THE MOUNTAIN SNOWFALL FORECAST NUMBERS
FROM THE 2006-2007 SEASON: (2005-06
in green and
2004-05 numbers in red)
ALTA SNOWFALL EVENTS:
|
(IN A 12 HOUR PERIOD) 1-6" |
NUMBER OF EVENTS 77 96 (91) |
TOTAL SEASONAL SNOWFALL 386
INCHES (averaging Alta Collins and
Alta UDOT)
(normal snowfall is 495") (639 and 562 inches)
FORECAST VERIFICATION NUMBERS:
(click for comparison graphs from past years)
|
0-12 hour forecast |
||
|
|
|
|
|
1-6" Events |
+0.59 (+0.72") (+0.69") |
1.75 (1.53") (1.67") |
|
6.5-12" Events |
-1.68 (+0.28") (-1.56") |
2.08 (2.81") (2.52") |
|
12.5-18" Events |
+1.7 (-6.45") (-3.4") |
1.7 (6.45") (5.8") |
|
>18" Events |
None -19" (-16") |
None 19" (16") |
|
12-24 hour forecast |
BIAS |
MAE |
|
|
|
|
|
1-6" Events |
+0.05 +0.71" (+0.65") |
1.60 1.94" (1.90") |
|
6.5-12" Events |
-1.49 -0.05" (-2.52") |
3.20 3.03" (3.48") |
|
12.5-18" Events |
-2.30 -6.45" (-4.6") |
2.30 6.45" (5.8") |
|
>18" Events |
None -19.5" (-14") |
None 19.5" (14") |
OVER-FORECASTING (click for comparison graphs from past years)
|
|
0-12 hour period |
12-24 hour period |
|
Forecast of 2-6" BUT <1" Observed |
10 times (28 times) (13 times) |
14 times (30 times) (24 times) |
|
Forecast of 6-10" BUT <1" Observed |
None (1 time) (None) |
None (2 times) (1 time) |
|
Forecast of >9" BUT <4" Observed |
None (4 times) (2 times) |
None ( None) (1 time) |
|
Forecast of >10" BUT <1" Observed |
None (2 times) (None) |
None (2 times) (None) |
UNDER-FORECASTING(click for graphs)
|
|
0-12 hour period |
12-24 hour period |
|
Forecast of <1" BUT 2-6" is observed |
1 time (None) (3 times) |
3 times (1 time) (3 times) |
|
Forecast of <1" BUT 6.5-12" is observed |
None (None) (None) |
None (None) (None) |
|
Forecast of <1" BUT >12.5" is observed |
None (None) (None) |
None (None) (None) |
|
Forecast of <4" BUT >9" is observed |
None (1 time) (1 time) |
None (1 time) (2 times) |
FORECASTS OF BIG EVENTS (>9") and 9 inches or greater occurs
0-12 hour period: 3 out of 10 events verified for 30 percent (7 events verified out of 23 forecasts) (8 out of 16 in 04-05)
12-24 hour period: 3 out of 8 events verified for 38 percent (9 events verified out of 21 forecasts) (6 out of 11 in 04-05)
VERIFICATION OF EVENTS WITHIN FORECAST RANGES (click for comparison graphs)
|
|
0-12 hour period |
12-24 hour period |
|
Events in Highest |
43% 46% (52%) |
36% 31% (50%) |
|
Events in |
12% 16% (24%) |
20% 26% (18%) |
|
Events in Either Range |
55% 61% (76%) |
56% 57% (68%) |
|
Events Outside Both Ranges |
45% 39% (24%) |
44% 43% (32%) |