Thursday, May 25, 2017

What a difference a year makes:


Last Summer, into December was dry across the Northeast and Mid Atlantic. Here are a few images from U.S. Drought Monitor for 2016, that show how dry we were.

 

The last 60-90 days has been wet across the eastern half of the CONUS.
From WeatherBELL 

Our drought in the Northeast has been erased. It has been replaced with well above average precipitation this Spring.




 

Soil Moisture chart shows just how wet we are now compared to May of 2016.



 

From WeatherBELL

The next 2-3 months look to be a bit wet. Now given the landfall possibilities I out laid in my hurricane outlook. The Northeast could end up with a tropical system bringing a lot of rainfall. So there is a chance we could be very wet by this Fall.

Climate Prediction Center:

Bit of house cleaning:

I've been asked many times, why don't I refer to or show the CPC three month temperature and precipitation forecast outlooks?

My answer is they are not a true forecast. Instead they are based on a percentage of the odds of probabilities. They are rated on an A,B,C score.  A is above average, B is near normal and C is Below normal. With EC meaning equal chance. For example

Forecast probability anomalies OF 20%, 30% and 40% for above normal

imply probabilities for all three classes (above, near, below)OF 53.3% - 33.3% - 13.3% --- 63.3% - 33.3% - 3.3% AND 73.3% - 23.3% - 3.3% respectively.

 

Here is the current CPC three month outlook for temperature and precipitation.

 


Here is the chart I did for my summer outlook. This is an actual forecast that can be verified.

 


Anyway back to my post.  

 

I've been saying for months, that this Summer will be a lot cooler than last Summer. I've been saying average to slightly above average for temperatures. Looking at some of the models we can see they are calling for the summer to be cool.

 

The next 6 weeks are forecast cooler on average in the EPS.

 
From WeatherBELL

The CFS latest run has the nation cool.

 

From WeatherBELL

We have a + Atlantic Multidecadal Oscillation (AMO) and a + Pacific Decadal Oscillation (PDO), this would explain at least in part, why the Spring has been behaving like it has.
 
The +AMO would also help account for the active severe season this year. There seems to be a linkage that shows an increase in the frequency of tornado outbreaks, when we have a +AMO. There is also some evidence that suggest + AMO leads to greater numbers of tornadoes associated with landfalling tropical cyclones.    


The Teleconnections are at odds on the ENSO. Many are backing off from the chance for El Nino developing.

From Tropical Tidbits.

Looking at the surface temperature anomalies  you can see how much colder (relative to average) the Central to Northeastern CONUS has been.
 
 


Since the first of the year, Sea Surface Temperature Anomalies (SSTAs) have warmed in the eastern tropical pacific, but cooled off in the Gulf Of Mexico ( GOM) and western Pacific and  the central Atlantic.  While the northern Atlantic and southern Pacific Ocean have warmed.
 

 
My estimate of the daily Nino 3.4 index is +0.7 which is a El Nino index Value. On the other hand, NOAA has the weekly Nino 3.4 at +0.4, a neutral value.

 
The SOI



I still believe we're going to see a weak El Nino Modoki (central based) this Fall going into the coming winter. If I'm right, we're going to see an active and cold winter for 2017-2018.

This is how things have gone so far, and where things look to head for the next three months.

Well that's about it.

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