Extreme Weather

In the North Atlantic, the tropical system known as Henri reached hurricane status on Saturday, August 21, 2021. At the time, it was approaching a landfall in New England. Between Friday and Sunday, Henri was observed three times by the Dual-frequency Precipitation Radar (DPR) on the core satellite of NASA's Global Precipitation Measurement (GPM) mission. The GPM satellite's first two flyovers of Henri occurred just 10 hours apart and revealed a remarkably unchanging structure that was being impacted by wind shear. A third overflight occurred a day later, when wind shear had abated and Henri

Tropical Storm Fred, the 6th named storm of the 2021 Atlantic hurricane season, began as a westward moving disturbance in the central Atlantic east of the Lesser Antilles. The system passed through the southern Leeward Islands during the early morning hours of August 10 but still lacked a well-defined center of circulation. Despite significant thunderstorm activity within the system, it wasn’t until late that evening, when the system was passing just south of Puerto Rico, that the National Hurricane Center (NHC) identified a well-defined circulation and upgraded the system to Tropical Storm

During July 17 to 28, 2021, several storm systems brought heavy rain to parts of China and surrounding countries, while a nine-month-long drought persists in an adjacent part of China. NASA's multi-satellite precipitation algorithm has been monitoring this rainfall in near real-time, and the estimates are distributed to weather-forecasting agencies and disaster-monitoring organizations. This algorithm is called IMERG, the Integrated Multi-satellitE Retrievals for GPM. GPM is the NASA / JAXA Global Precipitation Measurement mission, which launched its Core Observatory satellite in 2014. Two

After a relatively quiet period of below normal activity that began in the latter part of June and extended into the first half of July, and which resulted in rainfall deficits over much of India, the South Asian monsoon surged to life last week, bringing heavy rains, widespread flooding and landslides. Among the hardest hit areas was the western state of Maharashtra, which extends from the central west coast of India inland. A key geographical feature along the west coast of India is the Western Ghats. This coastal mountain range runs roughly north-south for about 1000 miles along the west

There is a monsoon that occurs in the southwestern U.S. each summer, and it brought heavy rain to the deserts of Arizona this week. This monsoon is less well known than India's Summer Monsoon, but both monsoons have similar causes [1, 2, 3]. In western Mexico and the southern edge of the southwest U.S., most of the year's rain typically falls in just three months: June, July, and August. The region is shown in light blue in the below climate map, which shows where summer rainfall predominates (Figure 1). This seasonal pattern is known as the North American Monsoon. The map was generated using

NASA combined data from multiple satellites in the GPM Constellation to estimate precipitation rates and totals from Tropical Cyclone Tauktae in May 2021. The below animation shows precipitation rates (blue/yellow shading) and accumulations (green shading) at half-hourly intervals from May 12-19, 2021, derived from NASA's IMERG algorithm. Underneath the precipitation data, cloud cover is shown in shades of white/gray based on geosynchronous satellite infrared observations. On top of the precipitation data, the cyclone's approximate track is displayed based on estimates from the Joint Typhoon

During the week ending on March 23, 2021, two locations in Australia experienced unusually high rainfall totals. According to news reports a persistent system brought flooding rains to Australia's east coast from Brisbane to Sydney and points further south. The preliminary estimate from NASA's multi-satellite global precipitation analysis is that more than 24 inches fell just off the coast of Australia in 7 days with accumulations in coastal areas exceeding 16 inches. Near the Strzelecki Desert in central Australia, a storm system brought 8 inches of precipitation during the same 7-day period. Most of the rain fell during a 3-day period (0000 UTC on 20 March to 2359 UTC on 22 March).

In mid-February 2021, large areas of the Continental United States experienced extreme cold temperatures as a result of a strong Arctic high pressure system. The cold temperatures were accompanied by several pulses of precipitation over the Southeast US through the mid-Atlantic, as well as the Pacific Northwest. The combination of cold temperatures and precipitation resulted in widespread power outages to millions of people in Texas, Kentucky, West Virginia, and Oregon, among other states.

NASA combined data from multiple satellites to estimate the rainfall from Tropical Cyclone Ana in the Southwest Pacific Ocean amid an ongoing Madden-Julian Oscillation (MJO) event. The Madden-Julian Oscillation is a 20 to 90 day pattern of alternating wet and dry conditions that often begins in the tropical Indian Ocean and moves eastward into the Pacific. This animation shows rainfall rates (blue/yellow shading) and rainfall accumulations (green shading) at half-hourly intervals from January 26 - February 2, 2021, using NASA's IMERG algorithm, overlaid on shades of white/gray from NOAA

NASA combined data from multiple satellites to estimate the rainfall from an "atmospheric river" event over the U.S. West Coast in near real-time at half-hourly intervals from January 25 - 29, 2021. Atmospheric rivers are long, narrow corridors of water vapor that can lead to heavy precipitation when they encounter land. This animation shows estimated rainfall rates in blue and yellow shading and total rainfall accumulations in green shading, from NASA's IMERG algorithm, overlaid on shades of white and gray from NOAA infrared satellite data which shows cloudiness. On January 25, 2021, a low