One of the products demonstrated at this year’s HWT is synthetic water vapor transmittance (WVT) imagery. The product, a ratio of 0.91 μm to 0.86 μm reflectances, is based on the existence of water vapor absorption at 0.91 μm. Dividing by 0.86 μm helps to highlight the water vapor signature. As NOAA does not yet operate a satellite channel at 0.91 μm, synthetic imagery is created for HWT from the High-Resolution Rapid Refresh model run through the Community Radiative Transfer Model. However, EUMETSAT’s latest geostationary satellite, Meteosat-12, does contain 0.91 μm and 0.86 μm channels on its Flexible Combined Imager (FCI), and is used to augment the synthetic imagery during HWT.
Figure 1 shows an FCI WVT loop over northeastern Africa and the Arabian Peninsula from 3 June 2026. The darker regions are indicative of higher amounts of total precipitable water (TPW). Noteworthy regions of higher TPW can be seen along the west and south coasts of Saudi Arabia and Yemen as moisture moves onshore from the Red Sea and the Gulf of Aden. The greater moisture along and equatorward of the Sahel is also very apparent. Protruding from this reservoir of high TPW is a stream of moisture moving north to southern Algeria and then northeast towards Israel. The existence of these high moisture areas can be confirmed by the corresponding TPW loop (Figure 2) created from blending retrievals from multiple polar-orbiting satellites. Additional confirmation of the moisture protrusion over Algeria can be seen in the surface dewpoints at the reporting stations (Figure 3). The stations in southeast Algeria have dewpoints above 40°F, whereas further north the dewpoints are 30°F or lower.
Figure 1. WVT product loop over Africa on 3 June 2026.
Figure 2. Corresponding TPW product created from multiple polar-orbiting satellites.
Figure 3. Surface observations over Algeria around 1300UTC 3 June 2026. Dewpoint temperature (°F) is shown in blue. Zooming in may be necessary to read the numbers.
Geogxi
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