GOES-15 0.63 µm visible channel images (click image to play animation)

A large outbreak of blowing dust developed in the wake of a cold frontal passage across parts of New Mexico, Texas, and Oklahoma on 22 January 2012. At Lubbock, Texas winds gusted to 60 mph, and surface visibility was reduced to 0.5 mile. The strongest wind gust was 77 mph, farther to the north in the Texas panhandle region (NWS Lubbock summary). Early in the day, the consolidation of numerous smaller blowing dust plumes into a single large blowing dust “cloud” could be seen on 1-km resolution GOES-15 (GOES-West) 0.63 µm visible channel images (above; click image to play animation).

Later in the day, due to a more favorable forward scattering angle, the areal extent of the airborne blowing dust could be better seen on 1-km resolution 0.63 µm visible channel images from the GOES-13 (GOES-East) satellite (below; click image to play animation). The leading edge of the primary large dust plume began to move northeastward over Oklahoma, while a number of smaller dust plumes could be seen moving southeastward across the Oklahoma and Texas panhandle regions behind a secondary cold front. Note that the GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-10 minutes.

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

A 250-meter resolution MODIS true color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below, viewed using Google Earth) displayed even greater detail in the structure of the blowig dust plume at 20:02 UTC.

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

There was also a bit of smoke mixed in with the blowing dust, due to a few small wildfires that were burning across the region. Three small wildfire “hot spots” (dark black to yellow pixels) could be seen on an AWIPS image of 1-km resolution MODIS 3.7 µm shortwave IR data at 20:00 UTC (below).

MODIS 3.7 µm shortwave IR image

Over southern Oklahoma at 21:23 UTC a pilot reported that at an altitude of 9000 feet the flight level visibility was zero due to blowing dust (below).

GOES-13 0.63 µm visible channel image + Aircraft pilot report

GOES-13 0.63 µm visible channel images

Strong northerly winds in the wake of a cold frontal passsage caused widespread blowing dust across parts of west Texas during the afternoon hours on 26 November 2011. The hazy plumes of blowing dust could be seen on GOES-13 0.63 µm visible channel images (above). At Midland, Texas (located near the center of the images) the winds gusted to 51 mph, and surface visibility was reduced to 0.5 mile at times.

After sunset, when visible imagery was no longer available, the southward progress of the airborne dust could still be tracked using a GOES-11 IR difference product (below), created by subtracting the 12.0 µm IR brightness temperature from the 10.7 µm IR brightness temperature. The larger IR difference values (around 2-3 degrees Kelvin, yellow color enhancement) represented the portions of the airborne dust cloud that were the most concentrated.

GOES-11 0.65 µm visible images + GOES-11 IR difference product images

It is important to note that GOES-11 (GOES-West) is the only remaining operational GOES satellite that still has the 4-km resolution 12.0 µm IR channel on the Imager instrument (a 10-km resolution 12.0 µm channel is still on the Sounder instrument on all GOES satellites) — and GOES-11 will soon be replaced by GOES-15 on 06 December 2011. After that time, using such an IR difference product to track areas of blowing dust will have to be done using polar orbiting satellites (such as POES, MODIS, or NPP) or the GOES Sounder that still have the 12.0 µm IR channel.

GOES-15 3.9 µm shortwave IR images (click image to play animation)

The 2000-acre “Caughlin Fire” started burning around 08:45 UTC (1:45 am local time) in the hilly terrain near Reno, Nevada, and soon grew out of control due to strong winds gusting as high as 74 mph. McIDAS images of GOES-15 3.9 µm shortwave IR data (above) showed the “hot spot” (black to yellow to red enhanced pixels) associated with the fire. At least 30 homes were destroyed, with many more damaged by the fire. Thousands of residents were evacuated.

Evidence of the strong winds across the region could be seen on an AWIPS image of MODIS 6.7 µm water vapor channel data (below), with a number of very pronounced mountain waves showing up on the image. These mountain waves persisted for several hours, and were responsible for pilot reports of severe turbulence, wind shear, and 50-knot crosswinds during descent to final approach into the Reno airport. The highest wind gust reported at the Reno airport was 44 mph, and surface visibility was also reduced to 6 miles at the airport due to smoke.

