Not again! The pattern of soggy weekend weather continues

Since the Fall season unofficially began after Labor Day, it has rained on at least one day of every single weekend. The only exception was the weekend of September 30th through October 1st; however, you'll probably remember that on the Friday preceding that weekend, former Tropical Storm Ophelia helped to fuel record-breaking rainfall in spots like Park Slope, Brooklyn (9.80"), while most of the Tri-State saw at least 5 inches of rain, more than a month's worth, in just one day. The incredible deluge led to public transit shutdowns and absolutely nightmarish scenes in the Five Boroughs and beyond. 

The calendars below show September and October (so far); the days marked in blue indicate when more than two-tenths of an inch of rain fell during that day. The second half of September was awfully soggy, and October has been drier, but the common thread is weekend rain. 

The blue boxes indicate days in September when NYC's Central Park recorded at least one tenth of an inch of rain. 

(Data from the National Weather Service office in Upton, NY)

The blue boxes indicate days in October when NYC's Central Park recorded at least one tenth of an inch of rain. 

(Data from the National Weather Service office in Upton, NY)

And the forecast for this weekend calls for more rain on both Friday and Saturday. What the heck is going on?!?

The forecast for Friday through Sunday from the National Weather Service office in Upton, NY on 

Thursday afternoon, October 19th. 

This may seem like an unfortunate coincidence, to have seven consecutive weekends with rain (or flooding-related cleanup), but it's not as flukey as it seems. A series of storm systems at the synoptic scale (don't worry, I'll explain) have moved across the United States at a fairly consistent speed, and it's going to take a break in this pattern to bring us a completely dry weekend. 

A typical planetary wave pattern from a vantage point above the North Pole.

Image courtesy of NOAA

Synoptic-scale systems comprise the largest size category in weather. A synoptic system can easily span over 1,000 miles. Weathermakers such as Nor'Easters are synoptic in scale, as are dry weather features like a dome of high pressure, such as the Bermuda High we're familiar with in the summertime. These systems move with the jet stream; surface low pressure systems (again, like Nor'Easters) are found in troughs, whereas high pressure areas are usually centered in ridges. The image above shows a typical trough-and-ridge pattern from the vantage point above the North Pole; you'll recognize the continental United States under trough #2. 

Notice that the pattern was similar last weekend, when we got nearly an inch of rain in Central Park on Saturday, October 14th. One of the dips in the wave, or troughs, had moved through the Tri-State, carrying a large storm system with it. 

Along with their size, synoptic-scale weather systems are relatively slow-moving. They last for days to weeks; in comparison to weather features like a single thunderstorm, which has a time scale spanning minutes to hours, synoptic systems last a long time. Imagine synoptic systems are like the elephants of the weather world; powerful and large, but not very nimble. In this analogy, thunderstorms are like jackrabbits. They're fast and can change direction quickly, but they cut a small path. 

Forecast surface analysis for Friday, October 20th from the Weather Prediction Center. 

Notice that the area of green has a long barbed blue line (cold front) 

draped through it; the length of this line is an indication of a synoptic-scale system.

Why is this relevant to our persistent pattern of wet weekends? Because, along with being unable to change speed or direction quickly, these large storm systems consequently tend to develop a regular cadence for the observer at a single spot- in this case, that spot is the Tri-State area. It will take a shift in this cadence, which could occur in the form of the development of a blocking pattern, to create a new rhythm in the atmosphere. Eventually, the pattern will change, even if it's because of the change in seasons, a lowering sun angle, and a natural shift of the polar jet stream southward. But if the texts I've been getting from my mother are any indication, my guess is that many people in the Tri-State are hoping for an earlier end to this pesky pattern. The good news is that it has been drier so far in October than it was last month, and the Climate Prediction Center believes that trend will continue.  

This weekend's partial eclipse will be a total miss for Tri-State viewers

Are you ready for Saturday's annular eclipse, which stargazers in the Tri-State have been waiting for since the summer of 2017? The eclipse, which will be visible on the East Coast around 1pm EDT, is also referred to as a "ring of fire" eclipse because of the effect produced by the moon blocking nearly all of the sun's rays, save for a narrow ring in the path of annularity. 

"Annular", by the way, means ring, so this is a fitting name! The path of annularity is narrow, and for this particular eclipse, it will trek across a less populated part of the continental United States. So, most of the people who will witness the full spectacle of this eclipse firsthand will have traveled some distance to get there. This interactive eclipse viewer from NASA is the origin of the image below, which shows the path for best viewing in gray:

NASA's interactive tool shows the path of annularity for Saturday's eclipse.

And as you can see, it's nowhere near the Tri-State area. (The total eclipse taking place next April will produce a better view for us... more on that later.)

