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 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 KMIW — above-anvil 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]

A ProbSevere time series for object 621481, above, is shown below; it indicated 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 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.


Southwest US monsoon convection: GOES-15 vs GOES-16

July 12th, 2018 |

GOES-15 Visible (0.63 µm, left) and GOES-16 Visible (0.64 µm, right) images [click to play MP4 animation]

GOES-15 Visible (0.63 µm, left) and GOES-16 “Red” Visible (0.64 µm, right) images [click to play MP4 animation]

GOES-15 (GOES-West) Visible (0.63 µm) and GOES-16 (GOES-East) “Red” Visible (0.64 µm) images — displayed in the native projection of each satellite, and centered on Las Vegas, Nevada — are shown above, depicting the development of deep convection across parts of the Desert Southwest on 12 July 2018. While the GOES-15 satellite was in Rapid Scan Operations mode (providing 2 extra images nearly every hour, at :11 and :41), a GOES-16 Mesoscale Sector was providing images at 1-minute intervals. Numerous flash flood watches, warnings and advisories were issued by NWS Las Vegas during the course of the day as some of the storms produced heavy rainfall (with as much as 0.75 inch at Cal Nev Ari and 0.61 inch at Needles, California KEED).

Note that the GOES-15 Visible images do not appear as bright as those from GOES-16 — prior to the GOES-R Series of satellites, the performance of visible detectors degraded over time, leading to imagery that appeared more dim as the Imager instrument aged. Visible detectors on the new ABI instrument benefit from on-orbit calibration to remedy this type of degradation.

The corresponding GOES-15 Infrared Window (10.7 µm) and GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed cloud-top infrared brightness temperatures around -70ºC (black enhancement) associated with some the stronger thunderstorms; this was the tropopause temperature at an altitude of 16.7 km / 48,300 feet on 00 UTC Las Vegas rawinsonde data. The improvement in spatial resolution from 4 km (at sub-satellite point) with GOES-15 to 2 km with GOES-16 is very apparent — even though the satellite viewing angle is about 10 degrees higher for GOES-16 than it is for GOES-15.

GOES-15 Infrared Window (10.7 µm, left) and GOES-16 "Clean" Infrared Window (10.3 µm, right) images [click to play MP4 animation]

GOES-15 Infrared Window (10.7 µm, left) and GOES-16 “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Higher spatial resolution Infrared Window images from Terra/Aqua MODIS and Suomi NPP VIIRS (below) revealed a cloud-top infrared brightness temperature as cold as -79ºC in far northwestern Arizona on the 2017 UTC VIIRS image.

Infrared Window images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Infrared Window images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

In addition to heavy rainfall, some thunderstorm winds created areas of blowing sand:

The GOES-16 Total Precipitable Water derived product (below) showed that rich moisture was present across the Desert Southwest, fueling the development of the widespread convection. TPW values in the 1.0 to 2.0 inch range were seen over southeastern California, southwestern Arizona and far southern Nevada.

GOES-16 Total Precipitable Water derived product [click to play MP4 animation]

GOES-16 Total Precipitable Water derived product [click to play MP4 animation]

A 4-km resolution Terra/Aqua MODIS Total Precipitable Water product (below) indicated values in the 40-55 mm or 1.6-2.2 inch range.

Terra/Aqua MODIS Total Precipitable Water product [click to enlarge]

Terra/Aqua MODIS Total Precipitable Water product [click to enlarge]

Natural gas explosion and fire in Sun Prairie, Wisconsin

July 10th, 2018 |

GOES-16 Shortwave Infrared (3.9 µm) image and Fire Temperature derived product [click to play animation]

GOES-16 Shortwave Infrared (3.9 µm) imagery and Fire Temperature derived product [click to play animation | MP4]

An explosion triggered by a damaged natural gas main in Sun Prairie, Wisconsin occurred around 0005 UTC / 7:05 pm CDT on 10 July 2018 (media story). Layered cloudiness was passing over the region at the time of the initial explosion, but once the clouds cleared a thermal signature (blue pixel) was seen from 0247 to 0342 UTC on the GOES-16 (GOES-East) Fire Temperature product (above) as the fire burned into the nighttime hours. The maximum Fire Temperature value was 537.6 K at 0332 UTC / 10:32 pm CDT.