MODIS 6.7 µm water vapor channel image

GOES-11, GOES-15, and GOES-13 visible channel images (click image to play animation)

A major blowing dust event occurred in the wake of a strong cold frontal boundary that moved rapidly southward across western Texas and eastern New Mexico late in the day on 17 October 2011 — the blowing dust reduced surface visibilities to near zero in some locations as winds gusted as high as 75 mph (see NWS Lubbock story). McIDAS images of GOES-11 (GOES-West), GOES-15, and GOES-13 (GOES-East) visible channel data during the daylight hours and shortwave IR data after sunset (above; click image to play animation) showed the southward propagation of the well-defined arc of blowing dust (or “haboob”), along with the surge of cooler air behind the cold front. A few wildfire “hot spots” (darker black pixels) were also evident on the GOES shortwave IR images, a result of fires started by downed power lines.

Much of that region had been experiencing long-term extreme to exceptional drought conditions — and an AWIPS image of the MODIS Normalized Difference Vegetation Index (below) showed very low NDVI values across much of western Texas the day before the dust storm.

MODIS Normalized Difference Vegetation Index

MODIS true color and false color RGB images (11 September)

MODIS true color and false color RGB images (12 September)

250-meter resolution MODIS true color and false color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (above) showed the very large pyrocumulus and smoke plume from the Pagami Creek wildfire that was burning in the Boundary Waters Canoe Area Wilderness region of northeastern Minnesota on 11 September 2011 and 12 September 2011. The wildfire “hot spot” appears as the large red-colored feature on the false color images.  Other options for viewing this MODIS imagery include the SSEC Web Mapping Service and WisconsinView sites: WMS MODIS image | WisconsinView: Terra and Aqua MODIS images. Additional information and photos are available from the Duluth National Weather Service.

A comparison of AWIPS images of 1-km resolution MODIS 0.65 µm visible channel, 3.7 µm shortwave IR channel, and 11.0 µm IR window channel data (below) revealed the very large fire “hot spot” on the shortwave IR image (red to yellow to black color enhancement) — and also note that the resulting pyrocumulus cloud just east of the fire hot spot exhibited a cloud top 11.0 µm IR window brightness temperature of -70º C (black color enhancement), which was just as cold as that associated with the thunderstorms farther to the north in Ontario, Canada!

MODIS 0.65 µm visible, 3.7 µm shortwave IR, and 11.0 µm IR images

AWIPS images of GOES-13 3.9 µm shortwave IR data (below) showed the diurnal changes to the size and intensity of the fire hot spot. Early in the animation during the overnight and morning hours, the hot spot was smaller and less intense as the wind speeds became very light– however, once strong southwesterly winds began to increase during the afternoon hours in advance of an approaching cold front, the hot spot was seen to dramatically increase in size as the fire quickly grew.

GOES-13 3.9 µm shortwave IR images (click image to play animation)

A comparison of the 4-km resolution GOES-13 3.9 µm and the 1-km resolution MODIS 3.7 µm shortwave IR images (below) demonstrated the advantage of better spatial resolution for more accurate location of the fire hot spot boundaries. In addition, the MODIS image revealed another small fire hot spot could be seen to the north, just across the Minnesota/Ontario border — this small fire was not seen on the GOES-13 image.

MODIS 3.7 µm and GOES-13 3.9 µm shortwave IR images

===== 13 September Update =====

A significant amount of smoke was transported southeastward across Wisconsin on 13 September 2011, as seen on GOES-13 0.63 µm visible channel images (below). The surface visibility was reduced to 2 miles at Milwaukee (station identifier KMKE), and 3 miles at Chicago O’Hare (station identifier KORD). Special Weather Statements were issued by the National Weather Service forecast offices at Milwaukee/Sullivan and Chicago/Romeoville to advise the public about the potential harmful effects of the smoke.

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

The smoke feature was even more apparent on the afternoon MODIS true color Red/Green/Blue (RGB) image (below), and this smoke produced an elevated signal on the MODIS Aerosol Optical Depth (AOD) product from the IDEA site.

MODIS true color Red/Green/Blue (RGB) image

CIMSS participation in GOES-R Proving Ground activities includes making a variety of MODIS images and products available for National Weather Service offices to add to their local AWIPS workstations. Currently there are 49 NWS offices receiving MODIS imagery and products from CIMSS.

GOES-13 3.9 µm shortwave IR channel + 0.63 µm visible channel images

McIDAS images of GOES-13 3.9 µm shortwave IR and 0.63 µm visible channel data (above; click image to play animation) showed the fire hot spot (dark black pixels) and large smoke plume associated with the Bastrop County fire complex in eastern Texas on 04 September 2011. This fire went on to set a record for the highest number of homes damaged (over 500) by a single fire in Texas history.

