This website works best with a newer web browser such as Chrome, Firefox, Safari or Microsoft Edge. Internet Explorer is not supported by this website.

CIMSS Satellite Blog

MENU

Subtropical Storm Biguá near the coast of Brazil

By Scott Bachmeier •

10-minute Full Disk scan GOES-16 (GOES-East) daytime True Color RGB + Nighttime Microphysics RGB images from the CSPP GeoSphere site (above) depicted the cyclonic (clockwise in the Southern Hemisphere) circulation associated with the formation of Subtropical Storm Biguá just off the coast of Rio Grande do Sul state in far southern Brazil during... Read More

GOES-16 daytime True Color RGB + Nighttime Microphysics RGB images, from 1200 UTC on 14th December to 1200 UTC on 16th December [click to play MP4 animation]

10-minute Full Disk scan GOES-16 (GOES-East) daytime True Color RGB + Nighttime Microphysics RGB images from the CSPP GeoSphere site (above) depicted the cyclonic (clockwise in the Southern Hemisphere) circulation associated with the formation of Subtropical Storm Biguá just off the coast of Rio Grande do Sul state in far southern Brazil during the 14th-16th December 2024 period.

12-hourly surface analyses shown below (source) indicated that this subtropical storm developed as an area of low pressure (denoted by a red “B”) moved southeast across Rio Grande do Sul on 14th December, becoming classified as Subtropical Storm (“Tempestade Subtropical”) Biguá shortly after it moved offshore at 0000 UTC on 15th December. 24 hours later, Biguá was downgraded to a Subtropical Depression (“Depressao Subtropical”) at 0000 UTC on 16th December.

Surface analyses from 0000 UTC on 14th December to 0000 UTC on 17th December [click to play animated GIF | MP4]

A sequence of ASCAT surface scatterometer winds (source) from Metop-B and Metop-C (below) showed that the compact low-level circulation center of Subtropical Storm Biguá remained just off the Brazilian coast on 15th December. The strongest winds were generally within the southern semicircle of the storm.

ASCAT winds from Metop-B and Metop-C on 15th December

View only this post Read Less

Cyclone Chido makes landfall in Mozambique

By Scott Bachmeier •

EUMETSAT Meteosat-9 Infrared Window (10.8 µm) images (above) showed Category 4 Cyclone Chido as its eye moved across the small island of Mayotte (airport identifier FMCZ) in the Mozambique Channel around 0730 UTC on 14th December 2024 — and went on to make landfall just south of Penba, Mozambique (airport identifier... Read More

EUMETSAT Meteosat-9 Infrared Window (10.8 µm) images, from 1800 UTC on 13th December to 0700 UTC on 15th December [click to play animated GIF | MP4]

EUMETSAT Meteosat-9 Infrared Window (10.8 µm) images (above) showed Category 4 Cyclone Chido as its eye moved across the small island of Mayotte (airport identifier FMCZ) in the Mozambique Channel around 0730 UTC on 14th December 2024 — and went on to make landfall just south of Penba, Mozambique (airport identifier MQPB) around 0400 UTC on 15th December. Chido traversed increasingly warmer sea surface temperatures (source) as it approached Mozambique.

As Cyclone Chido passed over Mayotte, the airport reported wind gusts of 92 kts (106 mph) as the eye approached and 91 kts (105 mph) as the eye departed (below).

Time series plot of surface report data from Dzaoudzi–Pamandzi International Airport on the island of Mayotte [click to enlarge]

Shortly before Chido made landfall in Mozambique, a Synthetic Aperture Radar (SAR) image at 0253 UTC (below) indicated that a derived maximum wind speed of 123.84 knots was present in the SE quadrant of the eyewall (source).

