John Homenuk

Here’s how to see archived model runs of historic storms

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The Blizzard of 2006 was a tremendous snowstorm in our local area. While it did fall in the middle of a warm and otherwise uneventful winter, it featured some tremendous dynamics and impressive banding. Do you remember what forecast models were showing prior to that event? Me neither. Up until now, it’s been fairly difficult to find archived model images dating back to the mid 2000’s, and even if you accessed them, the images were coarse and the graphics difficult to comprehend.

That has changed. Unknown to some, there is an easy and simple way to  access model data from the wildly popular free model data website at Penn State University. Known as “Ewall” to meteorologists and hobbyists alike, this website has been around for many years, and has served as a central hub for model data while remaining “new” to the times with upgrades and new graphics. The website also houses a freely accessible archive of model images dating back to 2004.

A simple manipulation of a link can lead you to archived model loops from the GFS, ECMWF, and CMC. Of course, the models will be archived as they were at the time. So, if you go back to the mid 2000’s you will see the GFS and CMC with much more coarse graphics than we know them to have today. Regardless, the images are impressive and can almost serve as a time capsule for weather enthusiasts. Here is the link format for those who want to get started immediately:

http://mp1.met.psu.edu/~fxg1/ARC/yearmonthday/AVNEAST_0z/avneastloop.html

You can manipulate this link in a few ways. First, you can obviously manipulate the year, month and day. So if you wanted to access the GFS model runs from just prior to Hurricane Sandy, you would change that area of the link to: 20121027. Accordingly, if you wanted to access the GFS from just prior to the Blizzard of 2010, you would change that area of the link to 20101225.

But beyond the dates, you can change the model run as well. If you wanted to see how the GFS changed each run prior to hurricane sandy, you would change the link from 20121027/AVNEAST_0z/ to another model run such as 20121027/AVNEAST/12z/. This gives you the ability to see all archived GFS runs from that day.

The best news of all? The link also works for other models. We have included the following models with base links showing forecasts prior to the December 26, 2010 Blizzard in New York City. Manipulating these links for dates and model runs will show you individual runs.

Regional NAM: http://mp1.met.psu.edu/~fxg1/ARC/20101225/WRFEAST_0z/wrfloop.html

Regional GFS: http://mp1.met.psu.edu/~fxg1/ARC/20101225/AVNEAST_0z/avneastloop.html

National GFS: http://mp1.met.psu.edu/~fxg1/ARC/20101225/AVN_0z/avnloopnew.html

CMC: http://mp1.met.psu.edu/~fxg1/ARC/20101225/CMC_0z/cmcloop.html

ECMWF: http://mp1.met.psu.edu/~fxg1/ARC/20101225/ECMWF_0z/ecmwfloop.html

We have included some images below showing some archived model images of famous storms from the past 10 years in the New York City Area. Happy model archive viewing!

February 2006 Snowstorm in New York City as modeled by the GFS a few days prior to the storm:

Hurricane Sandy can be viewed as modeled on the GFS just a few days prior to its impacts in our area:

And finally, the Boxing Day Blizzard of 2010 can also be viewed just a few days prior to its impact here: