Lanternflies have invaded the mid-Atlantic this summer, and have become more numerous during the past few weeks, many social media users are saying. Thousands of the invasive pests are showing up from North Carolina to Massachusetts, according to a Cornell infestation map. They hatched in late Spring and can hang around until December.

Most state governments, including Pennsylvania, recommend killing the bugs when you see them.

Recently, a number of local TV meteorologists have said because there are so many lanternflies, they can be seen on weather radar, but is that really true?

Probably not. It's much more likely you're seeing other insects or birds.

Lanternflies most commonly spread by attaching themselves to vehicles or agricultural products that are transferred over long distances.

Dr. Andrew Farnsworth, who runs Cornell Lab’s BirdCast project, told AccuWeather that, while insects often dominate the radar screen during the day, at night, birds are the main contributor to radar echoes when there's no precipitation around.

Friday night, more than 345.9 million birds were in flight across the United States, estimated by weather radar, a BirdCast map said. While those numbers did decrease by sunrise, more than 45 million birds were still in flight as of Friday morning.

While weather radars can identify what they believe to be biological targets, they can't tell if they are groups of insects, birds, or bats. Because birds are bigger and more numerous, they are the most likely to be observed.

"To say these echoes, especially at night, are all or even mostly lanternflies is almost certainly incorrect. I have no doubt that there are large numbers of insects aloft, and at altitude, for sure. But many other species of insects are involved in these movements, without question, and likely even in larger numbers and proportions," Farnsworth said.

"Separating the biological targets can at times be difficult, but birds — especially small songbirds — dominate the radar data on many nights where and when they are aloft, which they are in large numbers at this time of the year," Farnsworth explained.

The bottom line: Insects can be seen on radar, whether drifting, swarming, or migrating wherever radar is sampling the skies. But at night, and especially at this time of the year and after cold fronts, most biological targets you see on radar are birds, not insects.

Have you seen a lot of leaves turning colors or even falling off the trees this August? A lot of people on social media have posted about this subject during the last few weeks, asking, "Is it an early fall?"

Well... don't get out the pumpkin spice lattes just yet. Although astronomical autumn doesn't start until Sept. 22, more leaves are falling than usual this time of year due to drought, causing what scientists call "tree stress." Since the beginning of August, drought has developed in areas of New England, New York, Pennsylvania, and New Jersey. This area has a large population, which helps explain why you've seen so many people posting on social media.

The Northeast's drought has improved markedly in the last week, but it's not just this part of the country where people are seeing leaves fall. Drought is increasing in the Mississippi Valley and is very severe in much of the Rocky Mountains, where meteorologist Chris Bianchi says the Aspens are turning yellow much earlier than usual. Trees are also turning colorful near Grand Junction, Colorado.

Even overseas, leaves are littering the streets in London, United Kingdom, and Paris, France. Those two areas are also seeing a drought. Until the drought lessens, leaves will continue to fall, but it will be a few more weeks for the color to really blossom in most areas.

Bottom line: While you may see some leaves falling, it's not an early fall, just unusually dry conditions. The real leaf-peeping season is still weeks away.

Did Hurricane Erin produce 100-foot waves?

Several weather enthusiasts have shared a scary-looking map of Hurricane Erin's waves this week, showing predictions of waves more than 100 feet or higher than a 10-story building. Here’s what the science actually shows.

The particular map in question uses an obscure method of measuring waves that isn't used by the equipment that measures them in the real world. The map comes from the ECMWF wave model forecast and is called "maximum wave height."

Data on actual waves from NDBC, the arm of the government that deploys buoys, uses a different method called "significant wave height." Significant wave height is calculated as the average of the highest one-third of all of the wave heights during a 20-minute sampling period.  Because buoys use significant wave height, that's what the record books use.

The map of significant wave height from the GFS wave model shows a maximum of over 40 feet, which is in line with observations from NDBC buoys. Buoy #41001 reported 45-feet waves on Thursday morning. Most hurricanes generate significant wave heights between 30 and 50 feet. It is very rare to see numbers over 50. The world record for significant wave height is 62.3 feet, set off the coast of Ireland in 2013.

Bottom line: Using the method waves are measured for scientific research, there hasn't been a wave over 45 feet yet from Hurricane Erin, and there likely won't be, as the storm is beginning to lose wind intensity.

