The road temperature (Fig. 10.48) predictions for this case were quite good during the
time of the event. After the event is over the temperatures are too warm during the day
and too cold during the overnight hours. Again, the cloud cover forecasts are likely to
have played a role. With fewer clouds forecast than were actually observed the
forecasted road temperatures were able to decrease and increase more quickly during the
night and day, respectively.
Error comparisons between Ames and the entire domain (Figs. 10.49 and 10.50) reveal
that problems were similar across the domain for the 0 UTC, 20 February RWFS run. Of
particular importance for this case were the gross under forecasts of cloud cover across
the domain during hours 18 to 36, resulting in low temperature and dew point predictions
after hour 24.
Road Temperature Comparison for Feb 20, 2004
10
AMW OB
RA
SN
8
6
4
2
0
-2
AMW RWIS OB
AMW RWIS wFSL
-4
AMW RWIS woFSL
SEG 3 wFSL
SEG3 woFSL
-6
0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22 0
Time (UTC)
Feb 20, 2004
Fig. 10.48. Road Temperature (C) time-series plot comparing the Ames
RWIS observations to the RWFS forecasts (both with and without the FSL
supplemental models) for the RWIS site and segment 3. The vertical lines
represent the time period that the Ames METAR was reporting falling
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