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(meteorobs) First computer model cloud forecasts...
The AVN model does have a total cloud cover forecast function, and it is run
every 6 hours for an 84 hour forecast..thus, the latest run, at 18Z today,
forecasts up to 6Z on Sunday..the next forecast will run to 12Z Sunday and thus
bracket the time of Leonid peak.
It's not particularly reliable with cloud forecasts this far out but it begins
to give you more of a specific idea.
It currently indicates these possible trouble areas (In order from densest
forecast possible cloud cover to lowest):
1) Kansas, Oklahoma, and Texas
2) North Dakota, Montana, Wyoming, Idaho, and Eastern Oregon
3) North Carolina and Virginia
4) South Florida
5) California
Interestingly, the last few runs the model has been indicating somewhat of a
small "cloud hole" over the Seattle area extending to the heavily populated
portions of Oregon with clear skies, so you folks there may not be as doomed as
you think.
California is an interesting and ambiguous case..model doesn't have it clear,
but it's not socked in, either.
The model maps can be viewed at:
http://www.arl.noaadot gov/ready/cmet.html
1) Select "Aviation Model (AVN 191 km) under "Interactive Forecast Maps"
2) To see a total US map, Change the selected longitude to -100 degrees, and set
the map radius to 20 or 25 degrees. You can create smaller maps centered on your
location by adjusting the lat-long and map radius.
3) In "Fields to Plot" select "no overlay" and in Field 1 select "total cloud
cover", set level to "surface", set contour type to "color-filled" and set
contour interval to "10.0". This will show total forecast cloud cover in
increments of 10%.
Note that my experience is that when the model portrays 30% or less cloud cover
for meteor observing purposes it is what we would basically consider "clear" or
good observing conditions. It's the 60-70% and higher indicated cloud cover that
really means the possibility of hopeless overcast conditions
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