forecasting tricks for the vail valley (february 4, 2014)

Forecasting tricks for the Vail Valley.

Photo: Connor Walberg ActionPhotoSchool.com

Meteorologist Joel Gratz

1960

2005

I want to remove the mystery of Colorado weather.

Hi, I’m Joel Gratz.I grew up in Pennsylvania, ski raced and instructed, then moved to Colorado after college.

And I started to miss powder days due to inaccurate forecasts.

Dec 2007 28 people email list

2008-2009 500 people email list

2009-2010 245,000 pageviews

2010-2011 1,315,000 pageviews

2011-2012 3,330,000 pageviews

2012-2013 12,000,000 pageviews

2013-2014 ~18,000,000 pageviews

So I learned how to forecast in Colorado, and started to share.

This is where we look for El Nino or La Nina.

Courtesy: Mike Baker, NWS Boulder

Storm tracks for La Nina.

Courtesy: Mike Baker, NWS Boulder

Storm tracks for El Nino.

But it is (probably) a La Nada.

Courtesy: Mike Baker, NWS Boulder

Storm tracks for La Nada.

It snowed in Aspen during September.

Of the past 22 Septembers with snow, 19 of the

ensuing winters have been average or above.

- Cory Gates, AspenWeather.net

Perhaps there’s another clue. !

We set a snowfall record in April and a rainfall record in September for Boulder. Does this tell us anything about winter snow in the mountains?

Each line shows amount of snow on the ground for various weather stations, during winters after heavy precipitation in Boulder.

100%

110%

120%

130%

140%

150%

160%

Dec 1 Jan 1 Feb 1 Mar 1 April 1

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!!

!_[(

Ouray

Aspen

Ouray

Pueblo

Durango

Alamosa

Boulder

Gunnison

Fort Collins

Grand Junction

Colorado Springs

Glenwood Springs

Steamboat Springs

Arkansas

South Platte

Gunnison

Upper Colorado Headwaters

Yampa and White

Upper Rio Grande

San Miguel, Dolores,

Animas and San Juan

Laramie and North Platte

114

123

84

115

82

121

105

118

Denver

§̈¦76

§̈¦25

ColoradoSNOTEL Current Snow Water Equivalent (SWE) % of Normal

§̈¦70

0 20 40 60 80 10010Miles

Provisional Data Subject to Revision

Current Snow WaterEquivalent (SWE)Basin-wide Percentof 1981-2010 Median

unavailable *

<50%

50 - 69%

70 - 89%

90 - 109%

110 - 129%

130 - 149%

>=150%

Feb 04, 2014

* Data unavailable at time of posting or measurement is not representative at this time of year

Prepared by the USDA/NRCS National Water and Climate Center Portland, Oregon http://www.wcc.nrcs.usda.gov/gis/Based on data from http://www.wcc.nrcs.usda.gov/reports/Science contact: Jim.Marron@por.usda.gov 503 414 3047

The snow water equivalent percent of normal represents the currentsnow water equivalent found at selected SNOTEL sites in or near the basin compared to the average value for those sites on this day. Data based on the first reading of the day (typically 00:00).

Pueblo

Durango

Alamosa

Gunnison

Leadville

Fort Collins

Grand Junction

Colorado Springs

Steamboat Springs

UPPER ARKANSAS

SOUTH PLATTE

GUNNISON

WHITE-YAMPA

REPUBLICAN

COLORADO HEADWATERS

RIO GRANDE HEADWATERS

UPPER SAN JUAN UPPER CIMARRON

UPPER COLORADO-DOLORES

NORTH PLATTE

SMOKY HILL

LOWER SAN JUAN

UPPER GREEN

Denver

54

97

86

80

80

90

92

57

96 9787

88

58

98

83

68

88

95

54

70

81

88

76

8089

59

111

105

103

127

126

131

108

105

114

120

107104

109

112 149

109

132

107

139

135

122

109

127

104

125

105

131

110

107

133

107

142

107

113

137

119

111

111

131

129

130

120

145

123

129

141

108

121

112

115

116

136

101

153

163

141

131

126

110

112

102

175

138

152

101 131

128

156113

76

25

ColoradoSNOTEL Snow Water Equivalent (SWE)

% of Normal

70

0 20 40 60 80 10010Miles

Prepared by theUSDA/NRCS National Water and Climate CenterPortland, Oregonhttp://www.wcc.nrcs.usda.gov/gis/

Provisional Data Subject to Revision

Current SWE % of 1981-2010Median

> 160%

140-160%

120-139%

100-119%

80-99%

60-79%

40-59%

1-39%

0%

Unavailable*

Feb 04, 2014

* Data unavailable at time of posting or unavailable long-term normal.

