Anthony left a very timely comment in the blog yesterday asking about the La Nin/El Nino (ENSO) effects on the weather with particular focus on the wild weather we are having so far this year in the U.S. I say “timely” because I just gave a presentation about El Nino and La Nina to the Central Wisconsin Boating club AND the latest monthly ENSO diagnostic discussion from the Climate Prediction Center was released yesterday.
First the details on the current situation. The La Nina gradually came to an end in May. Now we are seeing neutral surface temperatures in the central Pacific ocean. What do neutral ENSO temperatures mean for our weather? Not much really. All it means is that La Nina or El Nino will not be affecting our weather this Summer. Neither of these has a very strong effect on our Summer weather anyway. The major effects usually happen during the cold season.
What lies in the future? Most of the CPC ENSO models are predicting essentiallyneutral conditions through the end of this year. Once again the COLA CCSM3 is the very odd “man” out predicting a record El Nino to develop (around 2.6 degrees above normal). At least this is better than last month when this same model was predicting a super-mega-monster El Nino of almost 3.0 degrees above normal. Even though the average of the models is still predicting neutral conditions, I did notice a slight shift toward the warmer side of ENSO so perhaps a weak El Nino is in the cards. Just remember that even though El Nino and La Nina are opposites, they don’t always follow each other. It is not like a perfect sine wave oscillation.
Now on to the question as to whether La Nina played a part in this year’s wild weather (mainly during the Spring). My instinct is to say yes. At the NWS Green Bay media seminar last month they shared data showing that La Nina typically did not have a strong influence on our Winter weather here in Wisconsin, however I have noticed that the last three La Nina Winters have been colder than normal with above normal snowfall (in Wausau). Perhaps a new trend is developing that wasn’t present in the past. With the (seemingly) La Nina induced colder weather in the northern half of the country this Spring, and warmer than normal temps over the Gulf of Mexico and southern U.S., it certainly seemed to set up a clash of air-masses a bit stronger than in past years. So I would say (preliminarily) that La Nina did have some effect on the wilder weather (and severe weather) this Spring.
A more significant ENSO Summer-time effect that might come into play is in relation to the hurricane season. When there is an El Nino occurring in the Pacific ocean, it usually has a dampening effect on hurricanes in the Antlantic. When the ENSO pattern is either neutral or in the La Nina phase then more stronger hurricanes are likely to occur and they tend to occur closer to the shores of the U.S. In fact, during the 2005 hurricane season when the ENSO temps were neutral, we had two category 5 hurricanes in the Gulf, Katrina and Rita. There is no guarantee we will have a repeat this year, just that stornger hurricanes are more likely.
Remaining Snow as of June 9th
How about an update on the snowmelt contest? I hiked up to the snow once again yesterday and took a picture. The 90 degree weather from earlier this week really did a number on the snow but there is still some left. Due to the colder trend for the next couple of days I think the contest will be prolonged into next week. I don’t think it will quite make it to the 20th but we shall see. Be sure to check here for more updates and pictures throughout next week.
Lastly, a little eye-candy for you on this Friday to help you whittle away the work-day. Perhaps you have seen this around the net already – the biggest explosion ever seen on the sun. It might not be the biggest ever, but it the biggest scientists have ever observed. This one was unique in that some of the plasma from the explosion rained back down on the sun. Check out the cool video here.
Have a good weekend! Meteorologist Justin Loew.
Posted under ENSO Update, Hurricanes, Snowmelt 2011, Space
This post was written by jloew on June 10, 2011