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.

Friday, April 7, 2017

My April, 2017 Atlantic Hurricane Outlook.


Back on March 26th I posted my thoughts on how the hurricane season looked to unfold.  Looking at everything, I really haven't changed my mind. As far as I can see, I was the first or just about the first to post numbers on the 2017 hurricane season. I wanted to post before the Annual National Tropical Weather Conference was held this year.  I also wanted to beat Colorado State University's April outlook. Why? Because I wanted to make it clear that my ideas are sound, and lay the groundwork , by getting my predictions out there first.

The Atlantic hurricane season runs from June 1st until November 30th. But that doesn't mean tropical cyclones can't form before or after those dates.

Back in March, I said my analog years were, 1951,1953,,1957,1972,1997,2015. Since then I looked at and added 1965, 1976, and 2002. All of these years had some similarities to 2017.


Teleconnections:

The North Atlantic Osculation as primarily been positive since January.  So the North Atlantic Sea Surface Temperature (SST) anomalies have been cold. The cooling off of the SST increased in March.  So now we have cool SST in the North Atlantic, cool tropical SST off the West Coast of Africa, with warm SST off the East Coast of the United States. This places the Atlantic Multidecadal Oscillation (AMO) in a basically negative phase.

The  El Nino-Southern Oscillation (ENSO) is currently neutral. I've been posting on My Facebook weather pages, and I also talked about it in my March 26th blog post. So I won't go into a lot of detail on that. But, the ENSO looks to head for El Nino conditions. During the 2016 hurricane season we were experiencing a strong El Nino. Then late in the fall we transitioned into La Nina. During winter 2016-2017 the La Nina stayed very weak. This is one of many reasons why the winter turned out the way it did.

This year I don't think we will see the return of a strong El Nino. Instead I think it will be weak to moderate.  I don't think we will see a El Nino until at least mid-summer. Right now, the atmosphere is still acting like we have a weak La Nina; it will take awhile for the atmosphere to catch up. So, there wouldn't be Atlantic influence until we get into the hurricane season. 

Predictions from other major weather outlets.

Colorado State University (CSU):

They issued there outlook on the 6th of April, 2017. The team from CSU said they expect 11 named storms, 4 hurricanes, 2 of them major Cat3 or higher.

Accuweather:

 Issued their hurricane forecast April 5th, 2017. They say 10 named storms will form, 5 will become hurricanes, 3 will become major.

Tropical Storm Risk, INC (TSR):

TSR a prestigious private hurricane forecasting company in Britain, issued their hurricane outlook on April 5th, 2017.  They say they expect, 12 named storms, 6 hurricanes, 2 of them major.  

Weatherbell:

They released their thoughts on numbers for the 2017 season, on 31 March, 2017. They have listed, 10-12 named storms, 4-6 hurricanes, 1-2 of them major.

The numbers I released on the 26th of March, 2017:

I said, my early thoughts were, 10-12 named storms, 3-4 hurricanes, with 1 major.

Last season's tropical cyclone numbers:

In 2016, there were 15 named storms, 7 of them became hurricanes, with 4 major hurricanes.


The bottom line:

The combination of a positive AMO and El Nino will increased trades winds over the Main Development Zone (MDZ) of the tropical Atlantic.  We also have those cool SSTs, in the eastern Atlantic.  All of this will severely curtail tropical development in the MDZ.  So the odds of Cape Verde tropical storms will be much lower than average.  This same thing happened in 2016.

Those warm SSTs off the East Coast of the U.S., and the warm waters in the Gulf of Mexico and Caribbean will set the stage, for tropical cyclone development in the western Atlantic Basin.  As was the case last year, most of the tropical development should develop closer to the U.S. main land.  The warm SSTs also, increased the odds of stronger hurricanes coming up the East Coast.

My Call based on right now, is 10-12 named storms, 4-5 hurricanes, with 1-2 of them major.
 

If I have to adjust anything, I will release an updated outlook, during the last half of May.
 
 

Thursday, April 6, 2017

Summer 2017 Outlook


Despite busting  my winter 2016-2017 temperature outlook, my snowfall outlook got it right for the most part. Which shows, you can get a lot of snow, even during a warm winter.  Summer outlooks are much harder to forecast,  than winter outlooks. For this reason this outlook is a little more limited in scope than my typical winter outlooks.
 

We have a developing El Nino in the Pacific. It won't be as strong as last summer's.  I do think it will act like the La Nina over the winter.  The 2017 El Nino will be short lived. It should be weakening as we head into the upcoming winter.  There is a good chance this will end up being a El Nino Modoki event. If this is the case late fall and the winter will see the greatest impacts in the Mid Atlantic and Northeast.






