Suomi NPP VIIRS 0.7 µm Day/Night Band, IR BTD “Fog/Stratus Product”, and 11.45 µm IR images

Parts of Kansas received up to 5-6 inches of snowfall on 18 October 2013 (NWS Local Storm Reports). The following night, after the clouds associated with the storm system had moved eastward, the southwest-to-northeast oriented bands of snow cover could be clearly seen on an AWIPS image of Suomi NPP VIIRS 0.7 µm Day/Night Band data at 08:33 UTC or 3:33 AM local time (above). Due to ample illumination from a Full Moon, the bands of fresh snow appeared quite bright, as did the back edge of the stratus cloud deck that covered far eastern Kansas and western Missouri (which showed up well on the IR brightness temperature difference “fog/stratus product” image). A thin patch of mid-level clouds was also moving over north-central Kansas — the 11.45 µm IR brightness temperatures of that cloud feature were generally warmer than -20º C (cyan color enhancement).

After sunrise on the next day (19 October), GOES-13 0.63 µm visible channel images (below; click image to play animation) showed that the bands of snow cover melted rather quickly, due to the relatively high October sun angle.

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

View only this post Read Less

MTSAT-2 visible channel (left) and shortwave IR channel (right) images (click to play animation)

Numerous bush fires began to burn in state of New South Wales near Sydney, Australia on 16-17 October 2013. On a comparison of MTSAT-2 visible channel and shortwave IR channel images (above; click image to play animation) some of the southeastward-drifting smoke plumes were evident on the visible images, while numerous fire “hot spots” (dark black pixels) could be seen on the shortwave IR images. Toward the end of the animation (06:32 UTC on 17 October), the hot fire pixels grew in areal coverage as winds increased in association with a cold frontal passage.

A 48-hour plot of surface data for Sydney Airport (below) showed that smoke reduced the surface visibility to 4-5 miles for several hours on 17 October. Prior to the passage of the cold front, surface air temperatures were unseasonably hot (in the middle 90s F), with wind gusts as high as 38 knots. In addition, note the sharp drop in dew point temperature to -2º F at 04 UTC on 17 October.

Plot of Sydney Airport surface meteorolofical data

A 250-meter resolution Aqua MODIS true color image from the NASA EOSDIS Worldview site (below) offers a closer view of the smoke plumes in the Sydney area.

Aqua MODIS true color image

View only this post Read Less

MTSAT-2 10.8 µm IR channel images (click to play animation)

McIDAS images of MTSAT-2 10.8 µm IR channel data (above; click image to play animation) showed the center of Typhoon Wipha moving just southeast of Japan on 15 October 2013. The asterisk at the center of the images denotes the location of Tokyo Narita International Airport — many areas in the Tokyo region received very heavy rainfall which caused flooding and mudslides. At Izu Oshima island just south of Tokyo, rainfall rates were as high as 11.8 mm (4.7 inches) per hour, with a 24-hour rainfall total of 824.9 mm (32.5 inches).

AWIPS images of the MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) revealed the large amount of tropical moisture that was transported northward toward Japan as Wipha began its poleward recurvature. At the end of the animation Wipha began its extratropical transition as it merged with a cold front that was exiting Asia and beginning to move southeastward across the North Pacific Ocean.

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

View only this post Read Less

GOES-15/GOES-13 6.5 µm water vapor channel images (click to play animation)

Flooding rains have occurred over south Texas during the past two days, and the animation of GOES water vapor imagery, above, and of MIMIC Total Precipitable Water, below, shows two airstreams moving moisture into that region. The GOES-15/GOES-13 Water Vapor image animation, above, shows upper-level moisture moving in from the tropical Pacific south of Mexico (much of it likely outflow from Tropical Storm Octave). MIMIC Total Precipitable Water animation (available from this site), below, shows a concomitant lower-level moisture source, the Gulf of Mexico. Plots at 925 mb, and 850 mb, show moist, easterly flow around a High centered over the mid-Mississippi valley. As a result, total precipitable water values exceeded 200% of normal over a wide region. (Blended Total Precipitable Water products are available here). The high values of Total Precipitable Water persist into the day on 14 October. (Link, analysis from SPC).

MIMIC Total Precipitable Water (click to play animation)

VIIRS 11.45 µm IR image (click to enlarge)

A Suomi-NPP VIIRS 11.45 µm IR image from late in the day on 13 October (above) showed strong convection near Laredo, TX, with very cold cloud tops (brightness temperature values over Mexico are as cold as -92º C!). Applying a different color enhancement, a comparison of this 1-km resolution VIIRS IR image at 20:11 UTC with the corresponding 4-km resolution GOES-13 10.7 µm IR image (below) highlights two advantages of polar orbiter imagery over geostationary imagery: (1) with the higher spatial resolution, the magnitude of the coldest overshooting cloud tops can be assessed: the -92º C minimum cloud-top IR brightness temperature on the VIIRS image was 14º C colder than the -78º C value seen on the GOES-13 image, and (2) with the minimal parallax error of polar orbiter imagery, the exact location of such cloud-top features can be more accurately determined.

Suomi NPP VIIRS 11.45 µm IR and GOES-13 10.7 µm IR channel images

The result of the strong convection near 2100 UTC, and from other convection apparent in the water vapor animation at top, was a broad region of heavy rains, (obtained from this site) shown below. Some of these rains fell over regions of Texas in drought (as shown here), so where damage was minimal, the heavy rains could be considered beneficial.

24-hour precipitation over Texas valid 1200 UTC 14 October from this site (click to enlarge)

View only this post Read Less