The corresponding GOES-15 Visible (0.63 um) and Infrared Window (10.7 um) images (below) revealed cloud-top infrared brightness temperature values as cold as -58 C (darker red color enhancement) at 0030 and 0100 UTC on 04 May.A comparison of Suomi NPP VIIRS false-color “Snow vs cloud discrimination” Red/Green/Blue (RGB), Visible (0.64 um), Shortwave Infrared (3.74 um), and Infrared Window (11.45 um) images at 1834 UTC (above) showed that while a large fire hot spot was apparent on the Shortwave Infrared image, there was no clear indication of any pyrocumulus cloud development at that time. However, a similar image comparison at 2018 UTC (below) revealed that a well-defined pyroCb cloud had formed (with a cloud-top infrared brightness temperature as cold as -60 C, dark red color enhancement) which was drifting just to the north of the Fort McMurray airport (whose cyan surface report is plotted near the center of the images). A 2104 UTC NOAA-19 AVHRR image provided by René Servranckx showed a minimum IR brightness temperature of -59.6 C. A closer look using Suomi NPP VIIRS true-color RGB and Shortwave Infrared (3.74 um) images from the SSEC RealEarth site (below) showed the initial pyroCb cloud as it had drifted just east of Fort McMurray, with the early stages of a second pyroCb cloud just south of the city. A nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 um) and Shortwave Infrared (3.74 um) images at 1015 UTC or 3:15 am local time (below; courtesy of William Straka, SSEC) showed the bright glow of the large Fort McMurray wildfire, as well as the lights associated with the nearby oil shale mining activity. A sequence of Suomi NPP VIIRS Shortwave Infrared (3.74 um) images covering the 02 April – 04 April period (below) showed the diurnal changes as well as the overall growth of the fire hot spot (darker black pixels). ]]>
A larger-scale view using GOES-13 (GOES-East) Visible (0.63 µm) images (below) showed the motion of this sea ice, which extended farther south off the coast of Newfoundland. The general southeastward ice motion was driven by the flow of the Labrador Current.According to data from the Canadian Ice Service, the concentration of this medium to thick “first year ice” (Labrador | Labrador/Newfoundland) was as high as 9/10 to 10/10 (below). The departure of normal of portions of this ice was as high as 9/10 to 10/10 above normal. ]]>
April 26 2016 was a day of well-anticipated severe weather (even a week out!) over the central and southern Plains, with a Moderate Risk of Severe Weather predicted for parts of Nebraska, Kansas, Oklahoma and Texas. The GOES-14 visible animation, above, shows the development of strong thunderstorms in north-central Oklahoma that propagated into south central Kansas, producing hail around 2000 UTC. Note the presence of an orphan anvil just downstream of the developing convection (to the south of the Green Arrow) at the beginning of the GOES-14 SRSO-R animation (that unfortunately has a 15-minute data gap starting at 1900 UTC).
How did the NOAA/CIMSS ProbSevere product perform with this severe cell? ProbSevere provides a probabilistic estimate of whether a cell will produce severe weather within the next 60 minutes. The animation below shows the quick development of the radar feature that became the hail producer. The Satellite Growth of this particular storm was not observed to be strong. Moderate satellite growth and weak glaciation was diagnosed. However, ProbSevere values became very large because of the environment in which the cell developed, because of the presence of large MRMS MESH observations, and active lightning. ProbSevere exceeded a 50% threshold at 1912 UTC, 6 minutes before the Severe Thunderstorm Warning was issued. The Table at the bottom shows the ProbSevere components as a function of time.
According to SPC storm reports, the cell produced a brief rope tornado at 2058 UTC in far southern Kansas. This storm was blogged about at the Hazardous Weather Testbed. Click here and here for blog posts on the environmental instability.
