The Bering Sea area has hosted some notable storms in recent years, such as the low-pressure system that slammed into Nome, Alaska, on November 8 and 9, 2011, with wind gusts up to 74 knots (85 miles per hour). Exactly three years later in 2014, Alaskans braced for another storm that was expected to intensify into the strongest low-pressure systems ever recorded in the Bering Sea.
The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime image of Tropical Storm Nuri at 15:55 Universal Time on November 6, 2014, as it tracked northeast off the coast of Japan and headed toward the Bering Sea and Alaska's Aleutian Islands.
The storm was imaged by a special "day-night band" that detects light in a range of wavelengths from green to near-infrared and uses light intensification to detect dim signals. The instrument can sense light as much as 100,000 times fainter than conventional visible-light sensors, making it very sensitive to moonlight and city lights. In this case, the cloud tops were lit by a full Moon.
On the day the image was acquired, Typhoon Nuri—once a powerful Category 5 super typhoon—had been downgraded to the status of tropical storm with maximum sustained winds of 56 knots (65 miles per hour). Further weakening and loss of structure, however, didn't mean the storm was over. Forecasts called for remnants of Nuri to rapidly intensify as they met with a powerful jet stream by November 7.
According to a blog post by Weather Underground's Jeff Masters, two different models predicted that the air pressure associated with the storm would bottom out on November 8 about 480 kilometers (300 miles) from Attu—the westernmost Aleutian Island.
Both forecasts suggested that the storm would reach a low pressure of 918 millibars, comparable to a Category 5 hurricane. For comparison, the 2011 storm saw air pressure bottom out at 945 millibars, comparable to a Category 3 hurricane.
The National Weather Service issued a hurricane force wind warning effective through the night of November 7 for southwest Alaska, Bristol Bay, the Alaska Peninsula waters, and the Aleutian Islands. For the westernmost Aleutian Islands of Kiska to Attu, the forecast called for 70-knot (81 mile-per-hour) winds and swell heights of about 14 meters (45 feet).
NASA Earth Observatory image by Jesse Allen, using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Kathryn Hansen.