzo and
Menan fluctuating around or just below flood stage. Despite
officially dropping below flood stage, we opted to maintain the
flood warning for the Snake at Lorenzo through the weekend. Gage
readings could fluctuate above or below the flood stage, and we
felt the warning was warranted under those conditions, even for
minor impacts. At the very least, the warning could serve to
inform recreationists of the threats of high and fast flows along
the river below the dam, especially with the pleasant weekend
forecast on tap. DMH



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