Thursday, June 27, 2013

WEATHER ANOMALIES: Extreme Weather Tied To Unusual Jet Stream - Responsible For Record Heat Wave, Damaging Tornadoes, Unseasonable Snowstorms, Historic Floods, And The Path Of Superstorm Sandy!

June 27, 2013 - UNITED STATES - Lately, the jet stream isn’t playing by the rules. Scientists say that big river of air high above Earth that dictates much of the weather for the Northern Hemisphere has been unusually erratic the past few years.

They blame it for everything from snowstorms in May to the path of Superstorm Sandy.

And last week, it was responsible for downpours that led to historic floods in Alberta, Canada, as well as record-breaking heat in parts of Alaska, experts say. The town of McGrath, Alaska, hit 94. Just a few weeks earlier, the same spot was 15 degrees.

The current heat wave in the Northeast is also linked.

“While it’s not unusual to have a heat wave in the east in June, it is part of the anomalous jet stream pattern that was responsible for the flooding in Alberta,” Rutgers University climate scientist Jennifer Francis said yesterday in an email.

The jet stream usually rushes rapidly from west to east in a mostly straight direction. But lately it’s been wobbling and weaving like a drunken driver, wreaking havoc as it goes. The more the jet stream undulates north and south, the more changeable and extreme the weather.

It’s a relatively new phenomenon that scientists are still trying to understand. Some say it’s related to global warming; others say it’s not.

In May, there was upside-down weather: Early California wildfires fueled by heat contrasted with more than a foot of snow in Minnesota. Seattle was the hottest spot in the nation one day, and Maine and Edmonton, Canada, were warmer than Miami and Phoenix.

Consider these unusual occurrences over the past few years:

• The winter of 2011-12 seemed to disappear, with little snow and record warmth in March. That was followed by the winter of 2012-13 when nor’easters seemed to queue up to strike the same coastal areas repeatedly.

•  Superstorm Sandy took an odd left turn in October from the Atlantic straight into New Jersey, something that happens once every 700 years or so.

•  One 12-month period had a record number of tornadoes. That was followed by 12 months that set a record for lack of tornadoes.

And here is what federal weather officials call a “spring paradox”: The U.S. had both an unusually large area of snow cover in March and April and a near-record low area of snow cover in May. The entire Northern Hemisphere had record snow coverage area in December but the third lowest snow extent for May.

“I’ve been doing meteorology for 30 years and the jet stream the last three years has done stuff I’ve never seen,” said Jeff Masters, meteorology director at the private service Weather Underground. “The fact that the jet stream is unusual could be an indicator of something. I’m not saying we know what it is.”

Rutgers’ Francis is in the camp that thinks climate change is probably playing a role in this.

“It’s been just a crazy fall and winter and spring all along, following a very abnormal sea ice condition in the Arctic,” Francis said, noting that last year set a record low for summer sea ice in the Arctic. “It’s possible what we’re seeing in this unusual weather is all connected.”

Other scientists don’t make the sea ice and global warming connections that Francis does. They see random weather or long-term cycles at work. And even more scientists are taking a wait-and-see approach about this latest theory. It’s far from a scientific consensus, but it is something that is being studied more often and getting a lot of scientific buzz.

“There are some viable hypotheses,” Stanford University climate scientist Noah Diffenbaugh said. “We’re going to need more evidence to fully test those hypotheses.”

The jet stream, or more precisely the polar jet stream, is the one that affects the Northern Hemisphere. It dips down from Alaska, across the United States or Canada, then across the Atlantic and over Europe and “has everything to do with the weather we experience,” Francis said.

It all starts with the difference between cold temperatures in the Arctic and warmer temperatures in the mid-latitudes, she explained. The bigger the temperature difference, the stronger the jet stream, the faster it moves and the straighter it flows. But as the northern polar regions warm two to three times faster than the rest of the world, augmented by unprecedented melting of Arctic sea ice and loss in snow cover, the temperature difference shrinks. Then the jet stream slows and undulates more.

The jet stream is about 14 percent slower in the fall now than in the 1990s, according to a recent study by Francis. And when it slows, it moves north-south instead of east-west, bringing more unusual weather, creating blocking patterns and cutoff lows that are associated with weird weather, the Rutgers scientist said.

Mike Halpert, the deputy director of NOAA’s Climate Prediction Center, said that recently the jet stream seems to create weather patterns that get stuck, making dry spells into droughts and hot days into heat waves.