How "big" is Hurricane Erin?

The Internet was also abuzz on Thursday morning with how "big" Hurricane Erin is. But is it really big compared to other hurricanes? Hurricanes are hard to compare, but we'll take a look.

First, many of the claims are approximating the size of Hurricane Erin by measuring the width of the storm on a satellite image. This is a very subjective way to measure storms, and records of previous storms don't exist. In these satellite images, Superstorm Sandy and Hurricane Erin appear to be about the same size, but Sandy was nearly twice as big.

The one measure that can be used is the size of the hurricane-force and tropical-storm-force winds stated by the National Hurricane Center. For current storms, those change every 3 hours, and it's hard to find maximum, minimum, or average data for those.

Here's what we know:

In the 11 a.m. EDT August 21 statement from the National Hurricane Center, it described Hurricane Erin as a "very large hurricane" -- the first time it had used that term with this storm -- with hurricane-force winds extending out 105 miles from the center and tropical storm-force winds going out 320 miles. Those numbers at this time on Wednesday were 90 and 265 miles, so it has increased in size, and that can be seen on the map showing the history of the wind fields.

Doubling the diameter of the tropical-storm-force winds to estimate a width of the storm, AccuWeather Lead Hurricane Expert Alex DaSilva said in a video on Thursday, "Hurricane Erin has a wind field diameter of about 600 miles. Eighty percent of tropical storms on record are smaller than Erin, so it's big. But it's nothing compared to Superstorm Sandy, which had a wind field of 1,150 miles."

According to a Washington Post study, storms wider than Hurricane Erin's tropical-storm-force winds this morning include Helene 2024, Irma 2017, and Katrina 2005, while smaller storms include Laura 2020, Michael 2018, and Harvey 2017.

Bottom line: Erin is a bigger hurricane than most tropical storms, but there have been plenty that were wider, including Hurricane Helene in 2024.

If you thought the United States was the tornado capital of the world, you'd be wrong, at least by one measure. Although the U.S. gets a lot of tornadoes, more than 1,000 per year on average, the tornado density in the United Kingdom is nearly twice that of the U.S., according to recent research.

The U.K. even has its own Tornado Alley, with the highest likelihood of seeing a tornado east of Reading and west of London.

A research study in 2023 concluded that the density of tornadoes was 2.3 tornadoes per year per 10,000 square kilometers in the U.K., whereas the U.S. has a density of 1.3 twisters.

While that seems hard to believe, the U.K. is a small country and there are wide swaths of the U.S. where tornadoes are rare (most of the West Coast and Rocky Mountains, for example). If you compare the U.K. density to a state in Tornado Alley closer to the size of the U.K., like Oklahoma (density 3.6) or Kansas (density 11.2), the U.S. state wins.

The European Severe Weather Database has documented just short of 800 tornadoes in the U.K. since 1950. The strongest tornado since 1950 hit London on Dec. 8, 1954, with winds between 187 and 212 mph on the TORRO rating scale, which would correspond to an EF3 or EF4 tornado on the Enhanced Fujita Scale. The most expensive twister in the U.K. was the Birmingham tornado in 2005, which caused $54 million in damage.

Also important to note: The U.K. twisters are not nearly as strong as those in the U.S., because most of them are not formed from supercell thunderstorms, but rather smaller tornadoes spawned by cold fronts.

Research is lacking on tornadoes in the United Kingdom, but scientists believe they may have found a reason why there are so many. It's called "horizontal shearing instability" and is the focus of future research.

Bottom line: When compared to the U.S., a much larger country, the U.K. has a higher tornado density, but comparing a similar-sized state in Tornado Alley, the U.S. wins.

You may have seen this image, or one like it, making the rounds on social media recently. A weather map showed a major hurricane positioned just off Mexico's Yucatan Peninsula, while another swirled near Bermuda.

Could this happen? Probably not. While this is the European computer forecast model, demonstrably more accurate than any other, this particular map shows only one forecast from hundreds of different weather models. Even within the European model, this is only one of 50 different predictions from ensemble members (forecasts generated with slightly different initial conditions to explore a broader range of possibilities).

During the 2024 Atlantic hurricane season, the European model predicted 129 tropical storms, but only 18 storms actually developed. That's not a great accuracy rate. And that only counts predictions up to seven days in the future; the model map shown above is from 15 days out, a notoriously inaccurate range for hurricanes shown on a computer model.

