GOES-14 SRSOR: Dissipation of river valley fog

August 20th, 2014
GOES-14 0.63 µm visible channel images, at 15 vs 5 vs 1-minute intervals (click to play Animated GIF)

GOES-14 0.63 µm visible channel images, at 15 vs 5 vs 1-minute intervals (click to play Animated GIF)

The GOES-14 satellite was in Super Rapid Scan Operations for GOES-R (SRSOR) mode, providing images at 1-minute intervals over the central US on 20 August 2014; an animation of 0.63 µm visible channel images (Animated GIF | MP4 movie | YouTube) showed the dissipation of river valley fog that had formed during the previous night over the Mississippi River and adjacent portions of southwestern Wisconsin, southeastern Minnesota, and northeastern Iowa. The 3 panels show images every 15 minutes (today’s current routine schedule), every 5 minutes (available during Rapid Scan Operations), and every 1 minute (which will be available from the ABI instrument on the next-generation GOES-R satellite).

Along the Wisconsin River valley, fog restricted the surface visibility to 0.15 mile at Prairie Du Chien KPDC and Boscobel KOVS, and 0.25 mile at Lone Rock KLNR (images with map and station location overlays).

GOES-14 SRSOR: Fog Dissipation over Pennsyvlania

August 18th, 2014
GOES-14 0.63 µm visible channel images (click to play animation)

GOES-14 0.63 µm visible channel images (click to play animation)

GOES-14 is in special SRSO-R operations that provides 1-minute imagery, allowing a compelling look at the dissipation of valley fog over Pennsylvania this morning. This animation is also available as a YouTube video, or as an mp4.

A description of the detection of the fog development overnight can be found on the CIMSS Fog Blog.

GOES-14 SRSOR: from morning fog/stratus to afternoon convection

May 13th, 2014
Suomi NPP VIIRS and POES AVHRR IR brightness temperature difference

Suomi NPP VIIRS and POES AVHRR IR brightness temperature difference “fog/stratus product” images

An AWIPS comparison of nighttime Suomi NPP VIIRS and POES AVHRR IR brightness temperature difference “fog/stratus product” images (above) exhibited signals of fog and/or stratus forming in river valleys straddling the West Virginia and Virginia border on 13 May 2014.

The GOES-14 satellite continued to be operated in Super Rapid Scan Operations for GOES-R (SRSOR) mode, providing images at 1-minute intervals. Early morning 0.63 µm visible channel images (below; click image to play an MP4 animation; also available as a QuickTime movie) showed the narrow fingers of river valley fog/stratus, which began to burn off as heating and mixing increased during the morning hours. There was then a rapid transition to the formation of cumulus clouds across the region, some of which became organized areas of deep convection that produced hail and damaging winds (SPC storm reports).

GOES-14 0.63 µm visible channel images (click to play MP4 animation)

GOES-14 0.63 µm visible channel images (click to play MP4 animation)

A 3-panel comparison showing the difference between standard or routine 15-minute interval, 5-7 minute interval Rapid Scan Operations (RSO), and 1-minute interval SRSO GOES-14 0.63 µm visible channel images (below; click image to play an MP4 animation; also available as a very large Animated GIF) demonstrated the clear advantage of higher temporal resolution for monitoring the rate of dissipation of river valley fog/stratus features, as well as subsequent convective initiation and development.

GOES-14 0.63 µm visible channel images: Standard, RSO, and SRSOR scan strategies (click to play MP4 animation)

GOES-14 0.63 µm visible channel images: Standard, RSO, and SRSOR scan strategies (click to play MP4 animation)

Consecutive overpasses of the Suomi NPP satellite provided a look at the rapid rate of convective cloud development on VIIRS 0.64 µm visible channel images (below).

Suomi NPP VIIRS 0.64 µm visible channel images, with surface observations and frontal boundaries

Suomi NPP VIIRS 0.64 µm visible channel images, with surface observations and frontal boundaries

On a 18:59 UTC MODIS 11.0 µm IR channel image (below), the coldest cloud-top IR brightness temperature was -78º C near the West Virginia/Virginia border.