 

Looking at the sea level pressures in the Pacific, the SOI is looking to be negative over the next 6 weeks, This trend looks to continue into Summer 2017.  Those cold SSTs in the Indian Ocean and around Indonesia means this won't be a long lasting El Nino. The upcoming El Nino should end up being weak to moderate.
 

My analogs  were difficult to compare to this year. But the closest I could find were: 1959, 1960,1961, 1980, 1983, 2002, 2006, 2009. None of these were a exact match. But they were close enough to gather some insight.   (Note: NOAA has been readjusting the old data. This makes past events look cooler than they might have been. ) So that doesn't help.






 

Temperatures:

The summer will start off warm. But then we will cool off after midsummer.  Typically transitions from La Nina to El Nino lead to overall cooler summer, especially during the 2nd half of summer.  This is because the atmosphere takes a little time to move from one phase to the other.  Overall, this upcoming summer, looks to be average to very slightly above average in temperatures.  Part of the reason will be those very warm sea surface temperatures off the East Coast.

 


Precipitation:

On my Facebook weather pages, I've been talking about how I expect to see a active severe season in the Northeast.  Also the threat that I see from close to the East Coast forming tropical cyclones, again those warm SSTs off the East Coast, has to be taken into account.
 
We have an ongoing drought going on in New England down into eastern Pennsylvania , New Jersey, and the Mid Atlantic. This is especially true for Connecticut and Long Island; the rest of the region is doing OK.  There is also drought in the Southern U.S. I do expect to see the active pattern we're in erode quite a bit of this over the next couple of weeks. But these areas will have to be watched. As, they would have a part to play on where the heat sets up.

I don't anticipate this to be a typical dry El Nino.      

 


Severe:

The severe season  in the Northeast runs from June through August. The Plains will be cooler than average June July and August. This is typical for El Nino years.  With a trough setting up in the Plains. We would see slight ridging over the east coast, with an active storm track looking to be in the cards. Severe weather in the Northeast will ramp up. This should end up a fairly active year for severe weather, with perhaps several severe outbreaks over the region.

 

Bottom Line:

This Summer is going to see temperatures warmer temperatures in June into July .  Then we will start to see a change to cooler overall temperatures mid to end of July and August.  I expect the temperatures to end up over all average to slightly above average for New England and New York State into Western Pennsylvania. With temperatures  over the rest of Pennsylvania and the Mid Atlantic to be moderately above average.  But we won't have the sweltering heat we had in Summer 2016.
This Summer will see a wet June and July, with things starting to dry up a little in August.  Overall I think precipitation will be average to slightly above average.  The wild card will be severe season and tropical activity. But if these play out like I think this Summer and Fall could be wet.
 
I will have a separate post on the 2017 Atlantic Hurricane Season, and my thoughts on the Severe Weather Outlook for June through August.

Tuesday, March 28, 2017

Tropical Cyclone information graphics changes for the 2017 season.


The National Hurricane Center (NHC) is making several changes to its tropical cyclone graphics.

The 2017 hurricane season will be here before you know it. So I wanted to go over these changes before June 1st.

1)  The NHC will be issuing advisories even before a disturbance becomes a depression or a named storm.  Any potential tropical cyclones that threaten land area with tropical storm or hurricane force winds within 48 hours will be given advisories, with discussions and tracking maps.

2)  The NHC started posting experimental alerts for storm surge last season. For 2017 those alerts will be mandatory. The NHC will be issuing storm surge watches and warnings for the Gulf and Atlantic Coast, for any storm that has the risk for life threatening surge conditions during any stage of a subtropical or tropical cyclone, even potential tropical cyclones.  
 

3)  For the 2017 hurricane season, the NHC will be issuing approximate arrival times of tropical storm force winds. The new graphic will display the earliest reasonable arrival time of winds of at least 39 mph.  A probability scale will be used along with the arrival time. The scale will show the probability threshold for 39 mph, 58 mph, and 74 mph wind speed will be met in a particular location. 
 

4)  The size of the Cone Of Uncertainty will be smaller. The cone will be based on the tracking error over the last four hurricane seasons. The cone doesn't represent where impacts like storm surge, wind, flooding, or tornadoes will be felt.
The old Cone of Uncertainty
 
The updated Cone of Uncertainty
 


Table showing the circle radii size of the cone
 

5)  Advisory graphics will be greatly improved.  New bolder colors and easier to read font should make the carts easier to view and understand.  The new graphics will include tropical storm and hurricane force wind fields.
 

