Tornado outbreak in Iowa

July 19th, 2018 |

GOES-16 Upper-level Water Vapor (6.2 µm, top left), Mid-level Water Vapor (6.9 µm, top right), Low-level Water Vapor (7.3 µm, bottom left) and

GOES-16 Upper-level Water Vapor (6.2 µm, top left), Mid-level Water Vapor (6.9 µm, top right), Low-level Water Vapor (7.3 µm, bottom left) and “Red” Visible (0.64 µm, bottom right) images [click to play MP4 animation]

GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm), Mid-level Water Vapor (6.9 µm), Low-level Water Vapor (7.3 µm) and “Red” Visible (0.64 µm) images (above) revealed the well-defined signature of a mid-tropospheric lobe of vorticity moving from southeastern South Dakota across Iowa during the day on 19 July 2018 — this feature provided synoptic-scale forcing for ascent which aided in the development of severe thunderstorms in central and eastern Iowa. A number of tornadoes were reported, along with some large hail and damaging winds (SPC storm reports).

GOES-16

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

A closer look using 1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) images (above) showed the line of thunderstorms as they developed in advance of an approaching cold/occluded front (surface analyses). Two larger storms were dominant, which produced tornadoes causing significant damage and injuries in Pella KPEA and Marshalltown KMIWabove-anvil cirrus plumes were evident with both of these supercells. In addition, early in the animation a few orphan anvils could be seen along the southern end of the line (southeast and east of Des Moines KDSM).

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) showed cloud-top infrared brightness temperatures of -65ºC to -70ºC with the larger Pella storm, and around -55ºC with the smaller Marshalltown storm to the north.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with SPC storm reports plotted in red [click to play MP4 animation]

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) image, with ProbSevere contour and parameters [click to enlarge]

The NOAA/CIMSS ProbSevere model (viewed using RealEarth) had a ProbTor value of 74% at 2055 UTC for the Pella storm (above) and 83% at 2130 UTC for the Marshalltown storm (below). GOES-derived Cloud-top glaciation rate (from infrared imagery) is one of the predictors used in the model.

GOES-16 Infrared image, with ProbSevere parameters [click to enlarge]

GOES-16 “Clean” Infrared Window (10.3 µm) image, with ProbSevere contour and parameters [click to enlarge]

ProbSevere time series plots for the Pella and Marshalltown cells are shown below. They indicated that the Pella storm was long-lived, persisting past 0300 UTC — and that ProbTor ramped up quickly and then down quickly, bracketing the time of the tornado in Marshalltown.

NOAA/CIMSS ProbHail (Green), ProbWind (Blue) and ProbTor (Red) for the cell that produced the Pella IA tornado. [click to enlarge]

NOAA/CIMSS ProbHail (Green), ProbWind (Blue) and ProbTor (Red) for the cell that produced the Pella IA tornado [click to enlarge]

NOAA/CIMSS ProbHail (Green), ProbWind (Blue) and ProbTor (Red) for the cell that produced the Marshalltown IA tornado [click to enlarge]

A toggle between 375-meter resolution Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1946 UTC (below) provided a look at the early stage of development of tornado-producing convection.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with plots of SPC tornado reports within +/- 30 minutes of the images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with plots of SPC tornado reports within +/- 30 minutes of the images [click to enlarge]

Additional satellite imagery and analysis of this event can be found on the Satellite Liaison Blog.


Tornado in Luzerne County, Pennsylvania

June 14th, 2018 |

GOES-16 ABI Band 2 (Red Visible, 0.64 µm) over northeastern Pennsylvania. Luzerne County is outlined in Yellow, and Wilkes-Barre’s location is highlighted as a yellow box (Click to animate)

A confirmed tornado struck Wilkes-Barre in Luzerne County in northeastern Pennsylvania shortly after sunset on 13 June 2018 (at about 0215 UTC). Visible imagery, above, shows the line of thunderstorms approaching the region before sunset. This video, from Citizens Voice Reporter Nico Rossi, shows some of the damage.

NOAA/CIMSS ProbTor captured the tornadic cell very well (Click this link for a discussion that includes infrared satellite animations). Click here for real-time access to ProbTor.

1-minute Mesoscale Sector GOES-16 Band 13 (Clean Infrared Window, 10.3 µm) images with plots of SPC storm reports are shown below. The Wilkes-Barre PA tornado is plotted as a red T on the 0200 UTC image.

GOES-16 Band 13 (Clean Infrared Window, 10.3 µm) images, with SPC storm reports plotted in red [click to animate]

GOES-16 Band 13 (Clean Infrared Window, 10.3 µm) images, with SPC storm reports plotted in red [click to animate]

Below is a 1-km resolution Terra MODIS Band 31 (Infrared Window, 11.0 µm) image from shortly after the Luzerne County tornado, showing the line of convection that had developed in advance of a cold front. The 2 overlapping SPC storm reports (listed as damaging winds, with report times of 2008 and 2015 UTC) for the Wilkes-Barre event are in the center of the image. The minimum cloud-top infrared brightness temperature was -66ºC.

Terra MODIS Band 31 (Infrared Window, 11.0 µm) image, with plots of cumulative SPC storm reports and the 03 UTC position of the surface cold front [click to enlarge]

Terra MODIS Band 31 (Infrared Window, 11.0 µm) image, with plots of cumulative SPC storm reports and the 03 UTC position of the surface cold front [click to enlarge]

Strong Thunderstorms move through Washington DC.

