Severe storms to kick off August for Northeast

 By Jessica Storm, AccuWeather Meteorologist

Updated Aug. 1, 2021 7:09 AM EDT

Cooler and less humid conditions are settling in across the Northeast, while residents receive a brief respite as they pick up the pieces after tornadoes ravaged the mid-Atlantic on Thursday evening. Unfortunately, more storms are on the way to the region before the weekend is over.

"A potent short wave of energy will sweep across the Great Lakes to the Northeast on Sunday delivering the threat for damaging storms by Sunday afternoon," said AccuWeather Senior Meteorologist Matt Benz.

A short wave is a disturbance in the middle or upper part of the atmosphere which induces upward motion ahead of it, according to the National Oceanic and Atmospheric Administration (NOAA). This upward motion allow storms to develop.

"A couple of pockets of severe weather are likely in the Northeast on Sunday, and the pattern switch may eventually lead to a great deal of rain in the Southeast and parts of the Northeast," added AccuWeather Senior Meteorologist Alex Sosnowski.

Much of the Northeast has already had its fair share of rain this month, with many cities having received over twice the amount of average rainfall so far in July. Boston has recorded over three times its normal amount. With storms bringing heavy downpours on Sunday, the region will likely start August quite wet as well.

"Unlike last week where there was ample moisture and very warm temperatures, this weekend is a bit cooler and less humid," said AccuWeather Senior Meteorologist Matt Benz. This means severe storms are more likely to impact areas closer to the upper air disturbance anticipated to move across northern Pennsylvania through Upstate New York and northern New England.

Cities in the path of this storm include Rochester, Syracuse and Binghamton, New York. Burlington, Vermont; Albany, New York; and Williamsport, Pennsylvania, could all be on the edge of this severe risk as well.

It's currently looking as though the Philadelphia area, previously damaged by several tornadoes on Thursday evening, won't be directly in the line of fire for these severe storms, however, this is not a guarantee.

"If moisture levels can rebound sufficiently on Sunday along with higher temperatures, that threat for damaging storms may creep southward across Pennsylvania and New Jersey and closer to areas that were hit hard by tornadoes late last week," Benz said.

Another area forecasters are predicting to experience severe weather on Sunday afternoon and evening is farther south, from the southern Delmarva Peninsula to coastal South Carolina. These storms can impact Myrtle Beach, South Carolina; Wilmington, North Carolina; Virginia Beach, Virginia and Ocean City, Maryland.

For both of these areas, expected impacts include flooding downpours, hail and damaging winds, with an AccuWeather Local StormMax™ of 70 mph.

Those spending time outside on Sunday should be extra cautious and aware of the situation, finding solid structures to take shelter in and checking the AccuWeather radar frequently. Flash flooding can occur, and motorists are reminded to never drive through floodwaters. Motorists should also be aware of changing visibilities in heavy rain.

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Damaging winds can cause power outages when tree limbs fall on power lines, so it's important to be prepared for loss of electricity, including air conditioning. The Red Cross suggests that deaf and hard-of-hearing people take extra precautions to stay safe during weather emergencies.

There can even be some isolated tornadoes, forecasters say.

Especially after Thursday's disastrous tornadoes in the Northeast, forecasters want to emphasize the dangers of these forces of nature. They urge residents to have a means of receiving warnings and to have a plan in place in case a tornado comes their way.

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Tornado Watch vs. Tornado Warning

It's important to know the difference between a tornado watch and a tornado warning when preparing for severe storms.

When a tornado watch is issued, that indicates that conditions are favorable for tornadoes to develop. With these watches, the necessary ingredients of a tornado may be present, but there is not yet any sign of a tornado. They are often issued hours in advance over large areas.

A tornado warning indicates that either a tornado has been sighted, or meteorologists have detected rotation that would indicate a tornado is likely present. Those under a tornado warning should seek shelter as soon as possible.

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.

Dallas to sweat in 110-degree RealFeel heat

 By Maura Kelly, AccuWeather meteorologist

Updated Aug. 1, 2021 5:53 AM EDT

Records were broken across the High Plains on Wednesday as above-normal temperatures persisted throughout the region and into the south-central U.S. -- but when will relief from the heat arrive?

Not just yet, but soon, AccuWeather forecasters say. The sweltering pattern that's been locked in across the middle of the nation will continue through the weekend for most places.

