A Tour of Today’s 0.91 µm Imagery over Europe from FCI

 

Figure 1: FCI satellite loop from 11:30 to 12:10 UTC 2026/04/30 showing GeoColor (top) and WVT (bottom).

Figure 2: GFS 12 UTC 2-meter dewpoint analysis. Source: pivotalweather.com

On a fairly inactive weather day over the continental United States, forecasters took a virtual tour of the European meteorological scene, viewing actual 0.91 µm-based water vapor transmittance (WVT) imagery from the MeteoSat Third Generation (MTG) Flexible Combined Imager (FCI) over Europe. This is analogous to information that will be available to U.S. forecasters after the launch of GeoXO. GeoXO Imager (GXI) synthetic imagery is currently being evaluated in the current Hazardous Weather Testbed.

Comparing the GeoColor imagery (Figure 1, top) to the WVT imagery (Figure 1, bottom), it is apparent that there is information about column water vapor in WVT that is not present in other visible/near-infrared channels.  For comparison, a GFS dewpoint analysis is shown in Figure 2.  A cyclone is present over the North Atlantic with an associated front trailing across Central Europe, west of Italy.

Some notable features in the WVT imagery:

• The dark “shadow” advancing northeastward across central France is indicative of moisture advecting in advance of the front.
• Moisture from the Mediterranean Sea is working its way inland in eastern Spain and northern Morocco.
• Low-level northeasterly flow can be seen as motion in the WVT clear-sky imagery over Germany.
• Clouds complicate interpretation of WVT imagery.  Higher clouds tend to be bright (for example along the front) while low clouds are often dark (for example over the western Mediterranean Sea off the Spanish coast).  For this reason, comparison of WVT imagery to GeoColor or visible imagery is a logical step in interpretation of the imagery.

The imagery from this blog can be viewed on CIRA SLIDER (with the left/right slider tool enabled) at https://col.st/ecye9.

-VortexTilting