Valley fog and mountain snow in the Catskills of New York

May 1st, 2018 |

As pointed out by NWS Binghamton, valley fog and higher-elevation snow cover was apparent on GOES-16 (GOES-East) Visible imagery in the Catskills of southeastern New York on the morning of 01 May 2018. A closer view comparing GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (below) showed the dissipation of the valley fog, followed by the melting of the snow cover in higher terrain (snowfall amounts of up to 3-4 inches fell in the area on 29 April). The Snow/Ice imagery was helpful in discriminating between the brighter valley fog features and the darker snow cover.

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Near-Infrared “Snow/Ice” (1.61 µm, right) images, with hourly plots of surface reports [click to play animation | MP4]

A 250-meter resolution Terra MODIS True-color Red-Green-Blue (RGB) image acquired from the SSEC Direct Broadcast ground station (below) showed the remaining snow cover over the Catskills (near the center of the image) at 1539 UTC.

Terra MODIS True-color image [click to enlarge]

Terra MODIS True-color image [click to enlarge]

Wildfires in northeastern Oklahoma

March 24th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with surface airport identifiers plotted in cyan [click to play MP4 animation)

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed smoke plumes and fire “hot spots” associated with numerous wildfires burning in northeastern Oklahoma on 24 March 2018.

A comparison of Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images (below) showed  higher-resolution view of the fire hot spots.

Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images with surface observations plotted in cyan [click to enlarge]

Terra/Aqua MODIS and Suomi NPP VIIRS Shortwave Infrared images with surface observations plotted in cyan [click to enlarge]

Icebreaking in Whitefish Bay on Lake Superior

March 24th, 2018 |

GOES-16 ABI Band 2 “Red” (0.64 µm) Visible imagery, 2202 UTC on 22 and 23 March 2018 (Click to enlarge)

Dan Miller, the Science and Operations Officer (SOO) in Duluth sent the imagery above. Constant icebreaking has been ongoing on Whitefish Bay prior to the opening of the SOO Locks this weekend. A faint black line representing open water is apparent in the 22 March imagery, and it’s even more apparent in the 23 March imagery.

A toggle below, from 24 March 2018, shows the Band 2 “Red” (0.64 µm) Visible and the Band 5 “Snow/Ice” (1.61 µm) Near-Infrared images. The open water is apparent in both images — dark in contrast to the white snow and lake ice in the visible, darker than the adjacent ice in the 1.61 µm. Recall that horizontal resolution in Band 2 is 0.5 km at the sub-satellite point (nadir), and in Band 5 it is 1 km.

GOES-16 ABI Band 2 “Red” (0.64 µm) Visible and Band 5 “Snow/Ice” (1.61 µm) near-infrared imagery, 2202 UTC on 22 and 23 March 2018 (Click to enlarge)

Suomi NPP and NOAA-20 also viewed the icebroken path on 24 March, and favorable orbit geometry for NOAA-20 and Suomi NPP on 24 March (orbit paths from this site) meant 2 sequential passes from both satellites both viewed Whitefish Bay. The 4 images are shown in an animation below, with imagery from NOAA-20 first, then Suomi NPP (the labels all say Suomi NPP erroneously). Note that NOAA-20 data are provisional, non-operational, and undergoing testing still).

VIIRS Visible (0.64 µm, I1) Imagery from NOAA-20 (1708, 1846 UTC) and Suomi-NPP (1756, 1937 UTC) on 24 March 2018 (Click to enlarge)

The break in the ice was also visible in Day Night Band Imagery from VIIRS at 0722 UTC (from NOAA-20) on 24 March 2018.  It is also apparent in the shortwave Infrared imagery from both GOES-16 (very subtly) and from VIIRS (which offers better spatial resolution).

The icebreaking track was also apparent on 250-meter resolution Terra MODIS True-color and False-color Red-Green-Blue (RGB) images from the MODIS Today site (below). In the False-color image, ice and snow (in areas of sparse vegetation) show up as shades of cyan.

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

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

Severe weather in the Mid-South, and heavy snow in the Upper Midwest

February 24th, 2018 |

GOES-16 Mid-level Water Vapor (6.9 µm), with hourly plots of surface weather type [click to play Animated GIF | MP4 also available]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly plots of surface weather type [click to play Animated GIF | MP4 also available]

GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) showed the flow of moisture from the lower Mississippi Valley into the Ohio Valley on 24 February 2018 — this fueled the development of flooding rainfall and severe thunderstorms (for more details, see the Satellite Liaison Blog). A special 21 UTC sounding from Little Rock AR indicated 37.3 mm or 1.47 inches of Total Precipitable Water (TPW) within the atmospheric column.

1-minute interval Mesoscale Sector GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (below) revealed the development of a small supercell thunderstorm just north of the Kentucky/Tennessee border — this storm produced an EF-2  tornado that was responsible for 1 fatality (NWS Louisville damage survey). This (along with another in Arkansas) was the first US tornado-related death in 283 days (a new record in terms of length), with the last occurring in Wisconsin on 16 May 2017.

GOES-16 "Red" Visible<em> (0.64 µm, left)</em> and "Clean" Infrared Window <em>(10.3 µm, right)</em> images, with hourly surface reports plotted in yellow and SPC storm reports plotted in red [click to play Animated GIF | <a href="http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2018/02/180224_goes16_visible_infrared_spc_storm_reports_KY_TN_severe_anim.mp4"><strong>MP4</strong></a> also available]

GOES-16 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.3 µm, right) images, with hourly surface reports plotted in yellow and SPC storm reports plotted in red [click to play Animated GIF | MP4 also available]

Farther to the north, bands of elevated convection (oriented generally west to east) developed across Minnesota and Wisconsin, as seen in GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images (below). Snowfall rates were 1-2 inches per hour at some locations, with many storm total accumulations of 7 to 9 inches. Note the small-scale “ripple structure” that was present along the tops of many of these convective bands (orthogonal to the long axis of each band).

GOES-16

GOES-16 “Red” Visible (0/64 µm) images [click to play animation]

GOES-16

GOES-16 “Clean ” Infrared Widow (10.3 µm) images [click to play animation]

Comparisons of Terra and Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images (below) also showed these bands of elevated convection that helped to enhance snowfall rates. The layer of instability aloft was evident on the 00 UTC sounding from Chanhassen MN.

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

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

Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Aqua MODIS Visible (0.65 µm) and Infrared Window (11.0 µm) images [click to enlarge]