My first real thoughts on the 2019 Atlantic Hurricane Season, and my ideas for Summer 2019.

In spite of the fact that northern areas are seeing snow, and most likely will see more snow over the next week or two, along with some cold shots for the Northeast and Middle Atlantic, there is no doubt that we're in a Spring time pattern.

Analog years:

1914, 1930, 1953, 1969, 1982, 1997,1999,2013, 2014,2015

Sea Surface Temperatures:

Images courtesy of WeatherBELL Analytics

The El Nino/Southern Oscillation (ENSO):

We're in a El Nino. Here is a look at Sea Surface Temperatures (SST) in the equatorial Pacific.

The El Nino looks to last into Summer and most likely beyond that, perhaps even into Winter 2019-2020.  The strength of the El Nino looks to be weak.

Back early in 2015 we had a weak El Nino; Right now the overall weak El Nino conditions look similar to 2015. But later during the 2015 season ENSO develop a strong El Nino. It is hard to predict what the ENSO will do this far out. So this is a wild card.  So the question is, will we see a strong El Nino in 2019?  I really don't think so. More than likely we will see the weak El Nino continue for the rest of this Spring into the Summer. It is difficult to know,  If at some point during the Summer the El Nino   becomes moderate tropical cyclone activity could be curtailed. Most of the long range models agree with this idea. But as has happened in the past, the models forecast on the ENSO can be very mistaken on what will happen. Based on some indicators, there is a chance this El Nino falls apart. If that happens, the season could become much more active than many think .

Image courtesy of International Research Institute  

The part of my hurricane forecast that relies on the ENSO is based on my idea of a weak El Nino to last into the first half of the hurricane season, then  we could go into a neutral  El Nino later in the season. But if the models are right, the entire season could be average to below average.  So the El Nino will have a huge impact on the Atlantic Basin hurricane season.

The 2019 Atlantic Basin Hurricane Season:

2018 was an above average season.   Two hurricanes of note were Florence and Michael, both of which had direct impacts on the Eastern CONUS.   One of the main reasons for the  above active year was the fact that the La Nina conditions hung on through the 2018 hurricane season.  The El Nino conditions started last fall, then they weakened, even reversed, only to come back during late Winter 2019.

El Nino's increase upper level wind flow, which results in increased wind shear over the tropical Main Development Region (MDR) in the Atlantic Basin, the region between Africa and the Caribbean.  This makes it harder for tropical cyclones to form in the Atlantic;  It also tends to inhibit intensification of tropical cyclones that do form.

El Nino's also cause sinking air in the tropical Atlantic, which also hinder Atlantic tropical cyclone development. The western Pacific could get quite active this year, after a slow start.  Hawaii could be in the crosshairs.

The Atlantic Multi-decadal Oscillation (AMO):

The Atlantic goes through upward and downward cycles.  Historically these swings can be tied to the AMO.  The AMO's decadal variability is based on Sea Surface Temperatures (SST). But while the AMO is constructed from SSTs which respond very quickly to forcing in the atmosphere. In fact the AMO is really subjugated by multi-decadal variations. These variations have to do with the meridional overturning circulation.   When the AMO is positive, we have a stronger overturning circulation than we do during the negative phase when the overturning circulation is weaker.

The AMO was positive from around 1995 to around 2015. Since then it does appear it has shifted to a cooler negative phase.  The Atlantic unquestionably has a look of a negative AMO. That is that colder than normal horseshoe shape in the northern Atlantic that drifts south through the eastern Atlantic and through the tropical Atlantic.

Basically, the Atlantic Basin SSTs are cooler south of 20 degrees North latitude, with warmer than average SSTs North of 20 degrees North latitude, especially North of 25 degrees North latitude. So this means the tropical Atlantic SSTs are below average. If this continues it will also impede tropical cyclone development in the Atlantic MDR.  Tropical cyclones need warm water to develop, the SST should be at least 80 F if you want a good chance of seeing any tropical storms or hurricanes.

The Central Atlantic and the western Atlantic including along the Eastern Seaboard into the eastern Gulf and Caribbean are warmer than average for this time of year.  So any tropical waves that do make it across the Atlantic MDR or Tropical Waves that form closer the US, will have a chance to develop into tropical cyclones. 

Any systems that form in the western Atlantic, Caribbean, and or Gulf of Mexico will pose a risk to the East and Gulf Coasts. One interesting tidbit, NOAA hurricane expert, Jim Kossin has hypnotized that less active years in the Atlantic, carry a greater risk for rapidly intensifying hurricanes close in to the U.S.  He based this on a study he conducted.  During the study, Kossin found that during the last quiet period, a major hurricane near the U.S. Coast was 3-6 times more likely to intensify by 15 knots or more within 6 hours than it was during the active period.

