Saturday, December 31, 2011

Happy New Year to those in the East US!

Potentially Major Winter Storm Shown on ECMWF

Hour 192 of 12z ECMWF
Here, we see two low pressure systems- a cutoff low in the Southwest as well as another system moving onshore Canada. As of right now, they appear to be 2 separate storm systems.
Hour 216 of 12z ECMWF
At hour 216, we are seeing the same two low pressure systems moving eastward. It looks like the cutoff low may be getting some energy from the Gulf, and I could see a snowstorm hitting Missouri and states to the west of Missouri. The other disturbance in Canada continues to move east.
Hour 240 of 12z ECMWF
At hour 240, we are seeing some major phasing occur in the Western Great Lakes, which may indicate a major winter storm could hit the far Northern Midwest areas into Canada.

12z ECMWF Strengthens Polar Vortex-Disrupting Ridge; GFS Introduces Deep Trough Pattern to Great Lakes

Both the ECMWF and GFS are portraying at least some sort of disruption in the polar vortex, as well as at least a slight indication of a cutoff low pattern in the Southwest judging by the 500mb height isobars. However, each model has a different scenario.
The ECMWF brings in a very strong ridge into the polar vortex. If this were to stay in place, essentially the polar vortex would break down, and all of the bitterly cold air would come rushing south, as the lack of motion by the deep low pressure systems would eventually take its toll. This would certainly be a very interesting development. But because not all models do good in the long range, we will have to take this as a 'heads up' item, rather than a sure fire assurance. Additionally, the ECMWF places a ridge in the Northeast.
The GFS introduces a lesser ridge into the polar vortex, but it's still enough to cause problems. A much bigger interest is how the GFS is showing a deep trough pattern in the Great Lakes, which appears to be stemming off of the low pressure systems in the polar vortex itself. It also shows a weak cutoff signal in the Southwest, judging by the isobars.
All in all, this will definitely be something to watch. I would get your snow removal equipment ready, because this is something i'm having a feeling may cause a snowstorm somewhere in the US.

New Years Day Forecast - Valid 1/1/12

New Year's Day 2012 is already upon us, and that means it's time for your New Year's Day Forecast!
POPcast from
Valid 7:00 am EST
Throughout the Day, we will be seeing some precipitation throughout the upper Midwest and Great Lakes as a system will be moving eastward from Canada. It will be a strong system, so plowable snow is likely. We have snow accumulations below.
POPcast from
Valid 7:00 pm EST
In the evening hours, there will still be potential for some precipitation in the Great Lakes area, where strong winds will bring in harshly cold air to start the new year.

48 hour snowfall from

48 hour snowfall from
There is potential for upwards of 8 inches in Michigan from this lake effect snow, with some 1-4 inches of snow across Minnesota and Wisconsin from the system itself, and some lake effect snow closer to the Lakes. By far, Michigan's both upper and lower sections will be the hardest hit. Accumulations may look light on the Eastern side of the Lakes, but that may be because the lake effect machine is only starting to kick in at the 48 hour mark.


WINDcast from
Winds will be very strong on New Year's day, with sustained winds over 30 MPH on land, and over 45 MPH on Lake Michigan.
Here's a meteogram based in Chicago IL, one of the harder hit areas we are expecting of the winds. You can use the dashed lines that say (i.e. 06z GFS Max MT) for wind gusts, because 'Max MT' is essentially meaning the maximum wind gust that may happen in the area, in this case Chicago. (Mean MT is the mean wind gust expected.)
Click to enlarge
The 6z GFS Max MT is up at 70 MPH! Now keep in mind that the Max MT is the ultimate maximum for wind speeds and probably will not happen. A more reliable wind gust measurement would be the mean MT.

Have a great New Years!