The only useful thing you can do from a model prediction that far out is to look at all the predictions, not just one. Rather than looking at that viral image, which is just one solution, here's what all 50 of the European ensembles are predicting for that time and date in the Southeast:

Each of the ensembles has the low pressure in a different place. It's a lot harder to hype a specific landfall location now, right?

To be more specific about time, place, and strength (remember, a hurricane is a tropical storm of a certain strength) you'd have to look at the other hundreds of models, and how they agree and trend over time. Then, you'd have to look at the overall weather pattern, what it will mean and has meant in the past in similar situations, and how that might affect each model prediction. That's what meteorologists do.

But could it happen theoretically? Ignoring the weather models crying wolf, yes, there have been several Atlantic hurricane seasons where two or more hurricanes have existed in the Atlantic basin at the same time. In fact, there have been three. Statistically, it is more likely to happen in late August into September, which is the peak of hurricane season.

Bottom line: Yes, two hurricanes could be in the Atlantic basin two weeks from now, but looking at one model prediction amongst hundreds is highly unlikely to be correct.

The water's hot in Florida, but is it unusual?

A viral social media post on X talked about a 97-degree water temperature reading at the Everglades National Park in southwest Florida yesterday, and 95 degrees at Tampa. While that sounds hot, it's the peak of summer, so it makes sense that the hottest annual water temperatures would be this time of year. Here's a map of the water temperatures at noon on Wednesday:

According to NOAA, the East Bay weather station in Tampa did, in fact, spike to a water temperature of 95 degrees Tuesday evening.

Is 95 degrees the hottest water temperature ever in Tampa? The East Bay station reached a water temperature peak of 93 degrees last year, on July 20, 94 degrees the year before, on July 15, 2023, and 95 degrees on August 1, 2022. So, this is not a new record.

A station at Port Manatee in Tampa Bay, more than 20 miles south of Tampa, also reached 95 degrees. Other sensors in the area stayed below 95.

Moving to the Everglades, the water at the Bob Allen station in Everglades National Park hit 97 on Wednesday, but was even higher earlier in the week. According to the NOAA graph, it spiked to around 99 degrees on Monday afternoon. However, all readings over 97 degrees are listed as "missing" in the data in the official record, likely because it was flagged by quality control, so it's not an official reading.

Are any of these record-breaking Florida water temperatures? Probably not. The station at Manatee Bay has stayed below 95 this week, and it reported 101 degrees in 2023.

Sidenote: An official station at South Port Everglades, Florida has also been reporting water temperatures as high as 104 degrees this week, but many observations are missing and this is likely bad data.

Caution must be used with water temperature readings for two reasons. First, not all stations on the NDBC website are official. Although they show nearly 30 stations in Southwest Florida, there are no official NOAA stations in that part of the state, and only two in the Florida Keys.

Secondly, there are few records for water temperature extremes, so it's hard to put high temperatures in context with what is normally measured at the station. Each station is at a different depth underwater, and temperatures vary greatly over a few feet. Stations with a sensor closer to the surface will read warmer, for example the Bob Allen station's sensor is at 5 feet below sea level, while the Tampa station is 7.9 feet down.

Bottom line: It's like bathwater in Florida this week, but they've seen hotter.

Social media was abuzz yesterday with announcements that the world heat index record had been broken in Iran, but it looks like that was likely an instrument error.

The measurement in question came from Dayrestan, Iran, which had a dew point of 97 degrees Fahrenheit with a temperature of 104, calculating a heat index of 182. You can see the observations online.

Here's a look at the highest heat index reported at various stations in the Persian Gulf this month. Notice how the 182 degree reading stands out as quite a bit higher than surrounding stations, with the next highest reading being 145 F at Lavan Island, Iran, and other stations reporting a heat index in the 130s and 140s.

This is one way to quickly check whether a weather observation is legit. You can never rule it out due to extreme localized weather conditions, but there are enough weather stations these days that more than one of them would have caught a heat index that high if it were real.

Airport weather stations are mostly automated, and operators generally don't question them unless there's a big reason to. Other nations may not have the same strict quality control rules that we do in the United States. Places that collect extreme weather data, like NOAA's NCEI or the WMO, might not look at the data for weeks, months or years to disqualify it.