Afternoon temperatures across cities such as Houston and Lubbock, Texas; Oklahoma City; Wichita, Kansas; and Little Rock, Arkansas; have been about 2-5 degrees above normal, on average, since last weekend.

This image shows temperatures (F) as of noon CDT Friday, July 30, 2021. (AccuWeather)

Dallas hit the 100-degree mark for this first time this year last Sunday then surged into the lower 100s F again on Monday and Tuesday, and then once more on Friday and Saturday. On average, Dallas typically reaches 100 degrees by the first day of July, and the latest date on which Dallas recorded its first 100-degree reading of the year was on Aug. 23 in 1989.

The heat will continue in Dallas with temperatures flirting with 100 on Sunday, AccuWeather forecasters predict, and the AccuWeather RealFeel® Temperature could soar as high as 110.

Triple-digit heat will make a run at cities farther north and west over the southern Plains, too.

The catalyst behind this heat wave, AccuWeather Meteorologist Mary Gilbert explained, has been a weather feature high in the atmosphere.

"A large area of high pressure at the upper levels of the atmosphere has been responsible in part for the increased heat across the region this week," said Gilbert.

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Airflow around this area of high pressure allowed the heat to spread northward along the High Plains, just east of the Rocky Mountains. Several new record-high temperatures were set across this region on Wednesday afternoon.

Temperatures in Denver climbed above normal earlier this week and continued to trend higher into the middle of the week. By Wednesday, the Mile High City reached 100 degrees, breaking the old daily record of 98 degrees set in 1867.

Normal high temperatures for the end of August range from around 90 F in Denver and Kansas City to 97 F in Dallas.

"Temperatures a few degrees above normal will likely continue for much of the south-central U.S. over the weekend," said Gilbert, as the area of high pressure is forecast to remain over the region.

Little Rock approached the triple digits on Saturday. Highs across the rest of the region were in the middle to upper 90s on Saturday.

Gilbert warned that the risk for heat-related illnesses will remain elevated throughout the weekend.

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"Anyone spending extended periods of time outdoors should try to limit that time to early morning or late afternoons to avoid being outside during the hottest part of the day," she advised.

However, if this is unavoidable, AccuWeather forecasters say it's essential to take breaks in the shade and drink plenty of water to avoid becoming overheated and dehydrated.

On Sunday, the area of high pressure will begin to break down and shift west into the southwestern U.S., allowing a cold front to sink south over the center of the country.

"Some places, like Oklahoma City, will begin to encounter relief from the heat as early as Sunday," Gilbert explained. "Locations farther south may have to wait until Monday for cooler conditions."

With the arrival of this cooler air mass, temperatures across the south-central U.S. are forecast to drop a few degrees below normal.

Dallas can return to the low 90s by Monday, while Oklahoma City and Wichita can dip below 90 by early this week.

On Sunday, Denver, where the average high temperature is around 90 degrees, may struggle to reach the 80-degree mark.

"Interestingly, despite the recent heat surge, a majority of locations across the south-central U.S. are still running cooler than normal for the month of July," Gilbert said. "As of Saturday, Dallas and Houston are running just over a degree below normal for the month, while Oklahoma City is running nearly two degrees below normal."

The temperature for the month is taken using an average of high and low temperatures recorded each day.

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.

Frenzy of tropical activity in Pacific could create rare weather phenomenon

 By Jessica Storm, AccuWeather Meteorologist

Updated Aug. 1, 2021 8:17 AM EDT

A cluster of tropical activity has developed across the Pacific Ocean, as three features battle for dominance and hold the potential for a phenomenon called the Fujiwhara Effect to occur.

"Tropical activity has picked up across the eastern Pacific," said AccuWeather Meteorologist Alex DaSilva.

The three main areas of interest are Tropical Rainstorm 9-E, Hurricane Hilda and an area of low pressure to their east.

The good news is that all three features are generally moving away from Mexico and will pose no threat to land except for some minor increased wave activity in western Mexico, according to DaSilva.

On Saturday evening local time, a tropical storm in the East Pacific Ocean strengthened into Hurricane Hilda. As of early Sunday morning, Hilda was a Category 1 hurricane on the Saffir-Simpson Hurricane Wind Scale, located about 860 miles southwest of the southern tip of Baja California. The hurricane was packing sustained winds of 85 mph, moving to the west-northwest at 10 mph.

