NOAA/CIMSS ProbSevere with a tornadic cell in Kansas/Oklahoma

April 26th, 2016
GOES-14 Visible (0.63 µm) Imagery, 26 April 2016. An orphan anvil is indicated by the Green Arrow at the start of the animation (click to play animation)

GOES-14 Visible (0.63 µm) Imagery, 26 April 2016. An orphan anvil is indicated by the Green Arrow at the start of the animation (click to play animation)

April 26 2016 was a day of well-anticipated severe weather (even a week out!) over the central and southern Plains, with a Moderate Risk of Severe Weather predicted for parts of Nebraska, Kansas, Oklahoma and Texas. The GOES-14 visible animation, above, shows the development of strong thunderstorms in north-central Oklahoma that propagated into south central Kansas, producing hail around 2000 UTC. Note the presence of an orphan anvil just downstream of the developing convection (to the south of the Green Arrow) at the beginning of the GOES-14 SRSO-R animation (that unfortunately has a 15-minute data gap starting at 1900 UTC).

How did the NOAA/CIMSS ProbSevere product perform with this severe cell? ProbSevere provides a probabilistic estimate of whether a cell will produce severe weather within the next 60 minutes. The animation below shows the quick development of the radar feature that became the hail producer. The Satellite Growth of this particular storm was not observed to be strong. Moderate satellite growth and weak glaciation was diagnosed. However, ProbSevere values became very large because of the environment in which the cell developed, because of the presence of large MRMS MESH observations, and active lightning. ProbSevere exceeded a 50% threshold at 1912 UTC, 6 minutes before the Severe Thunderstorm Warning was issued.  The Table at the bottom shows the ProbSevere components as a function of time.

According to SPC storm reports, the cell produced a brief rope tornado at 2058 UTC in far southern Kansas. This storm was blogged about at the Hazardous Weather Testbed. Click here and here for blog posts on the environmental instability.

NOAA/CIMSS ProbSevere Output, 1824-1946 UTC on 26 April 2016 (click to play animation)

NOAA/CIMSS ProbSevere Output, 1824-1946 UTC on 26 April 2016 (click to play animation)

A zoomed-in animation of the Visible Imagery shows the orphan anvil developing around 1740 UTC. (A rocking animation is here).

GOES-14 Visible (0.63 µm) Imagery, 26 April 2016. The orphan anvil is indicated by the Cyan Arrows through the animation (click to play animation)

GOES-14 Visible (0.63 µm) Imagery, 26 April 2016. The orphan anvil is indicated by the Cyan Arrows through the animation (click to play animation)

 

Time (UTC) ProbSevere MUCAPE Env. Bulk Shear MRMS MESH (Inches) Satellite Growth Satellite Glaciation # Flashes
1854
1858 20% 4739 41.9 0.29 1.9% (Moderate) 0.02 (Weak) 0
1900 29% 4702 41.8 0.45 1.9% (Moderate) 0.02 (Weak) 0
1908 34% 4640 40.9 0.54 1.9% (Moderate) 0.02 (Weak) 5
1910 47% 4628 40.7 0.65 1.9% (Moderate) 0.02 (Weak) 13
1912 59% 4623 40.4 0.65 1.9% (Moderate) 0.02 (Weak) 24
1914 58% 4619 40.1 0.65 1.9% (Moderate) 0.02 (Weak) 24
1916 58% 4614 39.8 0.65 1.9% (Moderate) 0.02 (Weak) 24
1918 54% 4614 39.8 0.60 1.9% (Moderate) 0.02 (Weak) 24
1920 60% 4592 39.4 0.74 1.9% (Moderate) 0.02 (Weak) 20
1922 65% 4591 39.1 0.80 1.9% (Moderate) 0.02 (Weak) 20
1924 73% 4591 39.1 0.80 1.9% (Moderate) 0.02 (Weak) 25
1926 75% 4572 38.8 0.84 1.9% (Moderate) 0.02 (Weak) 26
1928 88% 4578 38.7 1.01 1.9% (Moderate) 0.02 (Weak) 31
1930 89% 4578 38.7 1.01 1.9% (Moderate) 0.02 (Weak) 36
1932 97% 4580 38.6 1.24 1.9% (Moderate) 0.02 (Weak) 49
1934 97% 4560 38.3 1.24 1.9% (Moderate) 0.02 (Weak) 58
1936 97% 4544 38.1 1.24 1.9% (Moderate) 0.02 (Weak) 58
1938 97% 4543 38.0 1.24 1.9% (Moderate) 0.02 (Weak) 58
1940 97% 4540 37.8 1.26 1.9% (Moderate) 0.02 (Weak) 58
1942 98% 4528 37.7 1.53 1.9% (Moderate) 0.02 (Weak) 56
1944 99% 4516 37.5 1.71 1.9% (Moderate) 0.02 (Weak) 56
1946 99% 4507 37.4 1.71 1.9% (Moderate) 0.02 (Weak) 56

