Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 200913
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
313 AM MDT Sun May 20 2018

.SHORT TERM...Today through Tuesday Night. There isn`t much else
to say but...more showers and thunderstorms to start out this
week. Most of the development today occurs across the South
Hills/Albion Mountains north across the Magic Valley into the
central mountains. The higher resolution models differ a bit on
the extent of thunderstorms across Snake Plain, mainly from
Craters to Pocatello and on to the northeast. The HRRR has a lot
more activity vs the 3km NAM. Yesterday, we had a similar issue
and ended up somewhere in between. We took a similar approach for
today in that area with at least scattered showers and storms. As
you head toward the Wyoming border, the risk drops off quite a bit
overall. With deep moisture (at least by May standards) remaining,
locally heavy rainfall/flooding remains a risk, along with small
hail and gusty winds. With a subtle increase in steering winds,
storms farther west could be a little more organized and
stronger. Does that mean we might see a couple of severe storms?
Perhaps, but not likely. For tonight, the bulk of the showers and
storms remained generally west of a Monida-Malta line with a few
lingering showers/storms farther east.

Shower and thunderstorm coverage remains a bit less certain for
the moment on Monday. The low is still forecast to dig quickly
toward the southern Sierras. There will still be plenty of heat
and humidity for showers and thunderstorms. The focus seems to be
in the central mountains and along the Montana border. There is
mixed results on what MIGHT help elsewhere. With the amount of
moisture in place across eastern Idaho, we should see at least
isolated showers and storms elsewhere. Based on that notion, we
did trend the forecast that direction. The same risks persist with
stronger storms. By Tuesday, the low turns northeast and scoots
toward eastern Idaho. Look for an increase in showers and
thunderstorms across the board especially later in the afternoon
into the nighttime hours. Keyes


.LONG TERM...Wednesday through Sunday.

Low pressure over the region will produce scattered showers and
thunderstorms for Wednesday and Thursday. The low will move into the
northern Plains on Friday. Isolated thunderstorms remain possible on
Friday, mainly across the high country during the afternoon, as
there is so much moisture around from recent rains. Saturday looks
dry as high pressure moves into the region. Sunday could be dry as
well, however the models are showing a new low arriving in the
Pacific northwest on Sunday. A more southerly track as some runs of
the European have shown would produce showers and thunderstorms on
Sunday. However, a more northerly track as shown by the GFS would
limit rain potential to the central Idaho mountains. Current
forecast will keep a threat in almost areawide for Sunday.

Valle

&&

.AVIATION...Low pressure over the area will continue the threat for
thunderstorms this afternoon and evening. Some models show showers
in the SUN and BYI areas this morning. Gusty winds, low ceilings and
visibilities are likely near thunderstorms. Otherwise, expect VFR
conditions.

Valle


&&

.HYDROLOGY...Rivers and streams remain pretty stable so far this
weekend, but still running high, fast and cold. We still have
minor flooding issues along the Big Wood River, where the FLOOD
ADVISORY will remain in place until the situation changes. We will
still be watching for rises due to snowmelt and/or heavy rain in
the coming days. Right now, heavy rain will be more localized. As
we head through the week, that should change (at least
temporarily) as more widespread rain returns Tuesday and Wednesday
across eastern Idaho. That could mean rivers that are bankfull now
could potentially go to flood stage, or at least push more
creek/rivers to bankfull conditions. Keyes


&&

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

$$



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