Hilda is gradually gaining strength, according to AccuWeather Senior Meteorologist Adam Douty. However, as Hilda continues to move to the northwest, the storm will encounter drier air, stronger wind shear and cooler ocean water.

Hurricanes thrive in moist, warm environments, so each of these will work to degrade Hilda's wind intensity, which could cause it to become a tropical storm again. While Hilda is not anticipated to impact land, shipping interests should be aware of higher seas from the hurricane.

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A tropical depression located to the west of Hilda became Tropical Rainstorm 9-E early Sunday morning, local time, about 1,405 miles west-southwest of Baja California and is remaining nearly stationary.

“Due to the lack of organization and convection associated with 9-E, the system has been classified as post tropical," said Douty. Though it was poorly organized on Sunday morning, there is a possibility of the rainstorm becoming a tropical depression again or even a tropical storm before moving into cooler waters. The next name on the list in the Pacific basin would be Ignacio.

There is also an area of low pressure on the opposite side of Hilda, which is forecast to develop into a tropical depression or even a tropical storm, battling Tropical Rainstorm 9-E to be the next named storm.

"There looks to be a small window for tropical development through about Monday," said Douty. Then, it is possible the low pressure will get close to Hilda, which can inhibit strengthening or even lead to weakening.

This area of low pressure is anticipated to interact with Hilda and could get "sucked in" by the hurricane sometime next week, according to DaSilva. This would occur in a process called the Fujiwhara Effect.

The Fujiwhara Effect happens when two tropical systems spinning in the same direction pass close enough to each other that they begin to "dance" around a common center, according to the National Weather Service. Oftentimes, the two systems can approach each other and merge.

This phenomenon occurred earlier this year off the coast of Western Australia, when two systems, known as Seroja and Odette, interacted.

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"Seroja was the dominant feature, with the system formally known as Tropical Low Odette rotating in the clockwise fashion around Seroja," AccuWeather Meteorologist Mary Gilbert said in April.

Seroja absorbed what was left of Odette in a Fujiwhara dance. Now, such an event could happen in the East Pacific basin.

"While it is possible there is a Fujiwhara interaction between the storms, I think it is too early to say this with much confidence that this specific type of interaction will happen," said Douty.

Elsewhere, another developing storm could make waves in the Pacific later this week.

This satellite image, taken early Sunday morning, local time, shows Tropical Rainstorm 9-E, Hilda and the low pressure area from left to right in the East Pacific. (RAMMB/CIRA)

"Models are hinting that another storm could develop west of Mexico late in the week or next weekend," said DaSilva. This storm has the potential to become a hurricane as well, though it is also expected to stay far off the coast, bringing few, if any impacts to Mexico.

Meanwhile, either Hilda or 9-E could bring an increase in moisture to Hawaii around Aug. 8 through Aug. 10, but cooler waters and wind shear mean the systems should dissipate around then, according to Douty.

While the East Pacific buzzes with activity, the Atlantic Ocean remains quiet, but not for long, according to DaSilva. The middle of the month, however, is looking to be a more active period for the Atlantic basin, and the peak of the season doesn't arrive until September, so there is plenty of time for the tropics to heat up.

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.

Another Olympic disruption? Brewing tropical system could target Japan

 By Maura Kelly, AccuWeather meteorologist

Updated Aug. 1, 2021 12:37 AM EDT

As Olympic officials try to handle the ongoing struggle with the heat in Tokyo, they will have to turn their attention to another potential trouble: a brewing tropical system.

The storm could bring impacts to the Olympic Games early this week -- and AccuWeather meteorologists warn this may not be the last tropical concern for the host country.

The tropical low is currently located to the southeast of mainland Japan in the northern Philippine Sea. While the low had a chance to develop into an organized tropical system, the window for that opportunity is quickly closing it moves into a harsher environment.

The storm is moving into an area of moderate wind shear and lower sea surface temperatures. Waters to the south and east of Japan were stirred up after Nepartak followed a similar track last weekend, which caused cooler water to come to the surface.

AccuWeather Meteorologist Rob Richards expects this storm to begin losing intensity rather quickly as it approaches northern Japan by Sunday, but it can still bring some impacts to the region.

