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Thursday March 26, 2020

Assignment: Predict the 24 hr maximum temperature (deg F) for Blue Canyon, CA (KBLU)

Blue Canyon, California is a fun weather station to watch in the winter. Along I-80 at 5000 ft elevation, it often receives a ton of snow when wet storm systems slam into the Sierra Nevadas. The statistical model forecasts for Thursday's high temperature are only in the mid-30's, about 10 F below average, but the NWS forecast is a little warmer. Let's predict the Tmax and see how it comes out.

Question: What effect would you expect a fresh layer of snow to have on the maximum temperature? Why?

What Happened?

I was a little surprised that Blue Canyon made it as high as 36 F, with fresh snow on the ground. So the NWS models did a good job. Several students were right that snow tends to hold down the daily maximum temperature, but the main reason is that the high albedo (reflectivity) of the snow reflects much of the incoming solar radiation (rather than absorbing it and making the ground warmer). And much of the absorbed radiation is used to melt the snow instead of raising the temperature of the ground.

Forecasts for Blue Canyon, CA (KBLU)
Forecaster Tmax, deg F (error) Comment Day Score
OBSERVED 36 Data through 0600 UTC
Reference
CLIMATE 48.1 (12.1) NCDC Climate Normals, 1981-2010 0.4
PERSISTENCE 30 (-6) 1.6
MOS
NAM-MOS-12-DAY01 34 (-2) 2.4
GFS-MOS-06-DAY02 35 (-1) 2.6
GFS-MOS-18-DAY02 35 (-1) 2.6
GFS-MOS-00-DAY01 35 (-1) 2.6
GFS-MOS-18-DAY01 37 (1) 2.6
GFS-MOS-06-DAY01 35 (-1) 2.6
NAM-MOS-12-DAY02 36 (0) 2.8
GFS-MOS-12-DAY02 36 (0) 2.8
NAM-MOS-00-DAY01 36 (0) 2.8
GFS-MOS-12-DAY01 36 (0) 2.8
NAM-MOS-00-DAY00 36 (0) 2.8
GFS-MOS-00-DAY00 36 (0) 2.8
StokesEarlyCollegeHigh-Mr.Price-SpringEarth/Env.Sciences
1. Grace15 36 (0) It would probably decrease the max temperature by a little bit especially depending on what time of day the snow hit because then throughout the day more snow would decrease temps even more. 2.8
2. Django15 37 (1) 2.6
2. Keith15 35 (-1) 2.6
2. Leah15 35 (-1) 2.6
2. EmilyS15 35 (-1) 2.6
2. Josh15 37 (1) The effect of a frsh layer of snow would lower the maximum temperature because in order for it to snow the temperature would have to get colder for it to stick. 2.6
2. EmilyV15 35 (-1) 2.6
2. Shelby15 35 (-1) 2.6
2. Anna15 37 (1) 2.6
10. Alex15 34.5 (-1.5) 2.5
11. T-Dawg15 34 (-2) 2.4
11. Gus15 38 (2) 2.4
11. Jasper15 38 (2) 2.4
14. Mathison15 33 (-3) 2.2
14. Elizabeth15 33 (-3) 2.2
16. Mikayleigh15 32 (-4) 2.0
16. Joscelyn15 40 (4) The effect a fresh layer of snow would have on the maximum temperature would make that day colder because the snow would absorb the heat and possible melt depending on the overall weather of that day. 2.0
18. Hailey15 31 (-5) 1.8
19. Sara15 30 (-6) 1.6
20. Abbygale15 43 (7) 1.4
21. Autumn15 45 (9) 1.0
22. Dorothy15 47 (11) 0.6
23. Emily15 48.1 (12.1) 0.4
24. Hannah15 23 (-13) 0.2
25. Miles15 60 (24) 0
Open
1. ashleigh15 34 (-2) 2.4
2. abigail15 23 (-13) 0.2