A thermal anomaly or “hot spot” (dark black pixels) was apparent on 1-km resolution Terra MODIS Shortwave Infrared (3.74 µm) imagery (below) at 0338 UTC / 10:38 pm CDT. The maximum infrared brightness temperature on the MODIS image was 335.4 K.

Terra MODIS Shortwave Infrared (3.74 µm) image, with plots of surface observations in yellow [click to enlarge]

Terra MODIS Shortwave Infrared (3.74 µm) image, with plots of surface observations in yellow [click to enlarge]

A very subtle thermal anomaly (darker gray pixels) was still evident after 07 UTC / 2 am CDT on Suomi NPP and Aqua MODIS Shortwave Infrared images (below).

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS Shortwave Infrared images [click to enlarge]

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS Shortwave Infrared images [click to enlarge]



Super Typhoon Maria

July 5th, 2018 |

Himawari-8 Visible (0.64 µm, left) and Infrared Window (10.4 µm, right) images [click to play MP4 animation]

Himawari-8 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.4 µm, right) images [click to play MP4 animation]

Typhoon Maria underwent a period of rapid intensification (ADT | SATCON) while it was just northwest of Guam late in the day on 05 July 2018, becoming the first Category 5 Super Typhoon of the 2018 West Pacific season. Rapid-scan Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images (above) showed Maria during this period of rapid intensification. Cloud-top infrared brightness temperatures reached -80ºC (violet enhancement) at times in the eyewall of the storm.

A GPM GMI Microwave (85 GHz) image from the CIMSS Tropical Cyclones site (below) showed the pinhole eye of Maria around the time it reached Category 5 intensity. The tropical cyclone was moving over water with high values of Ocean Heat Content — and was in an environment characterized by low values of Deep-layer Wind Shear.

GPM GMI Microwave (85 GHz) image [click to enlarge]

GPM GMI Microwave (85 GHz) image [click to enlarge]

Mesovortices could be seen within the eye on Himawari-8 Visible imagery (below). However, note how the eye became less distinct and increased in diameter toward the end of the animation.

Himawari-8

Himawari-8 “Red” Visible (0.64 µm) images [click to play MP4 animation]

Shortly after 00 UTC on 06 July, Maria began the process of an eyewall replacement cycle as shown in MIMIC TC morphed microwave imagery (below) — and during the following 6-12 hours a decreasing trend in storm intensity was seen (ADT | SATCON).

MIMIC TC morphed microwave image product [click to play animation]

MIMIC TC morphed microwave image product [click to play animation]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1603 UTC on 06 July (below; courtesy of William Straka, CIMSS) showed Category 4 Typhoon Maria after the eye had filled following the eyewall replacement cycle.

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

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

===== 08 July Update =====

Himawari-8

Himawari-8 “Clean” Infrared Window (10.4 µm) images [click to play MP4 animation]

Super Typhoon Maria re-intensified to Category 5 intensity at 12 UTC on 08 July (SATCON) — Himawari-8 “Clean” Infrared Window (10.4 µm) images (above) displayed a large (30 nautical mile wide) eye. The subtle signature of mesovortices could be seen rotating within the eye.

During the preceding daylight hours, Himawari-8 “Red” Visible (0.64 µm) images (below) showed the eye mesovortices in better detail.

Himawari-8

Himawari-8 “Red” Visible (0.64 µm) images [click to play MP4 animation]

However, Maria was again downgraded to a Category 4 storm at 00 UTC on 09 July, as another eyewall replacement cycle took place (DMSP-17 microwave image) and the storm began to move over water having slightly cooler Sea Surface Temperature and Ocean Heat Content. The eye and its mesovortices continued to be prominent in Himawari-8 Visible and Infrared imagery (below).

Himawari-8

Himawari-8 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.4 µm, right) images [click to play MP4 animation]