Arctic Blast

December has arrived. And even though the winter season most of us are familiar with, "astronomical" winter, doesn't begin until the winter solstice on Dec. 21, we meteorologists have already started ourwinter season. Meteorological winter began Dec. 1 and runs through the last day of February.

It looks like Mother Nature is following the meteorologists' calendar this year as bitterly cold arctic air plunges southward across much of the West and eventually expands across the Plains, Midwest and parts of the South. This will send temperatures to their lowest levels of the season – and in some cases, potentially the coldest in several years.

Along with the cold comes a nasty bout of snow and ice associated with Winter Storm Cleon

http://www.weather.com/news/weather-winter/arctic-cold-blast-subzero-rockies-plains-dakotas-20131202

Sea Level Rising

If you don't live in a coastal city, sea level rise is likely one of the impacts of climate change that doesn't sound like a big deal. Especially because it's happening so slowly, by only a few millimeters every year in most places around the world.

But if you live in a place like South Florida or along the coast of Louisiana, rising sea levels already are beginning to interfere with daily life. Witness the street flooding that now regularly occurs during high tides in parts of Miami Beach, with or without rain.

Events like these were the inspiration for a series of portraits titled "Sea Level Rise in My Lifetime," commissioned by Florida Atlantic University for its annual Sea Level Rise Summit, and shown in the photo slideshow above.

Created by Florida-based photographer Mary Brandenburg, the portraits aim to show what kind of future awaits for the children now living in many of the nation's biggest coastal cities, by depicting how far sea levels will rise by the time those children reach their natural life expectancy.

"I don't think we realized how powerful they would be," said Mary Beth Hartman of the university's Center for Environmental Studies, who worked with Climate Central's Ben Strauss to calculate for each photo how far in inches sea levels are expected to rise in different coastal cities around the U.S.

http://www.weather.com/news/science/environment/future-sea-level-rise-around-us-photos-20131203

Midwest Tornadoes

Tornadoes, Damaging Storms Sweep Through Midwest

 http://abcnews.go.com/US/wireStory/midwest-high-storm-threat-20915138

 Dozens of tornadoes and intense thunderstorms swept across the Midwest on Sunday, causing extensive damage in several central Illinois communities, killing at least three people and prompting officials at Chicago's Soldier Field to evacuate the stands and delay the Bears game.Just how many tornadoes hit was unclear Sunday afternoon. According to the National Weather Services' website, a total of 65 tornadoes had struck, the bulk of them in Illinois. But meteorologist Matt Friedlein said the total might fall because emergency workers, tornado spotters and others often report the same tornado.

Moore Oklahoma Tornado

This was the question posed by Ryan Wade, a University of Alabama-Huntsville (UAH) severe weather researcher, at the annual meeting of the National Weather Association in North Charleston, S.C. on Oct. 15.
Wade was presenting findings from an investigation of supercell mergers and other storm-scale interactions in recent tornado outbreaks with fellow UAH researchers Todd Murphy and Dr. Kevin Knupp.
In the radar loop above from the National Weather Service in Norman, Okla. (hereafter, NWS-Norman), you can see the Moore supercell with a pronounced hook echo first developing as it passed northwest of the town of Newcastle.
Highlighted by the yellow arrow is a decaying cluster of weak thundershowers moving northeast toward the supercell.
Wade noted an outflow surge — a surge of stronger winds associated with the supercell's rear-flank downdraft — occurred just after supercell merged with the decaying thundershowers. The supercell's hook echo then became more pronounced, with a distinct debris ball signature (circular area of red/purple reflectivity headed toward Moore), indicative of wind-lofted tornado debris.
"Combining damage surveys with the radar characteristics of the Moore supercell indicate the Moore tornado intensified after the cell mergers," said Wade.
Specifically, Wade noted that EF4 and EF5 damage, shown by red and purple contours in the map below, occurred after this cell merger and subsequent outflow surge.

Inside Winter Storm Cleon

http://www.weather.com/video/reporting-inside-winter-storm-cleon-41914?

