“Southerly surge” of stratus along the coast of California

April 22nd, 2013
GOES-15 0.63 µm visible channel images (click image to play animation)

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

McIDAS images of GOES-15 0.63 µm visible channel data (above; click image to play animation) revealed a well-defined “southerly surge” of stratus clouds, which were moving northward along the coast of the Big Sur region of central California on 22 April 2013.

AWIPS images of the GOES-R Marginal Visual Flight Rules (MVFR) product algorithm applied to GOES-15 data (below; click image to play animation) showed the northward progression of the narrow band of stratus clouds, as a mesoscale reversal in the boundary layer winds just off the coast (from northerly, to southerly) was seen in the buoy data.

GOES-15 Marginal Visual Flight Rules (MVFR) Probability product (click image to play animation)

GOES-15 Marginal Visual Flight Rules (MVFR) Probability product (click image to play animation)

A 1-km resolution MODIS 11-3.7 µm IR brightness temperature difference (BTD) “fog/stratus product” image at 05:34 UTC or 10:34 PM local time (below) showed the initial stages of the southerly surge stratus cloud feature, in the Santa Barbara Channel north of the Channel Islands off the coast of southern California (and south of Point Conception). Farther offshore, the BTD image also displayed a well-defined eddy and a few ship tracks embedded within the marine boundary layer stratus clouds.

MODIS IR brightness temperature difference

MODIS IR brightness temperature difference “fog/stratus product”

Several hours later, a 1-km resolution Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) image at 09:56 UTC or 2:26 AM local time (below) indicated that the leading edge of the southerly surge stratus cloud feature had moved to the north of Point Conception. This demonstrates that the VIIRS DNB can provide a “visible image at night”, given sufficient illumination by the Moon (or other light sources). On this night the Moon was in the waxing gibbous phase, at 95% full.

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Suomi NPP VIIRS 0.7 µm Day/Night Band image

A Suomi NPP VIIRS 0.64 µm visible channel image at 21:13 UTC or 2:13 PM local time (below) showed leading edge of the southward surge stratus feature as it was curving eastward into the Monterey Bay area. Not far to the north, San Francisco reached a record high temperature of 83º F.

Suomi NPP VIIRS 0.64 µm visible channel image

Suomi NPP VIIRS 0.64 µm visible channel image

===== 23 April Update =====

A comparison of 1-km resolution Suomi NPP VIIRS 0.7 µm Day/Night Band and IR brightness temperature difference (BTD) “Fog/stratus product” images at 09:28 UTC or 2:29 AM local time (below) showed that the leading edge of the southerly surge stratus clouds had progressed just to the north of Point Reyes. Once again, the BTD image revealed the presence of cloud eddies and ship tracks within the marine boundary layer stratus clouds.

Suomi NPP VIIRS 0.7 µm Day/Night Band and IR brightness temperature difference

Suomi NPP VIIRS 0.7 µm Day/Night Band and IR brightness temperature difference “Fog/stratus product” images

 

Earth Day 2013

April 22nd, 2013
Global composite of geostationary IR images at 12:00 UTC (click image to play animation)

Global composite of geostationary IR images at 12:00 UTC (click image to play animation)

In honor of Earth Day, we offer a glimpse of the cloud cover across the planet, using a rotating global composite of geostationary IR images (data from the GOES-East, GOES-West, Meteosat, and MTSAT satellites) at 12:00 UTC on 22 April 2013 (above; click image to play animation). The most recent rotating global IR composite (updated every 3 hours) can be seen here.

lobal composite of IR imagery, land surface temperature, and sea surface temperature (click image for most recent animation)

Global composite of IR imagery, land surface temperature, and sea surface temperature (click image for most recent animation)

Other global satellite image composites created at SSEC include IR, surface air temperature, and sea surface temperature (above; click image for most recent animation) and water vapor channel  imagery (below; click image for most recent animation).

Global composite of water vapor imagery (click image for most recent animation)

Global composite of water vapor imagery (click image for most recent animation)

The effect of heavy precipitation on rivers in Illinois

April 21st, 2013
Total observed precipitation during the 07-21 April 2013 period

Total observed precipitation during the 07-21 April 2013 period

The middle part of April 2013 brought periods of very heavy rainfall to portions of Illinois and the Upper Midwest region, with many areas receiving 5-7 inches of rainfall. A map of the 14-day total observed precipitation during the 07-21 April period (above) shows the widespread distribution of the heavy rainfall, which was 4-5 inches above normal and 300-400% of normal at many locations for this time of the year. Additional information can be found at the NWS Chicago and NWS Lincoln sites.

The effect of this heavy rainfall was very apparent in a before (05 April) and after (21 April) comparison of 250-meter resolution MODIS false-color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below) — obvious changes can be seen in the width of sections of the Illinois River (which runs fron northeast through southwest across the center of the images) and many of its tributaries. 138 river gauges were reporting moderate to major flooding levels on 21 April.

MODIS false-color Red/Green/Blue (RGB) images from 05 April and 21 April 2013

MODIS false-color Red/Green/Blue (RGB) images from 05 April and 21 April 2013

AWIPS image comparisons of the standard 0.64/0.65 µm visible channel with the corresponding 0.86 µm visible channel from the VIIRS and MODIS instruments (below) show that the 0.86 µm imagery can be useful for helping to monitor the areal coverage of significant water inundation following heavy rainfall events such as this. Rivers, lakes, and flooded areas show up as darker features on the 0.86 µm images.

Suomi NPP VIIRS 0.64 µm visible and 0.86 µm visible channel images

Suomi NPP VIIRS 0.64 µm visible and 0.86 µm visible channel images

MODIS 0.65 µm (Band 1) visible channel and 0.86 µm (Band 2) visible channel images

MODIS 0.65 µm (Band 1) visible channel and 0.86 µm (Band 2) visible channel images

Satellite signatures of the West, Texas fertilizer plant explosion

April 18th, 2013
GOES-13 3.9 µm shortwave IR image

GOES-13 3.9 µm shortwave IR image

A powerful and deadly explosion at a fertilizer plant in the city of West, Texas occurred on the evening of 17 April 2013. A thinning of the layered cloudiness across the region allowed the 4-km resolution GOES-13 3.9 µm shortwave IR channel image (above) to reveal a subtle “hot spot” (yellow color enhancement) signature of the large fire that burned into the night.

Shown below is a comparison of  images from the Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) at 08:00 UTC or 3:00 AM local time on 17 April (the night before the explosion) and 07:41 UTC or 2:41 AM local time on 18 April (the night after the explosion). The 18 April DNB image appears to display a brighter signal in the West, Texas area (circled), although it is unclear whether this brighter signal on the later Day/Night Band image is due to the fire, or the large amount of emergency response activity, or some combination of the two factors. The presence of optically-thick cloud layers across the region may also be playing a role in the apparent West, Texas brightness differences sensed by the DNB detectors; this effect is very notable in the city light signature of the Dallas/Ft.Worth area in the upper center portion of the 2 images.

 

Night-time Suomi NPP VIIRS Day/Night Band images on 17 April and 18 April

Night-time Suomi NPP VIIRS Day/Night Band images on 17 April and 18 April