From: NASA HQ
Posted: Monday, September 7, 2015
The VIIRS instrument aboard NASA-NOAA's Suomi satellite captured this infrared image of Hurricane Jimena on August 28 at 10:16 UTC (6:16 a.m. EDT). Strongest part of the hurricane appears in red. Credits: NRL/NASA/NOAA
Hurricane Jimena is on a downward spiral and is expected to continue weakening. NASA-NOAA's Suomi NPP satellite flew over Hurricane Jimena and saw the strongest thunderstorms were on its southern and northeastern sides. Jimena is expected to bring rough surf to the Hawaiian Islands over the weekend of Sept. 5 and 6.
The Visible Infrared Imaging Radiometer Suite or VIIRS instrument aboard the satellite provided infrared data of the storm that showed the coldest cloud top temperatures, which indicate the strongest thunderstorms were in Jimena's northern quadrant. Cloud top temperatures there were as cold as -80 Celsius (-112 Fahrenheit) indicating strong storms with the potential for heavy rainfall.
NOAA's Central Pacific Hurricane Center (CPHC) said that water vapor imagery strongly suggests that very dry is being drawn into the system which will diminish the development of thunderstorms. In addition, CPHC noted that the outflow (air at the top of the storm being pushed to the fringes of the hurricane from the center) was "showing some restrictions in the western quadrant." In the VIIRS image, the western quadrant lacked strong thunderstorms.
VIIRS is a scanning radiometer that collects visible and infrared imagery and "radiometric" measurements. Basically it means that VIIRS data is used to measure cloud and aerosol properties, ocean color, and ocean and land surface temperatures.
On September 4, 2015, Jimena was far to the northwest of Hawaii. At 11 a.m. EDT (5 a.m. HST/1500 UTC) Jimena's center was located near latitude 19.7 north and longitude 145.1 west. That's about 650 miles (1,045 km) east of Hilo, Hawaii and 835 miles (1,345 km) east of Honolulu.
Despite the distance from Hawaii, the CPHC expects rough surf to continue affecting Hawaii. CPHC said "large and powerful long-period swells generated by Hurricane Jimena will produce hazardous and potentially damaging surf in the main Hawaiian islands through this weekend (Sept. 5 and 6), primarily along east facing shores.
Maximum sustained winds are near 85 mph (140 kph) and gradual weakening is expected. The estimated minimum central pressure is 975 millibars. Jimena was moving toward the northwest near 5 mph (7 kph) and is expected to move to the north-northwest. For updated forecasts visit NOAA's Central Pacific Hurricane Center at: http://www.prh.noaa.gov/cphc.
The CPHC noted that by Monday and Tuesday, Sept. 7 and 8, an elongated area of high pressure in the middle-atmosphere situated north of Jimena is forecast to strengthen. As a result, it will likely push the storm in a westward direction. CPHC forecasts steady weakening over the next several days and by Sept. 9, expect Jimena to be a depression.
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