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 Mon Oct 23 2017

.SHORT TERM...Tonight through Wednesday. We remain under dry
northwest flow, as the ridge doesn`t quite push far enough east
before the next storm breaks it down. We had some stratus and fog
this morning and we went with FOG ONLY late tonight and Tuesday
morning vs both for now. This could impact a good portion of the
Snake Plain, lower elevations of the Upper Snake and southeast
highlands, and the Stanley Basin. It will be dense in some areas
and depending on temperatures, could becoming freezing fog and
leave a few slick spots and surfaces. More is possible across the
Snake Plain and Stanley Basin Wednesday morning. Drier air will
lead to more cold morning and warmer afternoons especially where
inversions develop at night. Afternoon temperatures will back in
the 60s by Wednesday at lower elevations, with mountains in the
40s and 50s.

For Wednesday night and Thursday. That storm that breaks down the
ridge quickly sweeps southeast along the Divide. Everything still
is trending drier (except for some showers along the Divide)
EXCEPT the European model, which still wants to produce showers
farther south into the central mountains as well as around Bear
Lake and City of Rocks. We are keeping the trend of lowering the
chance of showers across the north, while keeping a slight chance
for those areas to the south. We will be cooler and breezy as the
flow becomes almost straight from the north and more oriented out
of Canada, 5-10 degrees cooler vs Wednesday. Keyes

.LONG TERM...Thu night through next Mon night. Large west
coast/eastern Pacific blocking high continues in the longwave
pattern with a less-deep upper level ridge staying over Hudson`s Bay
to the mid-west. There are indications of a slight retrograde
movement that might bring the trough closer to the Gem State.
Factoring in the short waves, the operational GFS and ECMWF keep
conditions dry until Sun night, with a peak on Mon. However, highest
PoPs are slight chance, mainly near the border with Montana/Wyoming,
nearest to the main trough. All the clear skies and calm wind will
mean a warming and drying as subsidence continues; by the weekend,
temperatures should be 10 to 15 deg F above normal, in the middle to
upper 60s. Messick


.AVIATION...Light wind made stratus more difficult to evaporate, but
it generally has and continued drying means no chance of stratus
or fog. Once wind settles down this evening, light wind expected
for the rest of the period. Messick


.FIRE WEATHER...High pressure will produce dry weather and light
winds through Wednesday. A cold front will arrive Wednesday night
and Thursday producing the next threat for showers.




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