Suppression Forecast
Issued by NWS Riverton, WY

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FNUS75 KRIW 161416
FWSRIW

Spot Forecast for GRTE Winter Road Conditions...Grand Teton National Park
National Weather Service Riverton WY
716 AM MST Sun Feb 16 2020

Forecast is based on forecast start time of 0800 MST on February 16.
If conditions become unrepresentative...contact the National Weather
Service.

...WINTER STORM WARNING IN EFFECT UNTIL 11 PM MST THIS EVENING...

Snow will continue through the evening. The heaviest snow is
expected to occur between 10 AM and 3 PM when snowfall rates
could approach 1 inch an hour for a brief period. Expect another
3 to 6 inches of snow today. Southerly winds will increase to
between 15 and 20 mph with gust around 30 to 35 mph by early
afternoon. This will cause areas of blowing and drifting of snow.
The widespread snow will come to an end by around 5 PM, but snow
showers will linger through midnight. Also the wind will remain
strong southerly through about 10 PM.

.DISCUSSION...

...Thunderstorms imply strong gusty and erratic winds...
...Haines index is high level haines both day and night...

FORECASTER...Murrell

.TODAY...

Sky/weather.........Snow. Moderate to heavy at times.
Max temperature.....29-32.
Min humidity........80 percent.
20-foot winds.......South southwest around 10 increasing
                    to between 15 and 20 mph with gusts
                    30 to 35 mph by early afternoon.
Ridge top winds.....Southwest 20 to 30 mph.
Snow Accumulation...3 to 6 inches of new snow.

TIME (MST)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........93  94  95  95  96  97  96  95  94  93  92  91
Weather cov.....DEF DEF DEF DEF DEF DEF DEF DEF DEF DEF DEF DEF
Weather type....SN  SN  SN  SN  SN  SN  SN  SN  SN  SN  SN  SN
Tstm cov........
Temp............25  25  27  29  29  29  30  30  30  30  30  29
RH..............96  83  75  71  71  77  80  83  82  78  78  78
20 FT wind dir..SW  SW  SW  SW  SW  SW  SW  SW  SW  SW  W   W
20 FT wind spd..4   10  10  10  13  14  18  20  22  21  21  20
20 FT wind gust.17  16  16  16  18  20  25  26  30  35  35  35

.TONIGHT...

Sky/weather.........Cloudy (80-90 percent). Snow early in the
                    evening, then snow likely late in the evening.
                    Chance of snow in the late evening and
                    overnight.
Min temperature.....6-9.
Max humidity........90-93 percent.
20-foot winds.......West winds 8 to 9 mph with gusts to around 12
                    mph early in the evening becoming
                    downslope/downvalley 4-7 mph.
Ridge top winds.....West 10 to 15 mph.

TIME (MST)      6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........89  88  87  85  84  83  82  82  82  81  81  81
Weather cov.....DEF DEF DEF LKY CHC CHC CHC CHC CHC CHC CHC CHC
Weather type....SN  SN  SN  SN  SN  SN  SN  SN  SN  SN  SN  SN
Tstm cov........
Temp............28  26  25  23  20  18  16  15  13  11  10  9
RH..............83  89  93  92  89  86  86  86  88  89  90  90
20 FT wind dir..SW  SW  SW  SW  SW   W   W   W   W   W   W   W
20 FT wind spd..15  15  16  17  14  12  12  10   6   6   5   5
20 FT wind gust.24  25  26  28  26  20  18  20   7   7   6   6

.WASHINGTONS BIRTHDAY...

Sky/weather.........Mostly cloudy (70-80 percent). Chance of snow
                    in the morning and early afternoon, then slight
                    chance of snow late in the afternoon.
Max temperature.....21-24.
Min humidity........53-56 percent.
20-foot winds.......Upslope/upvalley 5-9 mph.
Ridge top winds.....West around 10 mph.

TIME (MST)      6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........81  81  81  82  82  82  79  77  74  71  69  66
Weather cov.....CHC CHC CHC CHC CHC CHC CHC CHC CHC SCH
Weather type....SN  SN  SN  SN  SN  SN  SN  SN  SN  SN
Tstm cov........
Temp............8   7   8   10  14  17  20  21  22  22  20  18
RH..............91  91  89  84  77  69  63  58  56  57  60  64
20 FT wind dir..W   W   W   W   W   W   W   W   W   W   W   W
20 FT wind spd..5   5   5   5   5   5   5   5   5   5   5   5
20 FT wind gust.6   6   6   6   6   6   6   6   6   6   6   6

.FORECAST DAYS 3 THROUGH 5...
.MONDAY NIGHT...
Colder. Mostly cloudy. Slight chance of snow overnight. Lows
around 3 below. Winds generally less than 10 mph.
.TUESDAY...
Partly cloudy. Lows around 4 below. Highs in the lower 20s. Winds
generally less than 10 mph.
.WEDNESDAY...
Clear. Lows around 6 below. Highs in the mid 20s. Winds generally
less than 10 mph.
.THURSDAY...
Mostly clear. Lows around 2. Highs in the upper 20s. Winds
generally less than 10 mph.

$$
Forecaster...Murrell
Requested by...Sam Newman
Type of request...OTHER
.TAG 2002365.0/RIW
.DELDT 02/16/20
.EMAIL GRTE_Dispatch@nps.gov


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