More Uncertainty Builds!

For NYC snow lovers, the 06Z NAM just dissapointed you in a major way. It has trended offshore towards the GFS. This could be a crushing blow to a promising storm. However, this is only 1 model run and we will see if it is blip or a trend, when the 12Z run comes out later this morning.

Potential Blizzard On The Way!

Winter officially begins in a couple of days and it may be off to quite a start this year, if things pan out the way they seem to be trending. Within 24 hours, a storm that appeared destined for the fish in the Atlantic Ocean, now has its sights set on the entire eastern seaboard.

This will be my first detailed weather model analysis and discussion of the storm. At this time, a good portion of the 00z model data has come in. The real eye opener came this afternoon with the 18Z NAM. It has a major shift of the storm track closer to the coast line. It hopped on board with the EURO (one of the more respected models). The GFS is basically the only model that has not jumped on the bandwagon at this poing. Being that it is currently the outlier, we'll use the 00z as the model of analysis.

Let's set the stage and look at the surface features in play. I have circled the key features in red. A strong, Canadian high pressure system is in control of the northeast. This is one of the coldest airmasses of the season. Unlike many storms that come up from the south, this one will not be able to drag a lot of warm air up with it, so it almost a guarantee that we are going to be dealing with snow only. An area of low pressure has already developed over the Gulf of Mexico. This is the storm we are watching.

Now, let's take a look at the latest run of the NAM. We'll start by looking at the initialized analysis at 500 mb. This gives us a flavor of the overall weather pattern and potential evolution and track of storms. One of the key things Meteorologists look at in determinng the potential of a major east coast snowstorm is a term called the "North Atlantic Oscillation" (NAO), which is the difference of normalized sea level pressure anomaly between Iceland and the subtropical eastern North Atlantic. It has 2 major phases: Positive and Negative. For big snowstorms along the east coast, we look for negative values. Negative values of NAO are associated with unusually high geopotential height values at 500 mb across the north atlantic. This is sometimes known as a "Greenland Block". This anomalous condition forces deep troughs of low pressure to form along the east coast, which can generate big storms. Because there is a blocking upstream, these troughs tend to negatively tilt and even cutoff. This leads to intense and slow moving storm systems that can produce very heavy precipitation. The image below is a great representation of a negative NAO situation, which is leading to this potential nor'easter. Anomalously high geopotential hight values of 570 DM are over Greenland and is producing a blocking situation. This is forcing the polar vortex south eastward to southern Canada. A strong, confluent flow is over the northeast.. a sign of high pressure over the region and typically a forerunner of east coast snow storms.



Now, let's jump ahead to the height of the storm and see how the 500 mb pattern evolves. As you'll see, what has not changed is the Greenland Block. But now, the trough that developed across the central and eastern United States amplified tremendously and a cutoff system is over the Atlantic. Boxed in red is an area of tremendous upper level divergence, which will aid in deepening the surface low pressure along the coast. Though not shown on this map, water temperatures are still rather warm, so the storm will feed on a tremendous temperature gradient and could likely cause a coastal front to form. These can generate a tremendous amount of snowfall.

The surface map for this same timeframe tells the story. A very heavy snowfall would be occurring Saturday night with 2-4 inch per hour snowfall rates.

There's alot more weather maps I can go through, but I'll leave you with what the potential snow amounts could be. Below is an output form BUFKIT, a tool which produces graphical outputs on many weather parameters. It is outputting 1.9 inches of snow. Now before you start wondering why I'm making a big stink over 1.9 inches... this is liquid equivalent. On average, 1 inch of liquid equates to 10 inches of snow. However, because this could be a dry, powdery snowfall, the ratios could be even higher. So, bottom line here is that we could be measuring snow in feet, not inches.

Stay tuned for further updates on the storm and predicted snowfall accumulations.

Earliest snowfall I can ever remember!