A close-up view of the Northeast and Mid-Atlantic from the NASA interactive viewer shows that people in the NYC area will have a 20%-25% blocked sun at the peak of the eclipse from our perspective. 

A close-up from NASA's interactive tool shows that we will have a very limited 

view of Saturday's eclipse.

Saturday's annular solar eclipse will look similar to this one for viewers in the Tri-State- except that, since this eclipse is happening around mid-day Eastern time, the sun will be high in the sky.
Photo courtesy of NASA

Not all solar eclipses are alike. The shadows they cast vary widely, with every location on Earth experiencing at least one eclipse at some point in history. And, some solar eclipses are total, with darkness instead of the "ring of fire" effect that an annular eclipse creates. These variations are made possible by the Moon's irregular orbit, and the fact that Earth's orbit around the Sun is not in sync with the Moon's orbit around Earth. 

Types of solar eclipses; NYC will experience the partial eclipse on October 14th, while viewers in locations like 

Texas's Hill Country and Medford, OR will be treated to a sight similar to the middle image. 
Graphic from NASA

When the Moon's orbit is closer to Earth and its path aligns with the Sun, a total solar eclipse happens. That's what will happen on April 8th of next year, when a path of totality will be created. 

Another close-up from NASA's interactive tool shows the path of totality for the eclipse on April 8th, 2024.

The irregular orbit of the Moon is also responsible for the phenomenon dubbed the "Supermoon", which is simply a full moon that occurs when the Moon's path is at perigee, or closest to Earth. Supermoons are more common than solar eclipses because the Sun is so much bigger; its diameter is about 401 times that of the Moon. The Sun is also about 389 times farther away from Earth than the Moon, which is why the two celestial objects appear to be the same size from our perspective!

This depiction of the setup for Saturday's annular eclipse is not to scale because it would be impossible to depict in a legible image. The distance from Earth to the Sun is much greater, and the Sun is much larger than Earth, too.

Graphic courtesy of Smithsonian Air and Space Museum

You can easily demonstrate the effect of the Moon's irregular path by moving your thumb closer and farther away from your eyes to block an object in front of you. When the Moon's path is farther from Earth, it does not block as much of the Sun's rays, causing a partial or annular eclipse like the one happening Friday. 

Unfortunately, the weather forecast is very bad news for anyone in the Northeast or Mid-Atlantic who's hoping for a crescent-shaped view of the sun. A storm system that moved onshore in the Pacific Northwest will trek all the way across the country, brining us clouds and rain by Saturday. Bummer! If you're hoping for a change to that forecast, keep tabs with the National Weather Service's NYC-area office... and maybe petition them for a sunnier outlook? In the meantime, we can hope for better weather for the total solar eclipse on April 8th, 2024; that eclipse's path will be much closer to the Tri-State, anyway. 

If you want to learn more about both upcoming eclipses from a real-life NASA heliophysicist (try saying that three times fast!), register for this free webinar organized by the AMS Weather Band, happening on Wednesday, October 11th. 

Why isn't this early October warmth a "Second Summer"?

The month of October has gotten off to a very warm start in the Tri-State. Through the first 5 days of the month, the average temperature is 70.4°, a whopping 7.6° above the 30-year normal. On the warmest day, October 4th, we reached a high temperature of 83° in Central Park, equal to the average high for a day in mid-August. It was like a second summer in the Tri-State... or was it?

In my youth, the term "Indian Summer" was commonly used to describe a late-season warmup. While the antiquated term is no longer recognized by the American Meteorological Society, its scientific definition and criteria are the same as for the term "Second Summer". The AMS Glossary defines Second Summer in the following way:

"A period of abnormally warm weather that occurs in mid- to late autumn and after the first frost.
The comparable period in Europe is termed the Old Wives' summer and, poetically, may be referred to as halcyon days. In England, dependent upon dates of occurrence, such a period may be called St. Martin's summer, St. Luke's summer, and formerly All-hallown summer."

Unlike other meteorological terms, like heat wave, Second Summer does not have a minimum number of days ascribed to it, nor does it have a threshold temperature or temperature departure from average. The only firm stat in the definition is a key phrase: "...after the first frost". And therein lies the reason this early-October warmup is not a Second Summer. We haven't even come close to our first frost of the season in the city. In fact, the lowest temperature we've had so far this season was a 50° low temperature on September 27th. The map below shows the average first fall frost in the Northeast and Mid-Atlantic:

Average first frost map, using the current 30-year average

from the Northeast Regional Climate Center

The Tri-State area stands out as one of the latest spots on the map to experience a killing frost. The average first frost in NYC doesn't happen until November 20th, and the earliest first frost happened at the Central Park observation site all the way back on October 15th, 1876.

