GOES-13 (GOES-East) Visible (0.63 µm) images (above) showed the growth of offshore ice in the western and northwestern portions of Hudson Bay on 24 November 2015. Also evident on the imagery was cloud streets aligned with the northerly/northwesterly flow of cold arctic air over the water, as well as the presence of a mesoscale low moving southeastward. Apparently this mesoscale low was behind the primary low (with its associated trailing occluded front), which was depicted to be over the eastern portion of Hudson Bay (surface analyses) during the daylight hours of the visible imagery.

A better view of the offshore ice (as well as the ice in central Hudson Bay, northeast of the aforementioned mesoscale low) was provided by Suomi NPP VIIRS true-color and false-color images, visulized using the SSEC RealEarth web map server (below). In the false-color image, snow cover and ice appear as darker shades of cyan.

A comparison of Canadian Ice Service analyses from 16 November and 23 November (below) showed the growth of the offshore ice along the western and northwestern edges of Hudson Bay, as well as the larger area of ice growing southward in the central portion of Hudson Bay during that 1-week period. The departure from normal images at the bottom indicated that ice concentration along the western and northwestern edges was well below normal (red), while the concentration of the large area of ice in central Hudson Bay was greater than normal (blue).

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On 20 November, at 0922 UTC, the GOES-13 Sounder experienced an anomaly (the GOES-13 Sounder had Filter Wheel anomalies in 2012 as well: Link; Link). GOES Engineers determined that the Filter Wheel had stopped moving (the filter wheel aligns the infrared detectors with the incoming data) so data were not scanned. The image above shows the 13.4 µm (a CO2 channel) image before and after the anomaly. All 18 infrared channels are affected; the visible channel (band 19) continues sending usable data. GOES Engineers continue to investigate the problem. GOES Sounder derived products (such as Total Precipitable Water) are affected, and are no longer being produced or disseminated (Link). From an email from SSD: (Link)

*Update #2: * **Effective immediately; all the GOES-13 (GOES-East)
sounding products are ceased to produce and stop distribution as we are
experiencing an anomaly with the sounder instrument. Engineers are
investigating the problem. We will inform you when we resume our normal
operations.

*Update #1: * GOES-13 (GOES-East) Sounder IR Data Outage

*Topic:* GOES-13 (GOES-East) Sounder IR Data Products Outage

*Date/Time**Issued:*November 20, 2015 1955Z*
*

*Product(s) or Data Impacted:*

GOES-13 (GOES-East) Sounder data
Blended Hydrometorological Products – Blended TPW
Microwave AWIPS Products – Blended TPW
Microwave McIDAS Products – Blended TPW
GOES Gridded Cloud Product
GOES VARiable data
AFEP/Ingestor – GOES
N-AWIPS Ingest
Single Field of View BUFR
Single Field of View SDPI for AWIPS
Single Field of View TPW
Sounding ASOS SCSP
Web Pages

*Date/Time of Initial Impact:*November 20, 2015 0922Z **

*Date/Time of Expected End:* TBD

*Length of Outage:* TBD

*Details/Specifics of Change:*GOES-13 (GOES-East) Sounder instrumentis experiencing an anomaly. Engineers are investigating the problem. GOES-13 Sounder IR data is not available. **Effective immediately all the GOES-13 (GOES-East) sounding products are ceased to produce and stop distribution as we are experiencing an anomaly with the sounder instrument. Engineers are investigating the problem. We will inform you when we will resume our normal operations.

==================================================================
Update 19 January 2016
==================================================================

GOES-14 is scheduled to broadcast 1-minute SRSO-R data starting 1 February. GOES-14 will be activated on 25 January, with a maneuver shortly thereafter. It is likely that GOES-14 Sounder data will be broadcast from 1-25 February (GOES-14 Sounder Timing will be adjusted to match GOES-13 Sounder Timing) when the GOES-14 Imager is broadcasting SRSO-R data.