Take the past two winters. They were as different as can be, but both had unusual jet stream activity. Normally, the jet stream plunges southwest from western Washington state, sloping across to Alabama. Then it curves slightly out to sea around the Outer Banks, a swoop that’s generally straight without dramatic bends.

During the mostly snowless winter of 2011-12 and the record warm March 2012, the jet stream instead formed a giant upside-down U, curving dramatically in the opposite direction. That trapped warm air over much of the Eastern U.S. A year later the jet stream was again unusual, this time with a sharp U-turn north. This trapped colder and snowier weather in places like Chicago and caused nor’easters in New England, Francis said.

But for true extremes, nothing beats tornadoes.

In 2011, the United States was hit over and over by killer twisters. From June 2010 to May 2011 the U.S. had a record number of substantial tornadoes, totaling 1,050. Then just a year later came a record tornado drought. From May 2012 to April 2013 there were only 217 tornadoes — 30 fewer than the old record, said Harold Brooks, a meteorologist at the National Severe Storms Laboratory. Brooks said both examples were related to unusual jet stream patterns.

Last fall, a dip in the jet stream over the United States and northward bulge of high pressure combined to pull Superstorm Sandy almost due west into New Jersey, Francis said. That track is so rare and nearly unprecedented that computer models indicate it would happen only once every 714 years, according to a new study by NASA and Columbia University scientists.

“Everyone would agree that we are in a pattern” of extremes, NOAA research meteorologist Martin Hoerling said. “We don’t know how long it will stay in this pattern.” - Valley News.

EXTREME WEATHER: High Floodwaters Force Hundreds To Evacuate Iowa Town - Radar Reveals East, Midwest Storms Triggering Life-Threatening Flooding; As Severe Storms Threaten 100 Million Citizens From Chicago To New York!

June 27, 2013 - UNITED STATESThe northeast Iowa town of New Hartford was mostly deserted Tuesday after authorities went door-to-door before dawn, warning residents a flooded stream would inundate most of the small community.

Floodwaters Force Hundreds To Evacuate Iowa Town.
Jim Johnson rows his boat down Main Street, Tuesday, June 25, 2013, in New Hartford, Iowa© Associated Press/Charlie Neibergall

"Everybody was notified and told to evacuate," said Butler County emergency management coordinator Mitch Nordmeyer as he surveyed the town, about 90 miles northeast of Des Moines. "If they stayed they were staying at their own risk."

Although most of New Hartford's 500-plus residents heeded warnings and left town, some stayed behind and there was no sense of panic.

Residents had seen the normally placid Beaver Creek flood before. And after some areas upstream received more than 7 inches of rain on Monday, few seemed surprised the stream was surging out of its banks again.

Jim Johnson, 49, rowed down Main Street just before noon. He's lived in town since the 1960s and said he's been through it before.

"I have about 8 inches of water in my basement," he said after getting out of the flat-bottom aluminum boat and tying it to a small tree.

He said a flood in 2008 was worse. That one flooded his home with about 4 feet of water.

"I've got this boat and another one with a motor," he said. "I usually stay until everything is lost."

But Johnson and authorities said most people had left, especially elderly people and residents with young children.

Residents were notified via a telephone emergency system on Monday about the danger, and an evacuation order came early Tuesday.

Up to 50 emergency services workers, sheriff's deputies and firefighters began to help townspeople flee at 3 a.m., before the water got too high and when boats and high-centered vehicles would have been required for rescues. Nordmeyer estimated about a third of the town's residents remained, but the town was largely silent by afternoon.

"Pretty much everyone who wants out is out, at this point," Nordmeyer said, adding that a sandbagged road to the north presented the only remaining route out of town. An emergency shelter was set up six miles away in Shell Rock.

Sue Ragsdale, 60, said she evacuated her home in the early hours but returned later in the day. She found a flooded barn but a dry home.

"I've seen it a lot worse," she said.

New Hartford firefighters Clint Olmstead, left, and Jon LeBahn walk through floodwaters on Tuesday in New Hartford, Iowa. Hundreds of residents obeyed an order to evacuate their homes in this northeast Iowa town before floodwaters from a rising creek could strand them.  Charlie Neibergall, AP

Nordmeyer estimated that the water was already 3 feet deep on the east side of town, and said floodwaters were pouring into the west side of town as well. The creek has topped a levy that surrounds the town on the east side near the elementary school, Nordmeyer said. He also suspected a breach had occurred Tuesday morning on a gravel road about three miles west of town that works as a makeshift levy. Officials couldn't get there to confirm his suspicions, he said.

