Chan-Hom in the western Pacific Ocean

July 6th, 2015 |
Himawari-8 10.35 µm infrared imagery, 1447-2002 UTC on 6 July 2015 (Click to animate)

Himawari-8 10.35 µm infrared imagery, 1447-2002 UTC on 6 July 2015 (click to animate)

Typhoon Chan-Hom in the western Pacific Ocean is forecast to strengthen and move towards Taiwan later this week. A Himawari-8 target sector is viewing the storm today, and a 5-hour animation with a 2.5-minute time step (10.35 µm infrared imagery) is shown above. Very cold overshooting tops (the yellow enhancement show tops colder than -90º C) periodically develop. The toggle below of Sea Surface Temperature and Wind Shear (taken from the CIMSS Tropical Cyclones site) shows conditions — very warm sea-surface temperatures and low values of deep-layer wind shear — favorable for strengthening.

Suomi NPP VIIRS 0.70 µm visible Day/Night Band and 11.45 µm - 3.74 µm Brightness Temperature Difference images, and Ceilings and Visibilities, ~0800 UTC (click to enlarge)

SSTs and Wind Shear superimposed on the forecast track of Typhoon Chan-Hom (click to enlarge)

The three water vapor images shown below, also from Himawari-8, show that Chan-Hom is the 2nd of three tropical systems in a row. Linfa is west of the Philippines and approaching the coast of China; Nangka is east of Chan-Hom. Note that the 6.2 µm imagery is more sensitive to water vapor higher in the troposphere: Cirrus shields are apparent. The 7.3 µm imagery is not so sensitive to upper-level moisture and can therefore detect cumulus fields underneath cirrus.

Himawari-8 6.2 µm, 6.9 µm and 7.3 µm infrared water vapor images, 2040 UTC on 6 July 2015 (Click to enlarge)

Himawari-8 6.2 µm, 6.9 µm and 7.3 µm infrared water vapor images, 2040 UTC on 6 July 2015 (click to enlarge)