2014-2015 Winter Forecast

christmas01

Winter is here again and Christmas is coming. It seems like Christmas comes sooner and sooner every year. This winter looks to be an interesting one.

What do I look at to predict what this coming winter will be like? I look at El Nino Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and now Northeast Pacific Warm Pool (NEPWP).

Here is why I added NEPWP to the forecast. Last winter, the NEPWP was very warm, which created ridiging over Alaska and Northwestern Canada, which allowed cold air to go down south into the Lower 48. It allows the East Pacific Oscillation (EPO) or North Pacific Oscillation (NPO) to be in negative, which allows riding.

I have also included the temperature anomaly of Baffin Bay and Hudson Bay. I call it Baffin Hudson (BH). I used the same method for NEPWP. It is based on a weighted average with Baffin Bay being weighted more than Hudson Bay as Baffin Bay temperature is more likely to correlate with North Atlantic Oscillation (NAO) and Arctic Oscillation (AO).

20141222_SST_GlobalAnomaly

Since El Nino is developing, I do not put much weight on PDO as PDO warms up with El Nino, like it happened in 2009-2010. This past winter was a borderline Neutral/La Nina. Here are analog winters solely on El Nino with a previous winter that is Cool Neutral to Weak La Nina.
1888-1889
1972-1973
1976-1977
1994-1995
2002-2003
2003-2004
2004-2005
2009-2010

So, how was Winter like in those analog years? Let’s start with temperature as it is on everyone’s mind when it comes to Winter.

2014-2015_WinterTemperatureAnomaly_NH

East of the Rocky Mountains is a cold one in those analog years. However, if you are in the Western Canada and Alaska, it is a warm one. It is brutally cold over Canadian Arctic Archipelago, Arctic Ocean, Siberia, and most of Russia. Most of the cold air for America comes from Arctic and Siberia. It also colder than normal in Southern China. Believe it or not, it can snow in Hong Kong despite being in a tropical latitude. It occurs mostly in the mountains where the air is colder.

The reason for cold air in Hong Kong is the large Asian continent and to the north. Land does not allow cold air to moderate, unlike here in North America, where we have the Gulf of Mexico, Pacific, and Atlatnic on all sides. Asia only has the Pacific to the east and South China Sea to the south. There is no ocean to the west as it is all land mass. Okay, let’s get back on topic. I think we could see multiple cold blasts this winter as I will explain later. This time let’s look at precipitation in those analog years.

2014-2015_WinterPrecipitationAnomaly_NH

Winter is wetter the further south you are in America. It is dry in the Pacific Northwest and around Appalachia. I suspect that data is suspect as I included 1888-1889, in which data is limited. The wetter than normal winter is good news for drought ridden California, Arizona, New Mexico, and Texas. El Nino is generally more favorable for rain. El Nino usually causes water to be warmer off the West Coast of America. Warmer water generally means wetter because warm air from the ocean water carries more moisture. Also, warmer water causes jet stream to go further south due to gradients in temperature. The jet stream allows storms to go over southern half of America and can bring cold air. This also increases the chance for winter weather events from freezing rain, sleet, and yes snow. Miami saw snow in 1977, which is one of the analog years I have.

In Southeast Texas, snow has occurred in these analog years.
1972-1973
1994-1995
2004-2005
2009-2010

1972-1973 has the most over 1 inch snowfall for Houston. There were three snowfall events that winter! A rarity for Houston area for sure. I think this Winter could see more winter weather events including snow.

Let’s look at the upper level at 18,000 feet.

2014-2015_500mbGeopotentialHeightAnomaly_NH

There is a lot of ridging over Alaska, Canada, Greenland, and Russia. Ridging over the area is more favorable for cold air to be shunted southwards. All the cold air shunted southwards makes Alaska and Northwestern Canada warmer. This increases the liklihood for cold blasts in the winter. Ridging over Alaska is a negative East Pacific Oscillation (EPO), while ridging over Greenland is North Atlantic Oscillation (NAO) and Arctic Oscillation (AO). The ridging over Eastern Russia is the West Pacific Oscillation (WPO). There is also ridging over North Central Siberia, in a unnamed atmospheric oscillation. Perhaps, scientists will identify and name that one.

The warmer than normal waters in Baffin Bay, Bering Sea, and Gulf of Alaska are more favorable for upper leveling ridging. Last winter was cold in part because of the abnormally warm Gulf of Alaska, which I call it the Northeast Pacific Warm Pool.

So, what will Winter be like? Depending on where you live, it could be warm or cold. For Southeast Texas, it is looking to be a cold and wet winter. Here is a table of average temperature in those analog winters. 1888-1889 is missing as it is from divisional data. It only goes back to 1895.

2014-2015AnalogTemperatureTable

For America, analog winters are slightly warmer than normal. That is due to the Western US being warmer than normal. Texas is cooler as cold air is more likely to go east of the Rocky Mountains. It is also due to the fact that the jet stream is further south than normal, which allows clouds to go over. The clouds keep things cooler. This also applies to the Upper Texas Coast.

2014-2015AnalogPrecipitationTable

Not much difference in terms of precipitation for America as it is within the means. However, median is slightly higher than nromal in terms of precipitation. One of the analog winters, 1976-1977 is the driest on record. For Texas and Upper Texas Coast, it is wetter than normal. As mentioned, the jet stream is further south than normal, which allows storm systems to go over and dump rain. One good thing about El Nino is the rain for Texas.

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