I hope you found this helpful. As always let me know what you think, or post any questions you might have.

Sunday, March 26, 2017

A first glimpse at the 2017 hurricane season.


With a possible subtropical system developing in the Caribbean, the system could become named, it could even become a full born tropical system . I thought I would post some thoughts I have on the upcoming  2017 Atlantic Hurricane season. This isn't going to go into a lot of detail. There is still a lot of data that has to come in before I can state how things look to go. My official tropical outlook will be released most likely at the end of April.

The first day of the Atlantic Hurricane Season begins on June 1st.  So there is plenty of time to look at the data and trends.

Even though there isn't a lot to go by yet, looking at the current Sea Surface Temperatures (SST)can give us a clue and a few answers.

Here is a look at SST as of 3/26/2017; in it we can see two things. First, is the developing El Nino. The second is the cool water west of Africa, and warm waters off the East Coast of the US. 
 
 

 
 
 
 

The analog years I've been looking at are 1951, 1953, 1957, 1972, 1997, and 2015. Number 1 was 1972 and number 2 was 1997.
 


 
 
The Pacific:

Looking at the tropical Pacific, we see warming in ENSO regions one and two. The current ENSO neutral conditions look to continue for the rest of Spring, then we will transition toward El Nino this Summer , and most likely be in an El Nino this Fall.

History tells us that El Nino's typically inhibit Atlantic tropical activity. The warm SST in the Pacific causes the air to rise over the tropical Pacific. Since weather in the Northern Hemisphere tends to go west to east, that  warm rising air in the Pacific sinks over the Atlantic; this helps stabilizes the atmosphere over the tropical Atlantic. More in the way of stable air leads to less in the way of thunder storm activity.  El Nino's  also tend to cause stronger winds to come off of Central America, these winds extend into the tropical development zone of the Atlantic. The winds shear the tops off of developing tropical cyclones, making it harder for hurricanes to develop. During El Nino years we also tend to see the Atlantic trade winds blow faster. This causes any thunderstorms that do develop to move faster , again leading to fewer hurricanes.

It is still uncertain if El Nino develops, or if it does if the atmosphere will respond quick enough to make a difference.

The Atlantic:

We have cool SSTs west of Africa in the prime development zone.  Tropical cyclones need warm SST's in order to develop. Cooler tropical waters lead to unfavorable hurricane conditions. This along with a developing El Nino means  long track Cape Verde tropical systems will have a hard time this year.

This time of year it's hard to make long term predictions. Why? Because this time of year is always a time of transition.  

 ACE:

It's becoming obvious that the upcoming season will have less ACE points than we saw in 2016.

An article by Weatherbell's Joe Bastardi was shared to me. Here is a few graphics from Bastardi's post. These will prove the point I'm making.
Image credit Joe Bastardi, Weatherbell Analytics
Mean sea level pressures of the 1950's
Image credit Joe Bastardi, Weatherbell Analytics
mean sea level pressure from 2006 to 2016
Image credit Joe Bastardi, Weatherbell Analytics
Image credit Joe Bastardi, Weatherbell Analytics
Image credit Joe Bastardi, Weatherbell Analytics

In the images you can see the warmer than normal SST off the Southeast U.S. and Caribbean

Colder than normal SST off the Northeast and North Atlantic.

So you have higher pressures in the north and lower pressures in the tropical development zone of the Atlantic .

Mean sea level pressures of the 1950's were higher than normal in the north, normal in the Atlantic, and lower than normal in the Caribbean. 

All of this causes tropical storms to  come close to the U.S. Southeast Coast and move up the coast.

SST and mean sea level pressure from 2006 to 2016. This period has seen no official major hurricane strikes on the East Coast, (But I personally count Sandy as a major hit, based on her impact).  
 

This year will have some similarities to last season.

The SST's are warmer off the East Coast into the Caribbean and Gulf. So, any tropical systems that do develop will develop on the western side of the Atlantic. The closer the storms form to the U.S. the greater the odds for landfalling tropical cyclones on the East and Gulf Coast of the U.S.

My early thoughts on the upcoming hurricane season  is for a average to slightly below average season. Something similar to1972, 1997, or 2015. So  I'm leaning toward 10-12 tropical systems, with 3-4 hurricanes with 1 major hurricane.

The warmer waters off the East Coast, would also help tropical systems retain strength or even intensify as they move up the coast. This would be worrisome, because the impacts could be similar to what we saw during the 1950's.   

That's it for now.