Monday, November 10, 2014

Winter Forecast 2014-2015

The follow winter forecast is based on current observations and historical data and will only forecast temperatures departures for average, snowfall percent of average, precipitation percent of average and some added forecast comments.

Here is the outline for the forecast:

A. Last winter compared to my forecast

B. Big Picture (driving mechanisms)
1. Arctic Sea Ice & Siberian Snow cover
2. ENSO phase
3. NAO & AO & EPO
4. PDO & AMO
5. QBO

C. The Checklist

D. Final Forecast
1. Temperature anomalies
2. Liquid Equivalent percent of average
3. Snowfall compared to average

A. Last winter

Here are some statistics:

-Total snowfall 71.2"
-94 days of snow cover
-66 days below freezing high temperatures
-Deepest snow pack was 33.6" on February 13th
-61 consecutive days of snow cover Mid-Jan through Mid-March
-Coldest daytime high was 2.1 degrees on January 7th
-Biggest snowfall was 17.1" on February 13th
-Earliest snowfall was November 12th with 0.5"
-Latest snowfall was April 15th with 1.0"

Now let's take a look at some charts:




When I look at the above statistics from last winter I see a very cold winter overall with above average snowfall. The cold is what made last winter stand out since the snow that fell never got a chance to melt before the next storm and so on. The cold came early and lasted through a good portion of the winter and even right into the summer months. The 71.2" of snow that fell is above the 10 year average of 51" but it was nothing extreme or record breaking. If it wasn't for the February 13th storm that dropped 15" - 20" then seasonal snowfall would have been at average.

Now was my forecast from last year correct? And should you believe anything I have to say this year? Let's find out. (

Last year I was expecting the coldest and snowiest weather (with respect to average) just to our west since I was forecasting the AO and NAO phases to stay mainly positive almost all winter. I was correct on the phase prediction, in fact it's safe to say I did a very good job with that. However, I over looked something that shifted my thinking just to our west by few hundred miles. The Eastern Pacific Oscillation was something I didn't take into consideration and it seems to have been the cause of the extreme cold since the other forcing mechanisms pointed in another direction. 

The image below pretty much sums up what happened last winter if we could shift the core of the cold a little more east. This will play another role this winter and honestly I see very similar conditions shaping up for this winter, but that's for part B.

B. The Big Picture 

When forecasting for the season you must look at EVERYTHING. Some people will look at just one or two aspects, compare it to winter 1995-1996 (1978, 2003, 2010...) and then the forecast is a bust. I've found out through research of the Arctic Oscillation that in New Jersey it only has a correlation coefficient of 14%-21% with respect to cold and snowy conditions, which means that yes it's significant BUT only a piece of the puzzle. If one piece of the meteorological puzzle is missing the picture it makes could be altered. 

1. Arctic Sea Ice & Siberian Snow Cover

Every single forecast I've seen on this winter has covered the above average snow cover over Siberia and what it means for us. Statistically whenever this occurs it generally ends up in a cold snowy winter over North America and some even relate it to negative Arctic Oscillation patterns. In my opinion statistics are great and can tell us a lot but there have been years where above average snow cover in Siberia has NOT been in favor for a cold snowy winter. I'll put extra consideration about this into my forecast but I won't let this dictate my overall product.

The images below show the sea ice and snow cover up till November 5th of this year and last year on the same day. The sea ice is about the same in area but as you can see the northern hemisphere snow cover is SIGNIFICANTLY ahead of last year. Will the cold come earlier this year than last year? Chances look favorable.

2. ENSO Phase

The El Nino Southern Oscillation can have huge effects on the weather in north America and is a household name to many. I can go for a very long time about this but I will make this short and sweet. A weak phase of El Nino is in the forecast for the winter months and unlike last year when we had a weak phase of La Nina (complete opposite). Perhaps this could throw more moisture into the mix for this winter which is why I would predict a boost in overall precipitation amounts than the average. When it comes to temperatures I don't believe it will have a warming effect on us like the extreme event that happened in 1998. 

