Deadly Fire in Portugal

June 18th, 2017 |

Suomi NPP VIIRS Day/Night Band Visible Imagery (0.70 µm) at 0240 UTC on 18 June 2017 (Click to enlarge)

(Images in this blog post were created by William Straka, SSEC. Thanks William!!)

Parts of Pedrogao Grande in central Portugal (northeast of Lisbon) burned over the weekend in a massive forest fire. At least 62 people were killed (News Link; Youtube Video 1, 2). Suomi NPP overflew the region shortly after the fire started, and annotated VIIRS (Visible Infrared Imaging Radiometer Suite) Day/Night Band imagery is shown above (Click here for an image without annotation).  The size of the bright light signature from the fire (overlain with thin clouds) rivals that of Lisbon.

Suomi NPP VIIRS Shortwave Infrared imagery ( 3.75 µm) at 0240 UTC on 18 June 2017 (Click to enlarge)

Shortwave Infrared channels on Suomi NPP also testify to the intensity of the fire. The 3.75 µm above (Click here for an image with no labels) shows a saturated pixel (exceeding 367 K) over the hottest part of the fire.  The 1.61 µm channel in the near infrared also had a strong signal.   The 4.05 µm imagery (Click here for an image without annotation) shown below had a maximum brightness temperature exceeding 550 K! (This channel was specifically designed for fire detection).

Suomi NPP VIIRS Shortwave Infrared Imagery (4.05 µm) at 0240 UTC on 18 June 2017 (Click to enlarge)

Meteosat-10 Severi Infrared Imagery (3.9 µm) from 0000 to 0400 UTC on 18 June 2017 (click to enlarge)

The SEVERI Instrument on Meteosat-10 also detected this fire, and because Meteosat is geostationary, it provided better temporal coverage vs. the single snapshot from Suomi NPP. The animation above shows considerable cloud cover over Portugal, but very warm pixels are present starting after 0145 UTC. The toggle below compares 3.9 µm SEVIRI at 0245 UTC with 3.75 µm Suomi NPP VIIRS at 0240 UTC. The better spatial resolution of the VIIRS instrument is apparent, as are much warmer temperatures as expected given the smaller pixel size on VIIRS.  Note also a slight parallax shift.

Shortwave Infrared Imagery (3.9 µm from Meteosat-10 SEVIRI at 0245 UTC and 3.75 µm from Suomi NPP VIIRS at 0240 UTC) over Portugal (Click to enlarge)


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Suomi NPP VIIRS Day/Night Band visible (0.70 µm) imagery at 0145 UTC on 19 June 2017 (Click to enlarge)

Data from the 0145 UTC 19 June overpass on Suomi NPP show that the fire continues, although with less intensity. The Day/Night Band (above) and the 3.75 µm Shortwave Infrared (below) show the fire locations.

Suomi NPP VIIRS Shortwave Infrared (3.75 µm) imagery at 0145 UTC on 19 June 2017 (Click to enlarge)

 

Large MCS affects Nebraska, Iowa, Kansas and Missouri

June 17th, 2017 |

GOES-16 Infrared Window (10.3 µm) images, with plots of SPC storm reports [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm) images, with plots of SPC storm reports [click to play MP4 animation]

** GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing **

A large Mesoscale Convective System (MCS)  developed over eastern Nebraska late in the day on 16 June 2017, which continued  to grow in size as it  propagated southeastward  and produced severe weather across western Iowa, northeastern Kansas  and northwestern Missouri during  the subsequent overnight hours (SPC storm reports). GOES-16 Infrared Window (10.3 µm) images (above) include plots of time-matched  SPC storm reports;  the report locations are parallax-corrected to match those of the cloud tops. The strong winds downed  numerous trees and power lines;  Kansas City Power & Light reported  that as many as 93,000 customers — more than 10 percent — were without power within the utility’s service area (which covers 46 counties in Kansas and Missouri).

