Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 232000

Area Forecast Discussion
National Weather Service Pocatello ID
200 PM MDT Thu Mar 23 2017

.SHORT TERM...Tonight through Monday.
Expect light showers in southeast corner to dissipate overnight
with dry weather expected through Friday morning. The next Pacific
system will begin to affect the region Friday afternoon with rain
and snow showers moving into the central mountains and spreading
east Friday night. Snow levels are expected to begin around 6500
feet and locations above that level may see 2 to 6 inches above
that level. Rain is expected below 6000 feet. Precipitation should
taper off Saturday afternoon with only light showers mainly in
the eastern highlands. Sunday should be mainly dry with another
Pacific system expected to spread precipiation over the entire
region Sunday night into Monday with snow levels again in the 6 to
7 thousand foot range expected. Temperatures are expected to
remain near seasonal normal Saturday through Monday after likely
well above normal highs on Friday.

.LONG TERM...Monday night through Thursday. GFS and ECMWF remain
similar on timing of major features through east Idaho but differ
significantly on how those features look and act. Trough axis
drives through the region Monday night into Tuesday, amplifying
into split system with low close off somewhere in the vicinity of
the four corners region. The models really struggle with where
this low center closes and how it moves east. Upper flow remains
progressive however with weak ridge/high pressure Tuesday
night/Wednesday. Next system drives across the region Wednesday
night and Thursday, again following a split but again with major
differences on what the split does. Given the uncertainty in the
details, kept overall blend going through the period, but with
some confidence in general timing of precipitation trends. DMH


.AVIATION...Low clouds have been stubborn to break up in at a couple
of the terminals but clearing line is slowly working southeast. HRRR
has been trying all day to generate some very weak showers KIDA/KPIH
and shifting this region southeast through the evening. Given recent
days performance of the HRRR am skeptical but weak instability along
edge of clearing line would be a common point for convective
initiation this afternoon. Added VCSH with 18Z run but also trended
cloud decks toward or continued VFR conditions. Could see some low
stratus return tonight, generally KPIH/KIDA/KDIJ where cloud cover
has been stubborn this morning. DMH


.HYDROLOGY...Snowmelt flooding continues. High flows into dams along
the Bear River have necessitated additional releases from those
dams. The river remains high but below flood stage so issued a flood
advisory, especially with concern towards tributaries to the river.
The Bear River remains at or just above flood stage with downstream
affects at Pegram and beyond. Portneuf River remains above flood
stage. Otherwise all advisories remain intact where current
flooding exist or where trouble spots have been identified by
emergency management. Cooler temperatures the next several days
will likely slow, but will NOT cease, snowmelt runoff. Anticipate
flooding concerns to continue. DMH


Flood Watch through Friday morning for IDZ017>019-022>025-031-


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