GOES-14 is in Super Rapid Scan Mode

April 18th, 2016

GOES-14 0.62 µm Visible Imagery, 18 April 2016 [click to play animation]

GOES-14 0.62 µm Visible Imagery, 18 April 2016 [click to play animation]

GOES-14 has entered super  rapid scan operations that will continue through 15 May 2016 (Link), in part to support the Hazardous Weather Testbed (HWT) at the Storm Prediction Center (GOES-R HWT Blog) and the VORTEX Southeast experiment. GOES-14 is viewing the central Plains today and tomorrow in anticipation of thunderstorm development. (SPC Day 1 Convective Outlook for 18 April; Day 2 Convective Outlook for 19 April). The visible animation above shows a strong thunderstorm early in the morning on 18 April 2016 near Kerrville TX.

Note that the Twitter Feed @SRSORbot is now active. The bot tweets out 1-hour animations (with 5-minute time steps) every 20 minutes using the latest GOES-14 SRSO-R visible (day) or infrared (night) imagery.

A longer version of the GOES-14 Visible image animation (with overlays of surface weather symbols) is shown below (also available as a large 203 Mbyte animated GIF).

GOES-14 Visible (0.63 µm) images, with plots of surface weather symbols [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images, with plots of surface weather symbols [click to play MP4 animation]

A comparison of GOES-15, GOES-14 and GOES-13 Shortwave Infrared (3.9 µm) images, below, demonstrates the advantage of 1-minute super rapid scan over the routine 15-minute routine scan interval for characterizing the intensity and trends of a short-lived grassfire in far western Oklahoma. Even though a fire hot spot (yellow color enhancement) appeared on the “2000 UTC” GOES-15 and GOES-13 images, the actual scan time of the fire for those 2 satellites was 2004 and 2003 UTC, respectively; a fire hot spot of 317.2 K was first detected on the 2101 UTC GOES-14 image. The magnitude of the fire hot spot then quickly increased to 332.8 K (red color enhancement) on the 2005 UTC GOES-14 image; the short-term fluctuations in the intensity of the fire hot spot were only adequately captured by the 1-minute super rapid scan interval of the GOES-14 images.

GOES-15 (left), GOES-14 (center) and GOES-13 (right Shortwave Infrared (3.9 µm) images [click to play animation]

GOES-15 (left), GOES-14 (center) and GOES-13 (right Shortwave Infrared (3.9 µm) images [click to play animation]

Large storm system over the western/central US

April 17th, 2016

GOES-14 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-14 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-14 Water Vapor (6.5 µm) images (above; also available as a large 85 Mbyte animated GIF) showed the development of a large upper-level closed low centered over the western US during the 15 April17 April 2016 period. This large storm system was responsible for a wide variety of weather, ranging from heavy snow and high winds in the Rocky Mountains to heavy rainfall and severe weather from eastern Colorado to Texas (SPC storm reports: 15 April | 16 April | 17 April).

Cyclone Fantala in the Indian Ocean

April 16th, 2016

Advanced Dvorak Technique intensity plot for Cyclone Fantala [click to enlarge]

Advanced Dvorak Technique intensity plot for Cyclone Fantala [click to enlarge]

A plot of the Advanced Dvorak Technique (ADT) hurricane intensity estimate (above) revealed that Indian Ocean Cyclone Fantala (19S) exhibited a period of rapid intensification on 15 April 2016, reaching Category 4 intensity with maximum sustained winds of 135 knots at 14 UTC.

EUMETSAT Meteosat-7 Infrared Window (11.5 µm) images (below) showed the formation of a well-defined eye after about 03 UTC.

Meteosat-7 Infrared (11.5 µm) images [click to play animation]

Meteosat-7 Infrared (11.5 µm) images [click to play animation]

A comparison of Meteosat-7 Infrared (11.5 µm) and DMSP-18 SSMI Microwave (85 GHz) images from the CIMSS Tropical Cyclones site (below) showed the eye structure around 15 UTC.

