Tornado outbreak in Indiana/Ohio

August 24th, 2016 |

GOES-13 Visible (0.63 µm) images, with SPC storm reports [click to play animation]

GOES-13 Visible (0.63 µm) images, with SPC storm reports [click to play animation]

An outbreak of tornadoes (SPC storm reports) occurred during the afternoon/early evening hours of 24 August 2016 from central Indiana to northwestern Ohio (NWS Indianapolis | NWS Northern Indiana | NWS Cleveland). In terms of forcing mechanisms, while the supercell thunderstorms developed well in advance of a cold frontal boundary (surface analyses), GOES-13 Visible (0.63 µm) images (above) showed a mesoscale convective vortex or MCV moving eastward across northern Illinois which may have played a role in helping to initiate convection. Moisture was also abundant across the region, with Total Precipitable Water (TPW) values as high as 53.1 mm or 2.1 inches on the 1200 UTC Lincoln IL rawinsonde report and 60.7 mm or 2.4 inches just east of the convection developing over central Indiana on the 1941 UTC Aqua MODIS TPW product (below).

Aqua MODIS Visible (0.65 µm) image and Total Precipitable Water product [click to enlarge]

Aqua MODIS Visible (0.65 µm) image and Total Precipitable Water product [click to enlarge]

A closer view of the 1841 UTC Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images (below) showed the thunderstorm complex over central Indiana just after the time of the first EF2-rated tornado in Montgomery County — the coldest cloud-top infrared brightness temperature was -80º C (violet color enhancement) over the southeastern portion of that county. In addition, an “enhanced-V” cloud top signature was evident over northeastern Clinton County — the next EF3-rated tornado formed just to the northeast in Howard County at 1920 UTC.

Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images [click to enlarge]

The GOES-13 (GOES-East) satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes — in the Visible (0.63 µm) images with plots of preliminary SPC storm reports of tornadoes (red) and hail/wind (cyan) shown below (also available as an MP4 animation), numerous overshooting tops can be seen. These overshooting tops were often in the vicinity of the parallax-corrected SPC storm reports (assuming a mean cloud top height of 12 km).

GOES-13 Visible (0.63 µm) images, with SPC storm reports of tornadoes in red and hail/wind in cyan [click to play animation]

GOES-13 Visible (0.63 µm) images, with SPC storm reports of tornadoes in red and hail/wind in cyan [click to play animation]

The corresponding GOES-13 Infrared Window (10.7 µm) images (below; also available as an MP4 animation) revealed cloud-top IR brightness temperatures as cold as -67º C (darker black enhancement) over Indiana at 1845 and 1855 UTC; the location of parallax-corrected preliminary SPC storm reports of tornadoes (white) and hail/wind (cyan) are also plotted on the images.

GOES-13 Infrared Window (10.7 µm) images, with plots of SPC storm reports of tornadoes in white and hail/wind in cyan [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with plots of SPC storm reports of tornadoes in white and hail/wind in cyan [click to play animation]

GOES-14 SRSO-R: wildfire in Idaho

August 21st, 2016 |

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images, with surface reports plotted in yellow [click to play MP4

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images, with surface reports plotted in yellow [click to play MP4 animation]

The Pioneer Fire in central Idaho produced another pyroCumulonimbus (pyroCb) cloud on 21 August 2016 (the first was on 19 August). GOES-14 was in SRSO-R mode, and sampled the fire with 1-minute imagery (above; also available as a large 73 Mbyte animated GIF) — a large smoke plume was evident on 0.63 µm Visible images as it moved eastward; large fire hot spots (red pixels) were seen on 3.9 µm Shortwave Infrared images; on 10.7 µm Infrared Window images, the cloud-top IR brightness temperature cooled to -35º C (darker green enhancement) between 2249-2307 UTC as it moved over Stanley Ranger Station (KSNY), not quite reaching the -40º C threshold to be classified as a pyroCb.

However, a 1-km resolution NOAA-19 AVHRR 10.8 µm Infrared Window image (below; courtesy of René Servranckx) revealed a minimum cloud-top IR brightness temperature of -48.3º C (dark green color enhancement).

NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right) [click to enlarge]

NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right) [click to enlarge]

A larger-scale comparison of the NOAA-19 AVHRR visible, shortwave infrared and infrared window images is shown below.

