The 2021 Summer Outlook for the Northeast and Northern Middle Atlantic.

 

I’ve been asked by many followers to provide a summer outlook. So, your wish is my command 😊

This outlook is based on the current weather pattern, teleconnections, historical weather data and weather patterns from this spring. Remember a seasonal outlook uses a broad brush; So, it’s not about the day to day or even week to week weather pattern; rather it’s about the general trend and pattern for the entire summer.

The start of summer is about two and a half weeks away. The meteorological summer runs June through August. But The summer will officially begin at 11:32 P.M. on June 21, 2021.

You can find my 2021 spring outlook here.

Analogs:

1983,1995, 2001, 2004,2005, 2008, , 2020 and especially 2011.

 

Teleconnections:

I want to point out that any one factor doesn’t necessarily correlate with a particular kind of summer. Instead, it’s a combination of many things.

 

Credit WeatherBELL.

The El Nino Southern Oscillation (ENSO):

El Nino: characterized by a positive ONI greater than or equal to +0.5ºC.

La Nina: characterized by a negative ONI less than or equal to -0.5ºC.

By historical standards, to be classified as a full-fledged El Nino or La Nina episode, these thresholds must be exceeded for a period of at least 5 consecutive overlapping 3-month seasons.

Credit Climate Prediction Center / NCEP

The ENSO is currently in La Nina (cool phase), with cooler waters persisting across the eastern Pacific equatorial region. On average the Northeast and Mid-Atlantic see warmer summers during la Nina years. The current La Nina is fading, and looks to become neutral heading into the first half of summer 2021.  On my Facebook Weather Page, and in my 2021 Atlantic Hurricane Outlook, I touched on how I think the La Nina is going to redevelop.  If it returns, it should end up being a central based (Modoki) La Nina.

 

Pacific Decadal Oscillation (PDO):

The PDO has been negative. Since March the negative PDO has trended generally stronger.  Typically, negative PDOs run parallel with La Nina. The idea of a moderate to strong PDO lasting through the Summer and Fall, is one of the major factors I see hinting at the possibility for a return to La Nina later this year.

 

Most of the climate models are also suggesting the idea of a warm summer, especially across Northeast into the Middle Atlantic Region.

 

So based on that idea, By June it should feel more summerlike. But, we should only see spurts of hot temperatures for the first month or so of Summer.  But as we get farther into Summer we'll start to see more in the way of heat and humidity, with temperatures climbing well into the 90s.

 

Last Summer was one of the hottest summers on record in the Northeast and Middle Atlantic. It was also fairly dry. This Summer could end up much different.

In the spring outlook I talked about the severe weather prospects. The Northeast looks to see above average severe weather chances this summer, especially for June and July.  The pattern is similar to last year, so there is going to be an enhanced risk for derechos this summer.

With June and Much of July looking to b somewhat stormy, it will keep the lid on for much in the way of long duration heat for the first half of summer 2021. The first part of June could become hot, but then a cool down is likely mid to late June. Right now, the Northeast looks to see the real summer heat take hold mid to late July and August.

 90-degree days:

90-degree days are one of the metrics used to determine just how much heat we see during a summer season. During the summer of 2020 even far northern areas of the Northeast, like Watertown, NY, Burlington, VT, and Caribou, ME saw an above average number of 90-degree days.

The entire Northeast and northern Mid Atlantic should see a similar number of 90-degree days as we saw in summer 2020. Here is a list of cities along the eastern seaboard showing my general idea for the number of 90-degree heat days for this summer.  

Boston 12-16

New York City 16-20

Philadelphia 32-37

Washington DC 43-46

Pittsburgh 17-22

Newark 38-43

New Brunswick 38-44

Baltimore 40-44

Atlantic City 41-45

 

Here is a chart showing a blend of my analog years, with 2011 being double weighted.

 

This outlook for a hotter than average summer is consistent with the National Oceanic and Atmospheric Administration’s outlook.

 

Conclusion:

Overall Temperature

As far as overall temperature ideas Temperatures are expected to average 1-3 degrees higher across the Northeast compared to 2019 and closer to 1-2 degrees higher along the I-95 corridor.

Overall Precipitation:

The wet first half of Summer 2021 should help keep the current Abnormally Dry and Moderate Drought conditions under control, July into the first week of August could end up being fairly wet. We could see a return to near average ground moisture levels by the end of July. 

Then as the La Nina returns, we could end up with a lack of precipitation for the end of summer into the fall. 

You can find my 2021 Atlantic Hurricane outlook here.

Well, that’s it. As always questions are welcomed.  You can leave them here or leave them on my Facebook weather page, that can be found here.

 

 

 

 

 

2021 Atlantic hurricane outlook part 3

 

Will the 2021 Atlantic Basin hurricane season be as bad as 2020’s record breaking season?

 

This is the final installment of my 2021 hurricane outlook for the Atlantic Basin. If you’re reading this, it’s assumed you have read parts 1 and 2. Part 1 can be found here, and part 2 can be found here.  May 9^th – 15^th is National Hurricane Preparedness Week; so, posted the 3^rd part seems appropriate. You can find preparedness information at the end of part 2.

For this outlook, I run down through many of the particulars, updating on La Nina, how many tropical storms and hurricanes I am expecting, along with the probability of path of many tropical systems this season, Please Like and Share!

The Atlantic hurricane season runs from June 1 to November 30; the season peaks during August through the first half of October. This is when the ocean waters are typically at their warmest.