A comparison of AWIPS images of 1-km resolution POES AVHRR 0.63 µm visible channel and 3.74 µm shortwave IR channel data (below) showed finer detail in the location of the individual fire hot spots (black to red to yellow color enhancement).

POES AVHRR 0.63 µm visible channel + 3.74 µm shortwave IR channel images

On the following day (05 September), the number of fires quickly grew to over 60 — a number of very large smoke plumes could be seen growing on GOES-13 0.63 µm visible channel images (below; click image to play animation). The thick smoke was causing air quality problems at a number of locations. Strong northerly winds around the circulation of the remnants of Tropical Storm Lee helped to create an environment that allowed many of the fires to quickly burn out of control.

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

The location of many of the larger fire hot spots (black to yellow to red color enhancement) could be seen on a comparison of GOES-15 and GOES-13 3.9 µm shortwave IR images (below; click image to play animation).

GOES-15 and GOES-13 3.9 µm shortwave IR images (click image to play animation)

MODIS true color Red/Green/Blue (RGB) images

A sequence of daily 250-meter resolution MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Direct Broadcast site (above) showed the development and evolution of the smoke plume emanating from a swamp fire that was burning in the Bayou Sauvage National Wildlife Refuge near New Orleans during the 26 August – 31 August 2011 time period. The change in daily wind directions resulted in very different smoke dispersion patterns on each day. Smoke from this fire caused air quality alerts to be issued for the New Orleans and Baton Rouge areas.

AWIPS images (below) of the 1-km resolution MODIS 0.65 µm visible channel data at 19:16 UTC (2:16 pm local time on 30 August) showed the curving smoke plume; about 9.5 hours later, the fire “hot spot” (black to red to yellow color enhanced pixels) was seen on a 1-km resolution MODIS 3.7 µm shortwave IR image at 04:42 UTC (11:42 pm local time on 30 August).

MODIS 0.65 µm visible image + MODIS 3.7 µm shortwave IR image

MODIS 3.7 µm shortwave IR images

AWIPS images of 1-km resolution MODIS 3.7 µm shortwave IR data (above) revealed a large number of “hot spots” (black to red to yellow color enhancement) due to wildfires that were burning across parts of western Ontario, Canada on 17 July – 18 July 2011.

McIDAS images of GOES-13 0.63 µm visible channel data (below) showed the unusually dense smoke plume resulting from these wildfires. Over Ontario, most of the smoke was located aloft (see the US Air Quality Smog Blog for more details), but surface visibilities were still being restricted to 2-5 miles at some locations. Farther away from the source region, the leading edge of the smoke moving over portions of New England and the Canadian Maritime Provinces exhibited significantly less optical thickness.

GOES-13 0.63 µm visible channel images

The hazy extent of the smoke plume could be more readily seen on a MODIS “true color” Red/Green/Blue (RGB) image from the SSEC MODIS Direct Broadcast site (below). As an aside, note that there are still some large ice floes in the open water of Hudson Bay.

MODIS true color Red/Green/Blue (RGB) image

GOES-11 0.65 µm visible and 10.7 µm IR images (click image to play animation)

Strong thunderstorm outflow winds (gusting as high as 69 mph) created a severe dust storm (or “haboob“) in the Phoenix, Arizona area around 02:00 to 03:00 UTC on 06 July 2011 (or 7pm to 8pm local time on 05 July 2011), restricting the surface visibility to near zero with blowing dust and forcing a 45-minute Ground Stop at Phoenix Sky Harbor Airport (an interesting YouTube video of the approaching dust storm is available here). The Phoenix National Weather Service forecast office published a summary of the event, and additional information and 3D radar animations are available on the AccuWeather WeatherMatrix blog. A high-resolution GOES image can be found at the NOAA Environmental Visualization Laboratory.

McIDAS images of GOES-11 0.65 µm visible channel data during the day and GOES-11 10.7 µm IR channel data at night (above; click image to play animation) show how the Mesoscale Convective System over Arizona on 05 July evolved into a Mesoscale Convective Vortex (MCV) on the following morning over the deserts of southern California, as the cirrus canopy of the convective system eroded to reveal the mid-level circulation. The MCV then appeared to play a role in helping to initiate new convective activity over California later in the afternoon on 06 July.

