Ramblings of a Graduate Student

I have previously discussed that the Winter Olympics this year were hurting for snow.  This winter is almost the worst case scenario for the Vancouver, British Columbia, Canada, the host city for the Winter Olympics in the 29th Olympiad.  In fact, the Olympic organizers are having to cancel the general admission tickets for some outdoor sports because of unsafe conditions in the standing room only areas.  This is after warm, heavy rains washed away more than a foot of snow on the mountain and made conditions unsafe for spectators.  This is typics during an El Nino winter – the Pacific Northwest of the United States and the southwest portion of Canada tend to be warmer and drier than normal.  This doesn’t mean that there is no precipitation, but it does mean that what little precipitation (compared to normal) tends to have a greater chance of falling as rain.  This appears to be the case this winter.

Tonight’s image is from the Hydrometeorological Prediction Center (HPC).  It is a forecast of where the middle troposphere highs and lows will be 84 hours into the future (essentially Thursday evening).  To a meteorologist, whenever the middle troposphere has a high (labeled with an H), this often means warm, dry conditions.  Notice that there is an H centered over southwest Canada.  This means that over the next few days, at least, we would expect to find (relatively) warm temperatures across this portion of North America.  Looking at forecasts for southwest British Columbia, it appears that temperatures in the mid 40s are expected throughout the week.  This will continue to melt snow and prevent new snow from falling.  If this forecast verifies, it doesn’t look good for those hoping conditions improve for the Olympics.

As we enter February, one of the world’s biggest sporting events is about to take center stage – the Olympics.  This year’s winter Olympics are being held in Vancouver, British Columbia (Canada) – about 120 miles north of Seattle, Washington.  This part of North America typically experiences a cool and rainy winter, allowing for a lot of snow to fall in the higher elevations – perfect for winter sports.  In fact, the National Severe Storms Laboratory (NSSL) has one of their experimental mobile radars in Canada to provide additional radar support.  (You can view this radar data by clicking here!).  Unfortunately, this year has not been typical.  We are currently in the El Nino phase of the El Nino Southern Oscillation which usually results in a more southern track for low pressure systems and storms across the United States.  For places in the Pacific Northwest, the weather tends to be warmer and drier than normal, and places in the southern United States tend to be cooler and wetter than normal.

The warm temperatures in the Pacific Northwest have resulted in a lack of falling snow, and a melting of snow that has previously fallen.  As you can imagine, this is causing all sorts of headaches for the Olympic Games organizers.  Recent news reports state that the Olympic organizers have resorted to trucking snow in from other mountains to ensure the Games will continue as planned.  Since the Olympic Games start in less than two weeks, I thought we’d take a look at the official National Weather Service forecast (provided by the Climate Prediction Center, [CPC]) for the northwestern portion of the United States.

The image above is the current 8-14 day (10-16 February) temperature probability outlook from the CPC.  Areas shaded in red indicate a greater than 33% chance that temperatures will be above normal during the 7 day period, areas shaded in blue indicate a greater than 33% change the temperature will be cooler than normal, and areas in white indicate equal chances that the temperature will be above, below, or near normal.  As you can see, the CPC does not forecast explicitly for British Columbia, but if we connect the Pacific Northwest forecast with the Alaskan forecast, we can assume that the forecast would be for a greater than 50% chance of above normal temperatures for the start of the Olympic Games.  This certainly is not good for the events requiring snow!

What if the temperature forecast is wrong and temperatures are near or below normal – which would support snow to fall?  Well, the image above is the CPC forecast precipitation probability outlook from the CPC.  It’s similar to the temperature outlook, except green implies a greater than 33% chance of being wetter than normal and brown indicates a greater than a 33% chance of being drier than normal.  Once again assuming what the CPC forecast would be for British Columbia, we see that there appears to be greater than a 40% chance that it will be drier than normal for the start of the Olympic Games.

What about for the entire month of February?  Well, the CPC is once again forecasting a greater than 50% chance of temperatures being above normal…

… and a greater than 40% chance of being drier than normal.

It is important to understand that these are probability forecasts, and not guarantees.  A 40% chance of being drier than normal means that there is a 60% chance of being normal or wetter than normal.  Furthermore, just because an area is drier than normal doesn’t mean that there won’t be any precipitation.  It just means that precipitation will probably be lighter than normal when it does occur and that you may go longer between precipitation events.  The same can also be said of the temperature.

So, if the Pacific Northwest is forecast to have temperatures that are above normal, and precipitation that is below normal, one might think that the chances of a drought occurring should also increase.  Well, in the figure above, you can see that the CPC is forecasting drought conditions to either develop or persist across a good portion of eastern Washington, northern Idaho, and fast western Montana.

The flip side to the drier than normal Pacific Northwest is that southern California and the southwestern United States should be slightly wetter than normal.  This should help with the ongoing droughts there and hopefully help restore water tables to near their normal levels.