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

===== 23 August Update =====

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm) and 11.45-3.74 µm brightness temperature difference images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm), Day/Night Band (0.7 µm) and 11.45-3.74 µm brightness temperature difference images [click to enlarge]

The Pioneer Fire continued to be very active on 22 August (exceeding 100,000 acres in total burn coverage since its start on 18 July), sending a large amount of smoke northeastward (OMPS Aerosol Index). During the following overnight hours, cold air drainage and the development of a boundary layer temperature inversion acted to trap a good deal of smoke in the Payette River valley to the west/southwest of Stanley KSNT. The active fire hot spots (black to yellow to red pixels) were evident on nighttime (1032 UTC or 4:32 AM local time) images (above) of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) data, while illumination from the Moon (in the Waning Gibbous phase, at 69% of Full) showed the ribbon of smoke trapped in the valley (note that this signal was not due to fog, since it did not show up in the VIIRS 11.45-3.74 µm brightness temperature difference or “fog/stratus product”).

During the subsequent daytime hours of 23 August, 1-minute GOES-14 Visible (0.63 µm) images (below; also available as a large 114 Mbyte animated GIF) showed the gradual ventilation of smoke from the Payette River valley as the temperature inversion eroded and mixing via winds increased.

GOES-14 Visible (0.63 um) images, with plots of hourly surface reports [click to play MP4 animation]

GOES-14 Visible (0.63 um) images, with plots of hourly surface reports [click to play MP4 animation]

Severe turbulence injures 24 on JetBlue Flight 429

August 11th, 2016 |

JetBlue Flight 429 flight path [click to enlarge]

JetBlue Flight 429 flight path [click to enlarge]

JetBlue Flight 429 encountered severe turbulence over south-central South Dakota around 0115 UTC on 12 August (7:15 pm local time on 11 August) 2016, which caused injuries to 22 passengers and 2 crew members (media story). The aircraft (flying from Boston MA to Sacramento CA) had to be diverted to Rapid City SD, as seen on the flight path map above (source: FlightAware.com).

GOES-13 Visible (0.63 µm) images, with pilot reports of turbulence [click to play animation]

GOES-13 Visible (0.63 µm) images, with pilot reports of turbulence [click to play animation]

1-km resolution GOES-13 Visible (0.63 µm) images (above) showed widespread thunderstorms across the region, with rapidly-developing new cells forming in the vicinity of the turbulence encounter. A Turbulence AIRMET had been issued around 23 UTC for that portion of the flight path, and Convective SIGMETs also advised of the potential for severe thunderstorms with tops above 45,000 feet (JetBlue 429 was cruising at an altitude of 32,000 feet).

The corresponding 4-km resolution GOES-13 Infrared Window (10.7 µm) images (below) indicated that cloud-top IR brightness temperatures were as cold as -54º C (orange color enhancement) just east of the pilot report at 0100 UTC.

GOES-13 Infrared Window (10.7 µm) images, with pilot reports of turbulence [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with pilot reports of turbulence [click to play animation]

1-km resolution POES AVHRR Visible (0.86 µm) and Infrared (12.0 µm) images at 0049 UTC (below) provided a more detailed view of the developing cells less than 30 minutes prior to the turbulence encounter.

POES AVHRR Visible (0.86 µm) and Infrared (12.0 µm) images, with pilot reports [click to enlarge]

POES AVHRR Visible (0.86 µm) and Infrared (12.0 µm) images, with pilot reports [click to enlarge]

Transverse banding: a signature of potential turbulence

July 20th, 2016 |

GOES-13 Infrared Window (10.7 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 Infrared Window (10.7 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 (GOES-East) Infrared Window (10.7 µm) images (above) showed the formation of tendrils of transverse banding along the northern semicircle of  decaying mesoscale convective systems as they moved eastward across Nebraska and Iowa on 19 July 2016. Pilot reports of turbulence are plotted on the images, along with Turbulence AIRMET polygons issued at 0800 UTC and 1400 UTC. Most of the pilot reports of turbulence were in the Light to Moderate category, although there was one report of Moderate to Severe intensity at 1612 UTC over eastern Iowa.

The corresponding GOES-13 Water Vapor (6.5 µm) images (below) perhaps highlighted the transverse banding features a bit better at times, since the weighting function for that spectral band generally peaks in the middle to upper troposphere where the transverse banding cloud features existed.

GOES-13 Water Vapor (6.5 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

GOES-13 Water Vapor (6.5 um) images, pilot reports of turbulence, Turbulence AIRMET boundaries [click to play animation]

A sequence of Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) (below) showed a higher-resolution view of the initial formation of transverse banding during the 0411 to 1008 UTC time period.

Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Infrared Window images from POES AVHRR (10.8 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Shown below are two other types of satellite imagery that can be helpful for identifying the areal extent of transverse banding cloud features: the Suomi NPP VIIRS Day/Night Band (0.7 µm), and the MODIS Cirrus band (1.37 µm). A similar Cirrus band will be part of the ABI instrument on GOES-R.

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]

Terra MODIS Infrared Window (11.0 µm) and Cirrus (1.37 µm) images [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) and Cirrus (1.37 µm) images [click to enlarge]