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.

10-5-13 Severe Weather Chances

We are going to start this off by saying that the severe weather threat today is going to be a lot lower then the severe weather threat was yesterday. Overall the guidance is not to impressive with severe from the NAM to the SREF... 

We do have a cold front that is slowly making its way to the east ..You can see this in the image below:

A stationary front is draped across the northern tier . The main threat with this cold front advancing to the east will be heavy rains . This cold front eventually will pick up what is left of what is still being called Tropical storm Karen which will help to enhance the rainfall..

Parameters today are not all that impressive.. 

Shear is greatest behind the cold front and not really in the vicinity of where the severe weather possibility is today. You can see that back behind the cold front the shear is about 70 knots. So one factor against a higher end severe is the lack of shear out with the cold front ..

Instability of CAPE is not as impressive today as it was yesterday with the range generally in the 1000 + with some isolated higher pockets...

Energy Helicity Index is generally around 1 or below with just a small isolated area in SW Ohio where it is slightly higher. This pales in comparison to what was showing yesterday and to tie in with this Helicity itself is not a factor ...

Which generally means that this will not be a day where we should see any Tornado's. 

The above is the NAM valid in the evening timeframe. 

Dew points and temperatures out ahead of the front will continue to be on the warm side with temperatures in the 80s and dewpoints in the 60s

So overall we are not very impressed with severe chances today and we think that the main threats with any severe would be damaging winds along with the possibility of some hail. 

The above reflects the area where we think will have the possibility for a chance of severe thunderstorms. Again, keep in mind , parameters are not very impressive and neither is the guidance . It would appear that heavy rain is going to be the main threat... This is showing rainfall for the next 2 days..

Severe Weather October 4th -Moderate Risk Needed

This is the 00z NAM at 27 hours out or 11 PM this evening. As we will show ingredients are in place for a severe weather event to occur ..However.. the highest impacted area will be in the vicinity of the area of low pressure to the North near and around Iowa..

The culprit will be a warm front that is draped across the north and a cold front that will be moving to the east. An area of low pressure will move along this cold front and be in a position near Iowa later this evening. The air out ahead of this cold front is quite unseasonably warm for this time of the year with temperatures in the 80s

Dew points in the 60s. Almost reminds one of a summer day even though we are now in the fall season.

As we mentioned all ingredients are in place.. when you have this type of heat in place..a strong trigger , as in a cold front with much colder air behind it ..and the dynamics in the atmosphere..it spells trouble with a capital T...

Lets look at the dynamics that will be in place...

We are going to start with two images that are really kind of "serious " images and that would be the Energy Helicity Index and the Helicity image...

You can see that the EHI is well above 1 across the region of Iowa. The NAM is actually showing EHI between 6-7. This is suggestive of Tornados and some that could be long tracked tornado's.

Helicity is not much better...

As you can see the Helicity itself is quite high at 300 +. Factoring this with the EHI brings a real concern for Tornadic activity and we have this area highlighted in red on our map.
Now when you have these dynamics in place then factor in shear and CAPE or convective Potential Energy.. You have the potential for an outbreak.. And we do have the shear in place...

50-80 knots of shear forecasted to be in place. 

Convective Available Potential energy 2000 + .. Lift in the atmosphere is around -8 to -10 .

You can see why we are saying that all the ingredients are in place for a significant severe weather outbreak. And we have this area as we mentioned highlighted in red which would be a moderate risk for Tornado's, wind damage and the potential for hail.

If you reside in the red zone please keep your eyes to the sky and make sure you have your NOAA weather radio near by and please seek shelter and heed any warnings that may occur... We wish everyone in path of this storm system to stay safe...