Pre Thanksgiving Storm System 11/27/13 Early Call

We been talking about this system a lot on facebook over the past few days and posting the various model runs. We have seen from the GFS multiple tracks of the low pressure area and multiple scenarios played out from an all out snowstorm across the east to an out to sea scenario to a heavy rainstorm. The GFS has now fallen in line with the rest of the guidance ..such as the European Computer Model , the GGEM or Canadian Model and the British model  aka the UKMET. All these models, outside the GFS have been showing an inland runner travelling northwards across East Central PA .. Folks lets be clear about something ... when you have this type of track in the heart of the winter you would NOT be looking at a snow storm for those that are in the track of the low or east of the low pressure . We are not in the heart of winter so this holds true even more so. 
In order for this storm to come up the coast it means that the heights have to rise and when the heights rise it means the southeast ridge flexes its muscle and warm southerly winds are ahead of the storm system. Hence those east of the low or in the path of the low are in the warm sector of the storm system and would be looking at very heavy rain.
Lets look at the guidance tonight and we will look at the GFS first ...

Now, even on tonights GFS model the model is still running to the east of the rest of the guidance..but never the less you can see the warm sector and you can see the rainfall that occurs and how the snow is well inland..

The above is the GGEM and once again you can see the inland track that would take this low across east central PA and then into central NY..
UKMET is also showing an inland runner..

And finally the ECM ...

You can see on the ECM @ 48 hrs that the 540 line is well to the west and the 850 line or the black line in the lower right hand image is across the PA/NY border and then by 72 hrs the 540 line shifts east along with the 850 line. You can also see how inland the low is . So while the in between frames are missing ..the low pressure area would travel inland much like the GGEM/UKMET models and this would as we explained above cause the heights to rise and the SE ridge to flex its muscle and put those east of the low into the warm sector.
There is simply no guidance to support a SNOWSTORM in E PA or NJ... Now as the arctic front crosses the area if there is any moisture left behind the front that is when the region to the east could see some snow occur..but for the most part it will be rainfall ...

So for Now we are taking a blending of the models and we came up with the following scenario..

Now the one thing that all these models have in common is the tight isobars around the area of the low pressure. This means that there is going to be strong and gusty winds involved with this system.

The other aspect will be the heavy rains for those areas that see majority rain. 

Brief Pattern Update - Pattern Change in the Making?

Its been awhile since we have updated this blog. We have been doing the majority of the updating on the facebook page for Real Wx Services. 
If one were to look at Climate Prediction Center it would appear as if a pattern change is on the way.

Definitely shows a much below normal pattern in the 6-10 day outlook. Do the teleconnections support this happening? Well...lets look at them... 
First the MJO which is in the circle of death...

This basically implies it has little bearing on the weather outcome and it could go either way with warmer then normal or colder then normal dependent on the other teleconnections.

Now what we did with these teleconnections is we drew two circles on each one. One is black which represents where the teleconnection is NOW...or Presently. The other is yellow which represents where we could be headed..

The PNA is negative presently but is shown to spike positive but then shown to dip right back down negative once again. This would indicate a period of ridging into the west which would teleconnect to a trough into the east...

And lo and behold we see this is the case starting at 144 hrs out or next weekend. Trough in the east and ridging into the west.
Now lets look at the AO ...

Presently the AO is very high but it is shown to be on the decline and then some members take it negative while other members keep it positive. This is important for sustained cold you want to see the AO negative and stay negative in tandem with that positive PNA...

Finally the NAO is currently very positive as well but like the AO is expected to decline and then the members are once again split with some going and staying negative but some staying positive. So this gives us mixed signals ...

What is clear is that there will be a shot of cold air next weekend....thanks to the PNA spike.. Lets what the progression here of this...

Troughing still in place at 168 hrs out on the ECM tonight...

At 192 hrs we have a reinforcing trough moving in as the other one moves on out.. Still pretty progressive flow that we are experiencing....
But then what happens... 