RCM-1 SAR image at 0253 UTC on 15th December [click to enlarge]

View only this post Read Less

Severe weather across the Bay Area of California

By Scott Bachmeier •

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Water Vapor (6.9 µm) images (above) showed a mid-tropospheric shortwave trough that was moving inland across central/northern California — along with associated surface warm and cold frontal features on 14th December 2024. Sporadic lightning activity within a few bands of convection was indicated by GLM Flash Points.  Of particular... Read More

1-minute GOES-18 Mid-level Water Vapor (6.9 µm) images, with plots of SPC Storm Reports of Severe Wind Gusts (cyan), hourly METAR site Peak Wind Gusts (red), GLM Flash Points (white) and 3-hourly Surface Fronts (beige); a Tornado Warning issued for the San Francisco area is depicted by a red polygon [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Water Vapor (6.9 µm) images (above) showed a mid-tropospheric shortwave trough that was moving inland across central/northern California — along with associated surface warm and cold frontal features on 14th December 2024. Sporadic lightning activity within a few bands of convection was indicated by GLM Flash Points.  Of particular interest was the Tornado Warning (red polygon) that was issued for San Francisco (possibly the first Tornado Warning issued for San Francisco proper?). There were several reports of strong winds across the Bay Area, most notably a gust to 72 knots (83 mph) at San Francisco International Airport.

1-minute GOES-18 Clean Infrared Window (10.3 µm) images, with time-matched (+/- 3 minutes) SPC Storm Reports plotted in red [click to play animated GIF | MP4]

1-minute GOES-18 Infrared (10.3 µm) images (above) included plots of SPC Storm Reports across the area.

Later in the day, a low-topped thunderstorm produced an EF1-rated tornado at Scotts Valley, the location of which was shown in 1-minute GOES-18 Visible (0.64 µm) and Infrared images (below).

1-minute GOES-18 Red Visible (0.64 µm, left) and Clean Infrared Window (10.3 µm, right) images, with time-matched (+/- 3 minutes) SPC Storm Report of a tornado (T) plotted in red [click to play animated GIF | MP4]

View only this post Read Less

Franklin Fire near Malibu, California

By Scott Bachmeier •

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Shortwave Infrared (3.9 µm) images (above) displayed a pronounced thermal signature associated with the Franklin Fire, which began burning just north-northwest Malibu, California around 0644 UTC on 10th December 2024 (or 10:24 PM PST on 9th December). This wildfire was driven by strong Santa Ana winds, which helped it to increase rapidly in... Read More

1-minute GOES-18 Shortwave Infrared (3.9 µm) images, from 0631-2130 UTC on 10th December [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Shortwave Infrared (3.9 µm) images (above) displayed a pronounced thermal signature associated with the Franklin Fire, which began burning just north-northwest Malibu, California around 0644 UTC on 10th December 2024 (or 10:24 PM PST on 9th December). This wildfire was driven by strong Santa Ana winds, which helped it to increase rapidly in size and intensity — in fact, the Franklin Fire began to exhibit 3.9 µm brightness temperatures of 137.88ºC (the saturation temperature of GOES-18 ABI Band 7 detectors) beginning at 0855 UTC (below), which persisted until 0947 UTC.

Sample of GOES-18 Shortwave Infrared (3.9 µm) brightness temperature NW of Malibu at 0855 UTC on 10th December [click to enlarge]

About 12 minutes after the Franklin Fire began to exhibit a thermal signature on GOES-18 Shortwave Infrared imagery, a RAWS site just east of the wildfire reported a wind gust of 52 mph at 0656 UTC (below). About 2.5 hours later, a RAWS site just northwest of the fire reported a wind gust of 50 mph at 0931 UTC. In addition to the strong winds, relative humidity values at those nearby RAWS sites were generally 10% or less.

GOES-18 Shortwave Infrared image at 0656 UTC, with a sample of RAWS site observation data just east of the Franklin Fire [click to enlarge]

Since the Franklin Fire began and rapidly intensified during the nighttime hours, its thermal signature was also apparent in the Near-Infrared 1.61 µm and 2.24 µm spectral bands (below).

1-minute GOES-18 Near-Infrared (1.61 µm and 2.24 µm, top and middle) and Shortwave Infrared (3.9 µm, bottom) images, from 0635-1430 UTC on 10th December [click to play animated GIF | MP4]

1-minute GOES-18 True Color RGB images from the CSPP GeoSphere site (below) revealed several pyrocumulus jumps over the Franklin Fire, in addition to a dense smoke plume drifting offshore.

1-minute GOES-18 True Color RGB images, from 1530-2359 UTC on 10th December [click to play MP4 animation]

View only this post Read Less

  • last_page First
  • Last last_page

Search blog