Winter weather « CIMSS Satellite Blog

Unusual late-season Nor’easter

May 26th, 2013

GOES-14 6.5 µm water vapor channel images (click image to play animation)

An unusual late-season nor’easter storm produced heavy rainfall (as much as 6.14 inches at Whiting, Maine) and heavy snow (as much as 13.4 inches at Mount Mansfield in Vermont and 34 inches at Whiteface Mountain, New York) during the 24 May – 26 May 2013 period. McIDAS images of GOES-14 6.5 µm water vapor channel data (above; click image to play animation) displayed some interesting storm structures during the 25-26 May timeframe.

AWIPS images of the MIMIC Total Precipitable Water product (below; click image to play animation) showed that a long atmospheric river was transporting abundant tropical moisture northward, which was then wrapping inland around the storm circulation.

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

A comparison of 1-km resolution Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR channel images at 05:52 UTC or 1:52 AM local time on 26 May (below) showed cloud features associated with the storm as it was centered just off the coast of Maine. Strong northerly/northwesterly winds along the back side of the storm (gusting as high as 102 mph at Mt. Washington, New Hampshire) were producing bands of orographic waves clouds over parts of Vermont and New York. This example helps to highlight the “visible image at night” capability of the VIIRS Day/Night Band (given ample illumination by moonlight).

Suomi NPP VIIRS 0.7 µm Day/Night Band abd 11.45 µm IR channel images (with overlay of surface analysis)

Posted in GOES-14, Heavy rain / flooding, Suomi NPP, VIIRS, Winter weather | No Comments »

Record snowfall in Rapid City, South Dakota

April 10th, 2013

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

A late-season winter storm brought heavy snowfall to much of the central US — Rapid City, South Dakota (station identifier RAP) set records that included 20.0 inches on 09 April 2013 (most snowfall on a calendar day) and 28.2 inches on 08 April – 10 April (greatest muti-day snowfall). McIDAS images of 4-km resolution GOES-13 6.5 µm water vapor channel data covering the 08 April – 10 April period (above; click image to play animation; also available as a QuickTime movie) showed the development of several convective elements that helped to enhance snowfall rates as they moved northward across the region on 09 April, as well deformation bands that formed as the circulation of the upper-level low slowly migrated over western South Dakota and western Nebraska on 10 April.

An AWIPS image of 1-km resolution MODIS 0.65 µm visible channel data (below) showed some of the convective elements responsible for producing a period of heavy snow at Rapid City on 09 April. Large thunderstorms were also seen at the time over notheastern Nebraska and southeastern South Dakota.

MODIS 0.65 µm visible channel image

A surface meteorogram (below) shows the conditions at Rapid City Regional Airport during the 08-10 April period.

Surface meteorogram for Rapid City Regional Airport

===== 12 April Update =====

Widespread cloudiness masked a good view of the areal extent of the resulting snow cover across South Dakota, but farther to the south over Nebraska and far northern Kansas an AWIPS comparison of 1-km resolution Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images (below) showed interesting detail in a number of mesoscale bands of snow cover. Snow appears as white on the visible image, and as darker shades of red on the RGB image; supercooled water droplet clouds are lighter shades of white, while ice crystal clouds appear as shades of pink on the false-color image.

Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue image

Posted in General interpretation, GOES-13, MODIS, Red/Green/Blue (RGB) images, Suomi NPP, VIIRS, Winter weather | No Comments »

Historic blizzard affects parts of Texas, Oklahoma, and Kansas

February 26th, 2013

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

A powerful winter storm brought historic snowfall amounts and widespread blizzard conditions to parts of Texas, Oklahoma, and Kansas during the 25 February – 26 February 2013 period (see additional information from the NWS forecast offices at Amarillo TX, Norman OK, Dodge City KS, Wichita KS, and Topeka KS). AWIPS images of 4-km resolution GOES-13 6.5 µm water vapor channel images (above; click image to play animation) showed the evolution of the storm system on 25 February, which included the development of well-defined dry slot and comma head signatures.

A comparison of 1-km resolution MODIS 0.65 µm visible channel, 11.0 µm IR channel, and 6.7 µm water vapor channel images (below) revealed a snapshot of the storm at 20:00 UTC or 3 PM local time on 25 February. A line of deep convection exhibiting cold cloud top temperatures extended from the Gulf of Mexico northward into Missouri, which produced large hail, damaging winds, and a tornado (SPC storm reports).

