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ABSTRACT:
We are looking at an extremely variable winter, with many possibilities as to what could occur. Overall however I am looking for an average to slightly above average winter temperature wise in the Mid-Atlantic including the following states: North Carolina, South Carolina, Virginia, Maryland, DC proper and southern New Jersey. Likewise I expect average to slightly above average precipitation in these areas (not just snow)… snow itself I feel could wind up average perhaps slightly above average. In the Northeast I expect normal to slightly below normal temperatures, with above average precipitation in which snow could be average to above average.
ANALYSIS:
While I have already given the general overlook, I suggest that you read on as to understand why I have predicted the above. The following analysis is not intended for an amateur audience as it is hard to write a good forecast without getting in-depth, however I will do my best to keep the attention of everyone.
One of the most important factors determining the strength of cold air this winter will be the snow cover. Yes the NAO and PNA will play a role in determining cold air, however this will determine more the fact of whether or not we have the opportunity for cold air and how often. The actual strength as usual is determined by the amount of NH snow cover. This said this brings us into our first problem with the forecast. The current snow cover is well below average in many areas.
http://www.socc.uwaterloo.ca/_images/snow/current.gif
http://www.ssd.noaa.gov/PS/SNOW/DATA/cursnow.gif
While the figure in early October doesn’t directly correlate to what the winter will feature, we are still very well below average. The problem being that winters with below average snow cover in central and northern are always and I reiterate always milder then average for the east coast. There are no exceptions. We cannot compare to last year however, because last year was a record setting snow cover, however the fact remains we need some snow cover and fast if we want really cold air in the east. The PV is hanging out over the pole now however, this would mean that it's not likely anytime soon the snow cover will rapidly increase. It does appear though that the models are becoming bullish on bringing the PV south towards Alaska, this would support cold air over Canada and the possibility of some snow cover build up there. IF the snow cover becomes respectable then it's very likely that once we see a -NAO and supporting pattern that the cold air could be quite extreme. Last year many can remember the pain of watching storms sinking south only to hope for that infamous northern trend. This can be directly attributed to the record setting snow cover in Canada that caused such cold air that the storm track was quite suppressed. Hence the Outer banks receiving 8-12" of snow.
http://cyclone.plymouth.edu/cgi-bin/gen ... &cu=latest
That setup looks generally fair for some cold air in Canada. In the abstract when I mentioned average or above average temperatures generally, that is taking the pessimistic side of the snow cover, if snow cover builds up then this will be revised to call for generally colder conditions.
Well that pretty much beat the snow cover issue to death there, but that is a very important factor, now moving onto some other issues. The next HUGE part of this winter is going to be ENSO. In general it would appear that a weak El Nino may develop the second half of this winter. With neutral conditions dominating October through at least January, the weather will not rely solely on the ENSO forecast.
http://www.cpc.ncep.noaa.gov/products/a ... ng/lanina/
***Those are the SST's currently. They have been warming near the ENSO region over the past few months in support of a weak El Nino that may develop.***
With a La Nada the winter has the potential to be extremely variable, depending heavily upon what other teleconnections do, like the NAO, QBO and the PNA etc. I'm not a big fan of long range climate models, I prefer to use climatology and analogs instead. With that said, I have examined the analogs, and have looked for the following concerning MEI (multi-relative Enso index). In 2002 the MEI index broke 1.1 thus a moderate El Nino had developed. After that it steadily decreased finally falling to neutral and down to -0.003 in June 2003. This was the closest we got to a La Nina, a La Nina never did affect the CONUS weather as it never really toke shape. As of September the index read 0.455 still considered neutral however coming steadily back up. Some years that appeared like this were 57, foretelling a 58-59 winter. 65 also looks like it could fit for Enso, meaning 66-67 possibly however this one would be loosely interpreted. 73-74 could also be a possible one to look into because of Enso. Even if you aren’t big into analogs, some basic ENSO theorems can help to predict it. We have been pretty steadily La Nada for about 6 months now, with changing atmospheric conditions it will be hard to keep this going much longer. Sometime by January I would expect a weak El Nino to develop. With the Enso becoming Nino mid to late winter possibly, I would again expect that this would create a stronger STJ with more gulf moisture and the chance for more coastal systems. Some basic SST principals is what I would like to cover next.
http://www.longpaddock.qld.gov.au/
If you look there at the SST mean for September you will notice a few significant things in the Pacific. A very cold build up off of Japan that is even now persisting can be noticed. A cold pool in the Enso regions 1+2 that has been progressively getting warmer can be noticed however. There is very warm northern and western Pacific, with very warm waters near Alaska and a small cold pool to the east of that very warm water. This tells us a few things. First off, the cold pool off of Japan is due to a trough pattern that has persisted there, this can be directly teleconnected to the amplified trough in the east for September. The northern warm Pacific is significant of a -EP pattern. When this occurs very warm waters near Alaska causes the mean height rise to be in the northern Pacific, also occurring a trough in the eastern Pacific (noted by the cold pool east of the very warm waters). The stronger this pattern is, the more this pumps the ridge in the western United States, creating a +PNA pattern. -EP's are also more common with an El Nino, leading me to believe that a -EP could be evident as a weak El Nino develops, this would lead to a +PNA pattern dominating the winter and more so likely in the mid to late winter. The next thing I want to cover is the QBO. A western QBO is usually better then an eastern QBO for the east coast as it creates a blocking pattern and likely cooler conditions. In Nino east when i did comparison, conditions were not horrible however they reeked of +NAO and a -PNA because there were high heights over the northeast and lower heights over the Pacific northwest.In Nino west there were cooler conditions in the east with warmer conditions in the southwest telling that a western ridge was evident therefore a +PNA and what looked like a -NAO. So the question is when will the QBO shift west?
