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Hazardous Weather Outlook

Hazardous Weather Outlook
National Weather Service Salt Lake City UT
610 AM MDT Tue Mar 20 2018

Cache Valley/Utah Portion-Northern Wasatch Front-
Salt Lake and Tooele Valleys-Southern Wasatch Front-
Great Salt Lake Desert and Mountains-Wasatch Mountain Valleys-
Wasatch Mountains I-80 North-Wasatch Mountains South of I-80-
Western Uinta Mountains-Wasatch Plateau/Book Cliffs-
Western Uinta Basin-Castle Country-San Rafael Swell-
Sanpete/Sevier Valleys-West Central Utah-Southwest Utah-
Utahs Dixie and Zion National Park-South Central Utah-
Glen Canyon Recreation Area/Lake Powell-Central Mountains-
Southern Mountains-Southwest Wyoming-
610 AM MDT Tue Mar 20 2018

This Hazardous Weather Outlook is for the western two thirds of
Utah and southwest Wyoming.

.DAY ONE...Today and Tonight

Dry conditions and seasonal temperatures will cover the outlook
area through tonight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Moisture working into Utah from the west will bring showers to
mainly far northern Utah and southwest Wyoming Wednesday. Breezy
south winds will develop during the afternoon and continue
Wednesday night across much of western Utah.

A developing storm system along the west coast will generate an
extended period of valley rain and mountain snow beginning
Thursday. Widespread valley rain and mountain snows will exist
Thursday evening and continue through most of the day Friday.

Persistent moderate to occasionally heavy rain is possible across
extreme southwest Utah late Thursday through Friday morning.
Significant increases in river flows are possible, though river
flooding is not expected at this time.

After a break in precipitation late Friday through Friday night,
a new round of rain and snow will develop as the main storm
system moves east across the region this weekend. The bulk of
this additional rain and snow will fall over northern Utah and
southwest Wyoming. Snow levels will be lowering as the storm
advances through the area. Significant accumulations of snow are
possible in the northern Utah mountains, with some accumulation
possible in the higher valleys through Sunday. Scattered showers
will continue across the north Sunday night then gradually
decrease during the day Monday.


Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.


For more information from NOAA/s National Weather Service visit...

For information on potential road travel impacts visit...

Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
530 AM MDT Tue Mar 20 2018

Jackson County Below 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-
Central and Southeast Park County-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
530 AM MDT Tue Mar 20 2018

This hazardous weather outlook is for northeast and north central

.DAY ONE...Today and Tonight

Light snow showers will continue off and on in the mountains, with
a couple inches of accumulation mainly above 9500 feet. Slick
travel conditions can be anticipated over the higher mountain

On the plains, it will be dry and breezy, and a warming trend will
begin with highs pushing into the lower to mid 50s today.

Strong west/northwest flow aloft across the state will produce the
mountain snow showers and breezy conditions.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.


Spotter activation will not be needed today or tonight.


Hazardous Weather Outlook
National Weather Service GRAND JUNCTION CO
443 AM MDT Tue Mar 20 2018

Lower Yampa River Basin-Central Yampa River Basin-
Roan and Tavaputs Plateaus-Elkhead and Park Mountains-
Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor-
Central Colorado River Basin-Grand and Battlement Mesas-
Gore and Elk Mountains/Central Mountain Valleys-
Central Gunnison and Uncompahgre River Basin-
West Elk and Sawatch Mountains-Flat Tops-
Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide-
Northwest San Juan Mountains-Southwest San Juan Mountains-
Paradox Valley/Lower Dolores River-
Four Corners/Upper Dolores River-Animas River Basin-
San Juan River Basin-Southeast Utah-Eastern Uinta Mountains-
Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat-
La Sal and Abajo Mountains-Canyonlands/Natural Bridges-
443 AM MDT Tue Mar 20 2018

This hazardous weather outlook is for eastern Utah and western

.DAY ONE...Today and Tonight

Snow will linger across Colorado`s northern and central mountains
today and tonight bringing an additional 1 to 3 inches of snow.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

The next chance for significant accumulating snow arrives
Wednesday night and could potentially bring prolonged periods of
rain and snow to the area into Friday.


Spotter activation will not be needed.


Hazardous Weather Outlook
National Weather Service Cheyenne WY
409 AM MDT Tue Mar 20 2018

Sierra Madre Range-Snowy Range-
409 AM MDT Tue Mar 20 2018

This hazardous weather outlook is for portions of south central


Scattered snow showers can be expected in the higher elevations of
the Sierra Madre and Snowy Ranges today. Snowfall is not expected
to be heavy with generally 1 to 2 inches of new snow expected.
Strong gusty winds today will result in wind chill readings at or
below zero through mid morning today.


