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

AWIPS images of 4-km resolution GOES-13 6.5 µm water vapor channel data (above; click image to play animation) showed the middle-tropospheric circulation and cloud features associated with the large storm system which brought heavy snow, heavy rainfall, and severe thunderstorms to much of the central US on 03 February – 04 February 2012. Snowfall amounts included 51.1 inches at Pinecliffe, Colorado, 26.0 inches at Laramie, Wyoming, 17.0 inches at Tyron, Nebraska, and 11.5 inches at Cumberland, Iowa.

Denver received 15.9 inches of snow during 02/03/04 February, setting a new 3-day record accumulation for the month of February. Boulder also set a new single-storm snowfall record, with 22.7 inches of snowfall (NWS Denver/Boulder CO storm summary).

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

As the storm departed, a comparison of AWIPS images of 1-km resolution POES AVHRR 0.63 µm visible channel and 3.74 µm shortwave IR data (above) at 15:06 UTC (8:06 am local time) on 04 February showed that some low clouds persisted across much of northeastern Colorado, backed up against the highest terrain of the Continental Divide in some places. The low clouds showed up as darker gray features on the shortwave IR image, due to the sensitivity of reflection of solar radiation off of cloud top supercooled water droplets at the 3.74 µm wavelength.

At 17:47 UTC (10:47 am local time), a comparison of AWIPS images of 1-km resolution MODIS 0.65 µm visible channel data with the corresponding MODIS false-color Red/Green/Blue (RGB) image (created using MODIS channel 01/07/07 as the red/green/blue components of the image) indicated that most of the low clouds (which appeared as varying shades of white on the false-color image) had dissipated, revealing a good deal of the snow cover (which appeared as darker shades of red on the false-color image). A few streaks of high-level cirrus clouds could also be seen over the snow cover. Bare ground appeared cyan on the false-color image.

MODIS 0.65 µm visible channel + False-color Red/Green/Blue (RGB) images

About 2 hours later, a more detailed example of using false color images to discriminate between snow cover and supercooled water droplet clouds can be seen with a 375-meter resolution Suomi NPP VIIRS Red/Green/Blue (RGB) image (below), created using Band I1 (0.64 micrometer visible) as the red component and Band I3 (1.61 micrometer near-IR) as the green and blue components of the image.

Suomi NPP VIIRS false color RGB image

Farther to the east and south, heavy rainfall amounts included 9.30 inches at Romayer, Texas, 5.69 inches at Alexandria, Louisiana, and 4.34 inches at Medicine Lodge, Kansas. Wichita, Kansas received 2.86 inches of rain — the wettest February day on record at that location. Severe thunderstorms produced one tornado and hail up to 2.0 inches in diameter in Texas (SPC storm reports). A McIDAS image of 375-meter resolution Suomi NPP VIIRS 11.45 µm IR channel data (below) showed very intricate detail to the cloud top IR brightess temperature structure associated with strong thunderstorms producing heavy rainfall and flash flooding across the Interstate 35 corridor in the Austin/San Antonio, Texas region during the pre-dawn hours on 04 February. VIIRS IR brightness temperatures were as cold as -81º C with the far southwestern storm — and rare “warm trench” signatures (a ring of warmer cloud top temperatures surrounding a well-defined cold overshootng top) were seen associated with the 2 storms located near Austin-Bergstrom International airport (KAUS) and Houston County Airport (KDKR).

Suomi NPP VIIRS 11.45 µm IR image + Station locations and Interstate highways

===== 05 February Update =====

A large portion of the resulting swath of snow on the ground across parts of Wyoming, Colorado, Nebraska, and Kansas could be seen on a 250-meter resolution MODIS true color RGB image from the SSEC MODIS Today site (below, viewed using Google Earth) at 20:17 UTC on 05 February 2012.

MODIS true color image (viewed using Google Earth)

1-day observed precipitation for 25 and 26 January 2012

Maps of the 1-day total precipitation for 25 January and 26 January 2012 (above) showed that much of Texas and Oklahoma received several inches of rainfall during that 48 hour period.

AWIPS images of the MODIS 0.65 µm visible channel and the corresponding  MODIS Land Surface Temperature (LST) product (below) revealed a large swath of rain-cooled ground across much of that region. LST values where heavy rain fell were in the 60s F (yellow to light orange color enhancement), in contrast to LST values in the 70s and 80s F (darker orange to red color enhancement) to the north and the to the south of the rain-cooled areas.

