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NUCAPS Sounding Availability

The Cross-Track Infrared Sounder (CrIS) on Suomi NPP suffered an anomaly back in late March and the mid-wave portion of the detectors are not functioning as designed; the wavelengths affected include those sensitive to water vapor. Because of this data outage, NUCAPS soundings are not being produced from Suomi NPP. Suomi NPP was the sole data source for... Read More

NUCAPS soundings from NOAA-20 at 0653 UTC on 16 May 2019, 34.4 N, 75.8 W (Click to enlarge)

The Cross-Track Infrared Sounder (CrIS) on Suomi NPP suffered an anomaly back in late March and the mid-wave portion of the detectors are not functioning as designed; the wavelengths affected include those sensitive to water vapor. Because of this data outage, NUCAPS soundings are not being produced from Suomi NPP. Suomi NPP was the sole data source for NUCAPS in National Weather Service offices over the contiguous United States.

As shown above, NUCAPS soundings are being produced by NOAA-20, which, like Suomi NPP, carries both the CrIS and the Advanced Technology Microwave Sounder (ATMS). NOAA-20 NUCAPS soundings are scheduled to replace the Suomi NPP NUCAPS soundings in National Weather Service Forecast Offices in late May 2019. NOAA-20 is in the same orbit as Suomi NPP, but offset by half an orbit; overpasses are offset by about 45 minutes, so the NUCAPS data should show up in forecast offices at about the same time of day. (Compare these Suomi NPP orbits over North America to these from NOAA-20; Orbital tracks for most polar orbiters are here.) Time latency for NOAA-20 soundings is improved over Suomi-NPP however; there will be less wait needed for the soundings.

NUCAPS soundings are also produced from Metop-A and Metop-B, satellites that carry the Infrared Atmospheric Sounding Interferometer (IASI) and the Advanced Microwave Sounding Unit (AMSU) and Microwave Humidity Sensor(MHS) instruments.

NUCAPS soundings from NOAA-20, Metop-A and Metop-B are available at this site. That site includes a map (shown here) To access the soundings, move the map to your desired location, and click on the small box in the upper left of the map (under the +/- that cause the map to zoom in and out).  After clicking the box, use a left click and mouse drag on the map to define a region where sounding points will appear. (Alternatively, click the ‘Thumbnail Viewer’ box above the map; as you mouse over the points, a sounding will appear in the window.) The points are color-coordinated based on how old the latest sounding is. Zoom in, and choose your point.  Three profiles are displayed: The initial regression profile (labeled MW+IR Regr), the microwave-only profile (labeled MW phys) and the final physical retrieval profile (labeled MW+IR phys).  The resultant sounding you see will be the latest, but 10 soundings near that point over the past several days can be accessed as well.

NUCAPS soundings from Suomi NPP are not gone for good, however.  The CrIS has redundant electronics, and ‘A’ side — that has partially failed — and a ‘B’ side that has not been tested since before launch (Suomi NPP was launched on 28 October 2011!  Here is one of its first images).  The ‘B’ side electronics can be activated, and if they work, NUCAPS algorithms would have to be recalibrated for an essentially new data source.  This would take several months.  Alternatively, NUCAPS for Suomi NPP could be reformulated to account for the missing data with the ‘A’ side electrontics, something that also would take several months.  A decision on the path to take is forthcoming.

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High pressure centered over Louisiana

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images, with 5-minute plots of Derived Motion Winds (above) revealed a cumulus cloud field that beautifully outlined the flow around an area of high pressure that was centered over Louisiana on 15 May 2019. Subsidence within the dome of high pressure prevented significant vertical development of these... Read More

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with plots of Derived Motion Winds [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images, with 5-minute plots of Derived Motion Winds (above) revealed a cumulus cloud field that beautifully outlined the flow around an area of high pressure that was centered over Louisiana on 15 May 2019. Subsidence within the dome of high pressure prevented significant vertical development of these cumulus clouds.

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Severe thunderstorms in North Carolina

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed clusters of severe thunderstorms that produced tornadoes and large hail (SPC storm reports) across parts of central and eastern North Carolina on 13 May 2019.A west-to-east oriented quasi-stationary frontal boundary was acting as a focusing mechanism for many of these thunderstorms... Read More

GOES-16

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images, with plots of SPC storm reports [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed clusters of severe thunderstorms that produced tornadoes and large hail (SPC storm reports) across parts of central and eastern North Carolina on 13 May 2019.

A west-to-east oriented quasi-stationary frontal boundary was acting as a focusing mechanism for many of these thunderstorms — the Terra MODIS Total Precipitable Water product at 1525 UTC (below) showed TPW values around 28 mm or 1.1 inch (lighter green enhancement) pooled immediately south of this frontal boundary.

Terra MODIS Total Precipitable Water product [click to enlarge]

Terra MODIS Total Precipitable Water product [click to enlarge]

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Asian dust entrained into a midlatitude cyclone

True Color Red-Green-Blue (RGB) images from the MODIS instrument (on the Terra satellite) and the VIIRS instrument (on the NOAA-20 and Suomii NPP satellites) as viewed using RealEarth (above) revealed a tan-colored swirl of dust that had been lofted from the surface and entrained into the circulation of a midlatitude... Read More

True Color RGB images from MODIS (Terra) and VIIRS (NOAA-20 and Suomi NPP) [click to enlarge]

True Color RGB images from MODIS (Terra) and VIIRS (NOAA-20 and Suomi NPP) [click to enlarge]

True Color Red-Green-Blue (RGB) images from the MODIS instrument (on the Terra satellite) and the VIIRS instrument (on the NOAA-20 and Suomii NPP satellites) as viewed using RealEarth (above) revealed a tan-colored swirl of dust that had been lofted from the surface and entrained into the circulation of a midlatitude cyclone along the Mongolia/China border on 12 May 2019.

A sequence of MODIS/VIIRS True Color RGB images from Terra and Suomi NPP on 10, 11 and 12 May (below) showed the initial signature of surface-based blowing dust appearing in the Kumul and Jiuquan areas of northwestern China on 11 May, before it became wrapped into the circulation of the aforementioned midlatitude cyclone on 12 May.

True Color RGB images from MODIS (Terra) and VIIRS (Suomi NPP) [click to enlarge]

True Color RGB images from MODIS (Terra) and VIIRS (Suomi NPP) [click to enlarge]

Surface analyses at 3-hour intervals (source), from 12 UTC on 11 May to 00 UTC on 13 May (below) illustrated the strong pressure gradient between a large dome of high pressure over Mongolia and a developing midlatitude cyclone along the Mongolia/China border on 11 May — strong surface winds generated by this pressure gradient initially caused the blowing dust to begin in northwestern China.

Surface analyses at 3-hour intervals from 12 UTC on 11 May to 00 UTC on 13 May [click to enlarge]

Surface analyses at 3-hour intervals from 12 UTC on 11 May to 00 UTC on 13 May [click to enlarge]

JMA Himawari-8 Split Window Difference (10.4-12.3 µm) images (below) showed the signature of dust (yellow to cyan enhancement) moving eastward from the desert source region in northwestern China and becoming wrapped into the circulation of the midlatitude cyclone along the Mongolia/China border.

Himawari-8 Split Window Difference (10.4-12.3 µm) iimages [click to play animation |MP4]

Himawari-8 Split Window Difference (10.4-12.3 µm) images [click to play animation | MP4]

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