This year

Average

2010-2011

Average

2010-2011

2013-2014

Long range forecasts stink! !

We cannot reliably predict snow accumulations beyond about two weeks. Seasonal outlooks are even worse.

Actual Storm Track

16 Day Forecast

15 Day Forecast

14 Day Forecast

13 Day Forecast

12 Day Forecast

11 Day Forecast

10 Day Forecast

9 Day Forecast

8 Day Forecast

7 Day Forecast

6 Day Forecast

5 Day Forecast

4 Day Forecast

3 Day Forecast

2 Day Forecast

1 Day Forecast

Actual Storm Track

Weather happens when moist air

gets high

1 2 3

Where’s the moisture?

Lots of moisture(ocean source)

Less moisture (land source)

OK moisture (ocean + plants)

Orographics get air high

Mountains = Precipitation

Indian Peaks / RMNP

Sangre deChristo

Park Range

Flattops

Grand Mesa

Elk Mtns

East San Juans

N&S San Juans

Sawatch

Gore

Ten Mile & Mosquito

Favorable wind directions

Wolf Creek

Silverton

Telluride

Powderhorn Crested Butte

AspenVail

Summit Co.

SteamboatRMNP

Vail: Northwest winds

BeaverCreek

Vail

Gore Range

VailPass

Beaver Creek: West winds

Vail

Gore Range

VailPass

BeaverCreek

Breckenridge: NW to N winds

Gore Range

VailPass

Telluride: West & WNW winds

http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm

Moi

stur

e in

the

air

Temperature >> colder

10F 0F

The best snow requires... • Lots of moisture

• Mountain top temperatures between about 0-10F

• Best wind for Beaver Creek = West Vail = Northwest

Wind directions? Complicated. What about radar? !

Nope. There’s a problem...

Radar

Jamming the Radar

Overshooting the Snow

0.5 deg

http://www.ncdc.noaa.gov/nexradinv/

Denver Airport

PuebloGrand Mesa

http://www.ncdc.noaa.gov/nexradinv/

RMNP

Steamboat

Telluride

Wolf Creek

Aspen

BC / Vail

Summit Co.

Crested Butte

http://www.ncdc.noaa.gov/nexradinv/

4.8 mile resolution

2.4 mile resolution

4.8 mile resolution

2.4 mile resolution

4.8 mile resolution

2.4 mile resolution

Model Accuracy at 6-day forecastEuropean = British = Canadian = American =

0.845 0.825 0.820 0.807

How to plan

7-10 days 4-5 days 2-3 days

Apps!

January 30-31: Explained

Weather happens when moist air

gets high

1 2 3

Weather happens when moist air

gets high

1 2 3

WEATHER 101: Five ways to get high

D is for dynamic.

http://www.clker.com/cliparts/e/4/9/a/12401693261710228990Kliponius_Mountain_in_a_Cartoon_Style.svg.med.png

This is complicated - it’s all physics.

30,000ft300mb

Jet Stream(river of fast air)

Induces upward motion by “pulling” surface air upward into the void left by the fast-moving air above. Similar to opening a car window while moving and having a piece of paper “sucked” out.

WEATHER 101: Five ways to get high

U is for undercut.

http://www.clker.com/cliparts/e/4/9/a/12401693261710228990Kliponius_Mountain_in_a_Cartoon_Style.svg.med.png

Cold Air Warm Air

Cold front moving left-to-right

http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm

http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm

Top

18,000ftMtn

Joel Gratz joel@opensnow.com

What’s the forecast?

To the internet!