"This low will move into northern Japan, bringing enhanced rain and gusty winds on Sunday, local time," explained Richards, adding that the most likely areas to be impacted by the storm are from the city of Sendai on north.

These areas, which include portions of the Tohoku and Hokkaido regions, can receive up to 1.00-1.50 inches (25-40 mm) of rainfall with locally higher amounts possible in the mountains. Wind gusts can also reach as high as 30-40 mph (50-60 km/h), especially near the center of the area of low pressure.

Kolohe Andino, of the United States, rides a wave during the first round of the men's surfing competition at the 2020 Summer Olympics, Sunday, July 25, 2021, at Tsurigasaki beach in Ichinomiya, Japan. (Olivier Morin/Pool Photo via AP)

This rain can lead to localized flooding in low-lying areas as well as in areas that received heavy rainfall from Nepartak last weekend.

While the last of the track and field and marathon events occurring in Sapporo took place on Friday, local time, any traveling between this northern location and Tokyo could be impacted by locally heavy rainfall.

Due to the forecast track of this low, major impacts are not expected across the Kanto region, including in Tokyo.

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This may not be the last chance for Tokyo to receive some enhanced rainfall. A plume of tropical moisture following behind the area of low pressure can move over Kanto on Monday and bring a couple of showers and thunderstorms to the region.

Paula Badosa, of Spain, is helped off the court in a wheelchair after retiring due to illness during the quarterfinals of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Any rainfall this weekend is unlikely to cause major delays, said Richards, but any showers could bring some short-lived relief from the heat plaguing Tokyo.

Regardless of the track of this tropical feature, it can bring increased wave heights and rough seas to the southern and eastern coasts of Honshu into early this week. This could pose some risk to the sailing events taking place in Sagami Bay.

Following in the wake of this tropical low, a second tropical low will begin to take shape over the same region of the Philippine Sea by early this week.

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"The next one could be one to watch since that has more potential to become a tropical depression or tropical storm," said Richards, adding that there is still plenty of uncertainty regarding how strong it can become and where it will track.

An area of high pressure is forecast to build over Japan this week, this could steer the brewing tropical system to the west before it has much chance to track northward, but it is still too early to completely rule out impacts to southern Japan this week.

According to Richards, it is not unusual for multiple systems to develop and then track over a similar area in the West Pacific tropical basin. "Sometimes a pattern can develop where back-to-back lows affect Japan or other areas of the basin."

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.

This Date in Weather History for August 1,2021

 Weather History

For Sunday, August 1,2021

1954 - Mount Rainier in Washington State was still covered with sixteen inches of snow at the 5500 foot level following a big snow season. (David Ludlum)

1985 - A nearly stationary thunderstorm deluged Cheyenne, WY, with rain and hail. Six inches of rain fell in six hours producing the most damaging flash flood of record for the state. Two to five feet of hail covered the ground following the storm, which claimed twelve lives, and caused 65 million dollars property damage. (Storm Data)

1986 - A powerful thunderstorm produced 100 mph winds and large hail in eastern Kansas and southwestern Missouri causing 71 million dollars damage, and injuring nineteen persons. It was one of the worst thunderstorms of record for Kansas. Crops were mowed to the ground in places and roofs blown off buildings along its path, 150 miles long and 30 miles wide, from near Abilene to southeast of Pittsburg. (The Weather Channel)

1987 - Record heat gripped parts of the Midwest. A dozen cities reported record high temperatures for the date, including Lincoln, NE, with a reading of 105 degrees, Moline, IL, with an afternoon high of 103 degrees, and Burlington, IA, with a reading of 102 degrees. (The National Weather Summary)

1988 - Two dozen cities in the Upper Midwest reported record high temperatures for the date, including La Crosse WI with a reading of 105 degrees. Highs of 103 degrees at Milwaukee, WI, and South Bend, IN, were records for the month of August. (The National Weather Summary)

1989 - Hurricane Chantal made landfall along the Upper Texas coast about sunrise. Chantal deluged parts of Galveston Island and southeastern Texas with 8 to 12 inches of rain. Unofficial totals ranged up to twenty inches. Winds gusted to 82 mph at Galveston, and reached 76 mph in the Houston area. Tides were 5 to 7 feet high. The hurricane claimed two lives, and caused 100 million dollars damage. (The National Weather Summary) (Storm Data)