Flood in Idaho, March 1 to 4, 2019

Area Forecast Discussion
National Weather Service Pocatello ID
342 AM MST Fri Mar 1 2019

.SHORT TERM...Today through Sunday. Expect an overall quiet
period with cool temperatures and limited snow. Early today look
for weak high pressure before a weak wave starts to move across
our western areas by late this afternoon. Late this afternoon into
the evening, expect around 1 inch of snow across the Central
mountains/Big Lost ranges and Southern Highlands with 2 to 4
inches of snow across our Eastern Highlands along the Wyoming
border, particularly for Caribou and Wasatch mountains. Light snow
across lower areas is possible, but little, if any, accumulation
is expected. Expect breezy and mostly dry northwest flow across
the area on Saturday and Sunday. The Island Park area could see
some light snow on Sunday. Expect temperatures around 10 degrees
below normal through the period. Wyatt

.LONG TERM...Monday through next Friday. Ahead of the next storm,
moisture will be limited Monday and Tuesday. The ECMWF is bone dry
while the GFS has some very light snow mainly across the mountains,
especially the Sawtooths and in the South Hills. The Blend of Models
looks very much like the GFS so we included that small potential in
the forecast. By Tuesday night and Wednesday, we will be back in the
soup with the middle of next week looking pretty wet across eastern
Idaho. As that next low/trough of low pressure develops along the
coast, we develop southwest flow and tap into moisture from the
Pacific. Looking at the amount of moisture getting pulled into the
state, we will be on the northern fringe of the deepest moisture
...with most of it staying south.  I am sure we will see this
changing a bit until we get closer. What does that mean? 1) We will
see more snow in the mountains and rain/snow for the lower
elevations. 2) We should NOT see the extreme amounts of moisture we
saw with this last storm. 3) Southwest flow will target the
Sawtooths and Island Park. 4) There will be wind so expect blowing
and drifting issues, but where and how low in elevation we see that
is not clear right now. The general pattern of low pressure over the
West persists through the end of next week. That means each day will
bring a chance of rain or snow to eastern Idaho. Again, we want to
stress we are not expecting a repeat of this past storm...but some
areas have already seen records amounts of snow and blowing/drifting
snow. Anything, even lesser amounts of it, may easily be a big
impact on any clean up or resources. Stay tuned. Keyes

&&

.AVIATION...We can expect mostly VFR weather today, although
showers/pockets of precipitation will redevelop later this
afternoon and evening. For right now with coverage being lower, we
will opt to go with VCSH for any TAF site that could be impacted. IF
precipitation ends up occurring on site at any particular time,
dropping into MVFR is certainly possible. Keyes

&&

.HYDROLOGY...Temperatures are in the mid to upper twenties across
the area currently this morning and are expected to drop to the low
twenties for morning lows for areas affected by flooding.
This afternoon these areas will reach above freezing, mid to
upper thirties (maybe low forties for Minidoka county), but should
drop below freezing fairly quickly with cloud cover and a weak
system expected later in the afternoon into the early evening.
With overall cold temperatures and no rain expected, water levels
will drop. Some areas will see significant improvement by this
afternoon. For others, particularly Minidoka and Bingham counties,
it may take all weekend to fully drop. We will reevaluate all
flood advisories and warnings for Lincoln, Minidoka, Bingham and
Jefferson counties later today. Wyatt

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.
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