Area Forecast Discussion
Issued by NWS Riverton, WY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

000
FXUS65 KRIW 170500
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1100 PM MDT Tue May 16 2017

.SHORT TERM...(This evening through Friday)
Issued at 155 PM MDT Tue May 16 2017

Upper level low pressure trough extending from western Montana
south southeast across eastern Idaho, eastern Utah into 4 Corners
will sweep east across western and central Wyoming this evening
spreading showers and isolated thunderstorms with small hail and
gusty winds. Most areas will see light precipitation while the
northern and central mountains will see mostly snow. As the first
low pressure trough moves east, a second stronger low pressure
storm system over the Pacific Northwest will dig rapidly southeast
into the Great Basin through Wednesday. Precipitation will
increase across the west and northern mountains with snow levels
around 8500 t0 9000 feet. Have continued winter storm watch for
the Absaroka and Bighorn mountains. Parts of the south and central
areas will likely get dry slotted initially Wednesday through
Wednesday night with precipitation over the north spreading south
across the lower elevations of Johnson and Natrona counties with
widespread rain. The dry slot will fill in late Wednesday night
and Thursday morning with rain spreading across Hot Springs,
Fremont and eastern Sweetwater counties. Some snow may occur down
to 6000 feet to 6500 feet, but mostly rain up to three quarters of
an inch is expected with local one inch amounts. Precipitation
expected to continue through Thursday night with colder
temperatures. Late Thursday night and Friday the precipitation
will taper off from west to east with some low clouds lingering
over the area with cold temperatures remaining.

.LONG TERM...(Friday night through Tuesday)
Issued at 155 PM MDT Tue May 16 2017

Our large and cold storm system will be pulling off to the east to
start this period with improving conds. It`ll be cold Friday night
but Saturday will be much improved with just some instability
showers forming over and near the higher terrain. The improvement
will be short lived as active nw flow with multiple embedded se
moving shortwaves start to impact the area late in the weekend
through early next week. The first one impacts the area Saturday
night into Sunday as it digs west of the divide with increasing
instability on Sunday along and west of the divide where
thunderstorms are a good bet. The associated cold front coming down
east of the divide will also help with some weak upslope/convergence
to aid in Sunday showers/storms. Another s to sewd moving shortwave
drops down Monday into Tuesday with more unsettled weather,
especially the north and east half.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday)
Issued at 1055 PM MDT Tue May 16 2017

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

Rain and snow showers will occur 18Z in most areas. Then the focus
of the rain and snow will be over northwest WY through 06Z Thursday.
The rest of the region will see isolated rain or snow showers after
18Z through 06Z Thursday. Areas of MVFR/IFR conditions will occur
through 18Z with improvement to VFR conditions in all but NW WY
after 18Z. Mountains will be obscured in NW WY through the period.
Windy conditions will be common Wednesday in southwest WY through
00Z Thurs. Please see terminal forecasts for details.

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

Isolated showers will occur through 18Z. Showers will become more
numerous over northern WY Wednesday afternoon and continue through
06Z Thursday. Expect areas of MVFR conditions over the north
Wednesday and Wed night. Windy conditions will occur in many
locations Wednesday with the wind decreasing after 00Z Thursday.

&&

.FIRE WEATHER...
Issued AT 155 PM MDT Tue May 16 2017

Upper level low pressure trough extending from western Montana
south southeast across eastern Idaho, eastern Utah into 4 Corners
will sweep east across western and central Wyoming this evening
spreading showers and isolated thunderstorms with small hail and
gusty winds. Most areas will see light precipitation while the
northern and central mountains will see mostly snow. As the first
low pressure trough moves east, a second stronger low pressure
storm system over the Pacific Northwest will dig rapidly southeast
into the Great Basin through Wednesday. Precipitation will
increase across the west and northern mountains with snow levels
around 8500 t0 9000 feet. Have continued winter storm watch for
the Absaroka and Bighorn mountains. Parts of the south and central
areas will likely get dry slotted initially Wednesday through
Wednesday night with precipitation over the north spreading south
across the lower elevations of Johnson and Natrona counties with
widespread rain. The dry slot will fill in late Wednesday night
and Thursday morning with rain spreading across Hot Springs,
Fremont and eastern Sweetwater counties. Some snow may occur down
to 6000 feet to 6500 feet, but mostly rain up to three quarters of
an inch is expected with local one inch amounts. Precipitation
expected to continue through Thursday night with colder
temperatures. Late Thursday night and Friday the precipitation
will taper off from west to east with some low clouds lingering
over the area with cold temperatures remaining. As clouds and
precipitation increase, mixing heights will decrease with
generally poor smoke dispersal expected.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...

Winter Weather Advisory until 6 PM MDT Wednesday for WYZ012-024.

Flood Watch from Wednesday evening through late Thursday night for
WYZ003>006-008-010-011-020.

Winter Storm Watch from 6 AM MDT Wednesday through Thursday
afternoon for WYZ008-009.

Winter Weather Advisory until 6 AM MDT Thursday for WYZ001.

Winter Storm Watch from 6 AM MDT Wednesday through Thursday morning
for WYZ002.


&&

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.