As Typhoon Mawar (also called Betty in the Philippines) has been making its way across the North Pacific, NOAA satellites, along with satellites operated by our international partners, have been carefully tracking the storm.
So far, Mawar is one of the strongest tropical cyclones in the Northern Hemisphere on record that occurred in the month of May as well as the most intense tropical cyclone worldwide this year so far.
After developing into a tropical depression on May 19, Mawar intensified, eventually becoming a super typhoon—in this case, the equivalent of a Category 4 Atlantic Hurricane on the Saffir-Simpson Hurricane Wind Scale—before passing just north of Guam on May 24. It barreled through the U.S. territory, shredding trees, tearing off roofs, and leaving much of the island of about 150,000 people without power and utilities. Luckily, there were no reported fatalities, and Guam’s governor, Lou Leon Guerrero, praised residents for keeping themselves safe and protected during the storm.
The central and northern parts of the island received more than two feet (60 centimeters) of rain as the eyewall passed. The strongest typhoon to hit the territory since 2002, Mawar briefly made landfall around 9 p.m. Wednesday as a Category 4 storm at Andersen Air Force Base on the northern tip of the island. It has since restrengthened to Category 5 force, becoming one of the top 10 strongest storms to occur globally since 2000.
Equally staggering is Mawar’s air pressure, or the weight of the air over a given location, which bottomed out around 897 millibars on Friday morning Eastern time. The average sea level air pressure is 1015 millibars. Lower air pressure signifies a stronger low-pressure system. The air pressure inside Mawar is equivalent to that atop a 3,000-foot mountain. This means that roughly a tenth of the atmosphere’s air is “missing” from the center of Mawar, spurring the powerful inward suction responsible for the storm’s extreme winds.
Although typhoons regularly impact Guam, Mawar has since achieved a strength, both in wind intensity and minimum central pressure, not seen in the tropical basin as a whole since deadly Typhoon Surigae in 2021 or in that specific part of the basin near Guam since Typhoon Damrey in 2000.
On Thursday, Mawar rapidly intensified further, becoming the equivalent of a Category 5 Atlantic hurricane, and by Friday, May 26, had sustained winds of 185 mph, according to the Joint Typhoon Warning Center. This tied Mawar with Phyllis of 1958 as the strongest typhoon observed in the month of May and makes Mawar the second-strongest tropical cyclone observed so early in the year behind Super Typhoon Surigae on April 17, 2021.
Mawar is also the Earth’s fifth storm of 2023 that has reached the equivalent of a Category 5 Atlantic hurricane status, behind cyclones Kevin, Freddy, Ilsa, and Mocha. The only other year that had more by this time was 2015, which had six storms by May 16.
The Philippines are considered the most exposed country to tropical cyclones in the world and face an average of 20 storms annually. Island states and territories in the region are experiencing threats from multiple fronts as global temperatures rise, including sea level rise, increasing frequency and intensity of droughts and storms, ocean acidification, and consequent damage to coral reefs and fisheries.
Typhoon Mawar was decelerating and weakening on Tuesday, May 30, as it inched north of the Philippines toward Taiwan and southern Japan, nearly a week after slamming Guam with rain and dangerous wind.
NOAA’s polar-orbiting satellites are providing critical data on the storm. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on both the Joint Polar Satellite System’s NOAA-20 and Suomi NPP satellites plays an important role in detecting and tracking storms. They measure the state of the atmosphere by taking precise measurements of sea surface temperatures and atmospheric temperature and moisture, which are critical to securing storm forecasts several days in advance. JPSS instruments provide data that is particularly useful in helping forecasters predict a hurricane’s path 3-7 days out.
NOAA-20 and Suomi-NPP also carry a microwave sounder called the Advanced Technology Microwave Sounder (ATMS) that penetrates clouds, allowing forecasters to see the internal structure of tropical cyclones. This helps forecasters understand the direction, movement, and intensity of these storms.
Geostationary satellites from our partners around the world, such as the Himawari satellites operated by the Japan Meteorological Agency (JMA), provide timely and potentially life-saving information about weather and storms in the Asia-Pacific region. Himawari's data are vital for global geostationary coverage, which is why NOAA and JMA have agreed to mutual backup arrangements for their geostationary systems.