Three Tropical Cyclones in the Atlantic Basin

August 29th, 2016

GOES-13 Water Vapor Infrared (6.5 µm) Imagery, 2345 UTC 23 August - 1945 UTC 29 August [click to animate]

GOES-13 Water Vapor Infrared (6.5 µm) Imagery, 2345 UTC 23 August – 1945 UTC 29 August [click to animate]

The hourly water vapor animation above over the Atlantic Basin shows the evolution of a strong tropical wave that moved through the Greater Antilles during the week of 23-29 August 2016. (GOES-14 viewed this system on 25 August and 28 August). There are many areas of convection, including Hurricane Gaston, which storm enters the domain from the east. Gaston is no threat to land, however.

Of more interest to the United States are Tropical Depression #8, a small system just southeast of Cape Hatteras, represented as a circular cluster of thunderstorms at the end of the animation, and Tropical Depression #9 near western Cuba. (Click here for an annotated water vapor imagery identifying the storms) Tropical Depression #9 has emerged from the system discussed here. Interests along the coast of North Carolina and Virginia should pay close attention to forecasts on Tropical Depression #8, and those on the Gulf Coast from Louisiana eastward should monitor Tropical Depression #9. For the latest information, see the webpages of the National Hurricane Center.

MIMIC Total Precipitable Water, below, for the 72 hours ending at 1800 UTC on 29 August (from this site), shows that Tropical Depression #8 and Hurricane Gaston, are near regions of dry air that might influence their evolution. In contrast, Tropical Depression #9 is embedded within an atmosphere rich in moisture.

The next two names for tropical cyclones in the Atlantic are Hermine and Ian.

Total Precipitable Water, 1900 UTC 26 August - 1800 UTC 29 August 2016 [click to enlarge]

Total Precipitable Water, 1900 UTC 26 August – 1800 UTC 29 August 2016 [click to enlarge]

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]

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]

Deep cyclone over Hudson Bay

August 11th, 2016

GOES-13 Water Vapor (6.5 µm) images, with hourly surface observations [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with hourly surface observations [click to play animation]

GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above) showed the intensification of a strong cyclone over Hudson Bay, Canada during the 09 August – 10 August 2016 period; the cyclone deepened to a central pressure of 980 hPa (28.94″ of mercury) at 06 UTC on 10 August.

Daily composites of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images visualized using RealEarth (below) showed the storm on 08, 09 and 10 August.

Suomi NPP VIIRS true-color RGB images [click to enlarge]

Suomi NPP VIIRS true-color RGB images [click to enlarge]