forecasting tricks for the vail valley (february 4, 2014)
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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
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!_[(
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: [email protected] 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
What’s the forecast?
To the internet!