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Geostationary satellite views of the most rain over 72-hours in 2007

The record for the most rain over a 72-hour period was in late February 2007, with 3.930m (154.72″)! This was on Reunion Island, associated with Tropical Cyclone Gamede in South Indian Ocean. The island is east of Madagascar. This island also holds... Read More

The record for the most rain over a 72-hour period was in late February 2007, with 3.930m (154.72″)! This was on Reunion Island, associated with Tropical Cyclone Gamede in South Indian Ocean. The island is east of Madagascar. This island also holds the record for the most rain (4,869 mm (191.7 in)) over a 96-hour period, associated with the same event. More on this case can be found in this 2009 BAMS article.

Meteosat-8

While the view of the cyclone from EUMETSAT‘s MET-8 was on the edge of the viewing area, the infrared window loop was still impressive.

A 3-day color-enhanced infrared window loop from EUMETSAT’s Meteosat-8 geostationary imager.

A longer loops of 3 and 4 days were also generated. Which shows Tropical Cyclone Favio as well. For these images, the coldest brightness temperatures have the green/yellow/red/pink colors. A one-day loop (February 25, 2007) in both mp4 and animated gif formats.

Meteosat-7

EUMETSAT’s Meteosat-7, due to its location over the Indian Ocean, had a more direct view of these cyclones.

A 3-day color-enhanced infrared window loop from EUMETSAT’s Meteosat-7 geostationary imager.

Note that the view angle is improved over Meteosat-8, but the image frequency is reduced. A longer Meteosat-7 loop was also generated. Again, Tropical Cyclone Favio can be seen.

A loop of Meteosat-7 visible band from February 25, 2007.

Visible loops (mp4 format) from February 23 and 24 and 26, 2007. The same loops as animated gifs: February 23, 24, 25 and 26, 2007.

H/T

Thanks to @Weather_History for the post on this event.

The above satellite data are from EUMETSAT, accessed via the University of Wisconsin-Madison Space Science and Engineering Center (SSEC) Data Services. The images were generated with McIDAS-X. More on EUMETSAT’s Meteosat Third Generation will appear in the Bulletin of the AMS.

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Snow squalls in Montana

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images (above) showed a cluster of convective features propagating south-southeastward over and to the east of Billings, Montana on 27 February 2021. The shades of green in the RGB images indicated that some of these cloud tops were glaciating, suggesting enough vertical development to produce... Read More

GOES-16 “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images (above) showed a cluster of convective features propagating south-southeastward over and to the east of Billings, Montana on 27 February 2021. The shades of green in the RGB images indicated that some of these cloud tops were glaciating, suggesting enough vertical development to produce significant precipitation — and the resulting snow squalls could have contributed to a multi-vehicle accident which closed down Interstate 90 (between Billings and the I-90/I-94 junction) shortly after 1900 UTC. A brief accumulation of 1.3 inches was reported just north of Billings around the time of the accident, and the 1900 UTC surface visibility dropped to 3/4 mile at Billings airport (but was likely lower where the more intense snow squalls were occurring farther east).

The corresponding GOES-17 (GOES-West) Visible/RGB animations are available here: GIF | MP4. A toggle between the 1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 is shown below. The satellite viewing angles are nearly equivalent from both satellites (around 60 degrees) — but the apparent location of the snow squall features is shifted, due to parallax.

1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 [click to enlarge]

1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 [click to enlarge]

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Using NUCAPS lapse rates to evaluate atmospheric stability

NUCAPS profiles derived from CrIS and ATMS data on NOAA-20 provide model-independent estimates of atmospheric thermodynamics globally, including, for this case over the central Pacific Ocean, in regions otherwise bereft of data.  NUCAPS lapse rates show a minimum in stability in low-levels in between two cloud features; the region includes... Read More

GOES-17 Visible Imagery (2300 UTC), NOAA-20 NUCAPS-derived lapse rate (925 – 700 mb, 23:03 UTC) and NUCAPS sounding points (2249 UTC) on 25 February 2021 (Click to enlarge)

NUCAPS profiles derived from CrIS and ATMS data on NOAA-20 provide model-independent estimates of atmospheric thermodynamics globally, including, for this case over the central Pacific Ocean, in regions otherwise bereft of data.  NUCAPS lapse rates show a minimum in stability in low-levels in between two cloud features; the region includes mostly ‘green’ NUCAPS retrieval points:  where infrared and microwave retrievals have both converged.  It is difficult in the case above to relate differences in cloud features to differences in the diagnosed stability.

Four minutes later (shown below), NOAA-20 was closer to the Pole on this ascending pass and the diagnosed stability does relate well to differences in cloud structures.  In particular, the change from lapse rates around 5 C/km northeast of Hawai’i to lapse rate closer to 2 or 3 C/km even farther northeast aligns with a boundary between cloud types.

