Area Forecast Discussion
Issued by NWS Pocatello, ID

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000
FXUS65 KPIH 200841
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
241 AM MDT Mon Mar 20 2017

.SHORT TERM...Today through Wednesday night...Surface boundary to
linger across Idaho with atmospheric river moisture continuing to
stream through at the same time early this week. Persistent
chances for precipitation are in the forecast each day as a
result. Minimal amounts of instability exists during the late
afternoon/evening hours as well; therefore a mention of
thunderstorms are noted in valley locations. Snow levels today are
at 7500 to 8000 ft, therefore only select mountains will
experience snow showers. But, those mountains can expect snow
showers through Wednesday with heavy snow possible late Tuesday.
Warmer than average temperatures are expected to continue today
and Tuesday with high temperatures in the 60s for the Snake Plain
and 50s in the mountains. Early Wednesday, a cold front is
expected to pass the area and will cool temperatures about 10
degrees in its wake. Wind speeds Tuesday into early Wednesday are
expected in the 15 to 20 mph range with stronger gusts, especially
through the Snake Plain and Highland locations. NP/JAM

.LONG TERM...Thu through Sun night. 500mb long wave pattern
indicates a west coast ridge slowly slides eastward as it de-
amplifies, but still stays fairly strong. However, there is a
major shortwave that breaks through during this time on Fri night
and Sat, bringing moderate to heavy precipitation after southerly
flow on Fri warms things up. After this storm, the GFS and ECMWF
are in less agreement, but prior they are very close. After this
strong storm passes, temperatures also cool down to near climatic
averages. Only Fri during this period has a dry forecast. So there
is a high uncertainty that the post-Sat forecast will stay wet,
with a long wave upper level ridge overhead. Messick

&&

.AVIATION...Cloud will increase during the morning, but it will be
almost all mid-level cloudiness and little or no precipitation
for the three valley airdromes. For KSUN and KDIJ, however, the
threat is a little higher, along with a possibility of -TSRA. The
clouds will be short-lived with decreasing clouds during the
afternoon. Winds not expected to do much today, especially for
the valley airports. Do not expect anything other than VFR at all
air fields today and tonight. Messick

&&

.HYDROLOGY...A Flood Warning is in effect for the Portneuf River at
Pocatello as moderate flooding is forecast this week and minor
flooding was and has been occuring. Flood watches continue for
several areas across Southeast Idaho for anticipated snowmelt due to
warmer than average temperatures. As this trend will persist today,
these watches will continue for the forseeable future. Additionally,
rain, or rain on top of snowmelt is possible today in these areas.
Flood Advisories are in effect for Central Blaine, East Central
Oneida, Southwest Bingham, Northeast Caribou and Southeast Bear Lake
County for reports of minor flooding issues in these areas.
Additional snowmelt and/or new precipitation today is possible.
NP/JAM.

&&

PIH WATCHES/WARNINGS/ADVISORIES... Flood Watch until noon MDT
today for IDZ017-019-021>025-031.

&&

$$



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