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

By Scott Bachmeier •

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

Categories: Aviation, GOES-13, Suomi NPP, VIIRS