Winter Storm Warning 2, NWS Denver/Boulder, CO

919 
WWUS45 KBOU 061016
WSWBOU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Denver CO
316 AM MST Tue Feb 6 2018


COZ034-061700-
/O.CAN.KBOU.WS.W.0002.000000T0000Z-180206T1200Z/
/O.NEW.KBOU.WW.Y.0010.180206T1016Z-180206T1700Z/
The Mountains of Summit County, the Mosquito Range, and the
Indian Peaks-
Including the cities of Berthoud Pass, Breckenridge, 
East Slopes Mosquito Range, East Slopes Southern Gore Range, 
Eisenhower Tunnel, Indian Peaks, Kenosha Mountains, Mount Evans, 
Williams Fork Mountains, and Winter Park
316 AM MST Tue Feb 6 2018

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 10 AM MST THIS
MORNING...
...WINTER STORM WARNING IS CANCELLED...

* WHAT...Snow occurring. Plan on slippery road conditions.
  Additional snow accumulations of 3 to 6 inches are expected.

* WHERE...The Mountains of Summit County, the Mosquito Range, the
  Indian Peaks and I-70 Mountain Corridor.

* WHEN...Until 10 AM MST this morning.

* ADDITIONAL DETAILS...Be prepared for reduced visibilities at 
  times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

$$

COZ031-033-061130-
/O.CAN.KBOU.WW.Y.0009.000000T0000Z-180206T1200Z/
Rabbit Ears Pass-
Rocky Mountain National Park and the Medicine Bow Range-
Including the cities of East Slopes Park and Northern Gore
Ranges, Gore Pass, Rabbit Ears Pass, Cameron Pass, 
Laramie and Medicine Bow Mountains, Rabbit Ears Range, 
Rocky Mountain National Park, and Willow Creek Pass
316 AM MST Tue Feb 6 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

Periods of light snow will continue through the day with
additional accumulations of 1 to 4 inches. 

$$

Area Forecast Discussion
National Weather Service Denver/Boulder CO
236 PM MST Mon Feb 5 2018

.SHORT TERM...(This evening through Tuesday)
Issued at 230 PM MST Mon Feb 5 2018

Cold front recently swept southwest through the area with
northeast wind gusts to 40 mph. Temperatures behind the front
quickly dropped into the 30s. As cold air advection continues
behind the front, temperatures will eventually fall into the 20s.
Radar showing snow bands over southern Wyoming and far northern
Colorado at this time. Models indicate lapse rates of 7-9 deg C/KM
from 500mb to 700mb, so expect snow showers and bands of snow to
continue into the evening. Short term models showing the snow
bands to the north slowly shifting eastward before dissipating.
They also have snow forming late tonight along and south of I-70
east of Denver. Will go with 2-3 inches of snow at these
locations. Elsewhere, plan on keeping snowfall amounts around an
inch or less.

For the mountains, a moist northwest flow aloft will continue to
produce snow over the mountains. Embedded snow bands will produce
locally heavy snow with snowfall rates of 2 inches per hour.
Moisture and snowfall will decrease after midnight with just a few
pockets of light snow remaining around sunrise Tuesday morning.
Snowfall amounts will greatly vary due showery nature of the snow.
In general, an additional 3-6 inches of snow is expected with
locally up to 10 inches. Will keep the Winter Weather Advisory
through the night and expire it at 12Z.

