VIIRS composite flood products over Bangladesh and India

June 21st, 2022 |

The five-day composite of the VIIRS flood product is just one flood product that can be viewed in RealEarth. VIIRS is an instrument aboard SNPP and NOAA-20, which are low earth orbiting satellites. This means that while only two daytime observations may be retrieved per day over a given region, the spatial resolution of 375-m is quite highly resolved. VIIRS flood composites, such as the five-day composite, provide the “maximal flood extent” during flood events. More information about VIIRS and other satellite flood products can be found here.

In areas of Bangladesh and northwest India, persistent rains have caused recent heavy flooding. Millions of people have already been displaced and the flooding is forecast to continue. The VIIRS five-day flood product composite over a six-day time period can be seen below, with the 7-day CMORPH2 satellite-derived precipitation accumulation product. Comparing the images, the spatial placement of flooding with accumulated precipitation coincides well.

Daily images of the five-day VIIRS flood product composite from 6-15-2022 to 6-20-2022 over Bangladesh and Northeastern India. The product estimates the severity of river flooding over the last five days [click to enlarge].
CMORPH2 accumulate precipitation from 6-20-2022 over the same area. This product represents the approximate precipitation (rainfall) accumulation over the last seven days [click to enlarge].
Convective storms occurring over Bangladesh and Northeast India on 6-19-2022 from 00:00Z to 15:50Z as seen from the Advanced Himawari Imager (AHI). This animation was created using CSPP’s geo2grid software.

Himawari-8 Rain Rates in AWIPS with Typhoon Malakas

April 12th, 2022 |
Himawari-8 Band 13 Infrared (10.41 ┬Ám) Imagery and Level 2 Rain Rate Product, 0800 UTC on 12 April 2022 (Click to enlarge)

Typhoon Malakas in the western Pacific is shown above in Himawari-8 infrared imagery between Guam and the Philippines. It is a well-developed storm (albeit asymmetric) with an obvious eye. Level 2 Rain Rate from Himawari-8 is also shown; the heaviest precipitation is diagnosed to the southeast of the eye, and in rain bands to the east of the storm.

For more information on Malakas, refer to the SSEC/CIMSS Tropical Weather Website and the Joint Typhoon Warning Center.

Himawari imagery is courtesy JMA (Thank you!). Real-time sectorized Himawari imagery from the Meteorological Satellite Center of JMA is also available here.

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.

Moisture returns to the US West Coast

October 22nd, 2021 |
MIMIC Total Precipitable water, rocking animation from 0000 UTC on 11 October to 2300 UTC on 21 October (click to enlarge)

A sequence of two intense storms in the north Pacific Ocean, noted in the GOES-17 airmass RGB below, has drawn moisture into the northwestern United States. A MIMIC (Morphed Integrated Microwave Imagery at CIMSS) Total Precipitable Water rocking animation, above (rocking animation from this site), shows the development of a ribbon of moisture that moved into the northwestern United States.

GOES-17 Airmass RGB with/without 0900 UTC analysis of fronts/pressure (Click to enlarge)

Advected Layer Precipitable Water (ALPW, from this website), differentiates the moisture into layers. At 1200 UTC, one moisture axis was right across the Bay Area of California, with 20-24 mm of moisture in the sfc-850 mb layer, 10-12 mm of moisture in the 850-700 mb layer, and 5 or 6 mm in the 700-500 mb layer.

Microwave estimates of total precipitable water in layers: Surface-850 mb, 850-700 mb, 700-500 mb, 500-300 mb, ca. 1200 UTC on 22 October 2021 (Click to enlarge)

Accumulated 1-hour precipitation (estimated with CMORPH-2) for the hour ending at 1200 UTC on 22 October, below, shows a ribbon of rain from just north of the Bay Area to central Oregon; largest amounts over northern California are 6-8 mm for the one hour. CMORPH-2 estimates of precipitation are available at RealEarth.

CMORPH estimates of 1-hour rainfall ending at 1200 UTC on 22 October 2021 (Click to enlarge)