Severe thunderstorms across Iowa

July 11th, 2020 |

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

Severe thunderstorms affected much of the Upper Midwest on 11 July 2020 — and 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed two separate clusters of thunderstorms that moved southeastward across Iowa, producing large hail and damaging winds (SPC Storm Reports). The initial round of storms produced a curved outflow boundary across central and eastern Iowa — and several orphan anvils could be seen forming along this outflow boundary before the second round of storms arrived. Numerous pulsing overshooting tops were evident within each of the storm clusters.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images are shown below. The coldest cloud-top infrared brightness temperatures were around -70ºC.

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images [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]

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

For the second round of storms that developed in far southern Minnesota during the early afternoon hours, GOES-16 Visible images (above) and Infrared images (below) include time-matched plots of SPC Storm Reports.

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

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

Tropical Storm Fay makes landfall in New Jersey

July 10th, 2020 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Tropical Storm Fay as it moved northward and made landfall just northeast of Atlantic City, New Jersey (station identifier KACY) around 2100 UTC on 10 July 2020. The exposed low-level center was completely devoid of deep convection.

GOES-16 Visible images with plots of Derived Motion Winds (below) revealed a few wind targets with speeds of 50 knots or higher (red barbs), but those were located well east/northeast of the storm center.

GOES-16 “Red” Visible (0.64 µm) images, with plots of Derived Motion Winds [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with plots of Derived Motion Winds [click to play animation | MP4]

In a sequence of GOES-16 Mid-level Water Vapor (6.9 µm) and Visible images (below), it could be seen that a tongue of dry air was wrapping into the southern and eastern portion of the circulation of Fay, moving directly over the low-level center (1201 UTC | 1501 UTC | 1801 UTC).

GOES-16 Mid-level Water Vapor (6.9 µm) and “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) and “Red” Visible (0.64 µm) images [click to play animation | MP4]

When Fay formed on the previous day, a Sea Surface Temperature analysis from the CIMSS Tropical Cyclones site (below) showed that its center was located over the warm water of the Gulf Stream — but as it moved northward it quickly colder waters around 25ºC off the Delmarva Peninsula and New Jersey coasts.

Sea Surface Temperature analysis [click to enlarge]

Sea Surface Temperature analysis [click to enlarge]

Fay was the earliest-forming 6th (F-named) storm on record for the Atlantic Basin — and was the first tropical cyclone to make landfall in New Jersey since Irene in 2011.

Plumes of blowing dust and salt in Bolivia

July 7th, 2020 |

GOES-16 True Color RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

GOES-16 True Color RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) displayed widespread plumes of blowing dust and salt originating from Salar de Uyuni in southwestern Bolivia on 07 July 2020. These aerosol sources are located within an elevated plateau with altitudes of 11-12,000 feet (3.3-3.6 km) — and similar episodes of blowing dust/salt are not uncommon during the austral winter (reference).

A longer animation of GOES-16 Dust RGB images (below) showed the continued eastward transport of dust/salt plumes for a few hours after sunset.

GOES-16 Dust RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

GOES-16 Dust RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

A sequence of GOES-16 Natural Color RGB, Dust RGB and Split Window Difference (10.3 µm – 12.3 µm) images from AWIPS (below) provided a less detailed view of the plumes — the spatial resolution of Full Disk GOES imagery in AWIPS is reduced to 6 km.

GOES-16 Natural Color RGB, Dust RGB and Split Window Difference (10.3 µm – 12.3 µm) images [click to play animation | MP4]

GOES-16 Natural Color RGB, Dust RGB and Split Window Difference (10.3 µm – 12.3 µm) images [click to play animation | MP4]

Winds across that region increased on 07 July as an intensifying subtropical jet streak was passing just to the north/northeast, as shown in plots of 700 hPa geopotential height and integrated water vapor transport from this site (below). Clouds associated with this jet streak could be seen in the northern portion of the GOES-16 images above.

Plots of 700 hPa geopotential height and integrated water vapor transport [click to enlarge]

Plots of 700 hPa geopotential height and integrated water vapor transport [click to enlarge]

Plots of rawinsonde data from Antofagasta, Chile at 12 UTC on 06, 07 and 08 July (below) showed the increase in northwesterly 700 hPa winds to 40 knots on 07 July. Antofagasta is located about 300 miles southwest of the Salar de Uyuni region.

Plots of rawinsonde data from Antofagasta, Chile at 12 UTC on 06, 07 and 08 July [click to enlarge]

Plots of rawinsonde data from Antofagasta, Chile at 12 UTC on 06, 07 and 08 July [click to enlarge]

Severe thunderstorms exhibiting Above-Anvil Cirrus Plumes over the Dakotas

July 4th, 2020 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed two severe thunderstorms along the North Dakota / South Dakota border region, which exhibited Above-Anvil Cirrus Plumes  (reference | VISIT training).

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

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

A longer animation of GOES-16 Visible images with plots of time-matched SPC Storm Reports is shown above, with GOES-16 Infrared images shown below.

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

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

Pulsing overshooting tops were seen whose cloud-top infrared brightness temperatures were in the -70 to -78ºC range — according to a plot of 00 UTC rawinsonde data from Aberdeen, South Dakota (below), this represented a 1-2 km overshoot of the Most Unstable (MU) air parcel’s Equilibrium Level (EL).

Plot of 00 UTC rawinsonde data from Aberdeen, South Dakota [click to enlarge]

Plot of 00 UTC rawinsonde data from Aberdeen, South Dakota [click to enlarge]

Several hours later, another thunderstorm that produced damaging winds in southwestern North Dakota exhibited a residual Above-Anvil Cirrus Plume in central North Dakota as the storm was dissipating, seen in Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0915 UTC (below). Coldest cloud-top infrared brightness temperatures in the overshooting top region were in the -60 to -66ºC range, while within the warmer AACP feature extending eastward they were in the -52 to -55ºC range.

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]