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]

2 structural fires: Beaver Dam, Wisconsin and San Francisco, California

March 17th, 2018 |

GOES-16 Shortwave Infrared (3.9 µm, left) and

GOES-16 Shortwave Infrared (3.9 µm, left) and “Red” Visible (0.64 µm, right) images, with hourly surface reports plotted in yellow [click to play animation]

As documented by NWS Milwaukee/Sullivan, the controlled burn of an apartment building occurred during the late morning hours on 15 March 2018. A comparison of GOES-16 (GOES-East) Shortwave Infrared (3.9 µm) and “Red” Visible (0.64 µm) images (above) displayed subtle “hot spot” signatures (darker red pixels, circled) as well as an occasional hint of a small smoke plume during the early phase of the fire. At the bottom of the images, note the appearance of a few larger and hotter fires (black pixels) in northern Illinois — likely agricultural fires to prepare fields for Spring planting.

2 days later, another structure fire occurred in the San Francisco area during the early evening hours of 17 March 2018:

Hot spot signatures were observed on the 0247 UTC and 0252 UTC (7:47 and 7:52 PM local time) Shortwave Infrared (3.9 µm) images, along with subtle lighter gray pixels on the Near-Infrared (2.24 µm) images (below).

GOES-16 Shortwave Infrared (3.9 µm, left) and Near-Infrared (2.24 µm, right) images, with station identifiers plotted in cyan [click to play animation]

GOES-16 Shortwave Infrared (3.9 µm, left) and Near-Infrared (2.24 µm, right) images, with airport identifiers plotted in cyan [click to play animation]

A timely overpass of the NOAA-15 satellite scanned the fire at 02:43:50 UTC (7:43:50 PM local time), showing a well-defined hot spot (darker red enhancement) on the 1-km resolution Shortwave Infrared (3.7 µm) image (below).

NOAA-15 Shortwave Infrared (3.7 µm) image [click to enlarge]

NOAA-15 Shortwave Infrared (3.7 µm) image [click to enlarge]