Severe weather across southern Wisconsin

May 9th, 2018 |

GOES-16

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

Severe weather (SPC | NWS ARX | NWS MKX) occurred across far southern Wisconsin on the afternoon of 09 May 2018, as a surface low moved eastward across the area. 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) provided a view of the isolated thunderstorm that rapidly developed in far southwestern Wisconsin around 1800 UTC. The evolution of overshooting tops was seen in both Visible and Infrared imagery — cloud-top infrared brightness temperatures cooled into the -50 to -60 ºC range (orange to red enhancement). On the Visible imagery, rear inflow feeder bands could be seen on the southwestern flank of the storm leading up to the time that it produced 1.00-inch diameter hail near Madison at 2045 UTC. SPC storm reports are “parallax corrected” so as to be plotted at a height corresponding to the cloud-top features of the parent storm.

A comparison of Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1923 UTC (below) showed the isolated thunderstorm as it was moving into northwestern Dane County. The rear inflow feeder bands were evident, and the minimum cloud-top infrared brightness temperature was -62 ºC.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]

GOES-16 Rayleigh-corrected pseudo true color Red-Green-Blue (RGB) images (below; courtesy of Pete Pokrandt, AOS) showed a large Mesoscale Convective Vortex (MCV) that moved through northern Illinois and Wisconsin during the early morning hours, along with the hazy signature of smoke from agricultural burning in the central Plains (which was being drawn northward across eastern Iowa ahead of the surface cold front).

GOES-16 Rayleigh-corrected RGB images [click to play YouTube video]

GOES-16 Rayleigh-corrected RGB images [click to play YouTube video]

Subtropical cyclone formation off the coast of Chile

May 9th, 2018 |

GOES-16

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

A very unusual subtropical cyclone formed off the coast of Chile during the 07-08 May 2018 period (Weather Channel | Weather Underground). The system transitioned from a typical cold core baroclinic mid-latitude cyclone to a shallow warm core cyclone with some deep convection around the center of circulation. GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images (above) showed the evolution from 06 May to 09 May. The surface report plotted in the lower right corner of the images is Concepción, Chile.

A Suomi NPP VIIRS True-color Red-Green-Blue (RGB) image viewed using RealEarth (below) depicted the circulation once it had drifted to a position northwest of Santiago, Chile at 1839 UTC on 08 May.

Suomi NPP VIIRS Ttue-color RGB image [click to enlarge]

Suomi NPP VIIRS Ttue-color RGB image [click to enlarge]

The hourly MIMIC Total Precipitable Water product (below) initially showed a long ribbon of subtropical moisture which was being transported ahead of a cold front into the baroclinic low on 05 May — then during the transition to a subtropical low, a small pocket of modest TPW migrated slowly northward  with the surface circulation.

MIMIC Total Precipitable Water product [click to play animation | MP4]

MIMIC Total Precipitable Water product [click to play animation | MP4]

Eruptions of Kilauea in Hawai’i

May 5th, 2018 |

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-15 Shortwave Infrared (3.9 µm) images, with hourly plots of surface reports [click to play MP4 animation]

Heightened seismic activity of the Kilauea volcano on the Big Island of Hawai’i had been ongoing since April 2018, but increased further in early May leading to a series of minor eruptions (Hawaiian Volcano Observatory | USGS) — and GOES-15 (GOES-West) Shortwave Infrared (3.9 µm) images (above) showed the nearly persistent thermal anomaly or “hot spot” (dark black to red enhancement) during the 03-05 May period. Among the numerous earthquakes, the strongest was an M6.9 which occurred at 2233 UTC on 04 May.

A nighttime image of Suomi NPP VIIRS Day/Night Band (0.7 µm) data viewed using RealEarth (below) revealed the bright glow from Kilauea, and also from the Leilani Estates subdivision where several fissure vents had opened (forcing some evacuations).

Suomi NPP VIIRS Day.Night Band (0.7 µm) images, with island boundary and Google Maps labels [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images, with the island boundary and Google Maps labels [click to enlarge]

A comparison of Suomi NPP VIIRS Day/Night Band images from 03 May and 04 May (below) showed the before/after difference in the bright signal emitted by the fissure vents near Leilani Estates.

Suomi NPP VIIRS Day/Night Band (0.7 µm) images from 03 May and 04 May [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images from 03 May and 04 May [click to enlarge]

===== 06 May Update =====

Eruptions of fissure vents became more continuous in the Leilani Estates subdivision on 06 May. A comparison of GOES-15 Visible and Shortwave Infrared images (below) showed a long volcanic plume streaming southwestward, with robust thermal anomaly activity at the plume source.

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2018/05/G15_VIS_SWIR_HI_06MAY2018_960x640_B12_2018126_201500_0002PANELS_00002.GIF

GOES-15 Visible (0.63 µm, left) and Shortwave Infrared (3.9 µm, right) images, with hourly plots of surface reports [click to play animation | MP4]

An Aqua MODIS True-color Red-Green-Blue (RGB) image (below) provided a more detailed view of the volcanic plume at 0007 UTC on 07 May. Note the cluster of red thermal anomalies in the vicinity of the Leilani Estates subdivision (the source of the plume).

Aqua MODIS True-color RGB image [click to enlarge]

Aqua MODIS True-color RGB image, with VIIRS thermal anomalies plotted in red [click to enlarge]

Valley fog and mountain snow in the Catskills of New York

May 1st, 2018 |

As pointed out by NWS Binghamton, valley fog and higher-elevation snow cover was apparent on GOES-16 (GOES-East) Visible imagery in the Catskills of southeastern New York on the morning of 01 May 2018. A closer view comparing GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below) showed the dissipation of the valley fog, followed by the melting of the snow cover in higher terrain (snowfall amounts of up to 3-4 inches fell in the area on 29 April). The Snow/Ice imagery was helpful in discriminating between the brighter valley fog features and the darker snow cover.

GOES-16

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

A 250-meter resolution Terra MODIS True-color Red-Green-Blue (RGB) image acquired from the SSEC Direct Broadcast ground station (below) showed the remaining snow cover over the Catskills (near the center of the image) at 1539 UTC.

Terra MODIS True-color image [click to enlarge]

Terra MODIS True-color image [click to enlarge]