Monday, December 14, 2009

Wrinkle Update

Taking a look at some of the computer model data this morning. The wrinkle previously mentioned in an earlier post is still there, but a few more details are starting to emerge.

One model, NOAA's global forecast model, has taken out the wrinkle on last night's run. However, the European model still is hinting at the possibility of "something".

Perhaps I am doing a little bit of "wish-casting" because I love snow. Lets take a look at last night's European run.

Here is the chart for 6pm CT Friday. You are looking at surface pressure along with temperatures at 850mb (roughly 5,000 feet).

The surface is low well south in the Gulf of Mexico. Moisture will be streamed north from the low, but it won't be very much if any at all.

Look back to the west over Idaho, Utah, and Wyoming. See the "dip" in the black lines? This is energy coming together at 500mb (approximately 18,000 feet). This is where I am watching to see if an upper-low develops.

Here is the chart for 6pm CT Saturday. This shows surface pressure and 850mb temperatures.

The surface low has moved across Florida and is now moving out to the Atlantic Ocean. This is taking the moisture with it. Cold air begins to stream in behind the low.

Now lets take a look up at 500mb for the 6pm CT Saturday time frame. We are looking at wind speeds.

I have cut out of hole in the image. This is where the upper level low continues to develop. It is rotating through southwest Missouri at this time. This will provide some energy in the upper levels.

Here is the 850mb temps/surface pressure chart for 6pm CT Sunday.

The surface low is moving up the east coast of the US. Cold air is implanted in the Midwest. Temperatures will probably be in the 30's around southeast Missouri, southern Illinois, western Kentucky, and northwest Tennessee.

Here is the 500mb chart for 6pm CT Sunday.

I cut a hole out in the chart to indicate where the upper-low is located. Right over the Midwest. There will be energy rotating around the upper-low Saturday and Sunday.

The big question now becomes, "Is there any moisture in the atmosphere?". If there is some moisture, the upper-low could kick out some snow showers. However, as we see above, the surface low is on the east coast. The surface low is what we need to kick moisture up our way to interact with the cold air.

With upper-low situations, we often do see snow flurries or light snow showers. However, these don't turn out to be big snow producers for this area.

Again, this is only one model's depiction of what could happen. As I said earlier, the other model that looks out at this range has taken the "wrinkle" out.

At this point, I wouldn't run to Las Vegas and put money on the fact we are getting an accumulating snow for the weekend.

Stay tuned...

The core of the cold air is building over southern Canada. Last night at 10pm CT, the air temperature in Edmonton, Canada was -33°. That was the air temperature, not the wind chill. BRRR! In the above 850mb charts, you can see the cold air spilling down in to the US. One thing is for sure, it is going to be colder this weekend.

0 comments:

Twitter Delicious Facebook Digg Stumbleupon Favorites More