Tuesday, February 14, 2012

February 14-18 Snow Event- Model Discussion (2/14/12)

Happy Valentines Day!

We re starting to see a southward shift in the models. Here's the last 4 runs of the GFS model.
You can see the trend south from earlier model runs using the color code on the bottom right. The storm we are tracking is the one going through South Missouri and Northwest Ohio. If this were to continue, cities such as Des Moines and Chicago may get in on the snowfall. That is yet to be determined, though.

However, some models are actually trending north...
CMC Model last 2 runs

The CMC Model has shifted north from it's last 12z run yesterday and now puts the system right over Chicago. I have yet to determine why and cannot this morning as I am unusually busy.
Even though the CMC model is going north and the GFS is going south, the UKMET looks like it's taking neutral ground at this point. I think, however, that based on the proximity to the event occurring and model trending that I will be looking towards the GFS for guidance.

In these times of model turbulence it is important to see 0z verification to determine potential accuracy.
The models closest to the bottom of the image are the most accurate. Using that, we see that the ECMWF is the model to watch until hour 72, when the SREF Ensembles take over the show. The ECMWF has frames that are 24 hours in between, so it's hard to track the storm at this time. So let's see the SREF.

The 21z (0z) run of the SREF Ensembles are still split right now. And they have a right to be. While the event is only a couple days out, the models themselves are not exactly pulled together. This is the 0z SREF, which shows 2 possible paths- the CMC (North) path against the GFS (South) path. The UKMET is in neutral territory.

Here is the latest 3z (6z) SREF Ensembles. These ones have cut down on the northern path and appear to be headed for the GFS or UKMET solutions, which are the southern track and neutral territory, respectively. I have always liked using the ensembles, as a group consensus is worth more than a singular proposition.

Analogues can still come in use right now.
Here's snowfall from the March 7th, 1999 snowstorm.
This is my personal favorite, as it is using a La Nina phase for the analogue. This could very well be possible for the Midwest and Ohio Valley. I don't know about the northeast, I have to read up on it.

All in all, this storm should be very interesting. When new data comes in this afternoon, I will certainly let you know.