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Tropical Depression In-fa (27W) formed well south of the Marshall Islands in the West Pacific Ocean on 17 November 2015, and proceeded to track northwestward to a position south of Guam on 20 November (above). Following a brief decrease in intensity on 18 September, In-fa began another period of intensification during the 19-20 September period. Rapid-scan (2.5-minute interval) Himawari-8 Visible (0.64 µm) images (below; also available as a large 73 Mbyte animated gif) showed a series of eyewall convective bursts and the occasional appearance of a recognizable eye. (Note: the ABI instrument on the upcoming GOES-R satellite will also have a rapid-scan capability, but at 1-minute or even 30-second intervals)

A longer animation spanning the entire 19-20 September period (below; also available as a large 120 Mbyte animated gif) revealed an improving trend in the overall satellite presentation of In-fa, with the eye becoming well defined by the end of the animation as the tropical cyclone reached Category 3 intensity.  In fact, this became the the 15th Category 3 or stronger typhoon in the Northwest Pacific basin in 2015 – the most on record in any tropical cyclone season by the date of 20 November.

A comparison of Suomi NPP VIIRS Infrared (11.45 µm) and Day/Night Band (0.7 µm) images at 1547 UTC (below; courtesy of William Straka, SSEC) showed the coldest cloud-top IR brightness temperatures in the southern hemisphere of the eyewall, along with the nighttime glow of lights from the island of Guam.

A well-defined eye was evident in MTSAT-2 Infrared (10.8 µm) and DMSP SSMIS Microwave (85 GHz) images around 2230 UTC on 20 September (below).

Mesovortices within the eye were seen in rapid-scan Himawari-8 Visible (0.64 µm) images beginning late in the day on 20 November as In-fa intensified to a Category 4 typhoon. (below;  also available as a large 50 Mbyte animated GIF).

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An EF-1 tornado was on the ground for about 20 minutes near Denair (Local Storm Report | Facebook post) in central California on 15 November 2015. 1-km resolution GOES-15 Visible (0.63 µm) images (above) showed that clusters of small thunderstorms rapidly developed in an environment of instability along and just behind a fast-moving cold frontal boundary. The location of the tornado is indicated by a red “T” on the 2145, 2200, and 2211 UTC images. Very strong southwesterly winds aloft allowed the upwind portion of the highly-tilted thunderstorms to be brightly illuminated by the low sun angle of late afternoon in mid-November.

The corresponding 4-km resolution GOES-15 Infrared (10.7 µm) images (below) revealed that cloud-top IR brightness temperatures quickly cooled from -23º C at 2130 UTC to -42º C at 2200 UTC.

There was a 30-minute gap in GOES-15 coverage from 2100 to 2130 UTC (due to a full disk scan), but a comparison of 1-km resolution NOAA-19 AVHRR Visible (0.63 µm) and Infrared (10.8 µm) caught the very early growth of the tornado-producing storm at 2115 UTC (below). The cloud-top IR brightness temperatures were as cold as -23º C at that time, indicating a high probability that cloud glaciation had begun.

A timely overpass of the Suomi NPP satellite allowed a comparison of 375-meter resolution VIIRS Visible (0.64 µm) and Infrared (11.45 µm) images during the time that the tornado was srill on the ground (below). Once again, the strong slant of the storms due to increasing wind speeds aloft allowed the western/southwestern sides of the thunderstorm clouds to be brightly illuminated on the visible image. The coldest cloud-top IR brightness temperature was -51º C (yellow color enhancement), which was just shy of the -53º C tropopause temperature reported on the Oakland rawinsonde report at 12 UTC.

A VIIRS true-color image of the storm visualized using RealEarth is shown below. The actual satellite overpass time was around 2151 UTC.

GOES-15 sounder Lifted Index (LI) derived product images (below) showed the pockets of post-frontal instability over central California — LI values less than -4 C were seen (yellow color enhancement).

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