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Thoughts on the CSU Hurricane Season Forecast

By: MAweatherboy1, 9:02 PM GMT en Abril 04, 2012

As you probably know, the annual April hurricane season prediction was released by Colorado State University (CSU) today. Their forecast numbers for the season are:
*10 named storms
*4 hurricanes
*2 major hurricanes
Clearly these numbers come as a major disappointment for many of us storm lovers. However, after looking through CSU's forecast, I've found a few rays of hope that could make this season more active than they have indicated.
*First and probably most important: CSU has to be at least somewhat conservative with their forecast, particularly in a season like this when there is a great deal of uncertainty as to how this season will play out. If they came out predicting higher numbers, they would potentially be setting themselves up for a major busted forecast. Next, here's a few more specific things they talk about...
*As has been stated pretty much everywhere, there is significant uncertainty as to how the ENSO will end up this year. While we certainly will not see a dominating La Nina like we did last year (nor will we see any La Nina) it is still entirely possible we will not go into El Nino and instead remain at a warm neutral level, or potentially not transition to El Nino until fall. If the El Nino does not develop as forecast, which is a real possibility, the numbers will likely be higher
*Staying with the El Nino theme, CSU puts a lot of weight on the European forecast model (ECMWF). This model has been one of the best performers for ENSO prediction in past years. However, I am wary of putting so much weight on it for two reasons:
1. It has been more aggresive with the El Nino than the vast majority of the models. I think more of a consensus forecast should have been used by CSU.
2. The Euro has been terrible at forecasting this Winter/early Spring, at least by its high standards, particularly in the longer range. While ENSO forecasting is much different than day to day forecasting, it still worries me that they weight the Euro so much
* Next, they explicitly note that the Eastern Atlantic is much cooler than average, but fail to mention extreme warmth in areas like the Gulf of Mexico. While the cool waters of the East Atlantic will heavily limit activity out there, the warmth in the Gulf could cause a large number of storms to form there or to form in the Caribbean and then strengthen in the Gulf. Ironically, they also talk about how the positive NAO has slowed warming in the Atlantic, just as the NAO plunges way negative for the first time in months. Obviously the NAO is a very unpredictable factor that could cause SSTs to be warmer than expected.
* With La Nina gone, the odds that Texas will suffer major drought decreases, meaning storms that form in or enter the Gulf have better odds of strengthening. This may not increase total storm number, but it could cause stronger storms closer to home. We saw the Texas drought wreak havoc on Don last year, but that should not happen this year.
* They talk about how wind shear has been high lately, but I think it is unwise to seriously consider current shear conditions so early in the year because it can change so easily and obviously has plenty of time to do so.
* Another classic reason: Simply the fact that we can never predict these things for sure. What's going to happen is going to happen no matter what anyone says, so we certianly shouldn't write the season off.
* And finally, no matter how unactive the season is, one storm can make a season

I don't mean to say CSU is wrong by any means with my above statements, because clearly the people who put that report together are far more knowledgeable than me. I am simply pointing out areas where they could POTENTIALLY be in error. I will stick with a prediction of somewhere around 12-13 storms, 5-6 hurricanes, 2-3 major hurricanes, numbers which are slightly shaved down from my original prediction. The great thing is, we'll be tracking whatever forms no matter what! Less than 2 months left!!!!!!!!!!!!!! (A month and two weeks or so for the East Pac!!)

Thank you as always for reading and enjoy the rest of your week. And because I probably won't post another blog for a few days... Happy Easter!

Updated: 9:46 PM GMT en Abril 04, 2012

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About MAweatherboy1

Just an average 18 year old weather nerd. I work as an observer at the Blue Hill Meteorological Observatory in Milton, MA.

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