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]

Tropical Invest 90E in the East Pacific

May 8th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of ship reports [click to play MP4 animation]

An organized area of low pressure (Invest 90E) developed in the East Pacific Ocean on 08 May 2018 — the NHC gave it a 50% chance of becoming a tropical depression within 48 hours. GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the formation of a large convective burst in the northwest quadrant of the circulation after 00 UTC on 09 April.

Metop ASCAT surface scatterometer winds from the CIMSS Tropical Cyclones site (below) showed velocities in the 20.0 to 29.9 knot range (dark blue barbs).

GOES-15 Visible (0.63 µm) image with Metop ASCAT surface scatterometer winds [click to enlarge]

GOES-15 Visible (0.63 µm) image with Metop ASCAT surface scatterometer winds [click to enlarge]

The Invest was located in a region of low deep-layer wind shear, with relatively warm Sea Surface Temperatures and modest values of Ocean Heat Content (below).

GOES-15 Visible (0.63 µm) image, with contours of deep-layer wind shear [click to enlarge]

GOES-15 Visible (0.63 µm) image, with contours of deep-layer wind shear [click to enlarge]

Sea Surface Temperature analysis [click to enlarge]

Sea Surface Temperature analysis [click to enlarge]

Ocean Heat Content analysis [click to enlarge]

Ocean Heat Content analysis [click to enlarge]

The hourly MIMIC Total Precipitable Water product (below) showed that Invest 90E was embedded within the ribbon of high moisture associated with the ITCZ.

MIMIC Total Precipitable Water product [click to enlarge]

MIMIC Total Precipitable Water product [click to enlarge]

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]

Severe weather in Kansas, Nebraska and Iowa

May 1st, 2018 |

GOES-16

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

Severe thunderstorms produced tornadoes, large hail and damaging winds across parts of Kansas, Nebraska and Iowa on 01 May 2018. A Mesoscale Domain Sector  provided images at 1-minute intervals — SPC storm reports are plotted on 0.64 µm “Red” Visible images (above) and 10.3 µm “Clean” Infrared Window images (below).

GOES-16

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

Many of the storms exhibited cloud-top signatures commonly associated with severe weather — for example, pronounced “enhanced-v” signatures with “cold/warm thermal couplets” were seen on Infrared imagery with the tornado-producing storms in northern Kansas and southern Nebraska (below), and both a well-defined “overshooting top” and an “above-anvil plume” were seen on Visible imagery with the Nebraska storm.

GOES-16

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images, with SPC storm reports [click to enlarge]