What Earth Would Look Like if All the Ice Melted

Stories about the loss of Arctic sea ice and the melting of the Greenland ice sheet have become commonplace in our warming world, but have you ever wondered what the planet would look like if all of it – every last mountain glacier and chunk of polar ice – melted for good?

National Geographic explored this exact scenario in a newly released set of artists' renderings of how Earth's coastlines would look if sea levels worldwide rose by 216 feet, the volume the magazine estimates is possible if all of the ice now on land melts away into the ocean.

The illustrations show what every continent in the world would look like in this scenario, with all of the world's current 5 million cubic miles of ice melted (which scientists say would take more than 5,000 years). From Houston, New Orleans, and Miami to Charleston, New York, and Boston – if this came to pass, all of them would be wiped off the map forever.

http://www.weather.com/news/science/environment/what-earth-would-look-if-all-ice-melted-20131105

Typhoon Haiyan Update

TACLOBAN, Philippines  -- Help is beginning to trickle in to the Philippines in the wake of the devastating Super Typhoon Haiyan, however it's from from enough. Desperation is setting in as thousands of people with nowhere to go wait for clean water, food, and medical care.

When two Philippine Air Force C-130s arrived at the typhoon-wrecked airport here just after dawn Tuesday, more than 3,000 people who had camped out hoping to escape the devastation surged onto the tarmac past a broken iron fence. Only a few hundred made it aboard; the rest were left in a shattered, rain-lashed city short of food and water and littered with uncounted bodies.

Just a dozen soldiers and several police held the crowd back. Mothers raised their babies high above their heads in the rain, in hopes of being prioritized. One woman in her 30s lay on a stretcher, shaking uncontrollably.

http://www.weather.com/news/weather-hurricanes/typhoon-haiyan-update-victims-aid-20131111

Super Typhoon Haiyan: Before and After

The amount of damage the massive storm wreaked on these towns can be seen in the aerial and satellite images above, which take a look at the regions before the storm and after it hit.

The towns of Tacloban, in the Philippine province of Leyte, and Guiuan, in the province of Eastern Samar, both suffered immense amounts of damage due to their proximity to the coast. Homes and structures in both low-lying areas were reduced to rubble.

http://www.weather.com/news/super-typhoon-haiyan-and-after-photos-20131112

Incredible Temperature Changes

Imagine bundling up to get the newspaper on an early morning at 7:30 a.m. with the temperature at a frigid -4 degrees.

Just two minutes later as you are letting Fido have a potty break on the lawn, you notice that the frigid air you walked out the door into is not so frigid anymore. You look at your thermometer and the temperature has shot up to 45 degrees. That's right, a temperature increase of 49 degrees in just two minutes!

But wait, that's not the end of this wild morning weather story. After the temperature climbs all the way to 54 degrees at 9 a.m., it crashes down again 58 degrees in 27 minutes to -4 degrees once again.

http://www.weather.com/sports-rec/below-zero/5-extreme-temperature-drops-20130118

50 States' Biggest Snow Days

The snowiest day on record for each state in the country covers a wide range from less than six inches to more than five feet.

On the following pages, you will find the highest single-day snowfall totals for all the states in the country starting with the lowest total in Florida and ending with the highest totals in the western states. The description under each image shows the exact location and date of each single-day snowfall record.

All of this information is from the National Climatic Data Center (NCDC) division of the National Oceanic Atmospheric Administration (NOAA), which has analyzed various snowfall records for the country in each state.

http://beta.weather.com/news/weather-winter/50-states-biggest-snow-days-20130112

Cold Temperatures Engulf Central, East; Snow in Midwest, Great Lakes

Surges of cold air will engulf the central and eastern states this week as a dip in the jet stream dominates to the east of the Rockies.

As a result, we will see a widespread area of below-average temperatures spreading south and east during the week ahead. We have the details on this late-October chill, including where we could see a frost, freeze and even some snow.

The change to a colder weather pattern began with an initial blast of chilly air that moved into the Upper Midwest and Great Lakes this past weekend.

