Severe weather in southern Wisconsin

June 16th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images, with SPC storm reports plotted in red/cyan and surface station identifiers plotted in yellow [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the development of thunderstorms over southern Wisconsin during the afternoon and evening hours on 16 June 2018. There were reports of hail, damaging winds and 1 brief tornado (SPC storm reports | NWS MKX summary). The pulsing of short-lived overshooting tops is evident in both Visible and Infrared imagery; above-anvil cloud plumes can also be seen in Visible imagery, drifting southeastward from the more robust overshooting tops. Note at 2000 UTC the boundary that was oriented approximately north-to-south, with widespread cumulus clouds to the west and generally cloud-free conditions to the east: this was a lake breeze boundary that had migrated inland from Lake Michigan. Many of the storms appeared to intensify as they interacted with this boundary.

Severe thunderstorms in North Dakota

June 14th, 2018 |

GOES-16 Mid-level Water Vapor (6.9 µm) images, with SPC storm reports plotted in red [click to play MP4 animation]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with SPC storm reports plotted in red [click to play MP4 animation]

GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) revealed the circulation of a shortwave aloft (500 hPa analyses) that was moving from the northern Rockies to the southern Canadian Prairie Provinces on 14 June 2018. The approach of this shortwave was helping to enhance large-scale forcing for ascent, as an occluded surface low developed over western North Dakota (surface analyses) — at 1630 UTC, SPC issued a Moderate Risk for severe thunderstorms across far northern North Dakota.

A Mesoscale Domain Sector was positioned over that region, providing images at 1-minute intervals; a comparison of “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed the development of this severe convection, which produced hail as large as 3.0 inches in diameter and 4 tornadoes (NWS Bismarck | NWS Grand Forks). The images include plots of SPC storm reports — just across the US/Canada border, storm reports in southern Saskatchewan/Manitoba can be seen here. Some of these storms exhibited very high radar reflectivity values, as shown here and here.

GOES-16

1-minute GOES-16 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in red/cyan [click to play MP4 animation]

A larger-scale view of 1-minute GOES-16 Visible images (below) showed well-defined parallel inflow feeder bands moving into the southern flank of the storm approaching Minot (KMOT) and Minot Air Force Base (KMIB) during the 1600-1900 UTC time period. Distinct above-anvil plumes were seen with a number of the stronger storms.

1-minute GOES-16

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

The corresponding larger-scale view of 1-minute GOES-16 Infrared images (below) extended past sunset, and showed the final tornado that began around 0324 UTC.

1-minute GOES-16

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

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]

Mesoscale Convective System in the Plains

June 11th, 2018 |

GOES-16

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

A Mesoscale Convective System (MCS) developed over eastern Nebraska early in the evening on 11 June 2018, then propagated southward across the Plains during the subsequent overnight hours. GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images with plots of SPC storm reports are shown above; a Mesoscale Sector was positioned over the region, providing images at 1-minute intervals.

A closer look over Kansas using Infrared imagery from polar-orbiting satellites (below) revealed some very cold cloud-top infrared brightness temperatures, which included -87ºC on MODIS, -90ºC on VIIRS and -92ºC on AVHRR.

POES AVHRR, Terra/Aqua MODIS and Suomi NPP VIIRS Infrared images, with plots of SPC storm reports [click to enlarge]

Metop-B AVHRR, Terra/Aqua MODIS and Suomi NPP VIIRS Infrared images, with plots of SPC storm reports [click to enlarge]

The coldest air temperature on 00 UTC rawinsonde data from Dodge City and Topeka, Kansas (below) was -69.5ºC (at altitudes of 14.6 km/49,900 feet at Dodge City, and 17.6 km/57,700 feet at Topeka) — so in theory air parcels and cloud material within a vigorous overshooting top could have ascended a few km (or thousands of feet) beyond those altitudes to exhibit an infrared brightness temperature of -92ºC.

Plots of rawinsonde data from Dodge City and Topeka, Kansas [click to enlarge]

Plots of rawinsonde data from Dodge City and Topeka, Kansas [click to enlarge]

A toggle between re-mapped versions of the GOES-16 ABI and Metop-B AVHRR Infrared imagery over Kansas at the time of the very cold cloud-top infrared brightness temperature (below) revealed 2 important points: (1) with improved spatial resolution (1 km for AVHRR, vs 2 km *at satellite sub-point* for ABI) the instrument detectors sensed much colder temperatures (-92.6ºC with AVHRR vs -81.2ºC with ABI), and (2) due to parallax. the GOES-16 image features are displaced to the northwest. In addition to the isolated cold overshooting top in south-central Kansas, note the pronounced “Enhanced-V” storm top signature in far northeastern Kansas.

Comparison of GOES-16 ABI and Metop-B AVHRR Infrared images [click to enlarge]

Comparison of GOES-16 ABI and Metop-B AVHRR Infrared images [click to enlarge]

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