From:
"Matt Weaver" < > (scroll down for
graphs)
Subject:
Battle Mountain Weather Analysis - Hourly Data - Conclusions / Charts
Date: Mon,
11 Feb 2002 08:38:04 -0800
Dear Battle Mountain WHPSC Racers/Organizers:
I completed analysis on over 11 years of
continuous weather data from Battle Mountain. Data was condensed to hourly
readings - about 100,000 or so records listing a bunch of parameters from the
station. Original data consists of closer to half billion readings on various
parameters. I wish I had that super-raw data, but I was able to conclude
plenty enough as is.
I analyzed the entire year, but I will present
here only the analysis for the Sept 1 - Oct 15 date range. Of that I will
present only the averages and not all the std deviations, etc.... My
conclusions will generally reflect what is significant in the data though I
lack the charting application to conveniently display the deviations.
Data presented below is organized by hour of day
and successive week in Sept-October.
Basic conclusions:
Hourly:
* Wind average and gust is minimum right
after sunrise (best time of day is in first hour "after" sunrise).
* Morning winds from sunrise until 11am PDT
are consistently lower than sunset.
* Wind appears to lull at sunrise and sunset
as wind direction changes, but "hourly" raw data does not fully reveal this
effect. See weeks of 17-Sept and 24-Sept where the hourly period coincides
well with the sunset lull.
* Wind Direction - During nighttime, wind
comes from the east (E to ESE, 90 to 100 degrees on wind compass), at sunrise
wind direction typically swings counter-clockwise (through direct Northerly)
to a steady WNW (300 deg) for remainder of daylight. At sunset wind direction
promptly reverses back to E. This clockwise sunset reversal explains the
consistent sunset Northerly (headwind as we run north) that we experienced
during the speed runs. If morning (8am to 11am) runs were performed, we'd be
more apt to have a steady WNW, but would miss the brief "lull" during the
transition.
* Temperature - reaches min just before
sunrise. Peaks mid-afternoon (along with winds).
Week-to-Week:
* Morning winds favorable for entire
Sept-Oct period.
* Winds drop off dramatically on 2nd week of
October.
* Progressively declining sunset peak gusts
in successive weeks
* 1st week of Oct exhibits higher afternoon
winds than the preceding weeks, but superior late afternoon and sunset winds.
* Temperatures progressively cooling.
* rain local "minimum" as previously noted
from 30-year daily data.
I calculated the sunrise/sunset for reference
with Battle Mountain. I did not synchronize the data with the diurnal cycle
as originally planned because the raw data was organized into hourly bins (too
course to conclude much detail about the sunrise/sunset "windows").
Please let me know if you have any questions on
insights from the data. In general, I would conclude that if sunset runs are
planned, that the October weeks appear superior to September. There appears
to be a lull with a distinct and consistent wind reversal at sunrise and
sunset (from nighttime E to daytime WNW passing through N in transition).
This should be utilized, but it is also notable that the mornings from sunrise
until 11am or so are consistently low wind. The afternoons from noon until
near sunset are out. In terms of precipitation, the first week of October
appears to offer some advantage as previously discussed.
I recommend the first week of October, with
sunset runs as proven before, and "events" in the morning hours. Possible AM
sprints if desired/feasible. Possible subsequent caravan to Las Vegas and the
Interbike bike show and head-to-head hour record attempt on LVMS.
Sincerely,
Matt Weaver
