Tropical Cyclone Veronica north of Australia

March 21st, 2019 |

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (1145 µm) images at 1716 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1716 UTC [click to enlarge]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above) showed Category 4 Cyclone Veronica off the northern coast of Western Australia at 1716 UTC on 21 March 2019. Ample illumination from a Full Moon maximized the “visible image at night” capability of the Day/Night Band.

In a comparison of Microwave images from Suomi NPP ATMS at 1716 UTC and from GCOM-W1 AMSR2 at 1732 UTC (below), an eyewall that was nearly completely closed was apparent. Suomi NPP and GCOM-W1 images courtesy of William Straka, CIMSS.

Microwave images from Suomi NPP ATMS at 1716 UTC and from GCOM-W1 AMSR2 at 1732 UTC [click to enlarge]

Microwave images from Suomi NPP ATMS at 1716 UTC and from GCOM-W1 AMSR2 at 1732 UTC [click to enlarge]

A DMSP-17 SSMIS Microwave (85 GHz) image at 2246 UTC from the CIMSS Tropical Cyclones site is shown below. The deep-layer Wind Shear at 21 UTC was low (green contours), and Sea Surface Temperature values were quite high — both factors favorable for continued intensification as Veronica moved slowly toward the coast.

DMSP-17 SSMIS Microwave (85 GHz) image at 2246 UTC, with an overlay of 21 UTC deep-layer Wind Shear, and Sea Surface Temperature [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 2246 UTC, with an overlay of 21 UTC deep-layer Wind Shear, and Sea Surface Temperature [click to enlarge]

2.5-minute interval rapid scan Himawari-8 Infrared Window (10.4 µm) images (below) showed increasing organization to the eyewall structure. At times the cloud-top infrared brightness temperatures were -90ºC and colder (yellow pixels embedded within darker purple). Note: the rapid scan sector was re-poositioned eastward at 0100 UTC (to monitor Cyclone Trevor), so 10-minute imaging resumed after that time.

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

After sunrise, rapid scan Himawari-8 “Red” Visible (0.64 µm) images (below) revealed that the large eye was completely cloud-filled.

Himawari-8 "Red" Visible (0.64 µm) images [click to play animation | MP4]

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]

Unusual early ice loss in the Bering Sea

March 9th, 2019 |

GCOM-W2 AMSR2 Sea Ice Concentration, 01 February - 09 March 2019 [click to play animation | MP4]

GCOM-W1 AMSR2 Sea Ice Concentration, 01 February – 09 March 2019 [click to play animation | MP4]

A persistent northward transport of anomalously-warm air across the Bering Sea during the month of February 2019 led to an unusual loss of sea ice there — daily images of GCOM-W1 AMSR2 Sea Ice Concentration (source) from 01 February to 09 March (above) showed the northward retreat of ice from the Bering Sea into the Chukchi Sea. The ice reached its maximum northward extent on 04 March; northward ice motion was very pronounced during the 25-26 February and 27-28 February periods. In early March a synoptic pattern change then allowed cold arctic air to flow back toward the south, helping the ice concentration to begin increasing again in the northern portion of the Bering Sea.

Minimal cloudiness on 28 February allowed the northward flow of ice through the Bering Strait to be seen on GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (below).

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]



GCOM-W1 AMSR2 microwave products

November 30th, 2018 |

GCOM-W! AMSR2 Total Precipitable Water and Wind Speed products, from 2256 UTC on 28 November to 1692 UTC on 30 November [click to play animation]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products, from 2256 UTC on 28 November to 1692 UTC on 30 November [click to play animation]

A series of GCOM-W1 AMSR2 swaths during the period from 2256 UTC on 28 November to 1692 UTC on 30 November 2018 (above) showed the global coverage of Total Precipitable Water and Wind Speed products from that polar-orbiting satellite.

GCOM-W1 AMSR2 Total Precipitable Water, Wind Speed, Surface Rain Rate and Cloud Liquid Water products [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water, Wind Speed, Surface Rain Rate and Cloud Liquid Water products [click to enlarge]

A closer look just south of the Atlantic provinces of Canada (above) showed a comparison of Total Precipitable Water, Wind Speed, Surface Rain Rate and Cloud Liquid Water products over a strong mid-latitude cyclone at 0545 UTC on 29 November (the 0532 UTC time stamp on the images denotes the beginning time of that particular satellite swath).

