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).

Strong Winter Storm over the upper Ohio River Valley with severe weather in the Mid-Atlantic

February 24th, 2016
GOES-14 Water Vapor Infrared (6.5 µm) images [click to play mp4 animation]

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

A strong winter storm produced a swath of winter weather from Arkansas through lower Michigan on 23-24 February. GOES-14 SRSO-R Imagery was centered on the occluded storm on 24 February, and the water vapor animation, above (available here as an animated gif image), shows strong flow north-northwest from the Mid-Atlantic states into the Upper Midwest, where Winter Storm and Blizzard Warnings were widespread. The end of the animation shows strong convection developing over the Mid-Altantic states where multiple reports of Severe Weather occurred. (A water vapor animation with weather symbols included is available here as an mp4 and here as an animated gif).

Rapid Refresh Model Simulation of 310 K Equivalent Potential Temperature Surface [click to play animation]

Rapid Refresh Model Simulation of 310 K Equivalent Potential Temperature Surface [click to play animation]

The thermal structure of the storm as revealed by Rapid Refresh analyses of the 310 Kelvin Equivalent Potential Temperature Surface, above, (and available here with contours of Mean Sea Level Pressure) suggests the presence of a Trough of Warm Air Aloft (TROWAL) that stretches from Tennessee to Michigan. Any dry air that moves northward over this region is likely to eroded from below as low-level moisture (not detected in the water vapor imagery) is forced upwards by frontogenetic circulations along the sloping isentropes. Note how cold cloud tops in the animation above appear with regularity over southern Michigan and northern Indiana. These cold clouds tops in the water vapor imagery could be manifestations of frontal forcings acting on the warm air in the TROWAL airstream. Simulated ABI Water Vapor Channels (available here or here), below, show the blossoming of cold cloud tops in the 7.3 µm channel. This toggle between the 6.2µm and 7.3µm channels at 2100 UTC shows how the different water vapor channels view different levels in the atmosphere because of different sensitivity to water vapor absorption at those two wavelengths: the 7.3µm channel typically sees deeper into the troposphere and therefore has warmer brightness temperatures.

Simulated ABI 7.3 µm Water Vapor Channel Imagery, hourly from 16-22 UTC on 24 February 2016 [click to play animation]

Simulated ABI 7.3 µm Water Vapor Channel Imagery, hourly from 16-22 UTC on 24 February 2016 [click to play animation]

GOES-13 Visible (0.65 µm) images [click to play animation]

GOES-13 Visible (0.65 µm) images [click to play animation]

When storms move north to the west of the spine of the Appalachians, downslope winds frequently cause clearing, and this occurred on 24 February, as shown in the half-hourly animation of GOES-13 Visible imagery above. Clear skies are widespread over southeastern Ohio and southwestern Pennsylvania. Cities in the region that cleared saw high temperatures in the mid-60s today. The visible imagery above shows evidence of strong shear in the warm sector (where SPC had issued a Moderate Risk). GOES-14 1-minute Visible Imagery for the 30 minutes ending at 2230 UTC, available here, shows a line of strong convection from the Piedmont of North Carolina northward to metropolitan Washington DC.

GOES-14 Visible (0.65 µm) images [click to play animation]

GOES-14 Visible (0.65 µm) images [click to play animation]

Visible SRSO-R Imagery from GOES-14, above, shows the strong storms moving rapidly to the northeast along a line stretching from Washington DC south to central North Carolina as the sun set on 24 February. (Animation available here as an mp4). Another animation of GOES-14 visible images centered on Virginia and North Carolina (covering the period from 1300-2159 UTC) with plots of station identifiers is available as an MP4 or an animated GIF.


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NOAA/CIMSS ProbSevere output superimposed on MRMS Merged QC Composite Reflectivity, times as Indicated [click to play animation]

NOAA/CIMSS ProbSevere output superimposed on MRMS Merged QC Composite Reflectivity, times as Indicated [click to play animation]

The NOAA/CIMSS ProbSevere model combines information about the storm environment (from the Rapid Refresh) with satellite indicators of cloud growth and with radar estimates of hail size. It is designed to predict when a developing convective cell will first produce severe weather. In the animation above, a growing cell has developed over South Carolina. At the start of the animation, 2134 UTC, the cell is displaying moderate growth rate, and weak glaciation. Two minutes later, at 2136 UTC, ProbSevere has jumped to 62% as the MRMS MESH (Maximum Expected Size of Hail) has jumped from 0.32 to 0.67 inches. By 2144 UTC, ProbSevere exceeds 90%, and it retains that value through the end of the animation at 2250 UTC. This cell produced wind damage three miles northwest of Brownsville SC at 2130 UTC. (SPC Storm Reports). The cell was associated with other wind events in Robeson County, NC at 2155 UTC.