Now another shot of even colder air is diving south, which has dropped temperatures 10 to 20 degrees below average across most of the Midwest. This latest blast of cold air will also surge into the southern and eastern states by Wednesday. By late week, another reinforcing shot of cold air will take over the central and eastern states. The three temperature forecast maps to the right illustrate the falling temperatures from the start to the end of the week.

In the Midwest, highs in the 40s will keep Chicago and Minneapolis shivering throughout the new work week.

http://www.weather.com/news/weather-winter/cold-temperatures-central-east-midwest-great-lakes-snow-20131021

Australian Wildfires

SYDNEY  -- Firefighters battling dozens of wildfires in Australia's most populous state merged two of the most worrying blazes on Tuesday to try to reduce the threat of a more unpredictable inferno taking hold.

There had been fears that three of the fires near the Blue Mountains west of Sydney would join to create a massive, erratic wall of fire that would be difficult to control. So firefighters struck first, combining two of the fires into one that is easier to manage and contain.

Cooler temperatures, calmer winds and a light drizzle were giving thousands of firefighters a reprieve in fighting the blazes Tuesday.

"As high pressure builds in across southeast Australia, cooler temperatures will take over the next few days," said weather.com meteorologist Chris Dolce. "Highs in Lithgow may not get out of the 50s on Wednesday, and then stay in the 60s the rest of the week. Gusty winds between 20 to 30 mph are expected Wednesday, which could make firefighting conditions difficult."

The fires have killed one man, destroyed 208 homes and damaged another 122 in New South Wales state since last week, the Rural Fire Service said.

The number of fires burning dropped from more than 100 last week to 60 on Tuesday, with 15 still out of control, Fire Service spokesman Joel Kursawe said. Fires that had previously been ranked the highest danger were all downgraded by the fire service.

Still, officials said the threat had not completely evaporated, as the weather was expected to heat back up on Wednesday.

http://www.weather.com/news/australian-wildfires-cooler-temps-rains-help-firefighters-20131022

Typhoon Produces Massive Waves

http://www.weather.com/video/typhoon-produces-massive-waves-39315

Winter Storm Atlas

RAPID CITY, S.D.— Residents in the Black Hills were navigating through a sloppy mess Sunday after warmer temperatures began melting record-setting snowfall, leaving standing water on plowed roads rather than making its way through drainage systems.

Law enforcement officials shifted their focus to recovery after having caught up with a backlog of emergency calls from the weekend storm that dumped 4 feet of snow near Deadwood and 3.5 feet near Lead. No fatalities were reported as a result of the bad weather.

"We're even Steven. We don't have 911 calls holding at this point," Rapid City-Pennington County emergency manager Dustin Willett said Sunday. "Most of our life safety missions have been completed and as we start out today, it's going to move to snow removal, debris removal and power restoration."

An estimated 5,000 people in the county were still without power, Willett said, down from more than 25,000 in the area on Saturday.

Temperatures rose several degrees Sunday, which led some people to venture out even though many roads had not been plowed. Some motorists were still getting stuck Sunday and impeding recovery efforts, Rapid City spokeswoman Tara Heupel said.

Willett said the melt from the "impressive drifts and ridiculous amounts of snow" was causing a "slushy watery quagmire," partly because the snow buildup on plowed highways was creating channels and making it difficult for the drainage system to work normally. However, Rapid Creek wasn't expected to flood.

"Is the creek going to be up? Absolutely. Is the creek going to be in an action stage or flood stage? Probably not," Willett said.

Dave Barber, National Weather Service meteorologist in Rapid City, said most flooding problems from snowmelt occur when the ground is frozen — that isn't the case with this storm.

"In this part of the state, it's been not real dry but relatively dry," he said. "So, stock dams and small ponds are, if not dry, at least low and have capacity to absorb a good bit of water that does run off."

(MORE: Tornado Hits Four States, Causes Widespread Damage)

Reports of 20 or more inches of snow were common throughout the Black Hills. Barber said the 21½ inches in Rapid City were a record for both a 24-hour period in October and the entire month.