Scattered snow showers and isolated thunderstorms are expected
late Thursday into Friday across the mountains of southern
Wyoming. At this time snowfall amounts don`t look to exceed a few
inches in the mountains.

.Spotter information statement...

Spotter activation will not be needed.


Hydrologic Outlook

Hydrologic Outlook
Hydrologic Outlook
National Weather Service Riverton WY
830 AM MDT Tue Mar 20 2018

....Increased snowmelt runoff below 7500 feet expected
Wednesday evening through Friday morning...

...Flooding of low lying areas possible over Star Valley
Thursday night through early Saturday morning...

Afternoon basin temperatures are expected to warm into the
middle to upper 40s Wednesday and Thursday across far western
Wyoming. Rainfall up to three quarters inch is forecasted Thursday
afternoon through early Friday morning.

Snow levels are expected to rise to 8500 to 9000 feet by Thursday
afternoon--then drop below 7500 feet by Friday evening.

Expect noticeable increases in snowmelt runoff below 7500 feet
Wednesday evening through Friday morning. Rain on snowmelt
along Star Valley will cause noticeable sharp rises along small
creeks and streams Thursday afternoon through Saturday morning.
Minor flooding is possible along low lying areas.

Residents living along small creeks and streams--especially
in Star Valley--should be vigilant for significant rises in
water levels Thursday and Friday. Road crossings along low lying
areas may become hazardous due to rising waters.

Snowmelt runoff is also expected to increase Wednesday afternoon
through Saturday morning across the Greys River Basin to include the
Porcupine Slide area.

Graphical forecasts are available at:
Visit and select the rivers & lakes tab for
graphical forecasts and additional information.


Hydrologic Outlook

Hydrologic Outlook
National Weather Service Great Falls MT
351 AM MDT Tue Mar 20 2018

...Increased runoff likely once again this week across portions
of Central and Southwest Montana...

Temperatures this past weekend cooled some, which helped to slow
the rate of snowmelt to some extent. However, moderating
temperatures this week will lead to increasing snowmelt rates once
again, especially at low- and mid-elevations. In addition, there
is the potential for a decent precipitation event later this week,
especially across Southwest Montana south of Interstate 90. If
this does occur, it could enhance runoff rates locally, especially
in valley locations.

If confidence in the potential of flooding continues to increase,
Flood Watches or Advisories may be necessary, so stay tuned for
later updates. Regardless, those living in flood prone areas,
especially near fields and streams, are encouraged to prepare for
new or additional flooding through the week.

If flooding is observed, please report it to local law enforcement,
and ask them to pass it on to the National Weather Service in Great



Hydrologic Outlook

Hydrologic Outlook
National Weather Service Pocatello ID
129 PM MDT Mon Mar 19 2018

...Potential For Rising River and Stream Levels, along With Sheet
Flooding Increasing This Week..

As warmer weather returns along with gusty winds through Thursday,
snowmelt is expected to pick up across eastern Idaho. This should
increase runoff on multiple rivers and streams, although river and
stream flooding is not forecast at this time. In areas where the
ground is still frozen with existing snow cover, sheet flooding is
certainly possible. The risk for both increases Wednesday
and especially Thursday as one or more rounds of rain and snow are
anticipated. Snow levels will be quite high, rain on top of snow
could seen above 7000 feet if not closer to 8000 feet by Thursday.
While details are still left to be worked out, including
precipitation amounts, it does look to be quite wet in a 24 to 48
hour period.

To minimize your risk of flooding, make sure you keep drains open.
Also you can create runoff ditches to direct flowing water. To
prevent basement flooding, remove snow from around your



318 PM MDT Sun Mar 18 2018

...Snow Melt Impacts Expected to Increase by Mid Week...

Warming temperatures through mid week are expected to increase
low elevation snow melt. The potential for impacts from this melt
will increase as well, especially for areas east of Billings where
the snow pack is heaviest.

Water flowing overland and accumulating in low lying areas may
result in low land flooding, water flowing over roadways, and
basement flooding. Increased runoff from snowmelt moving into
creeks and streams will increase the potential for ice jam
flooding. In areas where ice jams are already occuring this could
increase flood waters or cause the ice jam to break up. Muddy
roads may strand vehicles and impede or cut off travel in some
rural areas.

The severity of these impacts will depend on the pace of the snow
melt. High temperatures are expect to be in the 40 to 55 degree
range for many areas by Wednesday.

Now is the time to move equipment and livestock out of low lying
areas, and away from waterways. Move heavy accumulations of snow
away from home foundations, and take steps to prevent water making
it into basements.

Stay tuned to the forecast for the latest temperature trends. If
flooding is observed, report it to local law enforcement and ask
them to pass it on to the National Weather Service.


U.S. Dept. of Commerce
NOAA National Weather Service
1325 East West Highway
Silver Spring, MD 20910
Page last modified: June 2, 2009
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