Record-setting lake effect snow event at Erie, Pennsylvania

December 26th, 2017 |

1-minute GOES-16 "Clean" Infrared Window (10.3 µm) images, with hourly surface reports plotted in cyan/yellow [click to play MP4 animation]

1-minute GOES-16 “Clean” Infrared Window (10.3 µm) images, with hourly surface reports plotted in cyan/yellow [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images centered over Lake Erie (above) showed the evolution of lake effect snow bands on 25 December26 December 2017, which produced very heavy snowfall at locations such as Erie, Pennsylvania (station identifier KERI); a Mesoscale Sector provided images at 1-minute intervals. Some noteworthy snowfall records were set at Erie PA:

(27 December Update: additional lake effect snow at Erie on 27 December brought the final storm total accumulation to 65.1 inches: NWS Cleveland summary. NOHRSC plots showed a maximum snow depth of 49 inches just southwest of downtown Erie; the maximum snow depth at Erie International Airport was 28 inches on 26 December, which was still less than their all-time record snow depth of 39 inches on 21 December 1989)

A sequence of Infrared Window images captured by Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) is shown below. The coldest cloud-top infrared brightness temperatures associated with the dominant lake effect snow bands were in the -30 to -35 ºC range (dark blue to pale green color enhancement), similar to what was seen in the GOES-16 Infrared Window imagery.

Infrared Window images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm), with surface reports plotted in yellow [click to enlarge]

Infrared Window images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm), with surface reports plotted in yellow [click to enlarge]

Farther to the northeast, these Lake Erie lake effect bands also produced significant snowfall in far southwestern New York, with 32 inches reported at Perrysburg (located 20 miles west of Dunkirk, station identifier KDKK). In addition, lake effect snow bands over Lake Ontario were responsible for even higher snowfall amounts:


1-minute GOES-16 “Red” Visible (0.64 µm) images (below) showed the lake effect snow bands over Lake Ontario on 26 December.

1-minute GOES-16 "Red" Visible (0.64 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

1-minute GOES-16 “Red” Visible (0.64 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

Aircraft hole punch and cloud dissipation features over Illinois, Indiana and Ohio

December 21st, 2017 |

Terra MODIS true-color and false-color RGB images [click to enlarge]

Terra MODIS True-color and False-color RGB images [click to enlarge]

A toggle between 250-meter resolution Terra MODIS True-color and False-color Red-Green-Blue (RGB) images from the MODIS Today site (above) revealed numerous aircraft “hole punch” and dissipation trail or “distrail” features over Illinois, Indiana and Ohio on 21 December 2017.  These cloud features were caused by aircraft that were either ascending or descending through a layer of cloud composed of supercooled water droplets — cooling from wake turbulence (reference) and/or particles from the jet engine exhaust acting as ice condensation nuclei causes the small supercooled water droplets to turn into larger ice crystals (many of which then fall from the cloud layer, creating “fall streak holes“). The ice crystal clouds appear as darker shades of cyan on the false-color image.

GOES-16 "Red" Visible (0.64 µm) and Near-Infrared "Snow/Ice" (1.61 µm) images over Illinois/Indiana [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images over Illinois/Indiana [click to play MP4 animation]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images showed the hole punch and distrail features over Illinois/Indiana (above) and over Indiana/Ohio (below). The glaciated (ice crystal) hole punch and distrail clouds appeared dark gray on the Snow/Ice images (since ice is a strong absorber of radiation at the 1.61 µm wavelength).

GOES-16 "Red" Visible (0.64 µm) and Near-Infrared "Snow/Ice" (1.61 µm) images over Indiana/Ohio [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images over Indiana/Ohio [click to play MP4 animation]

RealEarth is used to display Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.9 µm), Near-Infrared (1.61 µm), True-color and False-color RGB images at 1841 UTC (below). O ne the Shortwave Infrared images, the hole punch and distrail features are colder (brighter white) than the surrounding supercooled water droplet cloud deck — since water droplet are effective absorbers of incoming solar radiation, such clouds appear warmer (darker gray) in 3.9 µm images.