"There was a lot of water vapor present on the east side of the system that got pulled around as the storm developed," Barber said. "It slowed down and did so in the right spot for western South Dakota to get clobbered."

Authorities used snowmobiles to help rescue some motorists Saturday. The storm closed many highways, including Interstate 90, which remained closed from Wall to the Wyoming border.

"At least we're beyond the phase where as soon as the plows go through, the road gets closed behind them because of blowing snow," Barber said. "That's what they were fighting Saturday, at least early in the day."

Wind gusts of more than 70 mph were reported around the Rapid City area, resulting in downed trees and branches. City officials on Sunday told residents to leave tree branches and debris on their property until drop-off sites could be prepared.

The Red Cross had 35 people at a shelter in a Rapid City high school Saturday night, including four residents who were displaced by a house fire, said Michelle Lewis, Red Cross spokeswoman. Volunteers from South Dakota and North Dakota were scheduled to arrive Monday with supplies and equipment, she said.

Sunday is expected to be sunny with his in the 40s - perhaps low 50s - in most of the Black Hills region.

"If there wasn't a whole lot of snow on the ground it would be an absolutely beautiful Sunday," Willett said.

http://www.weather.com/news/snow-buries-south-dakota-wyoming-winter-storm-atlas-threatens-midwest-20131004

Four Hurricanes at Once

http://www.b.weather.com/video/four-hurricanes-at-once-39073

Tropical Storm Update

http://www.b.weather.com/video/whats-brewing-now-6584?

Colorado Flooding Emergency

At least six people have died in massive floods in the Front Range of Colorado, and two more people are missing and presumed dead. At the height of the tragic event, approximately 1,200 people were unaccounted for, according to the Associated Press. Hundreds of those people have finally been contacted, but dozens more remain out of touch.

The disaster could end up costing billions of dollars and has left many residents homeless who opted out of flood insurance. Above is our collection of images from the areas affected by the floods as rainfall records were shattered in areas like Boulder.

http://www.weather.com/news/colorado-flooding-emergency-photos-20130912

Typhoon Usagi Sets Sights on Hong Kong

Typhoon Usagi, a strong tropical cyclone in the western Pacific Ocean, is packing winds equivalent to a category 3 Hurricane. Over the next 24 hours Usagi will threaten Hong Kong and parts of mainland China.

The storm has already dumped more than a foot of rain in parts of Taiwan and is blamed for the deaths of two people in The Philippines 

Usagi had strengthened to a super typhoon Friday morning before weakening slightly. It's now below super typhoon strength.  Further weakening is expected before making landfall late late Sunday or early Monday, local time. 

A tropical cyclone is dubbed a "super typhoon" when maximum sustained winds reach at least 150 mph. Usagi underwent a period of rapid intensification from early Wednesday through midday Thursday (U.S. Eastern time), going from a 55-knot tropical storm to a 140-knot super typhoon in just 33 hours, or just under a 100 mph intensification, based on satellite estimates of intensity.

By Friday night, though, Usagi underwent an eyewall replacement cycle, causing the storm to weaken slightly. In addition, the outer rain bands began to interact with Tawain and Luzon, disrupting the storm's low-level inflow, further weakening the storm.

Nevertheless, Usagi is still a powerful typhoon, and it is expected to maintain a west-northwest path through the weekend. Here are the potential forecast impacts by location for Usagi:

http://www.weather.com/news/weather-hurricanes/typhoon-usagi-threatens-taiwan-hong-kong-20130919

Two Tropical Storms Converge on Mexico

VERACRUZ, Mexico -- Two tropical systems were converging on Mexico's east and west coasts Saturday, sparking authorities to evacuate coastal residents and set up shelters while watching rising rivers.

Hurricane Ingrid was gathering strength off Mexico's Gulf Coast, with forecasters predicting further increases in speed. They said Ingrid would likely become a hurricane Saturday afternoon.

"Mexico will have to deal with not just one, but two, tropical entities," said weather.com meteorologist Chrissy Warrilow. "Ingrid will be lashing the eastern coast bringing as much as two feet of rain to areas already inundated by Tropical Storm Ferdinand and Tropical Depression 8."

