Long Range Lookout: November Lost to Warmth

I believe that November is, unfortunately, lost as far as winter potential goes, as a poorly-timed Rossby Wave train begins to set in for November.

Hour 204

Hour 384

The Rossby Wave train is a 'train' of storm systems pushing southwest from the North Pole. What happens in response to storm systems pushing in the West? If you guessed a warm East US, you are correct. Hour 204 from November 6th's latest GFS Ensembles shows that scenario.

Rossby Wave trains typically have a full cycle in which 3 stages occur. Stage 1 involves the pattern in a dormant state, not really doing much. Stage 2 is when you start to pick up on some storm systems hitting the same area over a period of time. Stage 3 is the full-blown active stage, as is forecasted in Hour 204 and 384. These three stages usually happen within a 4-6 week cycle, so it's no surprise that the farthest GFS Ensemble forecasts still show the Rossby waves in action.

Because this will be developing in early November, we can expect this poorly-timed pattern to last through November, likely ending in early December at the earliest and mid-December at the latest.

But don't lose hope!

I have been tracking this Rossby wave train for a while now. If I extrapolate (use observations in a forecast) this Rossby wave train will progress into the North Pacific. In response, the high pressure tendencies will be placed over the West, leading to a much stormier, colder pattern for the East. Couple that with favorable late-winter signals from Siberia in October and it looks like we could have a more back-loaded winter coming up.

Andrew

Long Range Christmas Forecast Suggests a Stormy Plains, Midwest

A very preliminary look at the Long Range Christmas Forecast suggests that a strong storm system could make for a messy couple of days across the Plains, Midwest and Great Lakes.

Using a pre-determined pattern for this winter (which many of you know as the LRC), tweaked slightly to fit what I believe is in line with observed conditions in the past several weeks, I have determined that there is a likelihood of a stormy Christmas for the Plains, Midwest and Great Lakes as a few storm system have the potential to follow on one another's heels, one of which could strike on Christmas Eve/Day.

The Southwest would likely emerge warm and dry from such a situation, while the Plains encounters frigid conditions in the wake of such a fast and strong train of storm systems. Snowfall accumulations would most likely be centered in the Plains and Great Lakes, while the Midwest could be in a dicey situation as far as precipitation potential goes.

This does have the potential to fail, but I believe I have a pretty good idea at the moment of what Christmas could be like. PLEASE DO NOT take this as an actual forecast. If you even want to think about this forecast, take it as ADVICE- we remain nearly 2 MONTHS away from Christmas- a huge timeframe for things to alter this forecast.

Andrew

Strong Nor'easter To Deliver Snow, Rain To Sandy-Stricken Regions

A strong coastal storm system will be delivering everything from snow to rain to wind in the Northeast, in the same regions already battered by Superstorm Sandy.

The above model image is of precipitation type roughly 3 days out, superimposed on forecasted MSLP values. The MSLP values indicate that the GEM model is predicting this storm system to get as low as 967mb. While that is certainly strong, it pales in comparison to the 940mb observation in Superstorm Sandy. Regardless, this storm will have many impacts, including:

•Cold temperatures
•Accumulating Snowfall
•Heavy precipitation
•Rising waters
•Additional beach erosion
•Heavy winds
•Additional loss of power and other services

This is the 102 hour snowfall forecast from the latest GFS (American) model:

The GFS believes many areas will see amounts below 6 inches, but the spots that do breach that benchmark could see amounts flirting with the 10 inch mark. The worst part of this storm system is that it will strike the areas worst-hit by Sandy. While many areas that still don't have power are in a bad situation, others could be in a much worse situation- those who have an unstable power source. If people badly hit by Sandy have a temporary power source for the time being (i.e. hastily placed power lines) in place of a more permanent power supply system, they may let their guard down, thinking they don't have any power issues to worry about. However, should the power go out, you've got quite a stormy night coming in.

The reason I haven't covered this too much is because storms can leave you uninterested in similar events for a while. For example, after tracking the 2011 Chicago blizzard, I had no desire to forecast snow for a good 5 days after the event, and I think the same is happening here in the wake of Sandy. I apologize, and I want to cover it more, but I have a feeling there won't be too many updates as this system comes along.

Andrew

Negative PDO Struggling

A comparison of October 3 and October 31 sea surface temperatures show that the previously strong negative PDO (characterized by a warm body of water in the North Pacific with cool waters surrounding it) is now weakening.

We are no longer seeing that arm of extremely above normal water temperatures from Japan through the Northern Pacific. Cool water anomalies are beginning to filter in to the region now, and this is posing problems for what used to be a very solid negative PDO.

Some of you may not know what the PDO is, so let's break it down. The PDO is the Pacific-Decadal Oscillation. It has two phases- positive and negative. The two phases are actually not what you think they are. A negative PDO consists of warm water anomalies stretched across the Northern Pacific, like what was seen on October 3. A positive PDO holds cool waters across the North Pacific, like we are currently seeing fill in.

The positive PDO generally brings cool conditions to the East, while the negative PDO is very warm for the same region. The Gulf Coast gets much of the precipitation during -PDO years, while +PDO years favor a dry East US in general. The +PDO is associated with El Ninos, and the -PDO with La Ninas.

Andrew

**FINAL CHANCE** Sign Up Here for Personal 2012-2013 Winter Forecasts

This is your FINAL OPPORTUNITY to sign up for personal winter forecasts for your own town!

Here's how it works:

-Comment below with the location(s) you want to get a personal winter forecast for.

**If you have already signed up, I have already included your location.

Andrew