Suomi NPP VIIRS

Suomi NPP VIIRS “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), Near-Infrared “Snow/Ice” (1.61 µm), True-color and False-color RGB images [click to enlarge]

Aircraft hole punch and distrail cloud features over southern Lake Michigan

December 20th, 2017 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and Near-Infrared “Snow/Ice” (1.61 µm. bottom) images, with surface station identifiers plotted in yellow [click to play MP4 animation]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) revealed a number of aircraft “hole punch clouds” and cloud dissipation or “distrail” features drifting eastward across southern Lake Michigan and adjacent states on 20 December 2017. These cloud features were caused by aircraft that were either ascending or descending through a layer of cloud composed of supercooled water droplets — cooling from wake turbulence (reference) and/or particles from the jet engine exhaust acting as ice condensation nuclei cause the small supercooled water droplets to turn into larger ice crystals (many of which then often fall from the cloud layer, creating “fall streak holes“). The darker gray appearance of the hole punch clouds on 1.61 µm images confirms that the features were composed of ice crystals (since ice is a strong absorber of radiation at that wavelength).

A good example of a hole punch cloud adjacent to a longer distrail feature was seen over far southeastern Minnesota and the Minnesota/Wisconsin border, using 250-meter resolution Aqua MODIS true-color and false-color Red-Green-Blue (RGB) images from the MODIS Today site (below). Glaciated (ice crystal) cloud features appeared as darker shades of cyan in the false-color image.

Aqua MODIS true-color and false-color RGB images [click to enlarge]

Aqua MODIS true-color and false-color RGB images [click to enlarge]

A very detailed view of a hole punch cloud over Lake Michigan was provided by 30-meter resolution Landsat-8 false-color imagery at 1635 UTC, viewed using RealEarth (below).

Landsat-8 false-color RGB image [click to enlarge]

Landsat-8 false-color RGB image [click to enlarge]

===== 21 December Update =====

Another example of numerous aircraft hole punch and distrail cloud features was seen on Terra MODIS true-color and false-color RGB images on 21 December. over northern Illinois and northern Indiana (below).

Terra MODIS true-color and false-color images [click to enlarge]

Terra MODIS true-color and false-color RGB images [click to enlarge]

Contrails over Virginia

December 18th, 2017 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top), Near-Infrared “Cirrus (1.38 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images [click to play animation]

A comparison of GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Cirrus (1.38 µm) and “Clean” Infrared Window (10.3 µm) images (above) revealed a number of aircraft contrails drifting eastward across Virginia during the morning hours on 18 December 2017. Note how many of the individual contrails were easier to identify and follow in the sequence of 1-minute interval Mesoscale Sector images.

A Cirrus band is also available on the MODIS instrument (aboard Terra and Aqua) as well as the VIIRS instrument (aboard Suomi NPP and NOAA-20) — a toggle between the Terra MODIS Cirrus (1.375 µm),  Infrared Window (11.0 µm) and Visible (0.65 µm) images at 1607 UTC (below) again showed that contrails and other ice crystal cloud features were better highlighted on the Cirrus image.

Terra MODIS Cirrus (1.375 µm), Infrared Window (11.0 µm) and Visible (0.65 µm) images [click to enlarge]

Terra MODIS Cirrus (1.375 µm), Infrared Window (11.0 µm) and Visible (0.65 µm) images [click to enlarge]

The 12 UTC rawinsonde profile from Washington Dulles Airport in northern Virginia (below) showed a relatively moist layer in the upper troposphere near the 300 hPa (9.5 km or 31,000 ft) level, which is a common altitude for commercial jets to fly — this likely contributed to the longevity of many of the contrail features.

Rawinsonde profile from Washington Dulles Airport in Virginia [click to enlarge]

Rawinsonde profile from Washington Dulles Airport in Virginia [click to enlarge]