Severe thunderstorms across Oklahoma, Kansas and Missouri

May 22nd, 2019 |

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the development of supercell thunderstorms that produced tornadoes, large hail and damaging winds (SPC Storm Reports) across parts of Oklahoma, Kansas and Missouri on 22 May 2019.

GOES-16 “Clean” Infrared Window (10.35 µm) images (below) showed the storms as they persisted into the nighttime hours — including storms that produced EF3-rated tornadoes that affected Golden City, Missouri around 0211 UTC (which was responsible for 3 fatalities) and Jefferson City, Missouri around 0440 UTC.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

A closer look at 1-minute GOES-16 Infrared images for the storm producing the EF-3 tornado that affected Golden City, Missouri  is shown below. A pulsing updraft with cold (brighter white) infrared brightness temperature overshooting tops could be seen with the parent supercell as it crossed the Oklahoma/Kansas border around 0000 UTC, moved across extreme southeastern Kansas, then moved into southwestern Missouri around 0100 UTC. The NWS Springfield damage survey listed the start time of the Garden City tornado at 0151 UTC.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

About 20 minutes prior to the Jefferson City tornado, a Terra MODIS Infrared Window (11.0 µm) image (below) displayed a well-defined Enhanced-V storm top signature.

Terra MODIS Infrared Window (11.0 µm) image. with plot of SPC storm reports [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) image, with plot of SPC storm reports [click to enlarge]

A closer look at 1-minute GOES-16 Infrared images for the storm producing the EF-3 tornado that affected Jefferson City (KJEF) is shown below — of note are the 2 pre-tornado updraft pulses west/southwest of KJEF at 0346 UTC and 0359 UTC, when cloud-top infrared brightness temperatures briefly cooled to -81ºC and -82ºC, respectively (violet pixels). The NWS St. Louis storm survey indicated that the tornado which eventually moved through Jefferson City began southwest of the city at 0420 UTC.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

A few hours later, a sequence of 3 VIIRS Infrared Window (11.45 µm) images (below) from Suomi NPP and NOAA-20 showed the line of supercell thunderstorms between 0704 and 0844 UTC.

VIIIRS Infrared Window (11.45 µm) images from Suomi NPP (0704 and 0844 UTC) and NOAA-20 (0754 UTC) [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from Suomi NPP (0704 and 0844 UTC) and NOAA-20 (0754 UTC) [click to enlarge]

A closer view of the Suomi NPP VIIRS Infrared Window (11.45 µm) image at 0704 UTC (below) revealed another well defined Enhanced-V signature in far northeastern Oklahoma.

Suomi NPP VIIRS Infrared Window (11.45 µm) image at 0704 UTC [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) image at 0704 UTC [click to enlarge]

The Suomi NPP VIIRS Infrared Window (11.45 µm) image at 0844 UTC (below) depicted an example of a warm “moat” surrounding a cold overshooting top having a minimum infrared brightness temperature of -81ºC (violet enhancement) east of Patoka, Illinois.

Suomi NPP VIIRS Infrared Window (11.45 µm) image at 0844 UTC [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) image at 0844 UTC [click to enlarge]

Mesoscale Convective System in the Midwest

May 16th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) displayed a Mesoscale Convective System (MCS) that moved southeast across the Midwestern US on 16 May 2019 (surface analyses), producing a variety of severe weather (SPC storm reports). New convection continued to develop along the MCS outflow boundary, whose western edge was marked by parallel cloud bands from eastern Iowa into northwestern Illinois.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images (below) revealed cloud-top infrared brightness temperatures as cold as -72ºC with some of the overshooting tops.

GOES-16 "Clean" Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

VIIRS Visible and Infrared images from Suomi NPP (at 1808 UTC) and NOAA-20 (at 1858 UTC) (below) revealed packets of concentric storm-top gravity waves, along with overshooting tops exhibiting infrared brightness temperatures as cold as -78ºC.

VIIRS Visible and Infrared images from Suomi NPP (at 1808 UTC) and NOAA-20 (at 1858 UTC) [click to enlarge]

VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images from Suomi NPP (at 1808 UTC) and NOAA-20 (at 1858 UTC) [click to enlarge]

As the MCS approached Madison, Wisconsin it produced a well-defined shelf cloud:

 

NUCAPS Sounding Availability

May 16th, 2019 |

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.

Asian dust entrained into a midlatitude cyclone

May 12th, 2019 |

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]