Model Musings

2015-03-16 17:14:35.000 – Nate Iannuccillo, Summit Intern

 

With the astronomical winter season coming to a close at the end of the week, it appears that we’ll be receiving some proper winter weather before entering the spring season.

Tomorrow will bring snow showers of scattered intensity throughout the day, and we’ll take a look at some of the discrepancies in the intensity of our precipitation as displayed by two different forecasting models.

The GFS model, the top synoptic scale model of our National Weather Service, shows showers somewhat scattered, and of varying intensity.

But conversely, if we look at the Unified model of the UK’s Meteorological Office, we can see precipitation magnitudes generally a bit higher and more sustained than those calculated by the GFS.

In the image below, we can see the comparison of the two models for 8am tomorrow morning. The UKMET output is pictured on the left and the GFS on the right.

Image courtesy of UQAM-Montreal Weather Centre

As we can see, there is some discrepancy in precipitation amounts, but as a whole, there is certainly some visible agreement between the two models. We’ll see how this changes as we look further into the future.

But first let’s check out the precipitation profile as forecast by the GFS model. The good news is that precipitation should remain as snow for most of New Hampshire.

Check it out.

 

Image courtesy of UQAM-Montreal Weather Centre

Green shows rain and blue predicts snow. The one red dot on the map is freezing rain and the yellow regions display mixed precipitation.

Let’s look a little further ahead now. Here is 8pm tomorrow night, a full twelve hours further in the future.

 

Image courtesy of UQAM-Montreal Weather Centre

Focusing on New Hampshire, we can see a little more discrepancy this time. The GFS shows very little precipitation in NH whereas the UK model shows some precipitation for all of New Hampshire. This is where the challenge of forecasting lies.

The Bottom line is we can be pretty sure of some snow for northern NH tomorrow despite uncertainties in snowfall intensity and duration.

 

Nate Iannuccillo, Summit Intern