A zoomed-in animation of the Visible Imagery shows the orphan anvil developing around 1740 UTC. (A rocking animation is here).
|Time (UTC)||ProbSevere||MUCAPE||Env. Bulk Shear||MRMS MESH (Inches)||Satellite Growth||Satellite Glaciation||# Flashes|
|1858||20%||4739||41.9||0.29||1.9% (Moderate)||0.02 (Weak)||0|
|1900||29%||4702||41.8||0.45||1.9% (Moderate)||0.02 (Weak)||0|
|1908||34%||4640||40.9||0.54||1.9% (Moderate)||0.02 (Weak)||5|
|1910||47%||4628||40.7||0.65||1.9% (Moderate)||0.02 (Weak)||13|
|1912||59%||4623||40.4||0.65||1.9% (Moderate)||0.02 (Weak)||24|
|1914||58%||4619||40.1||0.65||1.9% (Moderate)||0.02 (Weak)||24|
|1916||58%||4614||39.8||0.65||1.9% (Moderate)||0.02 (Weak)||24|
|1918||54%||4614||39.8||0.60||1.9% (Moderate)||0.02 (Weak)||24|
|1920||60%||4592||39.4||0.74||1.9% (Moderate)||0.02 (Weak)||20|
|1922||65%||4591||39.1||0.80||1.9% (Moderate)||0.02 (Weak)||20|
|1924||73%||4591||39.1||0.80||1.9% (Moderate)||0.02 (Weak)||25|
|1926||75%||4572||38.8||0.84||1.9% (Moderate)||0.02 (Weak)||26|
|1928||88%||4578||38.7||1.01||1.9% (Moderate)||0.02 (Weak)||31|
|1930||89%||4578||38.7||1.01||1.9% (Moderate)||0.02 (Weak)||36|
|1932||97%||4580||38.6||1.24||1.9% (Moderate)||0.02 (Weak)||49|
|1934||97%||4560||38.3||1.24||1.9% (Moderate)||0.02 (Weak)||58|
|1936||97%||4544||38.1||1.24||1.9% (Moderate)||0.02 (Weak)||58|
|1938||97%||4543||38.0||1.24||1.9% (Moderate)||0.02 (Weak)||58|
|1940||97%||4540||37.8||1.26||1.9% (Moderate)||0.02 (Weak)||58|
|1942||98%||4528||37.7||1.53||1.9% (Moderate)||0.02 (Weak)||56|
|1944||99%||4516||37.5||1.71||1.9% (Moderate)||0.02 (Weak)||56|
|1946||99%||4507||37.4||1.71||1.9% (Moderate)||0.02 (Weak)||56|
Hat tip to Jim Strain, who sent out the Tweet:
You can pick up the Storm Hill smoke column in the SD portion of Scott’s tweeted sat pix. #StormHillfire https://t.co/oSEKKhW45N
— Jim Strain (@jim_strain) April 24, 2016
On the corresponding GOES-14 Water Vapor (6.5 µm) images (below; also available as a large 126 Mbyte animated GIF), a very subtle signature of the western part of the outflow boundary could be seen in the dryer atmosphere (where the water vapor weighting functions were shifted to lower altitudes). Also of interest were a few long and narrow contrails which appeared within that same dry region of the atmosphere after about 1800 UTC — these thin contrails were not evident in the GOES-14 visible or infrared imagery.A comparison of the 3 Water Vapor bands (6.5 µm, 7.0 µm and 7.4 µm) available from the GOES-14 sounder instrument (below) demonstrated how each of the individual bands was detecting radiation emitted from a different layer of the troposphere; this was further shown by examining plots of the water vapor weighting functions for the 1 imager and the 3 sounder water vapor bands (calculated using 12 UTC rawinsonde data from Del Rio, Texas KDRT). The ABI instrument on GOES-R will have 3 water vapor bands similar to those on the current generation sounder instrument, but with significantly improved spatial and temporal resolution. ]]>
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).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. ]]>
EUMETSAT Meteosat-7 Infrared Window (11.5 µm) images (below) showed the formation of a well-defined eye after about 03 UTC.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.
===== 18 April Update =====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.
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.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. 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). ]]>