MODIS 0.65 µm visible, 11.0 µm IR, and 6.7 µm water vapor channel images

Very strong winds were associated with this storm, which created a large area of blowing dust across southwest Texas and southeastern New Mexico on 24 February — and GOES-13 0.63 µm visible channel images (below; click image to play animation) revealed additional areas of blowing dust across drought-stricken areas of southern Texas on 25 February, where winds gusted as high as 56 mph and visibilities were reduced to 1 mile or less in some locations (see NWS Brownsville TX summary).

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

During the following overnight hours the clouds had cleared across the Texas panhandle region, which allowed the Suomi NPP VIIRS 0.7 µm Day/Night Band (below) to provide a “visible image at night” (aided by bright illumination from the “full snow moon”) to display the areal extent of the fresh snow cover at 08:38 UTC or 3:38 AM local time. While the deep snow pack appeared somewhat colder on the corresponding VIIRS 11.45 µm IR image, the exact edges of the snow cover were easier to see on the Day/Night Band image.

Suomi NPP VIIRS 0.7 µm Day/Night Band and 11.45 µm IR images

During the afternoon hours on 26 February, a comparison of the Suomi NPP VIIRS 0.64 µm visible channel image with the corresponding false-color Red/Green/Blue (RGB) image at 20:02 UTC or 3:02 PM local time (below) aided in the discrimination between snow cover (varying shades of darker red on the RGB image) and supercooled water droplet cloud features (lighter shades of white). Glaciated (ice crystal) cloud features exhibit a lighter pink appearance in the RGB image.

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

Posted in Air quality, GOES-13, Google Earth, MODIS, Red/Green/Blue (RGB) images, Suomi NPP, VIIRS, Winter weather | No Comments »

Development of an intense winter storm off the US East Coast

February 8th, 2013

POES AVHRR 0.86 µm, MODIS 0.65 µm, and Suomi NPP VIIRS 0.64 µm visible channel images

A winter storm began to intensify just off the East Coast of the US on 08 February 2013. A sequence of 1-km resolution POES AVHRR 0.86 µm, MODIS 0.65 µm, and Suomi NPP VIIRS 0.64 µm visible channel images (above) revealed the formation of gravity waves in the lower-tropospheric cloud field within the southwest quadrant of the area of low pressure (corresponding IR images).

GOES-13 4-km resolution 6.5 µm water vapor channel images (below; click image to play animation) showed a very well-defined dry slot and the development of a distinct comma head. Strong northwesterly winds were also causing mountain waves to the lee of the Appalachians.

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

The MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) showed TPW values as high as 48 mm or 1.9 inches being drawn northward into the intensifying low.

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

Similarly, the Blended Total Precipitable Water product (below; click image to play animation) also showed high values of TPW (up to 36 mm or 1.4 inches) off the Virginia/North Carolina coast as the low was intensifying.

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

These TPW values were in excess of 200% of normal for this region and this time of year (below; click image to play animation).

Percent of Normal TPW product (click image to play animation)

A MODIS 11.0 µm IR image at 03:04 UTC on 09 February (10:04 PM local time on 08 February) revealed a distinct hook-shaped pattern to the cloud features near the storm center as it continued to intensify (below). Peak wind gusts at this time were 58 knots at Nantucket and 54 knots at Boston.

MODIS 11.0 µm IR image with overlays of surface/buoy resports and surface analysis

===== 09 February Update =====

MODIS 0.65 µm visible image with surface/buoy reports and surface analysis

As the storm was nearing peak intensity on the morning of 09 February 2013, the formation of a tight circulation around its center was becoming evident in 1-km resolution visible channel images with overlays of surface data from MODIS at 15:06 UTC (above) and VIIRS at 17:01 UTC (below).

Suomi NPP VIIRS 0.64 µm visible image with surface/buoy reports

A 250-meter resolution MODIS true-color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below; displayed using Google Earth) showed the locations of maximum snowfall totals for select states (which included 40.0 inches at Hamden, Connecticut), as well as some of the maximum wind gusts (which included 83 mph at Cuttyhunk, Massachusetts).