GOES-17 Visible Imagery (2310 UTC), NOAA-20 NUCAPS-derived lapse rate (925 – 700 mb, 23:07 UTC) and NUCAPS sounding points (2249 UTC) on 25 February 2021 (Click to enlarge)

The subsequent NOAA-20 pass was west of the main Hawai’ian Island chain.  Again, differences in lapse rates are related to cloud features in the visible imagery.  Stable air — with lapse rates between 3 and 4 C/km — overlies a region of very little cumuliform development.  A region of larger lapse rates over the eastern 1/3rd of the pass, just to the west of the Hawai’ian Islands is accompanied by cumulus development.  NUCAPS thermodynamic fields, even though they have limited resolution in the vertical (at most 10 layers in the enter tropopause), can give useful information on stability over the ocean that can help in the real-time diagnosis of the atmosphere.

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Using 1-minute GOES-17 imagery to monitor tropical convection near American Samoa

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Clean” Infrared Window (10.35 µm) images (above) showed thunderstorms associated with the South Pacific Convergence Zone (SPCZ) on 21 February 2021. The 3 METAR stations plotted on the imagery are, from left to right, Hihifo Airport, Wallis and Fotuna (NLWW), Apia, Samoa (NSFA) and Pago Pago, American Samoa (NSTU).In spite... Read More

GOES-17 Infrared images [click to play animation | MP4]

GOES-17 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Clean” Infrared Window (10.35 µm) images (above) showed thunderstorms associated with the South Pacific Convergence Zone (SPCZ) on 21 February 2021. The 3 METAR stations plotted on the imagery are, from left to right, Hihifo Airport, Wallis and Fotuna (NLWW), Apia, Samoa (NSFA) and Pago Pago, American Samoa (NSTU).

In spite of their degraded quality due to GOES-17 ABI Loop Heat Pipe thermal issues (which reaches one of its peaks at the end February), the Infrared images were still helpful in confirming that the primary SPCZ axis was remaining just north of the Samoan islands — and since the NWS Pago Pago office lacks radar coverage, they highlighted the importance of satellite imagery in one of their forecast discussions:

The active South Pacific Convergence zone (SPCZ) is lingering over the Samoan 
island chain, as seen on latest GOES-17 mesoscale this afternoon.
We have a very difficult time with confirming the wind forecast by model data, 
as there are no observations available of the persistent convection brewing 
just off-shore the islands. However, the models coupled with satellite are 
our only tools.

===== 22 February Update =====

GOES-17

GOES-17 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

The Fiji Meteorological Service determined that Tropical Depression 10F formed along the SPCZ  around 00 UTC on 22 February (surface analysis). Shortly after that time, a convective burst developed just east of the disturbance center, which exhibited cloud-top infrared brightness temperatures as cold as -94.3ºC — which indicated a significant overshoot of the Equilibrium Level as analyzed on 00 UTC rawinsonde data from Pago Pago, American Samoa.

GOES-17 Infrared images, with plots of upper-level satellite winds and contours of upper-level convergence [click to enlarge]

GOES-17 Infrared images, with plots of upper-level satellite winds and contours of upper-level convergence [click to enlarge]

GOES-17 Infrared images with plots of upper-level satellite winds and contours of upper-level convergence (above) and plots of low-level satellite winds and contours of low-level convergence (below) from the CIMSS Tropical Cyclones site showed that the deep convection developing within the SPCZ was sustained by an environment of favorable kinematic fields. Tropical Depression 10F was also located within a narrow ribbon of relatively low deep-layer wind shear.

GOES-17 Infrared images, with plots of low-level satellite winds and contours of low-level convergence [click to enlarge]

GOES-17 Infrared images, with plots of low-level satellite winds and contours of low-level convergence [click to enlarge]

The MIMIC TPW product (below) highlighted the rich tropical moisture within the NW-SE oriented SPCZ.

MIMIC TPW product [click to enlarge]

MIMIC TPW product [click to enlarge]

A closer look at the MIMC TPW product over the Samoan islands at 16 UTC on 22 February is shown below. With such high tropical moisture in place across the region, thunderstorms were producing heavy rainfall and/or wind damage in some of the islands (local storm reports).

MIMC TPW product over the Samoan islands at 16 UTC

MIMC TPW product over the Samoan islands at 16 UTC [click to enlarge]

===== 23 February Update =====

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

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

GOES-17 “Red” Visible (0.64 µm) images (above) showed that as deep convection began to diminish, the low-level circulation center of TD 10F slowly became more exposed as the tropical disturbance weakened — prompting the Fiji Meteorological Service to discontinue classifying feature as a tropical depression as of 2100 UTC on 23 February (below).

Surface analyses at 18 UTC and 21 UTC on 23 February (map time stamps are Fiji local time) [click to enlarge]

Surface analyses at 1800 UTC and 2100 UTC on 23 February (map time stamps are Fiji local time) [click to enlarge]

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