A look at weather extremes and the big-picture climate connections.

Strongest Storm on Earth En Route to Hong Kong

Super-Typhoon Usagi became the strongest storm on Earth on Thursday. Though it’s weakened since then, the storm is still churning toward Hong Kong and could create major disruptions with a likely landfall as early as Sunday.

On Thursday, Usagi measured sustained wind speeds of 160 mph. Those winds made it the strongest storm on Earth this year, besting Utor, which recorded wind speeds of 150 mph prior to making landfall in the Philippines in mid-August according to the Capital Weather Gang. NASA created a 3D satellite image of Usagi at its peak, showing an extremely well-developed eyewall.

Satellite image of Super-Typhoon Usagi spinning in the Philippines Sea on Thursday.
Credit: Cooperative Institute for Meteorological Satellite Studies

Measurements by the Joint Typhoon Warning Center on Friday morning showed that Usagi had sustained winds of 150 mph with gusts up to 184 mph. That’s still enough to classify it as a supertyphoon or make it the equivalent of a Category 4 hurricane. The storm is also kicking up waves as high as 45 feet.

The storm is expected to deliver a sharp blow to Taiwan on Friday and Saturday before likely heading toward Hong Kong. Taiwan’s Central Weather Bureau has issued an “extremely torrential rain advisory” for the southeastern part of island. The storm could potentially drop 20-30 inches of rain on Taiwan over the next two days. That’s prompted the Defense Ministry to deploy more than 1,600 soldiers to areas most prone to...


Sunburned in Siberia: Heat Wave Leads to Wildfires

An intense heat wave in Siberia has contributed to an unusual flare up of wildfires across the fragile and carbon-rich landscape. Smoke from the fires is lofting high into the atmosphere, and is drifting toward the Arctic, where soot can hasten the melting of snow and sea ice. 

The map above shows land surface temperature anomalies for July 20–27, 2013, collected by the MODIS imager on NASA's Terra satellite. 
Click on the image to enlarge. Credit: NASA Earth Observatory.

The Siberian city of Norilsk, the most northerly city in the world with a population greater than 100,000, recorded temperatures above 83°F over eight consecutive days starting on July 18, according to blogger Chris Burt of Weather Underground. During that timespan, Burt reported, the mercury hit 90°F, breaking the record for the hottest temperature recorded for the city. For comparison the average July high temperature in Norilsk is a comparatively chilly 61°F.

Norilsk isn’t an isolated example, but rather sits amid a sea of abnormally hot temperatures and smoky conditions in north-central Siberia. According to NASA’s Earth Observatory, from July 20 through July 27, temperatures were about 30°F above average across a large swath of this vast, sparsely populated region.

The warm weather has contributed to a spike in wildfires. As of July 29, wildfires continued to burn at least 22,200 acres in Siberia, according to news reports. Heavy smoke from them grounded commercial flights in Omsk, a city in southwestern Siberia, Russia Today reported. 

The Siberian fires come on the heels of Russia’s worst wildfire season on record in 2012.  Fires burned roughly 74 million acres that...


Mid-July Heat Wave Bakes U.S. From Coast to Coast

A map showing maximum temperatures across the U.S. for July 10-19, 2013. Gray represents temperatures of 70°F while dark red represents temperatures above 107°F.
Credit: NOAA Environmental Visualization Laboratory

The heat wave that gripped the U.S. in mid-July had most of the country sweating bullets. Temperatures ratcheted up from coast to coast from July 10 to July 19 as the graphic above from the National Oceanic and Atmospheric Administration shows. During the period, 134 high temperature records fell or were tied.

Records were set indiscriminate of geographical location. Maynard, Mass., a suburb of Boston, set records on July 18 and 19 with a high of 99°F on both days. Areas around other big cities such as Denver and New York also saw record-high temperatures. Rural areas weren't exempt from sweltering heat. Cave Junction, Ore., topped out at 104°F on July 11 while Haiwee Reservoir, Calif., saw the mercury rise to an eye-popping 111°F on July 15.

Even in places where records weren’t set, high temperatures still ran well above average for this time of year. For example, during the period Salt Lake City was 5 degrees above its July average. The intense heat also caused New York state to break its all-time energy use in a single day on July 19.

Also of note is that while 134 record-high temperatures were recorded, 716 records for highest overnight minimum temperatures were also felled or tied. A cold front moved into the Northeast on Sunday, bringing relief to that region. However, areas west of the Mississippi will have to wait until later this week for relief from sizzling temperatures.

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All-Time Heat Records Broken in . . . Alaska?!

A massive dome of high pressure, sometimes referred to as a "heat dome," has set up shop over Alaska, bringing all-time record temperatures just a few weeks after parts of the state had a record cold start to spring. In some cases, towns in Alaska were warmer on Monday and Tuesday than most locations in the lower 48 states.

Forecast temperature anomalies on June 19 from the GFS computer model.
Click image to enlarge. Credit: WeatherBell.com.

For example, Talkeetna set an all-time high temperature record of 96°F on Monday, smashing its previous mark of 91°F set a day earlier, and previously set in June of 1969. In fact, it was warmer in Talkeetna, which is about 110 miles north of Anchorage, than it was in Miami, based on data from the National Weather Service (NWS). (As Weather Underground's Christopher Burt notes, there was an unofficial observation of 98°F on Monday, which would rank among the hottest all-time temperature records for the state.)

In Valdez, which sits along the cool waters of Prince William Sound, the temperature reached a remarkable 90°F Monday, beating the previous all-time mark of 87°F. And in Seward, another coastal port, the temperature hit 88°F, breaking the previous all-time high of 87°F that was set on July 4, 1999.

Here is how the National Weather Service described the Valdez record (the ALL CAPS style is from the original public statement):



Tropical Storm Andrea Brings Heavy Rain to East Coast

Tropical Storm Andrea is barrelling up the eastern seaboard after bringing heavy rain, high winds, a modest storm surge, and nearly a dozen tornadoes to Florida on Thursday. The storm is mainly a rain producer now, and is losing its tropical characteristics as it moves from the Carolinas northeastward to a position near Nantucket Island by Saturday morning, according to the National Hurricane Center.

Tropical Storm Andrea covered most of the East Coast on Friday morning.
Click on the image to enlarge. Credit: NASA via CIMSS.

The storm is sending a plume of tropical moisture up the East Coast, hugging the I-95 corridor, and 2 to 4 inches or more of rainfall is falling from South Carolina to Maine. The rainfall is already causing flash flooding, and may result in river flooding as well, particularly in the Mid-Atlantic and Northeast. The National Weather Service forecast office in New York City warned of potential rainfall rates of 1 inch per hour for several hours on Friday afternoon and Friday night.

Forecast total rainfall from Tropical Storm Andrea, showing the bullseye right along the Mid-Atlantic and Northeast coastline.
Click on the image to enlarge. Credit: NOAA/HPC.

The storm’s strongest winds are mainly confined to the immediate coastline of the Carolinas, and as the remnants of Andrea move northeast, the wind field is likely to stay offshore, sparing the I-95 corridor of tropical storm force winds, although it will still be windy.

Minor storm surge flooding is possible from the Carolinas to Virginia, but is not a threat for the Chesapeake Bay or New Jersey coastline, which is good news after the devastation wrought by Hurricane Sandy last year.

Satellite animation of T.S. Andrea as it made landfall in Florida's Big B...