Interesting contrail in North Dakota

November 21st, 2017 |

As mentioned in a Tweet from NWS Grand Forks (above), an interesting contrail was seen over eastern North Dakota on 21 November 2017. They noted that the contrail was most easily seen using imagery from the water vapor bands.

A comparison of GOES-16 ABI Lower-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (below) showed the formation and motion of the contrail feature (which was likely caused by military aircraft, based in Grand Forks and/or Minot, performing training exercises).

GOES-16 Lower-level (10.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images, with surface station identifiers plotted in cyan [click to play animation]

GOES-16 Lower-level (10.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images [click to play animation]

A comparison of three of the GOES-16 Near-Infrared bands (below) showed that the high-altitude ice crystal contrail feature was also very apparent in “Cirrus” (1.37 µm) images; the contrails themselves were very subtle in the “Vegetation” (0.86 µm) and “Snow/Ice” (1.61 µm) images, but their darker shadows which were cast upon the surface (to the east-northeast) were more obvious — for example, on the 2132 UTC images.

GOES-16 Vegetation (0.86 µm, left), Cirrus (1.37 µm, center) and Snow/Ice (1.61 µm, right) images [click to play animation]

GOES-16 Vegetation (0.86 µm, left), Cirrus (1.37 µm, center) and Snow/Ice (1.61 µm, right) images [click to play animation]

Cyclone Numa in the Mediterranean Sea

November 19th, 2017 |

Terra MODIS and Suomi NPP VIIRS true-color RGB images [click to enlarge]

Terra MODIS and Suomi NPP VIIRS true-color RGB images [click to enlarge]

A toggle between Terra MODIS and Suomi NPP VIIRS Red-Green-Blue (RGB) images, viewed using RealEarth (above), revealed the well-defined eye structure of Cyclone Numa over the Ionian Sea (between Italy and Greece) on 18 November 2017. Tracing its origin back to the remnants of Tropical Storm Rina (track), Cyclone Numa had acquired subtropical characteristics on this day, making it a relatively rare Medicane.

EUMETSAT Meteosat-10 High Resolution Visible (0.8 µm) images (below) showed the evolution of the storm on 18 November. Plots of hourly surface reports (in metric units) are plotted on the images.

Meteosat-10 Visible (0.8 µm) images, with plots of hourly surface reports [click to play MP4 animation]

Meteosat-10 Visible (0.8 µm) images, with plots of hourly surface reports [click to play MP4 animation]

Meteosat-10 Infrared Window (10.8 µm) images (below) showed cloud-top infrared brightness temperatures around -60ºC (darker red enhancement) associated with some of the convective bursts during the 18-19 November period, as the system eventually moved inland across Greece.

Meteosat-10 Infrared Window (10.8 µm) images, with plots of hourly surface reports [click to play MP4 animation]

Meteosat-10 Infrared Window (10.8 µm) images, with plots of hourly surface reports [click to play MP4 animation]

Alaska’s first -40º temperature of the 2017-2018 winter season

November 19th, 2017 |

NOAA-18 Infrared Window (10.8 mm) image, with surface identifiers and air temperatures plotted in red [click to enlarge]

NOAA-18 Infrared Window (10.8 mm) image, with surface identifiers and air temperatures plotted in red [click to enlarge]

Alaska’s first (official) surface air temperature of -40º or colder for the 2017-2018 winter season was reported by the Cooperative Observer at Chicken (-43ºF) on 19 November 2017. A NOAA-18 Infrared Window (10.8 µm) image at 0320 UTC (above) showed cold air drainage into river valleys, with the coldest infrared brightness temperatures around -40ºC/-40ºF (darker blue color enhancement). Chicken is located about midway between Eagle (PAEG) and Northway (PAOR), where 03 UTC surface air temperatures were -17ºF and -24ºF, respectively. However, PAEG reached their minimum temperature around 11 UTC after additional hours of cloud-free radiational cooling.

An automated RAWS site at Chicken reached a minimum temperature of -34ºF at 1120 UTC — the dew point at that time was -42ºF. However, a MesoWest map (below) shows that the RAWS tower is located on a small hill (at an elevation of 2060 feet) — and the Cooperative Observer instrument shelter was likely located in the lower elevations of the settlement.

MesoWest map showing the location of the Chicken RAWS site [click to enlarge]

MesoWest map showing the location of the Chicken RAWS site [click to enlarge]

For comparison, note the 2011-2012 and 2010-2011 winter seasons.

Satellite signatures of the JPSS-1 launch

November 18th, 2017 |

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

The JPSS-1 satellite was successfully launched at 0947 UTC (1:47 AM local time) on 18 November 2017 from Vandenberg Air Force Base, California (Spaceflight Now). A Suomi NPP VIIRS Day/Night Band (0.7 µm) image about 22 minutes prior to launch (above; courtesy of William Straka, CIMSS) showed light emitted by the launch facility as well as nearby cites and offshore buoys.

A comparison of 3 consecutive images of GOES-16 Near-Infrared “Snow/Ice” (1.61 µm), Near-Infrared “Cloud Particle Size” (2.24 µm) and Shortwave Infrared (3.9 mm) data (below) revealed the thermal signature of the launch rocket booster engines at 0947 UTC (just west of the California coast). The hot thermal signature is brighter white on the Near-Infrared images, and darker gray on the Shortwave Infrared image. Nearby 09 UTC surface observations are also plotted (KVBG = Vandenberg AFB).

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm, left), Near-Infrared “Cloud Particle Size” (2.24 µm, center) and Shortwave Infrared (3.9 mm, right) images, with plots of surface observations [click to enlarge]

Since the GOES-16 Water Vapor bands — Lower-level 7.3 µm, Mid-level 6.9 µm and Upper-level 6.2 µm —  are essentially Infrared bands (which sense the mean temperature of a layer of moisture), a warm thermal signature was evident on all three of the 0947 UTC images (below).

GOES-16 Lower-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images, with plots of surface reports [click to enlarge]

GOES-16 Lower-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images, with plots of surface reports [click to enlarge]

Read about SSEC scientists’ efforts to calibrate and validate CrIS and VIIRS on JPSS-1 here.

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