http://www.cdc.noaa.gov/Correlation/qbo.data
It APPEARS as though the QBO has bottomed out, as it has come up to -22.51 from being -24.64 in August. The October number will be critical because we will further grasp how quickly this may be becoming Westerly. Climatology suggests that in past years, QBO east's that have bottomed out around -20-24 have taken on average around 3-4 months to come back to west after they bottomed out. It seems on average that Easterly phases last longer then Westerly phases do, generally in the 10-13 month range, with ones that bottomed out in the -20's taking closer to 13 months to come back to west. Since we bottomed out at -24 and as of September were in the 10th month of the easterly phase, it seems as though we may have 3-4 months to go before seeing the westerly phase of the QBO take shape. That would place us in December to January. I personally think it is more likely to be January possibly even February before we see the westerly phase of the QBO. It really depends on how fast the numbers rise towards 0, making the October number very critical as we will then be able to establish with good reason what the QBO may be doing. As far as ENSO and the QBO are concerned here is how I see it month by month.
October: La Nada- Increasing West (-20 to -15)
November: La Nada-Increasing West (-15 to -10)
December: La Nada- Increasing West (-10 to -5)
January: Near El Nino-Near Westerly phase (-5 to 0)
February: Weak El Nino- West (0-2)
March: Weak El Nino- West (2-5)
Well that about takes care of ENSO and the QBO and most of the teleconnections I wanted to cover. So let me point out a few key features and things to watch for this winter, and then I will break it down and give the month by month deal.
This winter some key features to look for will be:
• Build up of snow cover as we head towards November
• SST patterns
• QBO number for October and monitoring its progress through the winter
• -NAO, +PNA, and other teleconnections
• ENSO patterns
• Caspian Connection
• Solar minimum conditions
For those that don’t know about the Caspian connection, it is when there is a ridge east of the Caspian Sea that helps to push the PV over the poles and into Canada. It is a very important event as it can help foretell future cold air outbreaks in the US.
One thing that is good is that we are not at a solar maximum and solar activity has been on the decrease recently.
So after all of that, what am I seeing month by month for the winter months?
Starting with December:
I believe December will be near average all around for the east coast with the midatlantic probably being above average temperature wise, although not by much, as for. Normal temperatures and normal precipitation is what I believe could happen further north with average precipitation also applying to the midatlantic. With a very variable atmosphere that could be a big player in this month, look for 1-2 minor to moderate snowfall events for the east coast.
January:
Average too slightly below average temperatures for the northeast with average temperatures further south. This month I expect to start to be the turning point for the winter as we head closer to February. If El Nino starts to develop during this month then the second half of January could feature cooler and wetter conditions, if it holds off then the month will be near average conditions for the most part. This month may feature 1-2 minor to moderate events, maybe 3 if conditions improve.
February: This month may be where the winter is made. As conditions improve to Nino West, we will start to see the STJ become more active, if we get enough cold air then we may see below average temperatures in the northeast with average to slightly below average temperatures further south. For precipitation, with the storm track most likely up the eastern seaboard, its possible that snowfall is above average for both areas, with more snow falling in the northern areas. Look for 1-2 moderate events during the month, with significant cold air possible and maybe 1 event that is more significant.
March: There is no reason that March can't feature the continuation of wintry conditions as well. Although the month by sure will turn more variable, it may still feature average to slightly cooler then average temperatures further north with average temperatures further south(possible slightly below average as well). As for precipitation I believe both areas may be average to above average, with snowfall being more above average further north and average further south. Look for variable conditions, 1-2 minor to moderate events during the month.
POSSIBLE seasonal snowfall totals for the winter for selected cities:
Where it says probably no more then… that is from the AVERAGE amount
Washington D.C- Average- 23" Forecast- 23+ (Probably no more then 5-10" above)
Baltimore- Average 21" Forecast- 21+ (Probably no more then 5-10" above)
Rehoboth Beach- Average-15" Forecast 15+ (Probably no more then 5-10" above)
Philadelphia-Average 21" Forecast- 25+ (Probably no more then 10-15" above)
New York City- Average 25" Forecast 35+ (Probably no more then 10-15" above)
Hartford-Average 47" Forecast-60+ (Probably no more then 10-15" above)
Boston- Average 40" Forecast 55" + (Probably no more then 10-15" above)
Allentown- Average 31" Forecast 40" + (Probably no more then 10-15" above)
So you see in the midatlantic the highest above average I think will be 5-10" with the potential for 10-15" above average at most in the northeast. However I think totals will stay closer to the actual number predicted next to forecast.
If you want a city added to the list- Try to pick a larger city near you please, then just let me know and I will let you know what I think.
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