.LONG TERM...(Tuesday night through Monday)
Issued at 230 PM MST Mon Feb 5 2018

Tuesday night, mid level qg subsidence will move across the region
as the trough axis exits the state. The flow will remain
northwesterly and in the moderate category. NAM12 spatial cross-
sections show enough moisture below 600 mb to keep some light
snow going along the west facing slopes. Winds above timberline
gusting to around 45 mph overnight. Across the northeast plains,
models still show sufficient boundary layer moisture for either
stratus or fog Tuesday night into Wednesday morning, especially
north and east of Denver. Wednesday morning the moisture will be
east of an inverted surface trough parked over eastern Larimer and
eastern Boulder counties at that time. The flow aloft will remain
northwesterly but drier and more subsident for Wednesday and
Thursday. Just isolated shower coverage along the north and west
facing slopes of the Medicine Bow Range. Drier and warmer across
the northeast plains of Colorado as well. Thursday night into
Friday, the upper ridge over the eastern Pacific flattens and the
jetstream sags south over the central Rockies. Weak mid level qg
ascent will brush across the state with a cold front backing into
the northeast plains of Colorado Friday morning. Highest pops will
be over the northern half of the cwa at that time. The flow aloft
will increase and become southwesterly Saturday and Saturday
night, with a trough dropping out of the Pacific Northwest and
splitting to the west and north of Colorado Saturday night.
Another frontal passage with a better chance of snow across the
entire cwa at that time. An upper level ridge builds over CO
Sunday as the western part of the splitting trough drops into the
Desert Southwest and a dry southerly flow spreads over the area.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 230 PM MST Mon Feb 5 2018

Gusty northeast winds behind a cold front will shift to the east
around 00Z and remain easterly through most of the night. A Denver
Cyclone will bring light shifting winds around 12Z. Low clouds
are expected form around or a little after 00Z, there will be
slight chance for freezing drizzle this evening 00-06Z. Most
precipitation should fall as snow. Airmass will be unstable and
will produce snow showers tonight. Best chance for snow will be
over eastern Colorado. For the Denver airports, if a heavy snow
band hits an airport and quick 2-3 inches of snow will be possible
in a couple of hours. Outside of the snow bands, snowfall is
expected to be light.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 AM MST Tuesday for COZ031-033-
034.

&&

SHORT TERM...Meier
LONG TERM...Cooper
AVIATION...Meier

Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
607 AM MST Mon Feb 5 2018

COZ030>051-061315-
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
County-
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
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
607 AM MST Mon Feb 5 2018

...SNOW CONTINUING IN THE MOUNTAINS TODAY AND TONIGHT...

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

Another round of Pacific moisture is moving into the northern
Colorado mountains today which will produce light to moderate snow
today and tonight. Winds aloft are also strong which will produce
gusty winds over peaks and ridges. New snow accumulations through
Tuesday morning are expected to range from 6 to 12 inches with
local amounts up to 15 inches. The gusty winds above timberline
will produce areas of blowing snow and reduced visibilities. West
winds 25 to 35 mph will occur with gusts up to 60 mph above
timberline. People travelling in the mountains should be
prepared for winter travel and slick road conditions today and
tonight.

On the plains, a cold front will move in this afternoon bringing
cooler temperatures and gusty northeast winds. By this evening,
clouds will increase with snow developing. An inch or two of new
snow is expected as a weather disturbance aloft passes over the
region.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Snow will linger in the mountains on Tuesday but end over the
plains in the morning. Warmer and drier weather is expected
across the area Wednesday and Thursday. The next system may affect
the area late Friday into Saturday bringing colder weather along
with a chance of snow.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight.

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
1206 PM MST MON FEB 5 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1000 AM     SNOW             2 SSE BRECKENRIDGE      39.47N 106.03W
02/05/2018  M2.1 INCH        SUMMIT             CO   TRAINED SPOTTER

0725 AM     NON-TSTM WND GST 1 ESE WHEAT RIDGE       39.77N 105.07W
02/05/2018  M55.00 MPH       JEFFERSON          CO   TRAINED SPOTTER

0225 AM     NON-TSTM WND GST 4 ENE NEDERLAND         39.99N 105.45W
02/05/2018  M68.00 MPH       BOULDER            CO   TRAINED SPOTTER

1251 AM     NON-TSTM WND GST 4 ENE NEDERLAND         39.99N 105.45W
02/05/2018  M66.00 MPH       BOULDER            CO   TRAINED SPOTTER

0504 PM     SNOW             JULESBURG               40.99N 102.26W
02/04/2018  M5.0 INCH        SEDGWICK           CO   TRAINED SPOTTER

            5 INCHES OVER 12 HOURS

&&

CL