MODIS 0.65 µm visible chanel image + MODIS Land Surface Temperature product

MTSAT-1R 10.8 µm IR images (click image to play animation)

MTSAT-1R 10.8 µm IR images from the CIMSS Tropical Cyclones site (above; click image to play animation) showed a fairly compact cluster of cold convective cloud tops associated with Tropical Storm Washi as it moved westward toward the Philippines during the 15-16 December 2011 period.

A closer view using MIMIC microwave imagery (below) also showed a relatively small area of enhanced brightness temperatures (representing heavy precipitation) crossing Mindanao Island in the southern Philippines on 16 December.

MIMIC microwave imagery

However, AWIPS images of the MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) revealed that Tropical Storm Washi was embedded within a long fetch of very rich tropical moisture, with TPW values in excess of 60 mm or 2.4 inches (darker red color enhancement). This abundance of moisture helped to fuel over 10 hours of heavy rainfall, which resulted in widespread flash flooding and reports of over 900 deaths in the Philippines.

MIMIC Total Precipitable Water product (click image to play animation)

MODIS true color images: 16 August and 28 August 2011

Heavy rainfall associated with Hurricane Irene included 20.40 inches at Virginia beach, Virginia and 20.00 inches at Jacksonville, North Carolina (HPC summary). Winds gusted as high as 115 mph at Cedar Island, North Carolina. The effects of the heavy rain and strong winds can be seen in a before/after comparison of 250-meter resolution MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (above). On the “before” image (16 August 2011), there was a large smoke plume seen from a fire that was burning in the Great Dismal Swamp area in far southeastern Virginia; on the “after” image (28 August 2011), water turbidity was significantly enhanced due to suspended sediment across the Outer Banks region of North Carolina — and a narrow filament of sediment was being actually being entrained into the flow of the Gulf Stream.

AWIPS images of the corresponding MODIS 0.65 µm visible channel data and the MODIS Sea Surface Temperature (SST) product (below) showed that the enhanced turbidity features seen on the MODIS true color image generally exhibited slightly cooler SST values (in the middle to upper 70s F, blue color enhancement) compares to the waters located closer to the Gulf Stream (SST values in the lower 80s F, darker red color enhancement).

MODIS 0.65 µm visible channel image + MODIS Sea Surface Temperature image

Farther to the north, another before/after MODIS true color image comparison revealed additional areas of sediment being carried off the coast of the Northeast US (below). Also note that there was a great deal of sediment in the Hudson River (perhaps better seen in this 20 August / 29 August comparison).

MODIS true color images: 26 August and 29 August 2011

MODIS 0.65 µm visible channel and 2.1 µm near-IR "snow/ice channel" images

AWIPS images of 1-km resolution MODIS 0.65 µm visible channel and MODIS 2.1 µm near-IR “snow/ice channel” data on 23 June 2011 (above) demonstrated the utility of the snow/ice channel to help highlight areas of potential flooding — because water is a strong absorber at the 2.1 µm wavelength, it appears very dark in the snow.ice images. The Souris River located in north-central North Dakota stands out in the images, along with the Missouri River to the southwest.

A comparison of 250-meter resolution MODIS true color and false color images (below) showed greater detail of the flooded areas on the false color image, as well as the fact that a great deal of sediment was flowing into the Missouri River and even into the western portion of Lake Sakakawea.

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

A comparison between MODIS false color images on 29 June 2010 and 23 June 2011 (below) showed the dramatic change in the Souris River, as well as in the Missouri River southwest of Williston, North Dakota. In June 2011 historic flooding was occurring in the city of Minot along the Souris River.

MODIS false color RGB image comparison: 29 June 2010 vs 23 June 2011

MODIS 0.65 µm visible channel image + MODIS 2.1 µm near-IR "snow/ice channel" image

AWIPS images of MODIS 0.65 µm visible channel data and MODIS 2.1 µm near-IR “snow/ice channel” data (above) demonstrated the utility of the snow/ice channel imagery for highlighting the areal extent of flooding along parts of the lower Mississippi River on 17 May 2011. Water is a strong absorber at the 2.1 µm wavelength, so it appears very dark on the MODIS snow/ice channel image.

CIMSS participation in GOES-R Proving Ground activities includes making MODIS imagery available for National Weather Service forecasters to add to their AWIPS workstations. The VISIT training lesson “MODIS Products in AWIPS” is also available to help users understand the products and their applications to weather analysis and forecasting.

