A satellite from NASA-NOAA’s Finnish nuclear power plant flew over Hurricane Jimena in the eastern Pacific and saw the strongest thunderstorms rise rapidly, especially in the northern quarter of the storm. Jimena picked up quickly overnight on August 27 and early August 28, and the National Hurricane Center expects it to become a major hurricane.

The Visible Infrared Imaging Radiometer Suite or VIIRS instrument on the satellite provided infrared data from the storm, indicating the coldest cloud temperatures, suggesting that the strongest thunderstorms were in the northern quarter of Jimena. Peak cloud temperatures were colder than -63 Fahrenheit (-53 Celsius).

VIIRS is a scanning radiometer that collects visible and infrared images as well as “radiometric” measurements. In essence, it means that VIIRS data is used to measure the properties of clouds and aerosols, the color of the ocean, and the temperatures of the oceans and land surface.

Berg, a forecaster at the National Hurricane Center (NHC), noted that the microwave data has shown the center of the eye under a dense cloud, and a clearer eye is only now becoming apparent in infrared satellite images.

At 11.00 EDT (8.00 PDT) / 1500 UTC on August 28, Hurricane Jimena Center was located near latitude 12.4 north and longitude 122.0 west. This locates downtown about 1,075 miles (1,720 km) southwest of Baja California, on the southern tip of Mexico.

Jimena was moving west near 12 mph (19 km / h), and this movement is expected to continue until the beginning of Saturday, August 29th. The estimated average pressure is 979 millibars.

The NHC noted that Jimena had picked up rapidly, with the biggest sustained winds having risen to near 90 mph (150 km / h) with higher gusts. Further reinforcement is forecast for the next 48 hours, and Jimena is expected to become a major hurricane tonight, August 28th.

Peak intensity is expected to be reached after about 48 hours, when the NHC expects Jimena’s continued maximum wind to rise to 125 knots, making it a powerful Category 4 hurricane on the Saffir-Simpson scale. After that, Jimena gradually deteriorates due to a slightly drier environment and lower ocean calorific values.