May 14th, 2018 |

GOES-16 ABI Channel 13 “Clean Window” (10.3 µm) at 1-minute time-steps from 1607-2359 UTC on 14 May 2018 (Click to animate)

A GOES-16 Mesoscale Sector produced 1-minute imagery as a strong thunderstorm complex approached Washington DC late in the afternoon/early evening of 14 May 2018.  The (150-megabyte (!!)) animated gif above shows overshooting tops quickly developing and decaying as the complex moved over the Potomac Basin.  Winds in excess of 60 knots were reported around the Washington DC metropolitan area, with widespread tree damage. (Smaller MP4 animations with plots of SPC storm reports are also available: Infrared | Visible)

NOAA/CIMSS ProbSevere All Hazards (Source), below, showed very high ProbHail and ProbWind with this cell as it approached Washington DC.

NOAA/CIMSS ProbSevere All Hazards, 2200 UTC on 14 May 2018 (Click to enlarge)

GOES-16 Geostationary Lightning Mapper (GLM) data from Real Earth (Link for animation), below, shows an increase in electrical activity to the storms as they moved through Washington DC.

CONUS Hybrid Radar Reflectivity overlain with GLM observations, 2200-2330 UTC 14 May 2018 with 15-minute timestep.

Hail-producing storm on the High Plains of Colorado and Kansas

May 14th, 2018 |

GOES-16 Red Visible (0.64 µm) from 1212 on 14 May 2018 through 0037 UTC on 15 May 2018 (Click to animate)

A Thunderstorm complex moved through eastern CO into western Kansas on 14 May 2018, producing 2 to 3 inch hail in Kit Carson and Cheyenne Counties in east-central Colorado and in Wallace County in northwest Kansas (SPC Storm Reports). Visible animation (0.64 µm) from GOES-16, above, shows the storms initiating near metropolitan Denver before moving eastward across the Plains.

GOES-16 ABI Clean Window imagery (10.3 µm), below, shows very cold overshooting  tops associated with these storms, with brightness temperatures colder than -60º C.  The area of coldest cloud tops shows a pronounced southeastward motion.

GOES-16 ABI “Clean Window” Infrared Imagery (10.3 µm), 1212 UTC 14 May 2018 to 0037 UTC on 15 May 2018 (Click to animate)

The GOES-16 ABI “Snow/Ice” Channel (at 1.61 µm) is important in diagnosing cloud-top properties in convection, in particular because glaciated clouds absorb solar energy at 1.61 µm (rather than reflecting it).  Thus, glaciated cloud tops will look dark.  That is the case with this system, shown below.  Note that above-anvil cirrus banners are apparent in this animation as well towards the end, stretching west-southwest to east-northeast.  These above-anvil banners are very well correlated with severe weather. This link shows a toggle between the Visible (0.64 µm) and Snow/Ice (1.61 µm) bands at 2302 UTC on 14 May, during the time when hail was occurring in eastern Colorado.

GOES-16 ABI “Snow/Ice” Near-Infrared Imagery (1.61 µm), 1212 UTC 14 May 2018 to 0037 UTC on 15 May 2018 (Click to animate)

One of the Derived Products available from GOES-16 is Lifted Index. This animation, from 1212 UTC on 14 May through 0037 UTC on 15 May shows widespread Lifted Indices of -3º to -5º in the inflow into this thunderstorm. (The clear-sky only Lifted Index is plotted on top of the Snow/Ice 1.61 µm Imagery). Note also that dewpoints over the High Plains of Colorado and Kansas were fairly high for that region: 40s and 50s Fahrenheit. (Click to view 2007 UTC “Veggie” Band 0.86 µm imagery with surface metars plotted).

NOAA/CIMSS ProbSevere All Hazards showed very high probabilities for this cell at 2330 UTC, when it was over eastern Colorado, as shown below (Source).

NOAA/CIMSS ProbSevere All Hazards, 2330 UTC on 14 May 2018 (Click to enlarge)

As noted elsewhere (link, link), hail deposited by this storm in central Colorado (in Douglas and Elbert counties) was widespread enough to be visible from satellite, below.  The hail appears white in the visible (0.64 µm) imagery and dark in the 1.61 µm Snow/Ice imagery because ice strongly absorbs energy with wavelengths of 1.61 µm.

GOES-16 Band 2 (“Red Visible”, 0.64 µm) and Band 5 (“Snow/Ice”, 1.61 µm) imagery at 2217 UTC on 15 May 2018 showing hail on the ground in Douglas and Elbert counties, Colorado (Click to enlarge)

GOES-16 Band 2 (“Red Visible”, 0.64 µm) and Band 5 (“Snow/Ice”, 1.61 µm) imagery at 2217 UTC on 15 May 2018 showing hail on the ground in Douglas and Elbert counties, Colorado (Click to enlarge)

Once the severe convection moved closer to the Colorado/Kansas border, a second hail swath was later seen to the east-northeast, below.

GOES-16 “Red” Visible (0.64 µm, top) and Near-Infrared

GOES-16 “Red” Visible (0.64 µm, top) and Near-Infrared “Snow/Ice” (1.61 µm, bottom) images, with SPC storm reports (red) and hourly plots of surface reports [click to play MP4 animation]