Meteosat-7 Infrared (11.5 µm) and DMSP-18 SSMI Microwave (85 GHz) images [click to enlarge]

Meteosat-7 Infrared (11.5 µm) and DMSP-18 SSMI Microwave (85 GHz) images [click to enlarge]

===== 18 April Update =====

Meteosat-7 Infrared Window (11.5 µm) images [click to play animation]

Meteosat-7 Infrared Window (11.5 µm) images [click to play animation]

During the 17-18 April period Cyclone Fantala reached Category 5 intensity (ADT plot), with maximum sustained winds of 150 knots (making it the strongest tropical cyclone on record in the South Indian Ocean); Fantala also became the longest-lived hurricane-strength tropical cyclone on record for that ocean basin. Meteosat-7 Infrared Window (11.5 µm) images (above) showed the storm reaching peak intensity as it moved just north of the island of Madagascar.

A comparison of Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images (below) offered a detailed nighttime view of the eye of Fantala at 2249 UTC on 17 April. Side lighting from the Moon (in the Waxing Gibbous phase, at 81% of full) helped to cast a distinct shadow within the eye, and also provided a good demonstration of the “visible image at night” capability of the Day/Night Band.

 

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm images [click to enlarge]

Blowing dust in northeastern Arkansas

April 12th, 2016

GOES-13 Visible (0.63 um) images [click to play animation]

GOES-13 Visible (0.63 um) images [click to play animation]

Strong southwesterly winds (gusting as high as 39 knots or 45 mph) created areas of blowing dust that reduced visibility to near zero and caused 2 incidents of multiple-vehicle accidents (NWS Local Storm Reports) near Portia in northeastern Arkansas on 10 April 2016. GOES-13 (GOES-East) Visible (0.63 um) images (above) showed the faint hazy signature of a few narrow plumes of blowing dust moving northeastward, one of which moved across Lawrence County and between Portia (denoted by the red * symbol) and Walnut Ridge (station identifier KARG). The blowing dust plumes are perhaps a bit easier to see on these images without county outlines and highways, though they are still somewhat difficult to identify with the patches of thin cirrus and contrails drifting from west to east overhead. Video of the conditions on the ground can be seen here.

Time series plots of surface data for Walnut Ridge (KARG) located just to the northeast and Newport (KM19) located farther to the south-southwest are shown below. Surface reports indicated that the visibility was reduced to less than 1 mile at 1756 UTC at Newport, and less than 3 miles at 1735 UTC at Walnut Ridge.

Time series plot of surface data for Walnut Ridge, Arkansas [click to enlarge]

Time series plot of surface data for Walnut Ridge, Arkansas [click to enlarge]

Time series plot of surface data for Newport, Arkansas [click to enlarge]

Time series plot of surface data for Newport, Arkansas [click to enlarge]

On the previous day, a comparison of the 1849 UTC Aqua MODIS Visible (0.65 µm) image and the corresponding Normalized Difference Vegetation Index (NDVI) product (below) showed that there were many areas upwind (to the southwest of) Portia and Walnut Ridge — in both southern Lawrence and northern Jackson counties — that exhibited low NDVI values (tan color enhancement), indicative of recently-plowed and/or unplanted agricultural fields within that part of the Mississippi Alluvial Plain. It is possible that field plowing activities on that windy day may have been the catalyst for the some of the  blowing dust plumes.

Aqua MODIS Visible (0.65 um) and Normalized Difference Vegetation Index (NDVI) product [click to enlarge]

Aqua MODIS Visible (0.65 um) and Normalized Difference Vegetation Index (NDVI) product [click to enlarge]

Similarly, a comparison of the 1849 UTC Aqua MODIS NDVI and Land Surface Temperature (LST) products (below) showed that the land surface in areas with less vegetation were warming up more quickly, with some LST values in excess of 90º F (darker red enhancement).

Aqua MODIS Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature products [click to enlarge]

Aqua MODIS Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature products [click to enlarge]