PyroCb in Ontario, Canada

May 22nd, 2018 |

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly plots of surface reports [click to play MP4 animation]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed that Canadian wildfires burning along the Manitoba/Ontario border produced a pyroCumulonimbus (pyroCb) around 1930 UTC on 22 May 2018.

As the pyroCb moved southeastward over western Ontario, the coldest GOES-16 cloud-top infrared brightness temperatures were around -55ºC (orange enhancement), which corresponded to altitudes of about 10.3 to 10.8 km according the rawinsonde data from Pickle Lake, Ontario (below).

Rawinsonde data profiles from Pickle Lake, Ontario [click to enlarge]

Rawinsonde data profiles from Pickle Lake, Ontario [click to enlarge]

In a comparison of 1-km resolution NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images at 2210 UTC (below), the minimum cloud-top infrared brightness temperature was -58.1ºC (darker orange enhancement), which roughly corresponded to altitudes of 10.6 to 11.0 km (just below the tropopause) on the Pickle Lake soundings.

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

Severe weather in the Northeastern US

May 15th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with SPC storm reports plotted in red [click to play MP4 animation]

Severe thunderstorms developed along and ahead of a cold front that was moving across the Northeastern US on 15 May 2018. 1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) images (above) showed the progression of these storms — and SPC storm reports (plotted in red, and parallax-corrected to align with the corresponding cloud-top feature) included an EF2 tornado at 2029 UTC near Kent, New York and a macroburst producing winds of 100-110 mph at 2044 UTC near Brookfield, Connecticut.

The corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below) showed the evolution of cold overshooting tops, as well as the development of a few “enhanced-v” signatures with a pronounced warm wake immediately downwind of the cold overshooting top.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with SPC storm reports plotted in cyan [click to play MP4 animation]

A toggle between 1-km resolution POES (NOAA-19) AVHRR Near-Infrared “Vegetation” (0.86 µm) and “Dirty” Infrared Window (12.0 µm) images (below) provided a more detailed view of the storm at 2004 UTC. SPC storm reports within +/- 30 minutes of the image are plotted on the 12.0 µm image.The coldest cloud-top infrared brightness temperature was -82ºC, associated with an overshooting top in southeastern New York.

POES (NOAA-19) Visible (0.86 µm) and Inrared (12.0 µm) images, with plots of SPC storm reports [click to enlarge]

POES (NOAA-19) Near-Infrared “Vegetation” (0.86 µm) and “Dirty” Infrared Window (12.0 µm) images, with plots of SPC storm reports [click to enlarge]

ACSPO SSTs in AWIPS at WFO Guam

April 24th, 2018 |

ACSPO SSTs constructed from AVHRR, MODIS and VIIRS data from various overpasses at Guam on 18 April 2018 (Click to enlarge)

Sea Surface Temperatures (SSTs) produced from the Advanced Clear-Sky Processor for Oceans (ACSPO) are now being created in real time at the National Weather Service Forecast Office on Guam (where the National Weather Service day begins). The algorithm is applied to data broadcast from polar orbiter satellites and received at the Direct Broadcast antenna sited at the forecast office.  Because there are so many polar orbiters broadcasting data — NOAA-18, NOAA-19, Metop-A, Metop-B, Suomi-NPP, Terra, Aqua — cloudy pixels on one pass are typically filled in with data from a subsequent pass.  When ACSPO software for NOAA-20 is available, data from that satellite will be incorporated as well.  The result is a very highly calibrated, accurate depiction of high spatial resolution tropical Pacific SSTs.  A composite created every 12 hours from the imagery is also available at the forecast office.

 

Contrails off the coast of Southern California

April 23rd, 2018 |

As pointed out by NWS San Diego, an interesting pattern of contrails formed off the coast late in the day on 23 April 2018. A comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm), Near-Infrared “Cirrus” (1.37 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed signatures during the daylight hours — Visible images revealed contrail shadows being cast upon the low-altitude cloud tops at 0142 and 0147 UTC — with an Infrared signature persisting after sunset. These contrails were likely caused by military aircraft performing training exercises, since chaff was seen with radar in that same area on the previous day.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left), Near-Infrared “Cirrus” (1.37 µm, center) and “Clean” Infrared Window (10.3 µm, right) images [click to play animation | MP4]

A better post-sunset signature was seen on a NOAA-15 Infrared Window (10.8 µm) image at 0212 UTC (below). A comparison with the corresponding GOES-16 “Clean” Infrared Window (10.3 µm)  image displayed a significant northwestward GOES-16 displacement due to parallax — and the 1.1 km spatial resolution of AVHRR data resulted in a clearer contrail signature.

NOAA-15 AVHRR Infrared Window (10.8 µm) and GOES-16 ABI

NOAA-15 AVHRR Infrared Window (10.8 µm) and GOES-16 ABI “Clean” Infrared Window (10.3 µm) images [click to enlarge]

The pattern of contrails could also be followed after sunset using GOES-16 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) imagery (below).

GOES-16 Low-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images [click to play animation | MP4]

GOES-16 Low-level (7.3 µm, left), Mid-level (6.9 µm, center) and Upper-level (6.2 µm, right) Water Vapor images [click to play animation | MP4]

The GOES-16 Water Vapor weighting function plots (below) displayed a bi-modal distribution for all 3 spectral bands, with peaks near 300 hPa and 500 hPa. The absence of a distinct contrail signature on the 6.2 µm imagery suggests that these features were located closer to the 500 hPa pressure level.

GOES-16 Water Vapor weighting functions, calculated using rawinsonde data from San Diego CA [click to enlarge]

GOES-16 Water Vapor weighting functions, calculated using rawinsonde data from San Diego CA [click to enlarge]