Local Forecast Discussion

000
FXUS65 KPIH 181938
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
138 PM MDT Mon Jun 18 2018

.DISCUSSION...A low pressure system over southwestern Idaho will
track into southwestern Montana by Tuesday morning. Satellite and
radar imagery pretty well highlight the circular fashion of showers
and thunderstorms around this disturbance. A Flood Watch remains in
effect for the Custer County area and the Upper Snake Highlands,
including Spencer, Island Park, and Driggs until midnight tonight.
The trend is towards less forecast rainfall the next 24-36 hours. A
few areas may see an additional half inch of rain. Portions of the
Central Mountains and Upper Snake Highlands have received over two
inches of rain with localized amounts around three inches over the.
past 72 hours. Wednesday afternoon scattered showers will linger over
the northern mountain areas while a transitory high pressure ridge
moves quickly through. Models are still having trouble with this
weak flow pattern. The latest GFS run brings a disturbance through
central Idaho and and Monida Pass to Island Park Thursday night and
Friday. This is followed quickly by another disturbance on Saturday.
The odd part is some of this activity was in the models a couple
days back, then disappeared and reappeared. The consensus looks to be
that the storm track will be across the northern half of Idaho,
close enough for showers in our area. For now, made few changes to
the extended to try an time these events. RS

&&

.AVIATION...With the low still in place, several rounds of showers
and thunderstorms will persist, although we COULD see a potential
break overnight in many places. That is IF the high resolution
models are correct. Even if there is a break, it appears with the
amount of moisture around low clouds are possible. The general
pattern is still in play: VFR weather is the norm. We could see
MVFR/IFR ceilings or visibility with either heavier showers/storms
AND low clouds/patchy fog where any breaks in rainfall occur.  The
latter scenario will be confined to tonight and Tuesday morning.
Keyes

&&

.FIRE WEATHER...The persistent low will finally begin a slow exit
tomorrow and Wednesday. Until then, multiple rounds of showers and
thunderstorms will continue with locally heavy rainfall possible.
Even with the ridge building in for Wednesday, look for showers and
isolated thunderstorms across Zones 422, 475 and 476. Similar
conditions for Zone 411 and the eastern half of Zones 410 and 413.
These storms will have wetting rains but nothing like what has been
experienced since late last week. By Thursday and Friday, another
storm drops across the Panhandle and into Wyoming.  This will be
bring yet another round of rain and isolated thunderstorms generally
the same locations. By the weekend, the potential forecast based on
the models is 180 from each other. One has dry and warmer with a
ridge developing. The other brings another closed low and more
precipitation our way. We went with showers and isolated
thunderstorms possible for all mountain fire zones, but gradually
decreasing overall. If we indeed get the drier pattern to stick
around, we would end up with a lower humidity/breezy Friday across
most of central and eastern Idaho with gusts 25-35mph currently in
the forecast.  Keyes

&&


.PIH WATCHES/WARNINGS/ADVISORIES...
Flood Watch until midnight MDT tonight for IDZ018-019-032.

&&

$$

NWS PIH Office Area Forecast Discussion