Why 1-minute satellite data matters: Monitoring Fires

February 18th, 2016

GOES-14 0.63 µm Visible (top) and 3.9 µm Shortwave Infrared (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (top) and 3.9 µm Shortwave Infrared (bottom) images [click to play MP4 animation]

Extensive wildfires (well-forecast by the Storm Prediction Center) occurred over the southern Plains on Thursday 18 February 2016, while GOES-14 was operating in SRSO-R mode. A comparison of 1-minute GOES-14 Visible (0.63 µm) and Shortwave Infrared (3.9 µm) images (above; also available as a large 112 Mbyte animated GIF) showed the broad areal coverage of smoke plumes and fire hot spots (dark black to yellow to red pixels) during the day over eastern Oklahoma.

GOES-14 0.63 µm Visible (left) and 3.9 µm Shortwave Infrared (right) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (left) and 3.9 µm Shortwave Infrared (right) images [click to play MP4 animation]

Of particular interest was a rapidly-intensifying and fast-moving grass fire over northwestern Oklahoma, in Harper County just west-northwest of the town of Buffalo, which burned 17,280 acres (media report). Note the warm air temperatures as seen in the surface plots — the high of 90º F at Gage OK (KGAG, south of the fire) tied for the warmest February temperature on record at that site. A closer view of the Buffalo fire is shown above — county outlines are shown as dashed white lines, while US and State highways are plotted in violet (also available as a large 63 Mbyte animated GIF). The shortwave infrared images revealed the initial appearance of a color-enhanced fire hot spot (exhibiting an IR brightness temperature of 327.5 K) at 2045 UTC; three minutes later (at 2048 UTC), the IR brightness temperature had already increased to 341.2 K (red enhancement) which is the saturation temperature of the GOES-14 shortwave IR detectors. The hot spots could also be seen racing northeastward toward the Oklahoma/Kansas border, with the fire eventually crossing US Highway 183 (which runs south-to-north through Buffalo and across the Kansas border). The early detection and subsequent accurate tracking of such rapid fire intensification and propagation could only have been possible using 1-minute imagery.

The two plots below show GOES-14 pixel values of 3.9 µm IR brightness temperature at the initial Buffalo fire site (top plot, at 36:51º N, 99:48º W) and at a site just to the northeast (bottom plot, at 36:54º N, 99:43º W) through which the moving fire propagated. The blue line shows every value, nominally at 1-minute intervals. The red dots show points sampled every five minutes. Very small temporal scale changes in the fire cannot be captured with a 5-minute sampling interval.

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures at 36:51:36º N, 99:48:27º W, 2040-2230 UTC on 18 February 2016 [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures at 36:51:36º N, 99:48:27º W, 2040-2230 UTC on 18 February 2016 [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures at 36:54:44º N, 99:43:22º W, 2115-2200 UTC on 18 February 2016 [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures at 36:54:44º N, 99:43:22º W, 2115-2200 UTC on 18 February 2016 [click to enlarge]

 

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm Shortwave Infrared images covering the initial period 2030-2100 UTC [click to play animation]

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm Shortwave Infrared images covering the initial period 2030-2100 UTC [click to play animation]

For the Buffalo fire, a three-satellite comparison of Shortwave Infrared (3.9 µm) images from GOES-15 (operational GOES-West), GOES-14, and GOES-13 (operational GOES-East) is shown for the initial 30-minute time period 2030-2100 UTC (above). The images are displayed in the native projection of each satellite. In terms of the first unambiguous fire hot spot detection (via a hot color-enhanced image pixel) during that initial period, it would appear from the image time stamps that both GOES-14 and GOES-13 detected the fire at 2045 UTC — however, because GOES-14 was scanning a much smaller sector, it did indeed scan the fire at 20:45 UTC (while GOES-13 scanned the fire at 2049 UTC, 4 minutes after its larger scan sector began in southern Canada). Also note that there were no GOES-15 images during that 30-minue period between 2030 and 2100 UTC, due to the satellite having to perform various “housekeeping” activities — so if a NWS forecast office AWIPS were localized to use GOES-15, initial fire detection would not have been posible until reception of the 2100 UTC image (which actually scanned the fire at 2104 UTC).

