1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the development of widespread thunderstorms that produced tornadoes, large hail (up to 5.5 inches in diameter in Texas) and damaging winds (as high as 94 mph in Oklahoma) (SPC storm reports) across parts of Texas and Oklahoma on 20 May 2019.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images (below) indicated that cloud-top infrared brightness temperatures were frequently as cold as -70 to -80ºC (black to white to violet enhancement) with the more vigorous thunderstorms.

Zoomed-in versions of the Visible images (above) and Infrared images (below) are centered at Childress, Texas — which provide a better view of the storms which produced the 5.5-inch hail (Visible | Infrared) at Wellington, Texas and the large tornado near Magnum, Oklahoma (Visible | Infrared | YouTube video).

One interesting aspect of this line of deep convection: it was effectively acting as an obstacle to the upstream southwesterly flow, resulting in the formation of a quasi-stationary band of gravity waves along its western edge — these waves were very evident in GOES-16 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (below).

GOES-16 Split Window Difference (10.3-12.3 µm) images (below) displayed the yellow signature of blowing dust in the vicinity of a cold front that was moving eastward across southeastern New Mexico and southwestern Texas. Blowing dust restricted surface visibility to 3 miles or less at El Paso in Texas and at Alamagordo and Artesia in New Mexico.

During the subsequent overnight hours, these thunderstorms produced heavy rainfall from northern Oklahoma into southern Kansas, causing flash flooding — and flooding from rising rivers across that region on the following day were captured by the Suomi NPP VIIRS Flood Detection Product (below).

The river flooding in northern/northwestern Oklahoma was also evident in a before/after comparison of Terra MODIS False Color RGB images from 15 May and 21 May (below). Water appears as darker shades of blue in the False Color images.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) highlighted the development a large and long-lived supercell thunderstorm that produced tornadoes and large hail (SPC storm reports) from northwestern Kansas to central Nebraska on 17 May 2019. Of note were the large number of tornado and large hail reports around 2259 UTC. Later in the day, concentric gravity waves were evident along the thunderstorm anvil top (for example, at 0022 UTC).

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images (below) revealed numerous overshooting tops that exhibited infrared brightness temperatures as cold as -70ºC (black enhancement).

After the first round of severe weather from Kansas to Nebraska, additional supercell thunderstorms developed which produced tornadoes/hail/winds across southwestern and central Kansas into the nighttime hours (below).

Farther to the south (and earlier in the day) over West Texas, an isolated supercell thunderstorm formed near Fort Stockton — 5-minute GOES-16 Visible and Infrared images (above) showed the development of this storm. Note the northeastward drift of an orphan anvil beginning at 1941 UTC, about 30 minutes prior to the formation of the thunderstorm that went on to produce a tornado and large hail; the appearance of an orphan anvil often signals the nearly-complete erosion of a capping temperature inversion aloft that had been acting to suppress deep convection. The erosion of the capping inversion was evident in a comparison of 12 UTC and 00 UTC rawinsonde data from Midland (KMAF).

Once the thunderstorm had developed, an Above-Anvil Cirrus Plume was also apparent in the Visible and Infrared imagery (for example, at 2236 UTC and 0101 UTC) — and this AACP feature was *colder* (shades of orange to red) than the adjacent storm top, due to the temperature profile above the equilibrium level/tropopause.

A GOES-17 (GOES-West) Mesoscale Domain Sector had been positioned over the region, providing 1-minute imagery of the storm development (below). The viewing angle from GOES-17 allowed the storm’s flanking line cloud bands to be seen.

A 2-panel comparison of GOES-17 and GOES-16 Visible images is shown below; those images are displayed in the native projection of each satellite (in contrast to being remapped to a common projection, as with the AWIPS images shown above).

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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.

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.

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

Storm approaching the @UWMadison campus. Photo taken from the top of the @UWCIMSS @UWSSEC and @UW_AOS building. pic.twitter.com/Cw5VWy8lqT

— Sarah Griffin (@smgriffin00) May 16, 2019

Here’s a panorama loop (west, northwest, and north UW-AOSS rooftop cameras) of today’s shelf cloud in Madison, WI. #wiwx #swiwx @UWMadScience @UW_AOS https://t.co/hnW6SM2PLB

The original mp4 file can be downloaded at https://t.co/QjdgngsHi5

— Pete Pokrandt (@PTH1) May 17, 2019

 

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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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