Beaver Creek rose 3 feet above flood stage and crested at 15.15 feet by 7:45 a.m. Tuesday. The National Weather Service said most of New Hartford floods when the creek rises to 14 feet. The weather service said the creek was at 14.8 feet as of noon Tuesday and the water continues to recede. It is expected to return to the creek by Wednesday evening.

The crest is about half a foot short of the record of 15.7 feet set in June 2008, and it is two feet higher than when the creek caused flooding last month.

The rest of Butler County is under a flash flood watch until Wednesday morning. The weather service said New Hartford is along a path in northern Iowa that may experience showers and thunderstorms Tuesday afternoon into the overnight hours. Meteorologist Kevin Skow said between 2 and 3 inches of rain could fall per hour from the systems moving through the area.

Any rain that falls over the town will flow back into Beaver Creek because the ground is saturated, said Skow, resulting in standing water possibly staying around for a bit longer than expected. - NBC.

Radar Reveals East, Midwest Storms Triggering Life-Threatening Flooding.
Storms hammering the Midwest and the East Coast are resulting in significant flooding across portions of Iowa, Illinois, Indiana, Wisconsin and Kentucky Wednesday.

The emergency manager in Independence, Iowa, referred to flooding as unprecedented and life-threatening Wednesday morning, following 6.10 inches of rain.

Moderate to major flight delays have been occurring at Chicago O'Hare International Airport and Midway Airport as a result of the drenching thunderstorms.

Louisville and Madisonville, Kentucky have been experiencing flash flooding as storms continue, according to law enforcement and an NWS employee.

Northeast Regional Radar:

Indianapolis Radar:

- AccuWeather.

As Severe Storms Threaten 100 Million Citizens From Chicago To New York.

Another show in a seemingly endless parade of severe weather will march through the Midwest and the Northeast into Wednesday night, bringing damaging winds, large hail, flash flooding and even the threat for tornadoes along with it.

Cities most at risk include New York City, Boston, Philadelphia, Pittsburgh, Baltimore, Washington, Chicago, Nashville, Tenn., Indianapolis and St. Louis.

The worst of the storms will produce damaging wind gusts as high as 70 mph, hail as large as golf balls and perhaps an isolated tornado.

Wind gusts to 70 mph can easily uproot trees, snap off large branches and bring down power lines. Sporadic power outages are possible in some areas. Winds of this strength can also damage roofs and send unsecured objects airborne.

Hail as large as golf balls can cause damage to vehicles and crops. Any people or livestock caught outside can easily be injured.

While the pattern does not favor a large outbreak of tornadoes by any means, a few short-lived twisters are possible, especially across southern Illinois, southern Indiana and western Kentucky.

The most dangerous storms are likely to fire from St. Louis into Indianapolis, Louisville and Cincinnati during the afternoon and evening hours.

If you have any plans to be out and about on Wednesday or Wednesday night, keep an eye out for rapidly changing weather conditions.

Soon after showers first develop, many will strengthen quickly into thunderstorms, and dangerous conditions could follow soon after.

Dark skies ahead can signal blinding downpours, powerful winds and possible hail. If you get caught driving through this weather, pull over to a safe location, away from any trees or power poles, and wait for it to pass.

A major concern across the region is the potential for flooding rain. The storm system has had a history of flooding and producing torrential rainfall on the order of 3 to 6 inches in some communities over the Midwest during the Tuesday night and early morning hours Wednesday.

 National Weather Service Current Weather Warnings

This storm system will have the ability to produce 1-3 inches of rain in as many hours, potentially across such cities such as Indianapolis, Columbus, Ohio, and Pittsburgh.

Flash flooding can easily become life-threatening, and given the already saturated soil across the region, it will not take much rain to cause flooding.

Current technology has advanced enough over recent years to provide ample alert of the potential for severe weather and the approach of localized severe storms. Be sure to understand the difference between a watch and a warning. A watch means that an area is being monitored for dangerous weather. A warning means that dangerous weather is imminent. When a warning is issued, there may be too little time to travel across town or across a county to escape the storm. The time to have a plan of action and move to the general vicinity of a storm shelter or safe area is when a watch is issued.

Keep in mind that lightning is one of Mother Nature's leading source of injuries and fatalities. If you can hear thunder, you are close enough to the storm to be struck by lightning, even if the sun is still shining. - AccuWeather.