MODIS 11.0 µm IR channel image

MODIS 11.0 µm IR channel image

Fog and stratus along the California coast

March 14th, 2014

In their Area Forecast Discussion issued at 11:57 UTC or 4:57 AM local time on 14 March 2014, the NWS San Francisco/Monterey Bay Area forecast office mentioned the Suomi NPP VIIRS Day/Night Band imagery which showed the coverage of coastal fog in their area of responsibility:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
457 AM PDT FRI MAR 14 2014

.DISCUSSION...AS OF 4:10 AM PDT FRIDAY...THE DRY TAIL END OF A
WEATHER SYSTEM MOVING IN TO THE PACIFIC NORTHWEST IS APPROACHING
OUR DISTRICT...AND RESULTING IN ENHANCEMENT OF THE MARINE LAYER
AND A RETURN OF THE MARINE STRATUS. LATEST GOES FOG PRODUCT
IMAGERY...AND IN RATHER SPECTACULAR DETAIL JUST REC`D SUOMI VIIRS
NIGHTTIME HIGH RES VISUAL IMAGE...SHOW COVERAGE ALONG MUCH OF THE
COAST FROM PT REYES SOUTH TO THE VICINITY OF THE MONTEREY
PENINSULA...AND A BROAD SWATH EXTENDING INLAND ACROSS SAN
FRANCISCO AND THROUGH THE GOLDEN GATE TO THE EAST BAY. LATEST
BODEGA BAY AND FT ORD PROFILER DATA INDICATE A MARINE LAYER DEPTH
OF ABOUT 1300 FT. SOME THIN HIGH CLOUDS ARE ALSO PASSING THROUGH ABOVE.

A comparison of AWIPS images of the Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) and the corresponding 11.45-3.74 µm IR brightness temperature difference (BTD) “fog/stratus product” (below) showed this band of fog and stratus at 09:39 UTC or 2:39 AM local time. With ample illumination by moonlight (the Moon was in the Waxing Gibbous phase, at 97% of full), the DNB image served as a “visible image at night” to help highlight the fog/stratus features along the coast. Farther inland over the eastern portion of the satellite scene, the bright signature of deep snow cover in the higher elevations of the Sierra Nevada was also very evident on the DNB image.

Suomi NPP VIIRS 0.7 µm Day/Night Band and IR BTD "Fog/stratus product" images

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

A sequence of three 1-km resolution IR BTD images (below) — Terra MODIS at 06:33 UTC, Suomi NPP VIIRS at 09:39 UTC, and Aqua MODIS at 10:44 UTC — offered detailed views of the inland progression of the fog/stratus features, especially in the San Francisco Bay area and also down the Salinas Valley. The appearance of degraded resolution of the features seen on the 10:44 UTC MODIS image is due to the so-called “bow-tie effect” near the edge of a MODIS scan swath — even with a bow-tie correction algorithm applied, the MODIS images tend to look less crisp and clear along the scan edges.

Terra MODIS, Suomi NPP VIIRS, and Aqua MODIS IR BTD "fog/stratus product" images

Terra MODIS, Suomi NPP VIIRS, and Aqua MODIS IR BTD “fog/stratus product” images

A GOES-R “Cloud Thickness – Highest Liquid Cloud Layer” product created using GOES-15 data (below; click image to play animation) showed the southward advancement of the band of fog/stratus during the overnight hours. The maximum thickness displayed was in excess of 1200 ft (lighter cyan color enhancement), which agreed well with the profiler depths mentioned in the NWS forecast discussion above.

GOES-15 Cloud Thickness product (click to play animation)

GOES-15 Cloud Thickness product (click to play animation)

Additional GOES-R products such as Marginal Visual Flight Rules (MVFR), Instrument Flight Rules (IFR), and Low Instrument Flight Rules (LIFR) Probability are shown below. These products help to better quantify the potential aviation impacts that features seen on the conventional BTD “fog/stratus product” might have.

GOES-15 MVFR Probability product (click to play animation)

GOES-15 MVFR Probability product (click to play animation)

GOES-15 IFR Probability product (click to play animation)

GOES-15 IFR Probability product (click to play animation)

GOES-15 LIFR Probability product (click to play animation)

GOES-15 LIFR Probability product (click to play animation)

For additional information on this event, see the GOES-R Fog Product Examples blog.