 

GOES-14 SRSO-R: Convection over Wyoming/Montana, and the Storm Hill Fire in South Dakota

April 24th, 2016

GOES-14 Visible (0.63 µm) images, with surface plots [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images, with surface plots [click to play MP4 animation]

GOES-14 was in SRSO-R mode on 23 April24 April 2016, providing 1-minute Visible (0.63 µm) images (above; also available as a large 115 Mbyte animated GIF) which showed the development of convection over far northern Utah/Colorado, much of Wyoming, southern Montana, and far western South Dakota during the daytime hours of 23 April. Some of this convection produced moderate to heavy rainfall (and some accumulating snowfall) across Wyoming and southern Montana.

Hat tip to Jim Strain, who sent out the Tweet:

Taking a closer look at the Black Hills of South Dakota with GOES-14 Visible (0.63 µm) and Shortwave Infrared (3.9 µm) images (below; also available as a large 151 Mbyte animated GIF), one can see intermittent smoke plumes from the Storm Hill Fire (located near the center of the red circle) on the Visible images during the late afternoon and early evening hours, with the continuation of a fire “hot spot” signature (dark black to yellow color enhancement) on the Shortwave Infrared images into the nighttime hours. The maximum shortwave IR brightness temperature was 324 K at 0424 UTC (10:24 pm local time); the fire hot spot became obscured by dense cloud cover after about 0600 UTC. Highways are plotted in dashed magenta lines on the images.

GOES-14 0.63 µm Visible (left) and 3.9 µm Shortwave Infrared (right) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (left) and 3.9 µm Shortwave Infrared (right) images [click to play MP4 animation]

GOES-14 SRSO-R: occluded low pressure in the Upper Midwest

April 21st, 2016

GOES-14 Visible (0.63 um) images, with plots of surface weather symbols in cyan and hail reports in yellow  [click to play MP4 animation]

GOES-14 Visible (0.63 um) images, with plots of surface weather symbols in cyan and hail reports in yellow [click to play MP4 animation]

The GOES-14 satellite was in SRSO-R mode on 21 April 2016, providing 1-minute Visible (0.63 um) images (above; also available as a large 253 Mbyte animated GIF) of the clouds associated with an occluded surface low (surface analyses) in the Upper Midwest. Near the end of the day, thunderstorms in Illinois produced hail of 1.00 and 1.25 inches in diameter (SPC storm reports | HWT Blog post 1 | HWT Blog post 2).

GOES-14 SRSO-R: convective outflow boundary in southern Texas

April 20th, 2016

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

1-minute interval SRSO-R GOES-14 Visible (0.63 µm) images (above; also available as a large 259 Mbyte animated GIF) showed a curved outflow boundary — produced by a strong quasi-linear convective system the preceding overnight hours in northern Texas — which continued to propagate southward across southern Texas during the day on 20 April 2016. New clusters of convection formed along and in the wake of the eastern portion of the outflow boundary (which dropped an additional 0.67 inch of rainfall in one hour across the flood-ravaged Houston area), while the western portion was marked by a low-level arc cloud.

On the corresponding GOES-14 Water Vapor (6.5 µm) images (below; also available as a large 126 Mbyte animated GIF), a very subtle signature of the western  part of the outflow boundary could be seen in the dryer atmosphere (where the water vapor weighting functions were shifted to lower altitudes). Also of interest were a few long and narrow contrails which appeared within that same dry region of the atmosphere after about 1800 UTC — these thin contrails were not evident in the GOES-14 visible or infrared imagery.

GOES-14 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-14 Water Vapor (6.5 µm) images [click to play MP4 animation]

A comparison of the 3 Water Vapor bands (6.5 µm, 7.0 µm and 7.4 µm) available from the GOES-14 sounder instrument (below) demonstrated how each of the individual bands was detecting radiation emitted from a different layer of the troposphere; this was further shown by examining plots of the water vapor weighting functions for the 1 imager and the 3 sounder water vapor bands (calculated using 12 UTC rawinsonde data from Del Rio, Texas KDRT). The ABI instrument on GOES-R will have 3 water vapor bands similar to those on the current generation sounder instrument, but with significantly improved spatial and temporal resolution.

GOES-14 sounder Water Vapor bands 6.5 µm (top), 7.0 µm (middle) and 7.4 µm (bottom) images [click to play animation]

GOES-14 sounder Water Vapor bands 6.5 µm (top), 7.0 µm (middle) and 7.4 µm (bottom) images [click to play animation]