Something I've learned working consumer and low-end professional weather stations, is that dew point sensors are the most likely to malfunction or read incorrectly. I assume that's no different for more expensive stations.

This station has a history of extremely high and unlikely readings; a heat index of 180 was recorded on Aug. 30, 2024. During the observation this week, the dew point was 97 degrees, 2 degrees above the world record, another reason that this observation was likely incorrect.

Bottom line: It's plenty hot in the Persian Gulf, but not 182 degrees. I wrote a whole article on extreme heat there last year, when the Persian Gulf International Airport in Asaluyeh, Iran, spiked to an AccuWeather RealFeel® Temperature of 149 degrees, even though RealFeel takes wind speed and other factors into account. The 140s shown on the map above are probably real. Just not the 182 degrees.

The second and final total lunar eclipse of the year will turn the moon a deep red on Sept. 7, and it’s already generating buzz online. Some are calling it one of the most widely visible eclipses in recent history, with the potential to be seen by up to 7 billion people — about 85% of Earth’s population, weather permitting.

The catch? It won't be visible from North America or South America.

Unlike total solar eclipses, which are only visible along a narrow path, total lunar eclipses can be seen from entire continents at once. This one will unfold over the most densely populated parts of the planet, including Asia, Europe, Africa and Australia.

Skywatchers in North America will have to wait until March 2–3, 2026, for their next glimpse of a blood moon.

Bottom line: Yes, 7 billion people live in areas where the next total lunar eclipse will be visible, but North America is not in the viewing area.

Update August 1, 2025:

The numbers haven't changed much, with the rest of the July data now in. San Francisco is now up to number 18 from the previous rank of 25th coolest summer.

Fremont has risen to number one, but they only have records going back 28 years; Napa fell to the number two coolest summer. Oakland, with records going back 46 years, jumped up one notch to number one.

According to the New York Times, paint staff for the Golden Gate Bridge have had to use heaters on the bridge to bring it up to painting temperature, which is something they haven't done "for a long time." Grapes in the Napa Valley softened and changed color later than in previous years, vintners say.

Answer: Not exactly, but it has been cooler than usual this season in the City by the Bay. As of July 21, the average temperature at the San Francisco's downtown station so far this summer was 58.2 degrees, making it the 25th coldest since reliable record-keeping began 131 years ago and the coolest since the summer of 1999. However, nearby stations that have shorter periods of record, such as Napa, are experiencing its top 3 coldest summers. Records in Napa go back 28 years. Oakland, Hayward and Fremont are the second coldest so far, with 45, 27 and 28 years of records, respectively.

"The cooler-than-historical-average summer in San Francisco can be attributed to a persistent trough of low pressure over California much of the summer," AccuWeather Senior Meteorologist Chad Merrill says, and it's been more about cool days than cool nights.

"It has allowed the marine layer to come inland into the Bay Area on more occasions than historical average, leading to much lower daytime high temperatures. The high temperatures at San Francisco's downtown station have been about 4 degrees below average this summer while the low temperatures have only been 1 degree below average."

Much of the viral buzz for this claim came from this map from the Climate Mapper tool at Climate Toolbox. While the map does show a zero percentile, i.e. number one ranking (dark blue) for some areas of the central California Coast, San Francisco is not included. The time range of the data is 60 days, instead of starting on June 1, and most importantly, the data is limited by its short period of record which starts in 1979.

Bottom line: It's been a cool summer in San Francisco, but not the coldest on record.

A total solar eclipse is coming, and it's going to be the longest one until 2114, lasting up to 6 minutes and 23 seconds. But as spectacular as this sounds, and contrary to some posts circulating on social media, there is still plenty of time to prepare for the event.

Several viral posts on Instagram, X and Facebook have touted the eclipse on Aug. 2 but leave out the important part -- that it's not until 2027. Additionally, it will require some travel to see as the path of totality will cross northern Africa, Saudi Arabia and Yemen.

In 2045, people across North America will be treated to a total solar eclipse similar to that on Aug. 2, 2027. On Aug. 12, 2045, a coast-to-coast total solar eclipse will plunge part of the United States into darkness. It will follow a similar track as the 2017 "Great American Eclipse" but will be significantly longer, lasting 6 minutes and 6 seconds.

Bottom line: There is a total solar eclipse in two years that will be the longest event of its kind anywhere on Earth for 87 years.