Microwave measures of moisture

December 8th, 2021 |
MIMIC Total Precipitable Water fields, 0000 UTC 29 November – 0000 8 December 2021 (Click to enlarge)

If you were restricted to just one satellite-based observation and had to describe a week of weather, what would you choose? Submitted for your consideration: Morphed microwave estimates of moisture. The animation above shows MIMIC estimates of total precipitable water (created by using GFS winds to morph individual swaths of MIRS TPW estimates) centered on Hawai’i from 29 November through 7 December. What do these fields show you? There is a general increase in moisture over the Hawai’ian islands from the end of November to 2 December, at which point a polar front associated with a strong southward moving extratropical cyclone moves through the islands, generating snow over the Big Island’s highest peaks. Subsequently, a westward-moving subtropical low develops and draws moisture up from the ITCZ, resulting in heavy rain over the island chain. By the end of the animation, dry air starts to move over the islands from the east.

MIMIC Total Precipitable Water fields are available here. A archive of all fields and various domains is here. Filenames are such that it’s relatively easy to create cron jobs that create animations showing the latest fields, for example here for the eastern Pacific, here for the western Pacific, and here for the southern Pacific.