From an email received on the morning of 23 November 2009: “Several hours ago, shortly past 7:00Z today, telemetry received from QuikSCAT indicates that the antenna rotation rate has dropped to zero and remains at zero. The motor remains powered. The system can be operated safely in this state for an indefinite period. The QuikSCAT operations team will be meeting later this morning, but in all likelihood this is probably the end of the nominal mission.”

The image above shows the last QuikSCAT data processed on the AWIPS system at the Cooperative Institute for Meteorological Satellite Studies (CIMSS). The scatterometer wind data show the flow around a developing cyclone located southeast of the southern tip of Greenland. The underlying GOES-12 IR and water vapor images also reveal a classic baroclinic leaf pattern southeast of the developing cyclone, which is a satellite signature of impending cyclogenesis.

With the loss of QuikSCAT, the only scatterometer winds available in AWIPS are those from ASCAT. For additional information, see the VISIT training modules QuikSCAT Winds and ASCAT Winds.

Addendum (24 November 2009): A loop of infrared imagery over the North Atlantic using imagery from every three hours after the image above nicely shows the evolution of cyclogenesis. The swirl at low levels diagnosed by QuikSCAT is evident as is the development of a comma shape to the higher clouds. Both are hallmarks of the developing storm.

The 1200 UTC analysis from 24 November shows a vigorous cyclone has developed over the North Atlantic from the region where the QuikSCAT near-surface winds showed a swirl on Monday.

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NOAA-18 10.8 µm IR image

A McIDAS image of the NOAA-18 10.8 µm IR channel (above) showed a region of very cold surface temperatures (darker blue to violet color enhancement) over the interior of Alaska on 19 November 2009, especially in the vicinity of Chandalar Lake (station identifier PALR) and Anuktuvuk Pass (station identifier PAKP). In addition, note the appearance of the warm signature of large cracks or “leads” in the ice over the Arctic Ocean (orange to red color enhancement), to the north and northeast of Kuparuk (station identifier PAKU).

A closer view with an overlay of the surface air temperatures (below) revealed a number of narrow fingers of very cold air — this represented the drainage of the coldest air into mountain valleys along the southern portion of the Brooks Range. The coldest IR brightness temperature in that area was -44º F, which happened to match the coldest surface air temperature from first-order weather stations of -44º F at Bettles (located near the center of the image). Bettles reported record low daily minimum temperatures of -45º F on 17 November, -46º F on 18 November, -47º F on 19 November, and -46º F on 20 November (the high temperature was only -40º F on that day!) — the normal high/low temperatures for Bettles during this period are +3º F and -10º F. This stretch of record cold temperatures followed a record 2-day snowfall of 23.7 inches on 11-12 November (the greatest 2-day snowfall on record for Bettles during the month of November).

However, note that the IR image also suggested the presence of a deck of clouds to the east of the very cold valley signatures — and surface air temperatures were significantly warmer under this cloud deck.

NOAA-18 10.8 µm IR image (with surface air temperatures)

AWIPS images of the AVHRR Cloud Type, Cloud Top Temperature, and Cloud Top Height products (below) indicated that the patch of clouds to the east and southeast of Bettles (station identifier PABT) was composed of supercooled water droplets (cyan color enhancement), with cloud top temperatures in the -30 to -38º C range and cloud top heights in the 3-5 km range. Note that the cloud product algorithms showed values of cloud properties over the region surrounding Bettles (even though it was clear there) — the very cold surface temperatures of -40 C and colder tricked the algorithms into thinking that there were high cirrus clouds over that particular area.

AVHRR Cloud Type, Cloud Top Temperature, and Cloud Top Height products

GOES-11 10.7 µm IR images (below) gave some subtle indication that this cloud deck was moving slowly northward across the region to the east of Bettles (note that north is toward the upper right corner, due to the North America projection of these particular AWIPS images).

GOES-11 10.7 µm IR images

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GOES-10 10.7 µm IR images

McIDAS images of the GOES-10 10.7 µm IR channel (above) showed very cold cloud top temperatures associated with a large Mesoscale Convective Complex (MCC) that developed over northern Argentina and moved across Uruguay and into far southern Brazil on 19 November 2009. The MCC exhibited unusually cold IR brightness temperature values, as low as -89º C (dark purple color enhancement) at 04:58 UTC. In addition, early in the animation you can see several “enhanced-v” signatures on the IR imagery — this satellite signature indicates that severe convective storms have a high potential for producing damaging winds, large hail, or tornadoes. There were media reports of a tornado and hail in parts of Uruguay, and according to the Metsul Blog this MCC produced very strong winds (gusting to 82 mph or 36.8 meters per second) and heavy rainfall (2.8 inches or 70 mm in 2 hours) as the storm moved into the Rio Grande do Sul region of southern Brazil.

GOES-10 (launched in 1997) is currently positioned in orbit at approximately 60 degrees West longitude in support of the Earth Observation Partnership of the Americas EOPA project or GEOSS Americas — however, due to end-of-life fuel conditions, GOES-10 will cease operations on 01 December 2009.

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MIMIC Total Precipitable Water product

AWIPS images of the MIMIC Total Precipitable Water (TPW) product (above) revealed the formation of a long “atmospheric river” of moisture over the North Atlantic Ocean during the 17-19 November 2009 period. MIMIC TPW values were as high as 60 mm (darker orange color enhancement) within the moisture plume.

The surface analysis (below) showed that this moist plume was along and ahead of a cold front that was trailing southward from a deepening mid-latitude cyclone. This plume of moisture was contributing to very heavy rainfall and significant flooding over parts of the United Kingdom — Seathwaite reported a 24-hour rainfall amount of 12.36 inches (314 mm), which if confirmed as accurate will set a new record for 24-hour precipitation in the UK (UK Met Office).

MIMIC TPW with surface analysis

A composite of GOES-12 and Meteosat-9 water vapor imagery (below) suggested that this long atmospheric river tapped into a pocket of deep tropical moisture (associated with the remnants of what was formerly Hurricane/Tropical Storm Ida), and was then brought northward within the warm conveyor belt in advance of the deepening cyclone over the North Atlantic Ocean.

GOES-12 and Meteosat-9 water vapor imagery

The Blended Total Precpitable Water – Percent of Normal product (below) indicated that this moist plume was rather anomalous for the season over the North Atlantic region, containing values of TPW that exceeded 200% of normal (yellow color enhancement).

Blended Total Precipitable Water - Percent of Normal

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