Accumulated Cyclone Energy (ACE):

ACE is generally used to measure the combined duration and strength of tropical cyclones. The ACE of a season is the sum of the ACE for each storm during the season, and takes into account the number, strength and duration of all the tropical storms during that season. Ace doesn't only measure tropical cyclone activity, it also measures the damage potential of an individual cyclone or a season. The higher the ACE number, the greater the odds are for increased tropical cyclone activity along with higher damage potential.

Based on the 1981-2010 median, a season with an ACE above 111 is considered above average;   an ACE of 104 is considered to be an average season, while an ACE below 66 is considered a below average season.

I think the ACE in the Atlantic Basin will be 110-125.

The outcome:  

Based on the factors listed above, most of the tropical activity should occur outside the MDR for 2019. I think much of the 2019 Atlantic hurricane season will feature hostile wind shear. But for the western Caribbean, Gulf and along the U.S. East Coast wind shear will end up being near average overall.  

The first third of the Atlantic season could be fairly quiet. But then the risk for systems closer to the U.S. would increase as would the number of possible tropical cyclones for the middle and last half of the hurricane season.

My preliminary call is .....15 named storms with 5 becoming hurricanes, and 1-2 major hurricanes.   The risk for a land falling tropical system on the U.S is about 50/50.

I think the greatest risk for a landfall is along the Southeast Coast. But based on the data including analog years. There is the real possibility for a tropical cyclone to come up the U.S East Coast, posing a threat to the Mid Atlantic and New England. 

I will issue an update, if I think it's needed in May.  

 Summer in the Northeast and Mid Atlantic:

Remember, this covers my ideas over a 3 month average over the entire Northeast into the Northern Mid Atlantic Region. Some localized areas could end up above or below my overall ideas.  
El Nino's affect on the weather in the Northeast and Middle Atlantic are muted quite a bit during the Summer.  The ENSO main time to influence our weather is Late Fall into early Spring.  That doesn't mean there isn't any impact, just that it is more subdued.  Ground moisture, other teleconnections, and SST in the Atlantic have a bigger role.  

Summer looks to be wetter than average and warmer than average for 2019. But with the warmer than average SSTs in the Western Atlantic Basin, the risk for tropical cyclone impacts on the Caribbean, and East and South Coast of the CONUS are slightly increased but not as high as the 2018 season.

Soil Moisture anomaly:

Image courtesy of Climate Prediction Center

The maps shows West of the Rockies it is wet.  But that shouldn't be a big surprise.   We've seen above average precipitation in the Mid Atlantic Region for the last several months in fact it has been wetter than average for over a year. 

All that ground moisture should keep it from getting overly hot this Summer.  Why is that? The Sun heat the ground to heat the air. So some of that solar energy has to evaporate some of the ground water, which reduces the amount of energy available to warm the air.  

We've had above average precipitation for quite some time. I do expect this trend to continue into the Summer. So I don't anticipate a huge drought problem in the Northeast or Mid Atlantic this Summer into Fall.

We could see an active severe season, again because of all that ground moisture.  It could lead to days with higher dew points, which could help fuel strong/severe storms.

The last few years daytime temperature anomalies have been average to slightly above average. But nighttime temperature anomalies have been above average to well above average.  Part of this has to do with the Heat Island Effect, part has to do with the warmer than average SST in the Western Atlantic, and part has to do with the above average precipitation for the last couple of years..  I expect the higher amounts of water vapor in the atmosphere will help make for some very humid and warm nights. along the East Coast.

The result of all this:

Much of the Northeast will be slightly warmer than average from June through August, While Southern Pennsylvania and the northern Mid Atlantic ends up a little warmer than that.

So the June, July, and August temperature  anomaly for 2019, across the region should be +1 to +2 above average overall. Northern Maine and Northern New York State most likely will see overall average temperatures, while the rest of New England, New York State into northern Pennsylvania see an overall 0 to +1 above average, with southern Pennsylvania, Maryland, Delaware, and southern New Jersey see an overall +1 to +2 above average temperature anomalies.  Once we get into Central Virginia into the Southeast the idea of an overall +3 to +5 above average temperature anomalies, are more likely.

As for precipitation during June through August the mid Atlantic into southern Pennsylvania should end up with overall precipitation  +2 to +3 inches above average overall . The rest of Pennsylvania , New York State, and New England should end up with overall precipitation  0 to +1 inches above average; the farther north you go the better the odds are for average precipitation.