Meteosat-7 IR images

Yemenia Airways Flight 626 departed from Sana in Yemen and crashed after an aborted landing attempt at Moroni in the Comoros Islands off the east coast of Africa on 29 June 2009. Meteosat-7 11.5 µm IR images (above) showed that there was a strong southerly flow over the region on that day, in the wake of a cold frontal passage. Meteosat-7 IR cloud drift winds from the CIMSS Tropical Cyclones site (below) showed that winds were generally in the 20-30 knot range over the region at the time of the crash.

Meteosat-7 IR cloud-tracked winds

These wind speeds are consistent with the surface METAR reports at Moroni Hahaya International Airport:

FMCH 292200Z 18022G33KT 9999 FEW020 24/17 Q1018 NOSIG=
FMCH 292300Z 21025G35KT 9999 FEW020 25/16 Q1017 TEMPO 18015G30KT=
FMCH 300000Z 21025G35KT 9999 FEW020 25/17 Q1016 TEMPO 19014KT=

Moroni Hahaya International Airport surface meteorogram

For additional information, see Yemenia Flight 626: A detailed meteorological analysis by Tim Vasquez.

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GOES-12 visible images

The GOES-O satellite was launched at 22:51 UTC on 27 June 2009 from Cape Canaveral, Florida (station identifier XMR). GOES-12 visible images (above) showed a portion of the rocket plume on the 23:02 UTC image (some ground-based photos of the launch are available here).

This satellite will become GOES-14 after the hand-off from NASA to NOAA, and will then undergo a Post Launch Test (PLT) during the July-December 2009 period — the first GOES-14 visible images should be made available on 27 July, with the first InfraRed images available in mid-August. CIMSS has calculated the weighting functions for the GOES-14 imager and sounder channels as well as the spectral response functions and Planck function constants for GOES-O…and CIMSS will also contribute to the NOAA Science Test portion of the PLT in November/December 2009.

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GOES-12 visible images

GOES-12 visible images (above) showed a nice example of convective initiation along an outflow boundary from thunderstorms a few hours earlier across northeastern Iowa on 25 June 2009. This new convection that developed along the outflow boundary produced hail of 1.5 inch in diameter and damaging winds in extreme northern Illinois (just south of the Wisconsin border) during the 20:42 -21:02 UTC period.

A comparison of AWIPS images of the MODIS visible channel and a Red/Green/Blue (RGB) composite using MODIS bands 01/07/31 (below) showed the value of the false-color RGB imagery to help highlight the darker green patch of wet ground produced by heavy rainfall from the initial area of thunderstorms. Ice crystal clouds appear as varying shades of pink in the RGB image, which also helps to identify growing areas of cumulus clouds that have glaciated.

The next generation of AWIPS (AWIPS2) should offer NWS forecasters the ability to create and display this type of 24-bit RGB imagery (which is not possible using the 8-bit graphics capability of the current AWIPS system).

MODIS visible + false-color RGB image

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GOES-12 water vapor images

A small “dry swirl” feature (yellow color enhancement) was seen on AWIPS images of the GOES-12 6.5 µm water vapor channel (above) off the East Coast of the US on 24 June – 25 June 2009.

A comparison of a GOES-12 water vapor image with the corresponding GOES-12 sounder Total Column Ozone product at 21:00 UTC on 24 June (below) confirmed that this was a small-scale “stratospheric intrusion vortex”, with ozone values greater than 370 Dobson Units (lighter green color enhancement) in the vicinity of the dry feature on the water vapor imagery.

GOES-12 water vapor + GOES-12 sounder Total Column Ozone product

An overlay of GFS40 model fields on GOES-12 water vapor and Total Column Ozone images (below) indicated that the dynamic tropopause (taken to be the pressure of the PV1.5 potential vorticity surface) was as low as the 400 hPa level at 12:00 UTC on 25 June.

GOES-12 water vapor image + GOES-12 sounder Total Column Ozone product

A more detailed view of the vortex could be seen using 1-km resolution MODIS 6.7 µm water vapor images (below).

MODIS water vapor images

A comparison of MODIS water vapor, IR window, and visible images (below) showed that there was a lack of high clouds with this stratospheric intrusion vortex — only low-level clouds existed over the region in the vicinity of the vortex.

MODIS water vapor + IR + visible images

A comparison of a MODIS water vapor image with 1-hour MADIS satellite winds and GFS40 400 hPa height (below) showed that the stratospheric intrusion vortex was located just to the northeast of the closed low that was off the US East Coast during the period.

MODIS water vapor image + satellite winds + GFS 400 hPa height

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