GPM IMERG Measures Rainfall Accumulation from Hurricane Dorian in the Caribbean

August 29, 2019

GPM IMERG Measures Rainfall Accumulation from Hurricane Dorian in the Caribbean

UPDATE 9/5/19:

Hurricane Dorian continues to generate tremendous amounts of rainfall, and has left over three feet of rain in some areas of the Bahamas and is now lashing the Carolinas. NASA’s IMERG product provided a look at those rainfall totals.

GPM IMERG estimated rainfall totals for Hurricane Dorian from August 31st - September 5th, 2019. Credit: Owen Kelley (NASA GSFC)

GPM IMERG estimated rainfall totals for Hurricane Dorian from August 31st - September 5th, 2019. Credit: Owen Kelley (NASA GSFC)

By September 5, Hurricane Dorian had dumped heavy rain on coastal South Carolina. An even greater accumulation of over 10 inches was occurring off shore along the path of Dorian’s inner core. In part because of Hurricane Dorian’s forward motion during the past two days, the recent rainfall totals have remained below the 36-inch accumulation observed when Dorian was stalled over the Bahamas. The graphic shows the distance that tropical-storm force (39 mph) winds extend from Hurricane Dorian’s low-pressure center as reported by the National Hurricane Center. The Saffir-Simpson intensity category is the number following the “H” in the label on the image. 

By Thursday morning, September 5, Hurricane Dorian had dumped heavy rain on coastal South Carolina.  An even greater accumulation of over 10 inches was occurring off shore along the path of Dorian’s inner core.  In part because of Hurricane Dorian’s forward motion during the past two days, the recent rainfall totals have remained below the 36-inch accumulation observed when Dorian was stalled over the Bahamas.

NASA has the ability to estimate the rainfall rates occurring in a storm or how much rain has fallen. Rainfall imagery was generated using the Integrated Multi-satEllite Retrievals for GPM or IMERG product at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. These near-realtime rain estimates come from the NASA IMERG algorithm, which combines observations from a fleet of satellites in the GPM or Global Precipitation Measurement mission constellation of satellites, and is calibrated with measurements from the GPM Core Observatory as well as rain gauge networks around the world. The measurements are done in near-real time, to provide global estimates of precipitation every 30 minutes.

The storm-total rainfall at a particular location varies with the forward speed of the hurricane, with the size of the hurricane’s wind field, and with how vigorous the updrafts are inside the hurricane.

UPDATE 9/3/19:

GPM IMERG rainfall accumulation for Hurricane Dorian from August 28th to September 3rd, 2019. Credit: Owen Kelley (NASA GSFC)

GPM IMERG rainfall accumulation for Hurricane Dorian from August 28th to September 3rd, 2019. Credit: Owen Kelley (NASA GSFC)

In the early hours of Tuesday, September 3, Hurricane Dorian had been stationary over the island of Grand Bahama for 18 hours, most of the time as a category 5 hurricane. Storm-total rain accumulation over parts of Grand Bahama and Abaco Islands have exceeded 24 inches according to NASA satellite-based estimates.

NASA’s IMERG storm-total rain accumulation over parts of Grand Bahama and Abaco islands have exceeded 24 inches according to NASA satellite-based estimates. The graphic also shows the distance that tropical-storm force (39 mph) winds extend from Hurricane Dorian’s low-pressure center, as reported by the National Hurricane Center. The symbols H and TS represent a hurricane of various Saffir-Simpson categories or a tropical storm, respectively.

Get more Hurricane Dorian news and updates at NASA's Hurricane Blog

UPDATE 8/30/19:

As Hurricane Dorian was upgraded to a Category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale, NASA’s fleet of satellites were gathering data during the day to assist weather forecasters and scientists.  At 2:00 pm EDT the National Hurricane Center (NHC) posted a supplemental advisory. NHC reports that “extremely dangerous  Hurricane Dorian poses a significant threat to Florida and the northwestern Bahamas.  The Hurricane Hunter plane finds Dorian is now a major hurricane.”

GPM IMERG rainfall accumulations from Hurricane Dorian over August 27th - 30th, 2019. Image Credit: Owen Kelley (NASA GSFC)

GPM IMERG rainfall accumulations from Hurricane Dorian over August 27th - 30th, 2019. Image Credit: Owen Kelley (NASA GSFC)

As of early on August 30, Hurricane Dorian has been producing 2 to 6 inches of rain along the path of its inner core for several days. This estimate comes from the NASA IMERG algorithm, which combines observations from a fleet of satellites, in near-realtime, to provide global estimates of precipitation every 30 minutes. The storm-total rainfall at a particular location varies with the forward speed of the hurricane, with the size of the hurricane’s wind field, and with how vigorous the updrafts are in the hurricane’s eyewall. The graphic also shows the distance that tropical-storm force (39 mph) winds extend from the Hurricane Dorians low-pressure center, as reported by the National Hurricane Center. The symbols H2, H1, and TS represent category 2 hurricane, category 1 hurricane, and tropical storm, respectively. 

NASA’s Global Precipitation Measurement mission satellite uses its IMERG algorithm with data from a fleet of satellites to provide global estimates of the precipitation within the storm every 30 minutes. This map displays the estimated rainfall accumulation for the region from August 27th - August 30th, prior to Dorian becoming a Category 3 storm.

Get more Hurricane Dorian news and updates at NASA's Hurricane Blog

Image Credit: Owen Kelley (NASA GSFC)
Text Credit: Lynn Jenner (NASA GSFC)

UPDATE 8/29/19:

This image shows estimated rainfall accumulations for the region affected by Hurricane Dorian over the 24 hour period of Aug.27 11:59 UTC to Aug. 28 11:59 UTC.

Image Credit: Jacob Reed (Telophase / NASA GSFC)

Hurricane Dorian is packing heavy rain as it moves toward the Bahamas as predicted by the National Hurricane Center. NASA's GPM mission recently analyzed the storm and found heavy rainfall in the storm as it passed through the Caribbean.

This image shows estimated rainfall accumulations for the region affected by Hurricane Dorian over a 24 hour period from August 27th - 28th. The imagery was generated using the Integrated Multi-satEllite Retrievals for GPM (IMERG) “early run” product. The data indicates that up to 120 mm (4.72 inches) of rainfall accumulated in certain regions during the 24 hour period.