Tehuano wind event

April 8th, 2014 |
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

As we have seen a number of times during the Winter 2013/2014 season, another strong Tehuano wind event occurred on 08 April 2014. McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed distinct arc clouds marking the leading edge of 2 pulses of gap winds emerging southward over the Gulf of Tehuantepec. The second (later) pulse of gap winds appeared to be stronger, and transported plumes of blowing dust to the south.

A timely overpass of a Metop polar-orbiting satellite provided ASCAT surface scaterometer winds which showed the fanning out of the Tehuano flow at 16:20 UTC (below). An advisory for the development of Storm Force winds had been issued by the NOAA Ocean Prediction Center for the Gulf of Tehuantepec.

GOES-13 10.7 µm IR image with Metop ASCAT surface scatterometer winds

GOES-13 10.7 µm IR image with Metop ASCAT surface scatterometer winds

MADIS 1-hour interval satellite winds (below; click image to play animation) tracked the velocity of the arc cloud and dust plumes during the day, which were moving at speeds up to 30 knots.

GOES-13 10.7 µm IR images with MADIS 1-hour satellite winds (click to play animation)

GOES-13 10.7 µm IR images with MADIS 1-hour satellite winds (click to play animation)

Past cases of well-defined Tehuano wind events can be found here.

Tehuano wind event in the wake of a strong eastern US winter storm

January 3rd, 2014 |
SSEC RealEarth 24-hour snowfall total map

SSEC RealEarth 24-hour snowfall total map

A strong winter storm affected much of the central and eastern US during the 02 January03 January 2014 period. A map of SSEC RealEarth 24-hour snowfall totals (above) shows how widespread the resulting snowfall was, with amounts as high as 24 inches in Massachusetts abd 22 inches in New York (WPC storm summary).

As the storm system departed over the Atlantic Ocean on 03 January, an AWIPS image comparison of the 17:53 UTC (12:53 PM Eastern time) Suomi NPP VIIRS 0.64 µm visible channel data and the corresponding false-color “snow vs cloud discrimination” Red/Green/Blue (RGB) product (below) showed the areal coverage of snow on the ground (varying shades of red on the RGB image). Some patches of supercooled water droplet clouds (varying shades of white on the RGB image) could be seen streaming off of Lake Erie and Lake Ontario; in fact, a closer look revealed mesoscale bands of “lake-effect snow” downwind of the Finger Lakes in western New York, and also downwind of Lake Champlain along the New York/Vermont border.

Suomi NPP VIIRS 0.64 µm visible channel image and False-color RGB image

Suomi NPP VIIRS 0.64 µm visible channel image and False-color RGB image

Cold air moving southward in the wake of the storm crossed the western Gulf of Mexico, moved through the Chivela mountain pass in southern Mexico, and eventually emerged over the Pacific Ocean in the Gulf of Tehuantepec — this type of mountain gap wind flow is known as a Tehuano wind event or a “Tehuantepecer”. An image of Metop ASCAT surface scatterometer winds at 02:36 UTC (below) showed that a large area of northerly gale force winds (red wind barbs) was present over the Gulf of Tehuantepec, with maximum remotely-sensed wind speeds of 41 knots. The tropical surface analysis (cyan) displayed the fractured cold frontal boundary that had advanced into southern Mexico; behind the cold front along the Gulf of Mexico coast at Veracruz (station identifier MMVR), the surface visibility at the time was reduced to 6 miles due to blowing sand (time series of MMVR surface reports). Surface reports at Ixtepec (station identifier MMIT) along the Gulf of Tehuantepec were sparse, but did show northerly winds gusting to 37 knots at 17 UTC (time series of MMIT surface reports).

GOES-13 10.7 µm IR image, with Metop ASCAT surface scatterometer winds

GOES-13 10.7 µm IR image, with Metop ASCAT surface scatterometer winds

Daytime images of GOES-13 0.63 µm visible channel data on 03 January (below; click image to play animation) showed the hazy plume of blowing dust and sand moving southwestward, with the boundaries of the strong Tehauno winds marked by long, narrow rope clouds.

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

A signature of the dry air (darker blue color enhancement) associated with the Tehuano winds could be seen on the MIMIC Total Precipitable Water product (below).

MIMIC Total Precipitable Water product, with tropical surface analyses

MIMIC Total Precipitable Water product, with tropical surface analyses

Tehuano wind event

November 27th, 2013 |
GOES-13 6.5 µm water vapor channel image, with surface pressure and surface front analysis

GOES-13 6.5 µm water vapor channel image, with surface pressure and surface front analysis

An AWIPS-1 image of GOES-13 6.5 µm water vapor channel data (above) showed a large storm that was affecting much of the eastern US during the 26 November 27 November 2013 period. Arctic air surging southward behind this storm system crossed the Gulf of Mexico, was funnelled through the mountain passes of southern Mexico, and eventually emerged into the Pacific Ocean in the Gulf of Tehuantepec. This type of “Tehauno wind event” tends to occur a few times each year during the cold season — a few other cases have been documented on this blog.

A series of AWIPS-2 images of GOES-13 10.7 µm IR channel data with overlays of surface and buoy reports and tropical surface analyses (below; click image to play animation) showed that the Gulf of Tehuantepec region was highlighted on 26 November as a region susceptible to developing Storm Force (48-55 knot) winds as the cold front approached from the north. Once the strong gap winds emerged from the southern coast of Mexico, parts of that area likely began to experience storm force winds.

GOES-13 10.7 µm IR images, with surface and buoy reports and tropical surface analysis (click to play animation)

GOES-13 10.7 µm IR images, with surface and buoy reports and tropical surface analysis (click to play animation)

The plume of dry air associated with the Tehuano wind event could be seen on AWIPS-1 images of the MIMIC Total Precipitable Water product (below; click image to play animation).

MIMIC Total Precipitable Water product, with tropical surface analysis (click to play animation)

MIMIC Total Precipitable Water product, with tropical surface analysis (click to play animation)

During the day on 27 November, the hazy signature of blowing dust and sand could be seen streaming southward across the Gulf of Tehuantepec on McIDAS images of GOES-13 0.63 µm visible channel data (below; click image to play animation).

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

Tehuano wind event following the 02 March 2012 severe weather outbreak

March 4th, 2012 |
METAR surface reports + tropical surface analyses + ASCAT scatterometer winds

METAR surface reports + tropical surface analyses + ASCAT scatterometer winds

The powerful mid-latitude cyclone that was responsible for the widespread outbreak of severe weather across parts of the eastern US on 02 March 2012 spawned a southward surge of cold air (OPC surface analyses) that traversed the Gulf of Mexico, crossed the mountainous terrain of far southern Mexico, and emerged across the Pacific Ocean as a strong gap wind event known as a Tehuano wind. AWIPS images showing METAR surface reports, Tropical surface analyses, and a pass of ASCAT scatterometer surface winds (above) showed that there was blowing sand reported at Veracruz (station identifier MMVR), with wind gusts to 45 knos at Minatitlan (station identifier MMMT) and 35 knots at Ixtepec (station identifier MMIT).

McIDAS images of GOES-13 0.63 µm visible channel data from 04 March 2012 (below; click image to play animation) showed the cloud arc that marked the leading edge of the Tehuano wind, and also showed the hazy signature of blowing dust that was being lofted southward across the Pacific coast and over the waters of the Gulf of Tehuantepec (hence the name “Tehuantepecer“ given to this type of strong wind event).

GOES-13 0.63 µm visible channel images (click image to play animation)

GOES-13 0.63 µm visible channel images (click image to play animation)

A similar Tehuano wind event was seen on 08 March 2008.