This outlook is based on many factors, including: La Nina and other teleconnections, Atlantic Basin Sea Surface Temperatures (SSTs), computer model guidance, atmospheric conditions in the North Atlantic, and past analogs years that exhibited a similar overall pattern.

 

Analogs:

I’ve came up with my final set of analog years. They are: 1887, 1996, 2005, 2008, 2011, 2012, 2017, 2020

Teleconnections:

The El Nino-Southern Oscillation (ENSO)

La Nina, we’re still in a moderate La Nina, the models do take it back toward neutral.  Meteorologist are split on whether the ENSO stays neutral or reverts back to La Nina conditions.  I still think we’re going to see the La Nina conditions reenergize later this year into the winter. But before that, the atmosphere isn’t going to respond to the neutral trend right away. Typically, the atmosphere response lags a few months, so we most likely won’t see a real drop off in tropical activity until late October or November.  La Nina, will result in much below average wind shear over the tropical Atlantic, Caribbean into the Gulf of Mexico (GOM).   Last seasons La Nina became one of the strongest in at least 10 years.

 

Here is a look at the latest IRI forecast chart of the ENSO for 2021.

 

 

The Atlantic Multidecadal Oscillation (AMO):

As I said in part 2, the AMO is generally positive. During the positive warm phase the conditions in the Atlantic Basin are much more favorable for tropical cyclone formation.

 

The North Atlantic Oscillation (NAO):

During a negative NAO tropical cyclone are more likely to make landfall in the GOM; we had a generally negative NAO during the 2020 season.

 

Conditions are going to be more favorable for tropical cyclone development over the eastern Atlantic and west Africa.  Due to a strong West African Monsoon.

I don’t think we will see as much Saharan Air Layer (SAL) …Saharan dust… this season as we saw last season. African dust over the Atlantic tends to make conditions over the Atlantic more hostile for tropical cyclone development. But even with 2020’s large and imposing dust layer, 2020 went on to be a hyperactive hurricane season.  A big reason for that was the strong La Nina in the Pacific.

The Bermuda High was very strong last season; this season it won’t be as strong, also it looks to be displaced a little more north and east. As a result, the East Coast is going to be at higher risk this season, due to the greater likelihood of tropical cyclones recurving out of the MDR into the western Atlantic off the Eastern Seaboard.

 

While the East Coast is going to be at a heightened risk, especially during the 2nd half of the hurricane season, that doesn’t mean the GOM won’t also be a risk.

There is going to be an enhanced risk for the Bahamas, Florida and the eastern GOM, unfortunately that might include Louisiana as well; who was hit very hard last season.

Last season the Southern and especially the southwest Caribbean was very active. This season is going to see a lot of that activity shift north into the northern Caribbean

 

Here is a look at the current Sea Surface Temperatures (SSTs) in the Atlantic Basin. in the Main Development Region (MDR), northern Caribbean, GOM, and along the East Coast and Atlantic Canada SSTs are well above average for this time of year; these temperatures are only going to get warmer as we move through the hurricane season.  Now the inter tropical convergence zone (TCZ) is slightly below average, but that too is going to warm up.

SSTs like these are typically seen prior to an active Atlantic hurricane season, and correlate very well with most of the analogs.    

 

With the warm SST in the Northern Caribbean, eastern GOM, and along the East Coast, we will have to be mindful of the possibility for rapid intensification as tropical cyclones move over that warm water.

 

 

 Courtesy of WeatherBELL Analytics

 

Courtesy of Coral Reef Watch

 

The overall pattern:

Last year, saw the most active Atlantic hurricane season in recorded history, with a total of 31 tropical cyclones, 30 named storms, 13 hurricanes, and 6 major hurricanes.  When we look back at April and May of last year and compare that to this year, we can see they’re remarkably similar to each other.

 

500mb images are courtesy of the University of Wyoming

 

500mb images are courtesy of NOAA/Storm Prediction Center

 

2M temperature charts are courtesy of NOAA/NCEI U.S. Climate Division

This Spring has seen a lot of persistent high latitude blocking near Greenland. This likely to continue. This is going to help allow for warmer water in the tropical Atlantic this season.

This season will most likely see quite a bit of upper level ridging in the Northern Pacific and in the Northwest Atlantic. If this does happen, the setup would help funnel tropical cyclones closer and into the East Coast.

 Conclusion:

Remember, even during an active year, there is no guarantee there will be a landfall. But with the pattern supporting the idea of recurving TC’s off the East Coast, the odds certainly support the idea of heightened landfall risk along the East Coast.  It’s been quite a while since the Northeast had to deal with a major hurricane. While there is no certainly; I think the Northeast is at a heightened risk for a major impact this season. 

 Like last year, I think we have a good chance to get through the entire naming list in the Atlantic Basin.

 The Atlantic Basin Numbers:

Accumulated Cyclone Energy (ACE)

ACE sums up the intensity and duration of storms. So, a weak, short-lived tropical storm counts for almost nothing, whereas a major, long-lived hurricane will quickly rack up dozens of points. The higher the ACE number the more powerful and destructive the storm or season:

 The ACE value for the 2020 Atlantic season ended up being 179.8

For 2021 I’m looking for an ACE value of 140-190

For 2021

Named Storms

18-26

Hurricanes

6-13

Major hurricanes

3-6

U.S. landfalling tropical cyclones

6-10

Well, that’s it, this is the last preseason outlook update. I could release some revisions to this during the season. Questions are always, welcome, either on here or on my Facebook weather page. The link to that page is here.