Snow Drought Continues

Welcome to the inaugural post on my new domain (!!! I plan on devoting more time to this blog and will do my best to explain the ever-changing weather patterns, so feel free to interact!

The question on many people’s minds so far this year is: “Where is winter?” Short answer. . .it’s hiding in Alaska, Siberia, and regions close to the North Pole. Many of you see no problem with this, but for those of us that enjoy snowstorms, this is getting ridiculous. My biggest concern when moving to the DC metro was dealing with the Beltway or I-95 in general during snow. I’m not too upset with this winter. . .but I figure many would like an explanation and possibly some hope.

Here it is:

Snowfall departure from normal for winter 2011-2012 courtesy of the National Operational Hydrologic Remote Sensing Center.

As you can see above, much of the nation is suffering from a snow drought, while a few remote locations in the Southwest or near the Cascades in Washington state are normal to above. In the last week, some snow has fallen in a few locations, but this is far below what was experienced the last two winters. Below are the snowfall totals so far this year compared to average and the 2010-2011 season (up to this point) for comparison.

City            2011-2012            Normal            2010-2011

Baltimore       0.4"                 5.8"              3.5"
DC              0.6"                 4.7"              3.5"
Philadelphia    0.5"                 6.0"              21.1"
NYC             2.9"                 7.9"              30.9"
Boston          1.5"                 15.8"             40.4"
Buffalo         11.9"                47.8"             50.0"
Cleveland       15.2"                26.2"             28.0"
Chicago         6.8"                 14.3"             22.7"
St. Louis       3.8"                 7.5"              12.0"
Des Moines      6.6"                 15.2"             19.3"
Minneapolis     10.7"                26.5"             49.9"

The departures from normal above average about 10.6″ below normal. Although this seems unprecedented for the time of year, it does not necessarily mean we are not going to see anymore snow. There have been some ridiculous flips in late January/early February in the past.

So, what gives this year? La Nina is a large part of the overall warmth in the east, but does not completely account for the lack of cold and snow in the Plains and Midwest. The North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) have both been positive through the Fall into the early part of this winter. Below are some composite maps of what this does to the pattern across the U.S. Red is warm, blue is cold.

Positive NAO composite map for North America courtesy of the Earth System Research Laboratory (ESRL).
Arctic Oscillation composite maps (positive AO left, negative AO right) courtesy of J. Wallace, University of Washington.
Positive Pacific North America pattern (PNA) composite maps courtesy of ESRL. For a negative PNA, flip the colors in both maps.
La Nina global effects composite map.

A La Nina promotes warmth east of the Mississippi River due to a stronger Southeast ridge with heavier precipitation into the Ohio River Valley. A positive Arctic Oscillation leads to short bursts of cold air into the U.S., but keeps the majority of the coldest air locked up at the North Pole. A positive North Atlantic Oscillation leads to warmer conditions along the East Coast and a storm track up the Appalachians, but little chance for coastal low formations (nor’easters) as the ridge along the Southeast blocks these attempts. Long story short. . .less chance for snowstorms east of the Mississippi.

Where do we go from here? First I’ll break down the teleconnections one by one and then I’ll give you my forecast.

Sea Surface Temperature (SST) anomalies animation courtesy of the Climate Prediction Center (CPC).
SST anomaly forecast from various climate models for the rest of 2012 into 2013 courtesy of CPC.

The anomaly animation above shows the colder anomalies in the equatorial East Pacific tied to the current La Nina conditions. Although the cold conditions are abating somewhat, there are no signs of an equatorial Kelvin wave (a wave of warmer water that crosses the equatorial Pacific and leads to warmer (El Nino) conditions – think of water sloshing back and forth in a bathtub). The climate models are not too excited about El Nino conditions developing as we head deeper into 2012, but there are signs of going more towards neutral. This has implications in the longer run, but not so much for the next two months. The Southeast ridge looks to continue as we head towards February and therefore, I would expect warm (relative to averages) temperatures and below normal snowfall to continue at least until mid-February.

CPC 8-14 day temperature forecast valid on 01/13/12
CPC 8-14 day precipitation forecast valid on 01/13/12.

As you can see from the 8-14 day temperature and precipitation forecasts from CPC, the conditions we have been experiencing look to continue for at least the next two weeks.

The GFS forecast for the PNA over the next two weeks.
The GFS forecast for the NAO over the next two weeks.
The GFS forecast for the AO over the next two weeks.

The PNA is forecast to slide negative allowing for cold, stormy weather to invade the Pacific Northwest into the Northern Plains during the next few days. The NAO is forecast to bounce positive again, allowing warmer air to flow northeast out of the Gulf Coast states with a storm track that will favor the Great Lakes. With the AO threatening to go negative with time and a stratospheric warming event underway, cold air will continue to make inroads into the U.S. over the coming month.

What does this mean for those of you that like snow and winter?

For DC through Boston, expect brief cold shots (lasting 2-3 days at best for now) with some light snow from time to time, but no major snowstorms are on the horizon. In fact, the storm pattern favors strong warmups (at times hitting 60F+) and possible thunderstorms.

For the Great Lakes, periodic lake effect events will continue and you will slowly make up for lost snow this year. You are not immune to warmups between these events as there is no indication of cold air locking in. . .yet.

For the Midwest, you will receive the brunt of these cold shots, but again 2-3 days at best. As for snow, maybe some pesky snows with the outbreaks, but a couple strong warmups are also possible.

The Gulf Coast into Florida. . .periodic colder outbreaks with a better chance of wet conditions near the western and central Gulf Coast, while FL, GA, SC, and parts of NC will continue to be dry.

On a side note: I will try to focus more time on this blog and update you on significant weather and the changing patterns, so stay tuned! Feel free to ask questions.

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