Progressive flow begins to move that trough out and we see at day 10 ....

Things are pretty much starting to moderate and the flow has become zonal and pacific driven once again. 
So we do get a cold shot that will be coming in by Next weekend but there after with the teleconnections giving mixed signals but the drop back down in the PNA indicates that we are not going into a sustained cold pattern but rather a couple days of colder weather during that PNA spike.
The severity of that cold shot will be dependent on just how the AO reacts... does it go strongly negative or does it stay positive BUT declined? We think the latter .
Remember in order to get locked in sustained cold weather you want to see a sustained positive PNA and a negative AO and a negative NAO.... We are not seeing that we are only seeing a temporary spike in the PNA before once again declining and bringing some semblence of the Southeast ridge and zonal flow back into play...
So right now we are cautiously optimistic on a pattern change. We really would like to see the teleconnections switch to the more favorable combination before we can jump on "a pattern change is happening"...

Note the GFS has a cold bias when it comes to beyond 180 hrs so ...we have not included that in this discussion.

Winter 2013-2014 Ramblings

Last winter was a winter that left snow lovers in the east lacking because we had a lack of cold weather and we had a lack of snow across the region. A lot of places ended up being above normal and below normal snowfall. So it has come to the time frame once again where we have to start looking at the winter of 2013-2014. 

Lets look at where we have been for the month of October....

We have been well above normal for the month of October. Does this look familiar? It should. Here was last year for the month of October ..

It can be argued that this month of October has actually been warmer then last year across parts of the region.  We all remember how last winter turned out ..

We like to look at certain patterns that build up during the months of October and also November..so these are just going to be some early thoughts but the winter outlook map that we are releasing is basically going to be what we expect this year.

The Arctic Oscillation showed above is shown to be very positive and looks to stay very positive as well. When this happens the cold air gets locked up over Canada and further north and is not able to make its way down into the CONUS.

The North American Oscillation is also on the positive side and is shown to stay on the positive side for some time as well. This also is a feature that allows temperatures to be warmer then normal into the CONUS dependent on the PNA ...

The Pacific North American Oscillation is neutral right now but forecasted to go negative and pretty much stay negative . When this happens any colder air will filter into the midwest and west because it puts a trough into the west and ridging into the east...
This is exactly what we see now ...

We see this 5 days from now ...

And we see this 10 days from now ..

And in between the ridging we have cold fronts moving thru bringing temporary shots of cooler air with low pressure systems cutting to the west because of the ridging in the east. This type of pattern looks to continue at least thru the first 10 days of November.... This is in response to having a positive NAO, a Positive AO and a Negative PNA.
If i were to go out on a limb right now I would say that the month of November will pretty much end up looking above normal by the time all is said and done. This again because of the teleconnections and the pattern in place.

So the pattern is not in our favor for cold weather. However there are other things we have to look at as well. 

The Pacific Decadal Oscillation index. According to http://jisao.washington.edu/pdo/PDO.latest , the PDO is negative. -0.48 . 

The Pacific Decadal Oscillation (PDO) is a pattern of Pacific climate variability similar to ENSO in character, but which varies over a much longer time scale. The PDO can remain in the same phase for 20 to 30 years, while ENSO cycles typically only last 6 to 18 months. The PDO, like ENSO, consists of a warm and cool phase which alters upper level atmospheric winds. Shifts in the PDO phase can have significant implications for global climate, affecting Pacific and Atlantic hurricane activity, droughts and flooding around the Pacific basin, the productivity of marine ecosystems, and global land temperature patterns. Experts also believe the PDO can intensify or diminish the impacts of ENSO according to its phase. If both ENSO and the PDO are in the same phase, it is believed that El Niño/La Nina impacts may be magnified. Conversely, if ENSO and the PDO are out of phase, it has been proposed that they may offset one another, preventing "true" ENSO impacts from occurring.
Warm PDO

