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Sentinel-1A’s overpass over the Gulf of Tehuantepec shortly after 0000 UTC on 13 December, shown above in a toggle with topography, corresponded with the beginning of an event of strong winds (colloquially called a “Tehuantepecker”) cause by funneling of wind through the Chivela Pass in the Sierra Madre mountains. At 0031 UTC, the time of the overpass (Normalized Radar Cross Section fields at that time are here<\/a>; note also the wind field on 17 December!), winds are near 40 knots over the Pacific Ocean, and the wind structure has a noticeable banded structure. This NOAA\/STAR website<\/a> also allows a user to view the Sentinel-1A NRCS fields<\/a>, and the winds<\/a>.<\/p>\n\n\n\n Advanced Scatterometer (ASCAT) winds over the same region similarly outline very strong winds from this event, over two days, with winds up to 40 knots. ASCAT horizontal resolution is insufficient to capture the different bands of strongest winds as seen in the SAR data.<\/p>\n\n\n\n Visible imagery from both 13 December and 14 December, shown below, show the characteristic clearing down wind of the Sierra Madre mountains as air descends (and dries).<\/p>\n\n\n\n![\"\"](\"https:\/\/www.star.nesdis.noaa.gov\/socd\/mecb\/sar\/AKDEMO_products\/APL_winds\/wind_images2\/2023-12\/S1A_ESA_2023_12_13_00_31_49_0755742709_095.25W_16.15N_VV_C5_GFS025CDF_wind.png\")
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![NRCS fields<\/a>, and](\"https:\/\/www.star.nesdis.noaa.gov\/socd\/mecb\/sar\/AKDEMO_products\/APL_winds\/wind_images2\/2023-12\/S1A_ESA_2023_12_13_00_31_49_0755742709_095.25W_16.15N_VV_C_nrcs.png\"){kind=link}