A closer view using 250-meter resolution MODIS true color (using channels 1/4/3) and false color (using channels 7/2/1) MODIS Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below) revealed the darker brown “muddy” appearance of much of the flooded areas adjacent to the Mississippi River, due to high sediment loading of the water. Water exhibited a very dark blue appearance on the MODIS false color image.

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

MIMIC TPW over the eastern Pacific Ocean

Images of MIMIC Total Precipitable Water, above, show moist air emerging from the Intertropical Convergence Zone and streaming north over the western islands of Hawaii.

GOES Imager Water Vapor imagery

GOES-West water vapor imagery (the rocking animation, above) shows the circulation north of the Hawaiian islands that is drawing moisture northward. Because the water vapor channel on the Imager is most accurate at sensing the temperature at the top of the moist layer, however, water vapor imagery can significantly underestimate the amount of water vapor that is in the atmospheric column. The warm temperatures evident over the western Hawaiian Islands (the blue and yellow enhancements) suggest that the water vapor that is emitting radiation sensed by the satellite is warm and confined to lower levels in the atmosphere. Images of Total Precipitable Water give a better indication of how much water vapor is available for precipitation.

Flash flood watches continue through late Tuesday, 10 May, for the western Islands of Hawaii (Oahu, Kauai and Niihau) as the moisture plume continues to drift westward.

The CIMSS MIMIC Total Precipitable Water product is also available for NWS forecast offices to add to their local AWIPS workstations (via Unidata LDM subscription) — a sample animation is shown below. To learn more about the MIMIC TPW product and its applications, a VISIT lesson is also available.

MIMIC Total Precipitable Water product (click image to play animation)

MODIS 0.65 µm visible channel image + MODIS 2.1 µm near-IR "snow/ice channel" image

A comparison of AWIPS images of the 1-km resolution MODIS 0.65 µm visible channel (first shown with a map overlay and location of METAR sites) and the corresponding 1-km resolution MODIS 2.1 µm near-IR “snow/ice channel” (above) shows the areal coverage of flood waters across the region of the confluence of the Mississippi River and the Ohio River on 04 May 2011. Since water happens to be a strong absorber at the 2.1 µm wavelength, it shows up as a very dark feature on the MODIS “snow/ice channel” image — making it more useful for locating areas of flooding than just a simple visible channel image.

A similar near-IR channel will be on the ABI instrument of the future GOES-R satellite. 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.

MODIS True-color imagery from the SSEC MODIS Today website can be used to compare data from this year and last year, shown below. In the linked-to-images, the Mississippi River north of Memphis (located at the bottom edge of each image) meanders through the center part of the images. There are several former meanders of the river in Arkansas and Tennessee that are filled with water this year, but not last.

MODIS true color images (04 May 2010 and 04 May 2011)

MODIS false color image comparison between 11 April and 24 April 2011

A comparison of MODIS false color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (above) shows the increase in areal coverage of flooding along the Red River of the North, from north of Grand Forks, North Dakota into southern Manitoba. Also evident is the melting of most of the snow cover across northeastern North Dakota, and the melting of portions of Devils Lake (snow and ice appear as cyan features on the false color images, while water has a darker blue appearance).

MODIS false color RGB image (displayed using Google Earth)

A MODIS false color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (above; courtesy of Kathy Strabala, CIMSS) showed the areal extent of the unprecedented overland flooding that was occurring along parts of the Red River in North Dakota on 11 April 2011. Spring snow-melt along with recent heavy rainfall were contributing to the flooding. Interstate 29 north of Fargo was closed on the previous day due to rising floodwater covering the roadway.

AWIPS images of 1-km resolution MODIS 0.65 µm visible channel and 2.1 µm near-IR “snow/ice” channel data (below) was also useful for helping to highlight the location of the flooded areas. Both water and frozen lakes appear as very dark features on the 2.1 µm “snow/ice” channel image — but the frozen lakes are brighter white on the visible image.

MODIS 0.65 µm visible image + MODIS 2.1 µm near-IR "snow/ice" image

A comparison of 250-meter resolution MODIS true color and false color RGB images (below) offered a more detailed view of the flooding in the Fargo and Grand Forks areas. The flooded areas exhibited a “muddy” light brown appearance on the true color image. Farther to the west, the still-frozen Devils Lake (whose water level had reached a new record high level) and portions of northeastern North Dakota that still had snow cover (as much as 6 inches remaining on the ground) could also be seen (snow cover and frozen lakes appeared as lighter blue to cyan features on the false color image).

250-meter resolution MODIS true color and false color RGB images