Blowing dust in northern Mexico, southwestern Texas, and southeastern New Mexico

November 10th, 2012 |
MODIS 11-12 µm IR brightnes temperature difference with surface METAR reports and frontal analysis

MODIS 11-12 µm IR brightnes temperature difference with surface METAR reports and frontal analysis

Strong southwesterly winds (gusting as high as 86 mph in New Mexico and 73 mph in Texas) ahead of an advancing cold front were causing dense plumes of blowing dust that restricted surface visibility to 0.5 mile at El Paso, Texas (station identifier KELP) on 10 November 2012. An AWIPS image of the 1-km resolution MODIS 11-12 µm IR brightness temperature difference (BTD) product (above) showed the areal coverage of the blowing dust (cyan to yellow color enhancement) at 20:17 UTC (3:17 PM local time).

The blowing dust plumes could also be seen on a 250-meter resolution MODIS true-color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below).

MODIS true-color Red/Green/Blue (RGB) image (displayed using Google Earth)

MODIS true-color Red/Green/Blue (RGB) image (displayed using Google Earth)

MODIS 0.65 µm visible channel and 11.0 µm IR channel images

MODIS 0.65 µm visible channel and 11.0 µm IR channel images

AWIPS comparisons of 1-km resolution MODIS (above) and Suomi NPP VIIRS (below) visible channel and IR channel images revealed that the airborne dust exhibited a cooler signature (lighter gray enhancement) on the IR imagery.

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

Satellite views of snow cover produced by a strong early season Nor’easter

November 9th, 2012 |
Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images

Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images

The first Nor’easter storm of the 2012-2013 winter season (as seen on 07 November 2012 MODIS images) produced snowfall amounts as high as 13 inches in parts of New Jersey and Connecticut (HPC storm summary). After the clouds had cleared in the wake of the departing system, the areal extent of the remaining snow on the ground — which ranged from 1-6 inches at some locations across New Jersey, New York, Connecticut, and Massachusetts — was shown in an AWIPS comparison of 375-meter resolution (re-projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images at 17:25 UTC (12:25 PM local time) on 09 November 2012 (above). In the false-color VIIRS RGB image, snow on the ground was enhanced in shades of pink.

Note to National Weather Service forecast offices: as a part of our participation in GOES-R Proving Ground activities, CIMSS is able to provide a limited set of VIIRS imagery for display in your local AWIPS (via LDM feed).

Additional detail could be seen in 250-meter resolution MODIS true-color and false-color RGB images at 18:02 UTC (1:08 PM local time) from the SSEC MODIS Today site (below). In the MODIS false-color RGB image, the snow cover appeared as shades of cyan.

MODIS true-color and false-color Red/Green/Blue (RGB) images

MODIS true-color and false-color Red/Green/Blue (RGB) images

The residual impact of Hurricane Sandy on the Gulf Stream

November 9th, 2012 |
MODIS Sea Surface Temperature (SST) product with overlay of RTG_SST High-Resolution model SST field

MODIS Sea Surface Temperature (SST) product with overlay of RTG_SST High-Resolution model SST field

An AWIPS image of the MODIS Sea Surface Temperature (SST) product on 09 November 2012 with an overlay of SST contours from the RTG_SST High-Resolution model valid about 6 hours later (above) showed the residual impact of Hurricane Sandy on the axis of the Gulf Stream, almost 2 weeks after Sandy moved through that area. There were large eddy perturbations seen in the axis of the Gulf Stream, and MODIS SST values of 80º F or higher (darker red color enhancement) that were not captured by the model analysis.

Mountain waves downwind of the Sierra Nevada Range in California

November 8th, 2012 |
GOES-15 6.5 µm water vapor channel images (click image to play animation)

GOES-15 6.5 µm water vapor channel images (click image to play animation)

McIDAS images of 4-km resolution GOES-15 6.5 µm “water vapor channel” data (above; click image to play animation) showed the development of a series of well-defined mountain waves immediately downwind of the high terrain of the Sierra Nevada mountains in California on 08 November 2012. This mountain wave signature indicates the potential for turbulence — and there were a few pilot reports of light to moderate turbulence in that region between the altitudes of 25,000 and 38,000 feet above ground level (17:02 UTC, 01:00 UTC).

Occasionally the crests of these mountain waves are marked by “rotor clouds” — but they also frequently occur in clear air, which underscores the importance of using water vapor imagery for their detection. AWIPS images of 1-km resolution MODIS 6.7 µm water vapor channel, 0.65 µm visible channel. and 11.0 µm IR channel data at 20:32 UTC (below) showed that there were no cloud features present with some of the mountain waves (or with the entire portion of any given mountain wave).

 

MODIS 6.5 µm water vapor channel, 6.5 µm visible channel. and 11.0 µm IR channel images

MODIS 6.5 µm water vapor channel, 6.5 µm visible channel. and 11.0 µm IR channel images