The broad area of above average water temperatures off the coast of North America from Alaska to the equator is a classic feature of the warm phase of the Pacific Decadal Oscillation (PDO). The warm waters wrap in a horseshoe shape around a core of cooler-than-average water. Impacts from the PDO depend in part on how it is aligned with the ENSO cycle; if the cycles are in opposite phases, then effects will be weakened. However, when both the PDO and ENSO are in the warm phase, meaning ENSO would be in the El Niño phase, expected impacts on the southeast include:

Below average winter temperatures

Above average winter precipitation

Cold PDO  (negative) 

Opposite of the warm PDO, the expansive area of below average water temperatures off the coast of North America from Alaska to the equator signals the cold phase of the PDO. The area of warmer-than-average sea surface temperatures in the central Pacific are surrounded by below average temperatures near the North American continent. Expected impacts from a cold PDO and ENSO (La Nina) phase on the southeast include:

Above average winter temperatures

Below average winter precipitation

As mentioned we are in the cold phase of the PDO which is negative and this generally means warmer then normal temps across the southeast.

The Quasi Bennial Oscillation...

Quasi Bennial Oscillation  (Positive) 

The quasi-biennial oscillation (QBO) is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards at about 1 km (0.6 mi) per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found.

Effects of the QBO include mixing of stratospheric ozone by the secondary circulation caused by the QBO, modification of monsoon precipitation, and an influence on stratospheric circulation in northern hemisphere winter (the sudden stratospheric warmings).

According to http://www.esrl.noaa.gov/psd/data/correlation/qbo.data  the QBO is 13.12 on the positive side. 

Finally there is the ENSO STATUS..

According to the following link 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• ENSO-neutral conditions continue.* 

• Equatorial sea surface temperatures (SST) are near average across much of the 

equatorial Pacific Ocean. 

• ENSO-neutral is expected into the Northern Hemisphere spring 2014.*

So what we have is a negative PDO and a Positive QBO along with Neutral conditions. So in order to get an idea about the upcoming winter we have to go with winters that had the same teleconnection state of atmosphere. 

First we will look at all the Neutral ENSO years....

1960-61 Positive PDO  Negative QBO

1961-62 Negtive PDO   Positive QBO 

1962-63 Negative PDO  Negative QBO 

1966-67 Negative PDO  Positive QBO 

1967-68 Negative PDO  Negative QBO 

1978-79 Negative PDO  Positive QBO 

1979-80 Negative to Positive Negative QBO 

1980-81 Negative to Positive Positive QBO 

1981-82 Positive PDO  Negative QBO 

1985-86 Positive PDO  Positive QBO 

1989-90 Negative PDO  Negative QBO 

1990-91 Negative PDO  Positive QBO 

1992-93 Positive PDO  Positive QBO 

1993-94 Positive PDO   Negative QBO 

1996-97 Negative to Positive Negative QBO 

2001-02 Negative to positive to negative Positive QBO 

2012-13  Negative PDO  Negative QBO 

Those are all the Neutral ENSO years and we have listed the PDO and the QBO as well for those years. Remember we have to look for years that have not only a neutral ENSO status but years that have a NEGATIVE PDO and a POSITIVE QBO...

Which leaves us with : 

1961-62

1966-67

1978-79

1990-91

Two of which were cold ..one which was average and one which was warm across the east and the southeast. 

So what we have decided to do is take a blend of the 4 remaining analog years and we came up with the following for temperatures...

We have come to this conclusion based on the fall pattern that is in place and along with the analog years. We think that the winter will contain alot of back and forth which will lead storms tracking the the west of the region. Snowfall we expect to be above normal in the Midwest and Extreme Northeast and average in the rest of the NE and east with below average in the SE region. The mid Atlantic could end up being the battle zone for winter storms. 

We feel again this will be a winter that could very well leave those in the east with a bitter taste in the mouth. 

One final thing we are watching is the solar activity and sunspots because if it continues to remain active this could strengthen the Polar Vortex over Alaska much like 2011..

We will issue further information before the start of Winter 2013-14.