Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 260517
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1017 PM MST Fri Nov 25 2016

.Short Term...Tonight Through Saturday (Issued at 134 PM MST)

High pressure will be over western and central Wyoming tonight
with some high clouds. Saturday morning southwest flow aloft will
move in ahead of a Pacific low pressure trough with windy
conditions forming along and near the east slopes of the mountains
and through the wind corridor across Sweetwater...southern Fremont
and Natrona counties. Wind gusts of 40 to 45 mph are expected.
Downslope winds will cause warming...while parts of the Bighorn
and Wind River basins will remain trapped by temperature
inversions with colder temperatures.

.Long Term...Saturday Night Through Friday

As the Pacific low pressure trough deepens and shifts east towards
Wyoming, clouds will begin to move northeast into southwest
Wyoming Saturday evening moving up from the Great Basin. Some
light rain and snow showers will move into the southwest late
Saturday night becoming more widespread and moving into the
western and central mountains Sunday morning. Much of the south
and west will see rain and snow showers, mainly snow above 7000
feet Sunday afternoon and evening. A cold front will begin moving
south from Montana in the afternoon as well. The flow aloft will
shift to the northwest as a low develops to the south of Wyoming
and ejects rapidly to the east across the Dakotas. Much of the
area will have light snow showers Sunday night with colder
temperatures moving in. Another Pacific trough will move east from
the Pacific Northwest Monday with snow spreading across the
western mountains and partial clearing occurring in the east with
windy areas across the south. This Pacific trough will drop into
the Great Basin Monday night with another wind shift to the north
and northwest bringing colder air and areas of snow spreading
south across the area through the night and Tuesday morning. The
precipitation will taper off from the northwest to southeast as
high pressure begins to move in from the west. This will bring
clearing through Wednesday. Late Wednesday afternoon and
evening...another Pacific trough will move into Idaho with snow
moving into the western mountains and winds increasing along and
near the east slopes of the mountains and through the wind
corridor across Sweetwater...southern Fremont and Natrona
counties. Slowly the trough will deepen and expand across the area
Wednesday night and Thursday with light snow increasing across the
area as temperatures fall with north to northwest winds. More cold
air will come south from Montana Thursday night with an increased
chance of light snow east of the Continental divide into Friday
morning with clearing and colder temperatures Friday as high
pressure again builds in from the west.

&&

.Aviation.../06Z Issuance/

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

VFR conditions to prevail through Saturday evening. LLWS is
expected at or near most terminal sites through 00Z Sunday.
Clouds will be on the increase after 00Z Sunday with a
few rain or snow showers developing in SW WY toward 06Z Sunday.

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR conditions will prevail through Saturday evening. KCPR
airport will continue with a gusty surface wind through 00Z
Sunday...then gradually decreasing speeds after 00Z Sun.
LLWS is expected at some of the terminal sites through
Saturday afternoon. See the latest terminal forecasts for
details.

&&

.Fire Weather...

High pressure will be over western and central Wyoming tonight
with some high clouds. Saturday morning southwest flow aloft will
move in ahead of a Pacific low pressure trough with windy
conditions forming along and near the east slopes of the mountains
and through the wind corridor across Sweetwater...southern Fremont
and Natrona counties. Wind gusts of 40 to 45 mph are expected.
Downslope winds will cause warming...while parts of the Bighorn
and Wind River basins will remain trapped by temperature
inversions with colder temperatures. The windy areas will see
fair to good smoke dispersal Friday afternoon with the trapped
valleys and basins experiencing poor smoke dispersal.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

SHORT TERM...C.Baker
LONG TERM...C.Baker
AVIATION...AR
FIRE WEATHER...C.Baker



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