Though Ingrid will likely make landfall in Mexico, the U.S. will still see some impact.

"U.S. cities including Brownsville and Corpus Christi by heavy rain and wind from Ingrid."

A hurricane watch is in effect north of Cabo Rojo to La Pesca. A tropical storm warning is in effect from Coatzacoalcos to Cabo Rojo.

Manuel is expected to produce 10 to 15 inches of rain over parts of the Mexican states of Oaxaca and Guerrero, and life-threatening flash floods and mudslides are likely.

"Manuel will be moving into areas of Mexico with lots of mountainous features," said Warrilow. "Heavy rain, mudslides, and dangerous flash flooding are expected to occur.

Elsewhere, the remnants of Tropical Storm Humberto were swirling in the Atlantic, far from land. It was expected to regenerate in a couple of days, according to the Hurricane Center.

In Veracruz state off the Gulf Coast, state officials were evacuating communities in eight cities near the Tecolutla river where authorities reported higher-than-normal water levels.

State officials said they had also opened 12 shelters where they've directed some 1,000 people. Many have opted to stay with relatives and others.

A bridge collapsed near the northern Veracruz city of Misantla Friday, cutting off the area from the state capital. Thirteen people died when a landslide buried their homes in heavy rains spawned by Tropical Depression Fernand on Monday.

State officials imposed an orange alert, the highest possible, in parts of southern Veracruz.

http://www.weather.com/news/weather-hurricanes/two-tropical-storms-converge-mexico-20130914

Colorado Flash Flooding

First, the ground was saturated with heavy rainfall both on Sept. 9 and 10. Radar estimates suggest parts of the Front Range, including the Denver metro, picked up well over 1 inch of rain each afternoon and evening.  Street flooding was particularly severe Tuesday in the east Denver metro, including Aurora.

The atmospheric setup at right consisted of an upper-level low pressure center over the Great Basin, blocked from moving east or north by a large dome of high pressure aloft over the Pacific Northwest and southwest Canada. Winds aloft were spreading apart, enhancing lift in the atmosphere for rain and thunderstorms.

This low pressure circulation tapped a plume of moisture from the Pacific Ocean off western Mexico into northern Colorado.

According to Dr. Jeff Masters from Weather Underground (blog), the amount of moisture in the atmosphere, or "precipitable water", over Denver as of 6 a.m. MDT Sep. 12 reached record values for the month of September (1.33 inches). Records date to 1948.

Finally, winds 15,000 feet above the ground were generally blowing from southeast to northwest and were light. This means the relatively low-topped rain and thunderstorms could not move off the Foothills and Front Range from west to east, but instead "trained" or lingered along or near the Foothills and Front Range Urban Corridor. This is a classic scenario for major flooding in northern Colorado.

From the afternoon of September 9 through midday on September 13, 14.62 inches of rain had fallen in Boulder, Colo. This included an incredible 9.08 inches of rain on September 12, alone!

According to the Western Regional Climate Center, the previous all-time record rainfall for any calendar day in Boulder was a 4.80 inch deluge on July 31, 1919., in records dating to 1893. September 12th's total almost doubled the previous record wet day.

Furthermore, the previous wettest September day was only 3.05 inches on Sep. 4, 1909. In fact, only two other September days featured over two inches of rain, none previously since 1938.

The ten previous wettest calendar days in Boulder since 1893 all occurred between early April and early August, according to National Weather Service.

Average September rainfall in Boulder is only 1.63 inches. So, Boulder picked up almost nine times their average September monthly rainfall...in almost four days! The previous wettest single month in Boulder was 9.59 inches in May 1995.

On September 12, a storm total of 11.5 inches came in from Aurora, Colo., an eastern Denver suburb. 

The average annual precipitation (rain + liquid from melted snow) in Denver is 14.92 inches.  That's over three-quarters of the yearly average precipitation occurring in the span of a day or so!

http://www.weather.com/news/weather-severe/colorado-flash-flood-how-it-happened-unusual-20130912