3. NAO & AO & EPO

The NAO and AO are blocking patterns in the atmosphere that vary by day, week, and months with no real forecast tools to predict more than a week out accurately. Generally negative phases in both mean cold and snowy weather. Certainly will be this winters wild card and when they tank expect increase chances for harsh weather.

The EPO is similar to the NAO but is centered over the northern Pacific and influenced by the ocean itself. Last winter saw this went negative and caused arctic air to be displaced from Alaska to center of the continent. 


The PDO has seen a flip in the last few months. It went negative back in 2007 and seemed to have went postive earlier this year. Whether it's just visiting the positive end or made its official switch it looks like increased precipitation this year with better forcing for Alaskan ridging assuming it stays in place. 

The AMO on the other hand is still in it's warm phase which will dominate the rest of this decade. This generally means more precipitation and warmer temperatures in the northern hemisphere. Not a end all for our winter because we have had plenty of rough winters while this phase has been in the red zone. However yet another clue points toward more precipitation.

5. QBO

 Last winter a huge concern for me was the QBO phase (an up level oscillation that can effect NAO and AO values). It went positive which meant the AO and NAO would be primarily positive during the winter. Was I right? Answer is yes. The chart below shows both phases last season staying mostly positive.

QBO 2012 till Present:
This season looks much more favorable for the NAO and AO to be negative. Primarily negative this time around. Another sign this winter is going to be rough.

C. The Checklist

(red= bad for snow lovers / blue= bad for snow haters / black= equal chances

-AMO (warm phase)

-QBO (easterly-negative)
-NAO (negative influence by QBO)
-AO (negative influence by QBO)
-PDO (warm phase=Alaska Ridge)
-Weak El Nino (add moisture)
-Arctic Sea Ice Extent (large increase)
-Siberian Snow Extent (well above average)

D. The Final Forecast

I have not included everything I researched for this winter forecast into this write up. In fact only about half made here for you to see. I still could not find a single item to put into the checklist that could indicate a mild and dry winter pattern. If there was ever a perfect set up this is it, and it seems quite obvious. 

1. Temperature Anomalies

The easterly QBO and it's influence on NAO and AO, the artic sea ice, the Siberian snow extent, PDO forcing an Alaskan ridge all point toward cooler weather. How ever a weak El Nino could help to serve some slight warming effect but not enough to alter this forecast. I can't find a single piece of evidence that would point toward a warmer than average, but I don't think it will be as cold as last winter when we had weak La Nina conditions.

Overall forecast for winter temperature anomalies is BELOW average

2. Liquid Equivalent Percent of Average 
All indices I've looked at suggests increased precipitation amounts for the eastern US. More precipitation could mean more intense storm systems than last year and increases the likelihood for a block bluster snow event measured in feet rather than inches. Also could mean heavier rain events as well on the warm side of a low pressure system. Unfortunately for the south west I don't see much in the way of relief for the record breaking drought.  

Overall Precipitation for New Jersey is ABOVE average

3. Snowfall Percent of Average
North Jersey has a wide range of seasonal snowfall totals. From around 24" near the city to as much as 55" in places like Highland Lakes and West Milford. My personal 10 year average for Netcong comes out to about 51" how ever areas with lower elevation just minutes away may only average about 40". Still the state as a whole does not see that much snow and just one event could make or break a seasonal forecast. One storm could bring Newark's seasonal average and could miss another portion of the state entirely and end up with below average snow. 

This season looks to bring above average precipitation which increases the likely hood of above average snowfall overall. Even if half of the events fall as rain, the other half could still bring average to above snowfall. With temperatures expected to be below average in combination with more precipitation chances look likely for MUCH ABOVE average snowfall.

This sums up the winter forecast and all we can do now is ride it out and see if the prediction hold true. There are sure to be times of extreme cold events and even times where it could feel spring like. The overall averages however will show that winter 2014-2015 is going to be remembered as a cold and snowy one.


Jack Ziegler said...

Very interesting forecast, looking forward to your updates throughout the winter.

Darren Milliron said...

Thanks. We will see how this turns out. I'm very confident with this forecast.