Last year, we had a bit of snow in late October, which I thought was pretty amazing. I didn't think it would be topped, but I was wrong. It was a surreal sight today watching snow fall and seeing most of the trees not even turning colors yet. I have to admit, I was a bit surprised how far south the snow got today... and with another coastal storm this weekend, there's another chance of a mixed precipitation event, and then back to reality. We should be back up near 60 by the middle of next week.

Not Like the Octobers of yester-years!

If you remember way back to 2 years ago, we had one of the warmest Octobers on record. That is not going to be the case this year. In fact, with a potential coastal storm late this week and a unsually cold airmass in place, you won't need to travel too far to see some snowflakes. Areas of central PA into central, NY actually have a decent shot of some accumulating snows. After this storm goes by, no big warmup in sight. It looks like we're stuck in a pretty cold and damp pattern.

Hints of Fall on the Horizon

Well... summer certainly flew by fast this year.. probably more so than other years, being that we really didn't have much summer like weather. In fact, September might end up being the best weather of the summer, eventhough, most people pretty much consider it over around Labor Day.

Now that Fall has arrived, we'll be having a lot of those cool nights and comfortable days. This weekend will feature some typical fall weather, especially Saturday. Many of our friends to the north of us will likely get their first frost or freeze of the season.

We do have something rather significant to keep an eye on for Tuesday. We've got a pretty powerful storm that will develop over the lakes states and move into Canada. This will create a very tight pressure gradient and we will likely have some issues with wind... might be looking at advisory criteria.. we'll have to watch it closely. Some higher elevation areas of New England have a shot at some snow flurries as well.

Winter is not too far away. As we head into the winter, keep it tuned to my blog. I'll have detailed analysis of major winter weather events.

Nice Start - Ugly Finish

After the summer we had, it's nice to be getting some of these sunny and warm days. Enjoy it while you can, because the weather will be going down hill again on Wednesday. After a few days of temperatures around 80, the bottom will drop out again and we set up for a weather pattern similar to last week. This is typical stuff to have some wild temperature swings this time of year, as we transition to the fall season. However, if you want to hold on to hope for a stretch of Indian Summer weather, there is some good news. Long range weather patterns are showing a nice stretch of sunny and warm weather for the last few weeks of September. We'll have to wait and see if this comes to fruition, but certainly the potential is there. It should be noted that while we may experience some nice late-September weather, the west may see some cool and unsettled weather, and yes, dare I say the "S" word.. that is a distinct possibility across the Rockies as we head into the next few weeks.

Unsettled Weather on the Way

Well... after a really good run of weather around here, it looks like it's going to come to an end later this week. It will really feel like fall on Thursday with a cool northeasterly breeze, along with rain. It does look like things get better in time for the weekend, but with a slow moving system, it can be a bit unpredictable. Next week looks like a return to nice weather.

The Beat Goes On

The great stretch of weather we've been having continues on for a good part of this week. We may finally get some rain by the end of the week, but it's certainly been a good run of weather after a rather miserable summer.

In other news, the tropics have quieted down considerably. We are in the peak time of the tropical season, so a close eye is still warranted.

Enjoy the holiday!

Hurricane Jimena

Category 5, Hurricane Jimena, is packing winds of 155 MPH. It might have some devastating impact on the Baja Peninsula of Mexico in the next few days. It is also not moving very quickly. This is a bad situation as storm surge and flooding will also be a huge concern.

Weatherjay.com has launched

After many long nights of hard work, I had a successful site launch this weekend. The launch was pretty smooth, with just a few bumps in the road. I'm looking forward to the start of the football season and starting up the pool. Some more testing is needed. I'll probably get a bit of help for that. We finally got a great stretch of weather. This is great for the start of the U.S. Open. I will be there Wednesday night. Well, it's late and got work tomorrow. Sleep time.

Welcome!

Welcome to Weatherjay's blog! As I sit here on a rainy Saturday morning, I am excited to be in the final stages of development of my new website... weatherjay.com. I will be focusing mostly on weather in this blog. Though my website will have NYC local forecasts and discussions, I will go into much more detail, especially during major weather events. Thanks again for visiting!