Even though they haven't been bitten by frost, a lot of the Tri-State's summer plant life is starting to wither. Our vegetable gardens have largely stopped producing anything new to eat. Despite the August-like temperatures we had this week, the October sun angle is preventing new growth from taking off. Just compare the image below of the sun angle's path through Central Park in October (first image) to its angle through the Park in June (second image):

NYC is solidly in the "midlatitudes", almost exactly halfway from the Equator to the North Pole, and this leads to a big variation in seasonal daylight. On the Summer Solstice, there's just over 15 hours between sunrise and sunset, but on October 6th, we're down to 11 hours and 33 minutes of daylight. With most veggies needing more than 6 hours of full, direct sun to flourish, the October sun is just not enough. It's no coincidence that the most recent full moon we had in September is referred to as the Harvest Moon!

One final thought for the gardeners reading this post: The amount of sunlight we have today is the same as it is on March 7th (in a non-Leap Year). This is why it's super helpful to start your plants inside, before the last frost of the Spring, which typically happens in April in the Tri-State. There's usually enough sunlight in your garden several weeks before the temperatures are high enough for plants to grow. Once the danger of frost has passed, you can permanently move everything outside and let them take advantage of all that sun! 

A new way to find trusted weather experts

In the 20 years or so since its inception, social media has produced a mixed bag of results for meteorologists. On the plus side, social media makes it easy for people who specialize in forecast communication to interact with their audience, sharing information quickly without the need for a TV timeslot. It also gives weather professionals access to real-time information from viewers, such as photos and snowfall amounts, during high-impact weather events. On the flip side, social media provides those same tools to bad actors, untrained or inexperienced forecasters, and even trolls. Today, every big weather event is forecasted and reported in a seemingly endless sea of websites, blogs, and apps- and unfortunately, some of the information is complete junk. But how can you know which sites to click, and which are just clickbait?

On Monday, the American Meteorological Society officially launched a program that aims to help credentialed meteorologists stand out in the digital space. It's called the Certified Digital Meteorologist Seal, and as the name implies, it was designed for meteorologists who are not on television and work primarily in digital media. When the CDM logo appears next to an article byline or a social media handle, it means that person attained a 4-year degree in atmospheric science, and that they passed a rigorous exam to assess their knowledge of meteorology and earth science. CDMs also submit a broad scope of work samples for review by a panel of experts in digital meteorology, appointed by the AMS. 

The snazzy new logo for the Certified Digital Meteorologist Seal, 

developed by the American Meteorological Society

I worked with staff and volunteers for the American Meteorological Society to develop this new Seal. Here was the process:

1. It started by talking to meteorologists working in the digital space- forecasters for newspaper websites (aka "digital dailies"), meteorologists for independent forecasting and consulting services, professional stormchasers, and the like. These folks gave me advice and feedback for the framework I would need for the next step.
2. Once I felt confident that we had a workable idea, I submitted a proposal for a new Seal (anyone can do this). The Professional Affairs Commission approved the proposal and recommended the formation of an Ad Hoc Committee to work out the details. 
3. Some of the folks from Step 1 served on the Ad Hoc Committee, and I reached out to other AMS Sealholders, both from the Broadcast Meteorology program and the Certified Consulting Meteorologist program, to provide additional support. About a third of the meteorologists who served on this Committee are bilingual. All Committee members are listed at the end of this post.
4. Over the next year, the Ad Hoc Committee worked with AMS Staff to determine the eligibility requirements for prospective Sealholders, including the type and quantity of work samples that would be required for assessment.
5. Then, the Committee developed a grading rubric and scoring guidance to reduce ambiguity and increase consistency in scoring. 
6. Finally, the Ad Hoc was dissolved and replaced with the AMS Board of Digital Meteorologists. Many of these inaugural Board members also served on the Ad Hoc. AMS Staff also drafted organizational procedures for this new Board.

If you'd like to apply for the CDM, find more details about the eligibility requirements and acceptable work samples here. To prep for this process, make sure you request a copy of your college transcript, start studying for the multiple choice exam, and save some of your best work samples published within 60 days before and/or after your application is received. Here's the application link: https://apply.ametsoc.org/prog/certified_digital_meteorologist_cdm_program/

Members of the CDM Ad Hoc:
Amy Aaronson, WBFF (Fox Baltimore)
Vanessa Alonso, Local Now/The Weather Channel
Steve DiMartino, NYNJPA Weather
Emily Gracey, The National Weather Desk/Sinclair
Joe Martucci, The Press of Atlantic City
Matt Lanza, Space City Weather
Jason Samenow, Capital Weather Gang/The Washington Post
Sean Sublette, Richmond Times-Dispatch
Mike Ventrice, PhD, DRW Holdings