A faster animation covering a longer 2.5-hour period from 2030-2300 UTC is shown below. Again, a true sense of the fast northeastward speed of fire propagation could only be gained using 1-minute imagery.

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm Shortwave Infrared images covering the 2.5-hour period 2030-2300 UTC [click to play animation]

GOES-15 (left), GOES-14 (center), and GOES-13 (right) 3.9 µm Shortwave Infrared images covering the 2.5 hour period 2030-2300 UTC [click to play animation]

GOES-14 Shortwave Infrared (3.9 µm) images [click to play animation]

GOES-14 Shortwave Infrared (3.9 µm) 9mages [click to play animation]

The animation above shows another view of 1-minute GOES-14 Shortwave Infrared (3.9 µm) imagery, centered over northeastern Oklahoma — in these images, the hottest fire pixels are darkest black. Time series of infrared brightness temperature values at two individual fire pixels (shown here) are plotted below. The Blue lines show the 1-minute data; Red dots show how 5-minute monitoring would have adequately captured the events. Pixel Brightness Temperature changes that occur on the order of 1 or 2 minutes are common, and peak values can be missed with 5-minute granularity.

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures at, 2138-2301 UTC on 18 February 2016 at 35:31:17 N, 96:05:55 W [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures from 2138-2301 UTC on 18 February 2016, at 35:31:17º N, 96:05:55º W [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures at, 2138-2301 UTC on 18 February 2016 at 35:23:51 N, 95:20:52 W [click to enlarge]

GOES-14 Shortwave Infrared (3.9 µm) Brightness Temperatures from 2138-2301 UTC on 18 February 2016, at 35:23:51º N, 95:20:52º W [click to enlarge]

In the GOES-R era, Fire Products will be produced every 5 minutes. Individual NWS Forecast Offices will be able to request Rapid-Scan Imagery (1-minute intervals) over a 1000 km x 1000 km mesoscale sector.

===== 19 February Update =====

Seen below are RealEarth comparisons of Aqua MODIS and Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images from the early afternoon of 18 February (before the Buffalo OK fire) and 19 February (after the Buffalo OK fire), which revealed the long southwest-to-northeast oriented burn scar. As seen on the GOES-14 animation above, the fire crossed US Highway 183 just to the north of Buffalo (that portion of the highway was closed for several hours).

Aqua MODIS true-color images on 18 February and 19 February [click to enlarge]

Aqua MODIS true-color images on 18 February and 19 February [click to enlarge]

Suomi NPP VIIRS true-color images on 18 February and 19 February [click to enlarge]

Suomi NPP VIIRS true-color images on 18 February and 19 February [click to enlarge]

In addition, a comparison of Suomi NPP VIIRS true-color and false-color images (below) helps to discriminate between the darker burn scar and the cloud shadows seen on the true-color image — the Buffalo fire burn scar appears as varying shades of brown in both the true-color and the false-color images.

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

===== 27 February Update =====

Landsat-8 false-color RGB images on 18 February (a few hours prior to the start of the fire) and 27 February (several says after the fire) [click to enlarge]

Landsat-8 false-color RGB images on 18 February (a few hours prior to the start of the fire) and 27 February (several says after the fire) [click to enlarge]

A comparison of 30-meter resolution Landsat-8 false-color (created using OLI bands 6/5/4) RGB images from 18 February (about 3.5 hours prior to the start of the Buffalo OK fire) and 27 February (several days after the fire) provided a very detailed view of the burn scar. Note that a few green fields remained within the burn scar, and also appeared to prevent the spread of the fire along portions of its perimeter — this is a result of the vast difference between the very low moisture content of the dry grassland (which burned quickly and easily) and the high moisture content of the well-irrigated fields of winter wheat, alfalfa, and canola crops.