By Tim Chuey From Eugene Daily News

There are a lot of things we care about like how our family members and friends are doing here and in other parts of the country, whether we can pay our bills, and even what the weather will be like in our neighborhood tomorrow. Those of us in the Pacific Northwest have, for the most part, not been too concerned with the crazy weather in the eastern US over this past Winter. Why then would we care what the forecast is for the Atlantic-Caribbean Tropical Storm/Hurricane season? As you have probably figured out by now I have the answer to that question. We should care because there is a relationship between the strength of the Atlantic-Caribbean Tropical Storm/Hurricane season and the major Jet Stream flow from the Pacific Ocean over the continental US to the Atlantic-Caribbean hurricane spawning grounds. That relationship is controlled by the phenomena called El Nino, La Nina, and La Nada. I explained that relationship in my column from September 16, 2013 called Whose Fault Is It? Could It Be El Nino, La Nina, Or Even La Nada?

What got me interested in discussing this subject now is the release of the annual report from Colorado State University’s (CSU) Department of Atmospheric Sciences predicting the details of the 2015 Atlantic-Caribbean Tropical Storm/Hurricane Season. The renowned Professor Emeritus of Atmospheric Science at CSU William M. Gray has become famous, infamous to some, for his hits and misses over the years.

As of 2006 Gray turned the lead author duties for the report to his top researcher Phillip J. Klotzbach. In this year’s report Gray commented with some humor on his current role by saying “Phil has been making all the final forecast decisions in recent years. He has, nevertheless, appointed me to serve in the important role of taking the blame for all forecast busts with all credit for successful forecasts going to him. I have fully embraced this special arrangement.” Professor Gray says he still goes to work every day and talks with Klotzbach nearly every day so they are usually on the same page, as it were. I’ll get back to the connection between our weather and this report a little later.

Now on to the results of their research for this year’s season. Here is the Extended Range Forecast Of Atlantic Seasonal Hurricane Activity And Landfall Probability For 2015 report’s opening statement: “We anticipate that the 2015 Atlantic Basin hurricane season will be one of the least active season’s since the mid 20th century. It appears quite likely that an El Nino of at least moderate strength will develop this summer and fall. The tropical and subtropical Atlantic are also quite cool at present. We anticipate a below-average probability for major hurricanes making landfall along the United States coastline and in the Caribbean. Despite the forecast for below-average activity, coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for them. They should prepare the same for every season, regardless of how much activity is predicted.”

The report predicts 7 named storms (median is 12), 3 hurricanes (median is 6.5), and 1 major hurricane (median is 2) for the 2015 season. They calculated the probabilities of at least one major hurricane (category 3, 4 or 5) landfall for the entire U.S. coastline is 28% while the average for the last century is 52%. For the U.S. East Coast, of course including Florida, the probability is 15% while the average for the last century is 31%. The storm sensitive Gulf coast that reaches from Brownsville, Texas eastward to the panhandle of Florida also has a 15% probability of a major hurricane landfall while the average for the last century is 30%. They also calculated the probability of at least one major hurricane tracking into the Caribbean at 22% while the average for the last century is 42%. If you want to read the entire report you can go to CSU report for all of the details.

The sea surface temperatures over the Atlantic Ocean have an influence over the formation of tropical cyclones off the African coast, in the mid-Atlantic Ocean, and therefore along the U.S. East Coast. The El Nino in the Pacific Ocean, the warm water pool that forms at the surface in the Eastern Pacific, is in a large-part responsible for this prediction of less tropical cyclone activity this year than average.

Global Sea Surface Currents | Image by global-currents.png

Tropical storms and hurricanes have very rarely struck the U.S. West Coast. I explained the reasons why in my previous column article Why Not Here? It’s Time To Explain. One of the reasons is explained by the sea surface currents in the Eastern Pacific Ocean which deflect the storms away from the U.S. West Coast. (see above)

Here is the answer to the why should you care question.The El Nino controls the basic position of the jet stream and therefore has serious influence over the weather here in the Pacific Northwest. A moderate to strong El Nino gives us a mild winter and what could be in our future, a very warm and dry summer. The warm water pool deflects the jet stream is such a way to keep a ridge of high pressure over the west with the jet diving down to form a trough in the eastern half of the country. Under that ridge we stay generally warmer and drier than normal. That will be problematic for the Pacific Northwest since we have been drier than normal when it comes to mountain snowfall particularly and therefore extremely low snow packs.

Without the snow melt runoff the forests and much of Oregon will possibly be dangerously dry which could produce the perfect conditions to generate very serious wildfire conditions. This would be a good time to do perform some fire prevention measures around your home. Clean up and debris, remove brush in a ring around the structures so a fire would be less likely to spread onto your property engulfing your house. Your local Fire Department and the Forest Service can give you the details.

Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].

Tim Chuey is a Member of the American Meteorological Society and the National Weather Association and has been Awarded Seals of Approval for television weathercasting from both organizations

IMAGES:

William M. Gray (Right) And Philip Klotzbach | Photo by hurricane.atmos.colostate.edu

Global Sea Surface Currents | Image by global-currents.png

Willamette Pass Resort Lodge (What It Should Look Like) | Photo by Willamette Pass Resort

For more on this story go to: http://eugenedailynews.com/2015/04/care/