Surface analyses from the OPC (below) classified this low pressure system as Hurricane Force at 00 UTC and Storm Force at 06 UTC — however, AMSR2 ocean surface wind speeds were as high as 71 knots west of the surface low, 84.8 knots north of the low and 95.6 knots in the vicinity of the occluded front.

Surface analyses at 00 UTC and 06 UTC [click to enlarge]

Surface analyses at 00 UTC and 06 UTC [click to enlarge]

Shortly after the overpass of GCOM-W1, additional views of the western portion of this storm were provided by Aqua MODIS and NOAA-20 VIIRS (below). (note: the NOAA-20 VIIRS images are incorrectly labeled as Suomi NPP)

Aqua MODIS Water Vapor (6.7 µm) and Infrared Window (11.0 µm) images at 0543 UTC [click to enlarge]

Aqua MODIS Water Vapor (6.7 µm) and Infrared Window (11.0 µm) images at 0543 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0557 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0557 UTC [click to enlarge]

Another overpass of GCOM-W1 about 10 hours later continued to show a broad region of strong post-frontal westerly winds to the south of the storm center (below). During that period, the occluded low continued to deepen from 957 to 952 hPa (surface analyses).

GCOM-W1 AMSR2 Total Precipitable Water, Wind Speed at 0532 and 1529 UTC [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products at 0532 and 1529 UTC [click to enlarge]

Additional features seen in the AMSR2 Total Precipitable Water and Wind Speed products in other parts of the world included the following:

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products at 0353 UTC on 29 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products south of Iceland at 0353 UTC on 29 November [click to enlarge]

Low pressure south of Iceland (surface analyses), with an ocean surface wind speed of 76 knots (above).

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products off the US West Coast at 1026 UTC on 29 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products off the US West Coast at 1026 UTC on 29 November [click to enlarge]

Low pressure off the US West Coast (surface analyses), with an ocean surface wind speed of  70 knots (above).

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products north of Hawai'i at 1202 UTC on 29 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products north of Hawai’i at 1202 UTC on 29 November [click to enlarge]

Low pressure and a cold front northwest of Hawai’i (surface analysis), with a long fetch of tropical moisture and widespread ocean surface wind speeds of 60-70 knots (above).

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products southwest of Australia at 1659 UTC on 29 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products southwest of Australia at 1659 UTC on 29 November [click to enlarge]

Low pressure southwest of Australia, with an ocean surface wind speed of 47 knots (above).

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products southeast of Argentina at 1659 UTC on 29 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products southeast of Argentina at 1659 UTC on 29 November [click to enlarge]

Low preesure and a cold front southeast of Argentina, with TPW as high as 2.2 inches and an ocean surface wind speed of 58.6 knots (above).

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products over the North Sea at 0259 UTC on 30 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products over the Norwegian Sea at 0259 UTC on 30 November [click to enlarge]

Low pressure over the Norwegian Sea (surface analysis), with an ocean surface wind speed of 75 knots (above).

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products over the Aleutian Islands at 1247 UTC on 30 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products over the Aleutian Islands at 1247 UTC on 30 November [click to enlarge]

A plume of moisture and strong winds ahead of a low pressure and cold front (surface analysis) moving across the Aleutian Islands (above).

Due to the frequent overlap of polar-orbiting satellite swaths at high latitudes, some locations can have data coverage from numerous consecutive overpasses. The example below shows the Barents Sea — between 70-80º N latitude — during 7 consecutive swaths from 2256 UTC on 28 November to 0847 UTC on 29 November.

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products over the Barents Sea from 2256 UTC on 28 November to 0847 UTC on 29 November [click to enlarge]

GCOM-W1 AMSR2 Total Precipitable Water and Wind Speed products over the Barents Sea from 2256 UTC on 28 November to 0847 UTC on 29 November [click to enlarge]