Wednesday, August 31, 2011

August 31: Katia Update: 0z ECMWF comes in north as 4 other models make an East Coast Run

A big development has occurred this morning, folks. After checking the 0z ECMWF, I did an unusual thing and put the ECMWF up against four other models: the GFS, HWRF, GDFL, GEM models. It turns out the ECMWF is the farthest north out of all 5 of the models put together. This is a significant development because it means some models could be calling for an East Coast run.
Here's the multi-model panel 126 hours out- just on the edge of the 5 day forecast.
You can differentiate which models are which by looking at the image headers. You can see maximum wind speed in that same area as well. Here's a piece of information. There are some biases on these models. I only know one or two, and here they are.
-HWRF is stronger than what actually pans out.
Yes, the HWRF is pretty much always stronger in tropical cyclones than what happens, so don't take strength forecasts too seriously. Now compare the 4 panel image to the 0z ECMWF of this morning.
Check out how far north the ECMWF is compared to the other models. This presents a problem to forecasters- which model suite should I choose? There's a majority of somewhat reliable models, up against  a heavy hitter model in the computer model world. Right now, we are not going to choose, but will watch all models carefully over the next couple days.

There is a rumor that Katia's models will have a change coming in the next 2 days as a typhoon will move over Japan.


Anonymous said...

We must also remember that the HWRF is depicting winds at 900 mb, thus winds are stronger in the image than they would be at the surface.

Andrew said...

Yes, but as stated, the HWRF is typically over-exggerated with winds.