Severe weather across the Deep South

March 19th, 2018 |

GOES-16

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

Thunderstorms developing in the warm sector of a low pressure system (surface analyses) produced tornadoes, large hail and damaging winds (SPC storm reports) across parts of the Deep South late in the day and into the night on 19 March 2018. GOES-16 (GOES-East) “Red” Visible (0.64 µm) images at 30-second intervals (above) showed numerous overshooting tops associated with this cluster of supercell convection.

In the corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below), cloud-top infrared brightness temperatures of some overshooting tops were around -70 ºC  (black enhancement).

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

Note that the EF-3 tornado that damaged the Jacksonville State University area in Alabama around 0135 UTC was the first EF-3 in 306 days — a new record.


Additional animations are available on the Satellite Liaison Blog.

Large hail in Texas

March 18th, 2018 |

GOES-16

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

Thunderstorms developing east of an advancing dryline (surface analyses) produced large hail (SPC storm reports) across south-central and eastern Texas late in the day on 18 March 2018. GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed well-defined overshooting tops and above-anvil cirrus plumes associated with this severe convection.

In the corresponding GOES-16 “Clean” Infrared Window (10.3 µm) images (below), cloud-top infrared brightness temperatures of some overshooting tops fluctuated within the -70 to -80 ºC range (black to white enhancement).

GOES-16

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

Using GLM data to monitor convective development

March 15th, 2018 |

GOES-16 Band 13 (10.3) “Clean Window” Infrared Imagery, 0815-1400 UTC, and GLM Group Density.

Strong convection developed on 15 March over the Pampas of Argentina and Uruguay, as shown above. Full Disk imagery is available only every 15 minutes, and considerable convective development is possible during the 15 minutes between scans. If a Mesoscale sector with 1-minute imagery is not over convection, Geostationary Lightning Mapper (GLM) data from GOES-16 can be used to monitor convection during the time interval between Full Disk Scans: GLM updates every minute. The 18-minute animation below (from Real Earth) includes 3 Full-Disk images and every-minute updates of GLM Group Density. Group Density between 0700-0715 shows no sign of diminishing.  It should not surprise that cloud-tops continue to expand and cool when the 0715 UTC ABI Imagery appears at the end of the loop.

Note:  When GOES-16 or GOES-17 (GOES-S achieved Geostationary Orbit on 12 March and became GOES-17) are operating under Mode 6 (vs. the present-day Mode 3), Full Disk imagery will be available every ten minutes vs. current fifteen minutes.

GOES-16 Band 13 (10.3) “Clean Window” Infrared Imagery, and GLM Group Density 0658-0717 UTC.

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).

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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]