I received the following very interesting email from Dave Theophilus,
WØNRW. Thanks, Dave, for putting this together. 73, Art KØAIZ

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Having worked for the National Weather Service (NWS) for 35 years, I am
occasionally asked which weather sites I prefer on the Internet. Partly
because of my work experience, but also because of the quality and
quantity, I generally prefer NWS sites to others that are available.

Living in the area served by NWS Omaha/Valley
(http://www.crh.noaa.gov/oax/) I can find most anything I want in the
way of weather on their site. For other areas, click on Organization
just below the heading, which will take you to a master list of NWS
sites.

However, during the monster storm that struck large parts of the county
around the beginning of February, a combination of extremely high loads
(20 million hits per hour) and equipment problems, caused the NWS
websites to become very slow and even shut down completely at times.

So, backup sites are a necessity. I rely mostly on the College of
DuPage in Illinois. Their radar page is at:
(http://weather.cod.edu/analysis/analysis.radar.html). Pick your radar
site from the map. They have recently added a looping capability to the
0.5 deg Base Reflectivity. During the thunderstorm season, the Storm
Relative Mean Velocity is useful when looking for circulations. The
VIL is a useful product when looking for areas likely to be receiving
hail.

I also rely very heavily on the College of DuPage NWS Text Page at:
(http://weather.cod.edu/danatext.html). I have found that warnings
issued by the NWS will show up on this page within a few seconds of
issuance.

Another site that is good for primary, as well as back-up use, is the
National Center for Atmospheric Research (NCAR) at:
(http://www.rap.ucar.edu/weather/).

On all these sites always pay close attention to the time stamps to
make sure you are looking at current data.

For Numerical Weather Prediction or model data, I like the page from
Golden Gate Weather Services at:
(http://ggweather.com/loops/ncep_loops.htm). I usually look at the
Global Forecast System (GFS) output for North America. I normally look
at the SLP/Thickness/Pcpn display by selecting a loop for the proper
hour and stepping through each time interval display (12 hours)
manually. This will run out to 384 hours or about 15 days. The two
main model runs are the 00Z and 12Z runs. For instance, model data
based on the 12Z (6 AM CST) data collection is usually all available
between 16Z and 17Z (10 and 11 AM CST).

The solid lines are sea level pressure lines, the dashed lines are
thickness lines (think temperature), and the shaded areas are 12-hour
precipitation (see scale on the left). The 540-thickness line is a
good first guess as the dividing line between rain and snow.

As you watch this model you will notice, especially in the far out
periods, that storms will come and go between successive model runs.
We need to become concerned when successive runs are similar on surface
features. At the closer in times, model variability usually lessens.

Also, note that if you click on the Model Name, you will jump to the
NWS Model page.

That is as far as I am going to go today. An explanation of everything
you will see on these pages would be a project of its own. If you have
questions, I would be glad to try to answer them.

Dave T. W0NRW
Dodge County (NE) ARES
ARRL Emergency Coordinator

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ARRL Nebraska Section
Section Manager: Arthur I Zygielbaum, K0AIZ

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