Thursday, January 12, 2012

Latest Pattern Change Thoughts

The second image shows the forecasted 30mb stratospheric temperatures. What we see is a sharp increase in temperatures followed by an equally sharp drop in temperatures, going back to the place where we currently are. In other words, there won't be enough time or warming for any major changes to occur, at least from the 30mb standpoint. Both 10mb and 30mb temperature forecasts are shown in the third image. What I find interesting is the 4th image, which projects 10mb and 30mb temperatures at the 60N line, which is pretty much far north Canada and the Arctic Circle, into far north Europe and Russia. It is encouraging that these temperatures are warming, and this may provide a better view than the first images I described. If the cold in the 60N area dies off and turns into a warming situation, the cold air fighting to get out of the Arctic will be able to do at least a bit more damage than what it is currently doing.
These images are geopotential and temperature waves. Each one has its own effects on the stratosphere. In the 1st image, we have Waves 1 and 2 showing for temperatures. What is ideal in a stratospheric warming scenario would be to have both Waves 1 and 2 at warm temperatures. However, we are seeing both waves actually drop into colder temperatures. Those are the waves at the 10mb level. At the 30mb level, Wave 1 is forecasted to cool down while Wave 2 is supposedly going to warm up. This would be quite interesting, to see the waves going in different directions. I would very much like to see the effects of that. The 3rd image is geopotential heights at 30mb. Wave 1 has seen rising GPM (geopotential) values, which indicates ridge of high pressure that batters the polar vortex to encourage cold air south. However, this wave is now forecasted to dramatically drop down again, where we may see a reforming polar vortex.

MY THOUGHTS
-There will be snow. This is not a 'one and done' scenario if you live in the Great Lakes, where there is currently a snowstorm occurring. I believe that this is the storm we needed to get the cold air in to stay. For instance, because Chicago is in the middle of the snow, we came across temperature forecasts and found not a single day reaching into the 50s for the next week.
-The long range forecasts are looking very dismal, to be honest. If the Wave 1 GPM values suddenly dive as shown above, I would not be surprised to see the +AO/+NAO regime once again take the reins.
-Henry Margusity, an Accuweather Meteorologist I closely follow, looks to be too caught up in the pattern change. He is predicting a major flip to cold, but unless something dramatically changes, I am not seeing January becoming stone cold and freakishly snowy.

400,000 pageviews reached

Thank you to everyone who has visited The Weather Centre over the past couple years as we reach this major milestone. Again, thank you!

Chicago, IL May Begin Seeing Stronger Snowfalls Soon

What we have here is surface vorticity (rising, denoted by color fills) and surface convergence/divergence (red and black, respectively). Convergence is associated with air converging on a point to make storms in the summer, and intense snow in the winter. We are seeing some convergence activity occurring on Lake Michigan westward into Chicago, where surface vorticity is also higher, suggesting that snowfall may become enhanced in those areas. We expect the lake enhancement to eventually turn to Michigan and dump snow on those areas. More updates as they come.

Wednesday, January 11, 2012

Midwest Winter Storm Update- 1/11/12 Afternoon

We have a lot to get through today, so let's get started.
DENDRITE GROWTH ZONE (DGZ): The DGZ is basically the area in which the most snow will fall. Dendrites are actually snowflakes, and the Dendrite Growth Zone indicates the potential for snowflakes to pile on top of each other, particularly dendrites, for maximum accumulations.

Hour 24 Forecast
At hour 24, the SPC's SREF Ensembles are predicting there to be a DGZ in east Iowa and Northwest Illinois. This could be where some of the heaviest accumulations occur based on this and other factors.

Hour 30 Forecast
At hour 30 we see a pretty sizable and sustained DGZ setting up in central Illinois into northern Illinois. This could also be an accumulating area, but because the DGZ is then supposed to move north, the accumulations will not be as significant.
Hour 33 Forecast
By hour 33 the DGZ has moved into Chicago and Lake Michigan, moving towards Michigan. This will occur as the system itself moves on away from the Great Lakes and finishes its business.

12 HOUR SNOW ACCUMULATIONS

Hour 36
At Hour 36, the heaviest snowfall appears to be located in North Illinois and extreme east Iowa, where we expect the system to have the most effect. It would not surprise me to see the dark blue (4-5 inches of snow in 12 hours) to be moved a bit west a bit farther into Iowa.
Hour 48
At Hour 48 we are seeing the big snow move off into Canada, with some lingering snow from the storm combining with Lake Effect Snow (LES) to make for a snowy Michigan state.

WATCHES AND WARNINGS
The purple areas are in a Winter Weather Advisory, while dark blue is a Winter Storm Watch.



We will be issuing many short posts with images on here in the next few days as we try to provide you with as much information as possible. Stay safe.

12 Hour Forecast Snow Accumulations- SPC SREF

Hour 36

Hour 48