AWIPS image comparison from 18:00 UTC on 06 July

MCVs maintain their structure through the release of latent heat associated with condensation when clouds form and especially when precipitation forms. This release of heat alters the stability of the atmosphere, inducing the formation of a cyclonic potential vorticity anomaly. MCVs erode when they encounter high wind shear.

An AWIPS image comparison (above) shows GOES visible channel data (the seam in the middle of the images demarcates data from GOES-11 or GOES-West and GOES-13 or GOES-East; note that the older GOES-11 data is darker because of the age and degradation of that satellite’s visible sensors), GOES 10.7 µm IR channel data, the Blended Total Precipitable Water (TPW) Percent of Normal product, and 850-300 hPa layer wind shear from the GFS and RUC models. In the present example, the MCV exists in an axis of low values of 850-300 hPa wind shear, as noted by model forecasts from the RUC and from the GFS. Abnormally high values of precipitable water are also present, exceeding 200% of normal according to the ‘Blended Product’ that combines observations from the GOES Sounder and ground-based GPS stations. Rawinsonde reports from Phoenix (00 UTC and 12 UTC on 06 July) and from Yuma (12 UTC and 14 UTC on the 06 July) show abundant moisture and relatively low shear. All of these data show environmental conditions that support MCVs.

GOES-11 Sounder TPW and LI derived product images

In the pre-convective environment across southern Arizona on 05 July, GOES-11 Sounder derived product images (above) showed Total Precipitable Water (TPW) values in the 40-50 mm (1.6 to 2.0 inch) range, and Lifted Index (LI) values as low as -5º to -8º C.

MODIS 11.0 µm IR image + negative and positive cloud-to-ground lightning strikes

As the MCS continued to move westward across Arizona, an AWIPS image of 1-km resolution MODIS 11.0 µm IR data at 05:33 UTC (above) showed cloud top IR brightness temperatures as cold as -72º C (black color enhancement), along with numerous negative and positive cloud-to-ground lightning strikes. At that time, the thunderstorm outflow winds were moving through Blythe, California (station identifier KBLH) producing wind gusts of 46 knots (52 mph) with a reduction in visibility to 1.5 miles, and also through Yuma, Arizona (station identifier KNYL) producing wind gusts of 40 knots (46 mph) with a reduction in visibility to 1.25 miles.

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

McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) revealed numerous pyrocumulus clouds and large areas of very dense smoke associated with the “Honey Prairie Fire” in the Okefenokee Swamp area of southeastern Georgia on 20 June 2011. The shadows cast by the pyrocumulus towers almost resembled those cast by overshooting tops which are often seen on the anvil tops of severe thunderstorms.

A sequence of 3 AWIPS images of POES AVHRR 0.63 µm visible channel data (below) offered a larger-scale view of the smoke as it drifted eastward across the adjacent offshore waters of the Atlantic Ocean. The shadow cast by a pyrocumulus tower could be seen on the final 21:22 UTC image. As expected, this dense smoke plume exhibited very high Aerosol Optical Depth (AOD) values (see the US Air Quality “Smog Blog” and the NOAA IDEA sites for AOD imagery).

POES AVHRR 0.63 µm visible channel images

The 21:22 UTC POES AVHRR 10.8 µm IR image (below) showed that the coldest cloud top IR brightness temperatures at that time were -18º C, which corresponded to an altitude of nearly 24,000 feet using the interactive Skew-T diagram with data from the rawinsonde report from Charleston, South Carolina.

POES AVHRR 10.8 µm IR image + interactive Skew-T for Charleston SC rawinsonde

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On the following day (21 June 2011) the winds were much lighter across the region, so the smoke was not being transported as far eastward over the Atlantic Ocean. In fact, GOES-13 0.63 µm visible channel images (below; click image to play animation) showed that significant amounts of the smoke remained just offshore — so when a sea breeze front began to move inland during the afternoon hours, much of this smoke was brought back inland. For example, at St. Augustine, Florida (surface identifier KSGJ), the surface visibility dropped from 10 miles to 0.75 mile after the surface winds shifted to easterly behind the sea breeze front.

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

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A sequence of 250-meter resolution MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below; displayed using Google Earth) showed varying regimes of transport of the thick smoke on 19 June, 20 June, 21 June, and 22 June 2011.

MODIS true color RGB images (displayed using Google Earth)