Severe turbulence over the Mid-Atlantic and Northeast regions of the US

January 16th, 2014 |

GOES-13 6.5 µm water vapor channel images [click to play animation]

GOES-13 6.5 µm water vapor channel images [click to play animation]

United Airlines Flight 89 enroute from Newark, New Jersey to Beijing, China encountered severe turbulence at an altitude of 33,000 feet over Vermont (pilot report) around 18:31 UTC on 16 January 2014, which injured 5 flight attendants and forced the flight to return to Newark where the injured crew members were taken to local hospitals for evaluation. AWIPS images of 4-km resolution GOES-13 6.5 µm water vapor channel data (above; click image to play animation) showed that a large baroclinic leaf signature was rapidly developing over the northeastern US and southeastern Canada during the day.

Suomi NPP VIIRS 0.64 µm visible channel images, with pilot reports of turbulence

Suomi NPP VIIRS 0.64 µm visible channel images, with pilot reports of turbulence

17:12 UTC images of 1-km resolution Suomi NPP VIIRS 0.64 µm visible channel data (above) and 11.45 µm IR channel data (below) displayed evidence of “transverse banding” structures along portions of the cloud top of the baroclinic leaf feature — such transverse banding is often associated with turbulence. Pilot reports of turbulence for the hours ending at 17, 18, and 19 UTC are also plotted on the VIIRS images; over this region there were 5 reports of severe turbulence within this 3 hour period.

Suomi NPP VIIRS 11.45 µm IR channel image, with pilot reports of turbulence

Suomi NPP VIIRS 11.45 µm IR channel image, with pilot reports of turbulence

GOES-13 water vapor images with overlays of CRAS model 250 hPa wind speed isotachs (below) showed that there was a strong (150-160 knot) upper level jet streak along the back (western) edge of the baroclinic leaf during the 12 UTC to 21 UTC period. At 18 UTC, the 2 pilot reports of severe turbulence were located in the vicinity of the left entrance region of the jet streak — an area generally expected to have strong downward vertical velocities forced by ageostrophic circulations near the altitude of the jet streak.

GOES-13 water vapor images, CRAS 250 hPa isotachs, and pilot reports of turbulence

GOES-13 water vapor images, CRAS 250 hPa isotachs, and pilot reports of turbulence

GOES-13 water vapor images with overlays of CRAS model pressure of the PV1.5 surface (below) — generally thought of as representing the dynamic tropopause — indicated that the tropopause was as low as 500-600 hPa within the narrow warm/dry band just west of the back edge of the baroclinic leaf during the 12 UTC – 21 UTC time period.

GOES-13 water vapor images, CRAS PV1.5 pressure, and pilot reports of turbulence

GOES-13 water vapor images, CRAS PV1.5 pressure, and pilot reports of turbulence

An automated Turbulence Risk product (below) also indicated that tropopause folding (blue) was occurring along the western edge of the baroclinic leaf, bringing the tropopause as low as 22,500 feet. The yellow ‘+’ symbols represent a portion of the flight track of United Airlines Flight 89.

Turbulence risk product

Turbulence risk product

Large bushfires in southeastern Australia

January 16th, 2014 |

MTSAT-2 0.68 µm visible channel (left) and 3.75 µm shortwave IR (right) images [click to play animation]

MTSAT-2 0.68 µm visible channel (left) and 3.75 µm shortwave IR (right) images [click to play animation]

An extended period of hot, dry weather led to the development of multiple large bushfires across parts of southeastern Australia, some of which began to produce pyrocumulonimbus (pyroCb) clouds during the 15-16 January 2014 period. McIDAS images of MTSAT-2 0.68 µm visible channel and 3.75 µm shortwave IR channel data (above; click image to play animation; also available as an MP4 animation) showed the development of a well-defined pyroCb associated with the Northern Grampions fire in the state of Victoria. After the visible images on the left panels faded to black during the night-time hours, the shortwave IR images on the right panels showed that many of the fire “hot spots” (denoted by the darker black pixels) continued to grow during the night.

MTSAT-2 10.8 µm longwave IR channel images (below; click image to play animation; also available as an MP4 animation) indicated that cloud-top IR brightness temperatures associated with the rapidly-growing pyroCb cloud became as cold as -38.7º C (lighter green color enhancement) at 07:32 UTC. Other areas of cold-topped thunderstorms developed near the coast, likely initiated by sea breeze and/or local terrain influences. Surface reports ploted on the IR images revealed very hot temperatures: for example, it was 109º F (42.8º C) at Melbourne Essondon (station identifier YMEN) at 04 UTC.

MTSAT-2 10.8 µm longwave IR images [click to play animation]

MTSAT-2 10.8 µm longwave IR images [click to play animation]

A larger-scale view of MTSAT-2 0.68 µm visible channel images (below, visualized using the SSEC RealEarth web map server) showed that there were some large bushfires to the northwest that were producing long, dense smoke plumes which were drifting southward off the coast.

MTSAT-2 0.68 µm visible channel images [click to play animation]

MTSAT-2 0.68 µm visible channel images [click to play animation] 

Blowing dust in Nebraska, Kansas, and Colorado

January 16th, 2014 |
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

McIDAS images of 1-km resolution GOES-13 (GOES-East) 0.63 µm visible channel data (above; click image to play animation) showed the development of widespread plumes of blowing dust across parts of southwestern Nebraska, northwestern Kansas, and eastern Colorado on 16 January 2014. Strong northerly to northwesterly winds in the wake of a morning cold frontal passage were  gusting over 40 knots across the entire region, with a peak wind gust of 64 knots in Broken Bow, Nebraska. These strong winds easily lofted the dry soils (the area was experiencing extreme drought conditions), which reduced surface visibilities and caused multiple vehicle accidents in Colorado and Kansas.

A closer view of the blowing dust using a 250-meter resolution Aqua MODIS true-color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below) clearly showed the source region of many of the dust plumes in southwestern Nebraska. The blowing dust plumes in eastern Colorado are not easily seen, due to patchy middle and high level clouds drifting over the region at that time.

Aqua MODIS true-color RGB image

Aqua MODIS true-color RGB image

A larger-scale view of the MODIS true-color image can be seen below, visualized using Google Earth.

Aqua MODIS true-color RGB image (viewed using Google Earth)

Aqua MODIS true-color RGB image (viewed using Google Earth)

For additional information and imagery of this blowing dust event, see the RAMMB GOES-R Proving Ground blog.