In a comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at  0721 UTC or 2:21 am local time on 17 June (below), the Day/Night Band image showed a bright cluster of lightning streaks (cloud tops illuminated by intense lightning activity) straddling the Kansas/Missouri border. Note how the city lights of the Kansas City area were almost completely attenuated by the dense and vertically thick MCS core, while a diffuse signature of city lights was seen through the thin cirrus canopy around the edges of the storm. Packets of cloud-top gravity waves evident on both images, and the coldest cloud-top Infrared brightness temperatures were -85º  C (darker violet color enhancement), located in both Kansas and Missouri.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11..45 µm) images, with cumulative plots of SPC storm reports [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11..45 µm) images, with cumulative plots of SPC storm reports [click to enlarge]

True-Color RGBs with GOES-16 Data

June 15th, 2017 |

GOES-16 ABI True-Color RGB over the Northern Hemisphere, 2030 UTC on 15 June 2017 (Click to enlarge)

GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing

True-Color Imagery can be computed quickly in AWIPS using several simple xml files and Python code. An example is shown above. The Green Band that is missing from the ABI is simulated using a combination of the Blue Visible (0.47 µm), Red Visible (0.64 µm), and Veggie Bands (0.86 µm), and that simulated Green is then combined with the Blue and Red bands to create the imagery seen above. Some modest stretching is done to enhance contrast.

Rapid convective development over Illinois and Wisconsin

June 14th, 2017 |

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with station identifiers plotted in white and SPC storm reports plotted in cyan [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left) and Infrared Window (10.3 µm, right) images, with station identifiers plotted in white and SPC storm reports plotted in cyan [click to play MP4 animation]

** GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing **

1-minute interval Mesoscale Sector GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images (above) showed the rapid development of convection across northern Illinois and southern Wisconsin on 14 June 2017. SPC storm reports indicated that these storms produced widespread hail, damaging winds and a few tornadoes.

GOES-16 Visible (0.64 µm) images [click to play MP4 animation]

GOES-16 Visible (0.64 µm) images [click to play MP4 animation]

Closer views centered along the Wisconsin/Illinois border with Visible (0.64 µm) imagery (above) showed the overshooting tops associated with these thunderstorms, while the Snow/Ice (1.61 µm) imagery (below) helped to discriminate between higher-altitude glaciated cloud tops (darker gray) and lower-level cloud tops composed of supercooled water droplets (brighter white).

GOES-16 Snow/Ice (1.61 µm) images [click to play MP4 animation]

GOES-16 Snow/Ice (1.61 µm) images [click to play MP4 animation]

The animation of Visible and color-enhanced Infrared imagery at the top of this blog post shows pockets of very cold cloud top temperatures within the cirrus canopy above the developing convection. These generally indicate overshooting tops, at the top of very strong updrafts. In contrast, the Shortwave Infrared (3.9 µm) animation, below, shows relatively warm pixels that are darker in the grey-scale enhancement in about the same region. Why the difference? Ice crystals that emerge from the top of a strong updraft are very effective reflectors of solar radiation at a wavelength of 3.9 µm. The satellite detects both terrestrial 3.9 µm energy emitted from the cold cloud top and solar 3.9 µm energy reflected off the cloud top. The amount detected will be largest (and a warmer temperature is inferred) where ice crystals are smallest and most reflective: at the top of very strong updrafts. Very little solar 10.3 µm radiation is reflected off clouds.

GOES-16 Shortwave Infrared (3.90 µm) images [click to play MP4 animation]

GOES-16 Shortwave Infrared (3.90 µm) images [click to play MP4 animation]

All 16 bands on ABI can be used to monitor the development of the strong convection — in the case shown below over west-central Illinois for one hour, from 1900-2000 UTC. Click here for a very zoomed-in animation over one cell!

GOES-16 ABI for all 16 channels, 1900-1959 UTC on 14 June 2017 [click to play MP4 animation]

GOES-16 ABI images from all 16 bands, 1900-1959 UTC on 14 June 2017 [click to play MP4 animation]