Plotting GOES-16 GLM data in McIDAS-X

July 11th, 2017 |

GOES-16 ABI Clean Window (10.3 µm) imagery at 1002 UTC, along with GLM Lightning Observations of Events, Groups, and Flashes from 0959-1000 UTC (Yellow), 1000-1001 UTC (Green) and 1001-1002 UTC (Red). [Click to enlarge]

GOES-16 ABI and GLM data posted on this page are preliminary, non-operational and are undergoing testing

 

The GOES-16 Geostationary Lightning Mapper (GLM) has achieved Beta Maturity and is being distributed via GOES Rebroadcast (GRB). A release of McIDAS-X slated for September 2017 has a GLM display, prototyped above.  GLM data processing in the Ground System groups lightning flashes from smallest increments (Events), to aggregates of Events (Groups) to aggregates of Groups (Flashes). Thus, Events, as shown above, are on a rectangular grid wherein each gridpoint is a GLM Field of View. Groups are plotted at the centroid of the Events that comprise the Group, and Flashes are plotted as the centroid of the Groups that comprise the Flash. Typically, the number of Events is greater than the number of Groups, which is greater than the number of Flashes.

Convection developing over east-central Illinois and west-central Indiana this morning at 1002 UTC (as depicted by the 10.3 µm imagery, above) was electrically active. Events, Groups and Flashes are shown for 1-minute increments. For this particular (small) increment of time, the large convective complex over central Indiana was electrically quiet.  (Here is an animation that shows a similar scene — but with three events, groups and flashes grouped in 5-minute intervals rather than 1).

Note:  The ‘+’ sign used in the plot does not describe the electrical polarity of the flash;  GLM cannot distinguish positive from negative activity.

Interesting Bore Features in Lake Superior Stratus

July 10th, 2017 |

GOES-16 Visible (0.64 µm) Imagery [click to play animated gif]

GOES-16 Visible (0.64 µm) Imagery [click to play animated gif]

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

High Dewpoints in mid-Summer in the Upper Midwest often leads to stratus and fog over Lake Superior. Such was the case on 10 July 2017, with dewpoints in the 50s and 60s F (GOES-16 Visible images with surface observations) and mid-lake water temperatures as cold as 40º F (buoy reports | MODIS SST values) — and very interesting waves were observed in the stratus deck. They had the appearance of Atmospheric Bores: parallel lines of clouds moving in one direction. It is unusual to have Bores moving in different directions at the same time, however.

One possible explanation for the differing motion of these undular bores could be internal reflection off the rugged northern and southern shorelines of Lake Superior.

The RTMA surface wind analyses at 17 UTC and 19 UTC, below, showed complex flow patterns over the lake — however, the surface wind flow did not always correspond well to the motion of the undular bores.

Terra MODIS Visible (0.65 µm) image, with RTMA surface winds [click to enlarge]

Terra MODIS Visible (0.65 µm) image, with RTMA surface winds [click to enlarge]

Aqua MODIS Visible (0.65 µm) image, with RTMA surface winds [click to enlarge]

Aqua MODIS Visible (0.65 µm) image, with RTMA surface winds [click to enlarge]

(Thanks to TJ Turnage, the SOO in Grand Rapids MI, for alerting us to this mesmerizing event).

Using GOES-16 Baseline Products to anticipate where heavy rain might fall

July 10th, 2017 |

GOES-16 10.3 µm “Clean Window” Superimposed on the Clear-Sky Baseline Total Precipitable Water Product, 0107 – 1337 UTC on 10 July (Click to play large animated gif)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

Very heavy rain (4-5″) fell over parts of southwestern Wisconsin early on 10 July 2017 as a Mesoscale Convective System traversed the Upper Midwest (0831 UTC VIIRS Infrared vs Day/Night Band). The animation above blends the Clean Window (10.3 µm) from GOES-16 with the Total Precipitable Water Baseline Product (This product is available online — with a time delay — here). Note that the largest values of Precipitable Water are diagnosed to be over southern and western of Wisconsin. Looking at the animation of the 10.3 µm imagery, can you decide where the heaviest rain fell?

A screen capture from this website, below, shows 24-hour precipitation over the Upper Midwest, with a northwest-to-southeast oriented maximum near the northwest-to-southeast gradient of diagnosed total precipitable water field shown in the animation above. (This summary from the National Weather Service in Milwaukee shows accumulated precipitation ending at 0900 Central Time).

The Hazardous Weather Testbed at the Storm Prediction Center evaluates GOES-16 (and other satellites, such as Suomi NPP) products. There have been many instances that noted convection was most intense along the gradient of the moisture (See this summary, for example, or this one.) When GOES-16 Baseline Products indicate a gradient, pay close attention when strong convection develops upstream.

24-hour Precipitation over the Upper Midwest ending at 1200 UTC on 10 July 2017 (Click to enlarge)

Added: One day later, again, convection initiated (and/or persisted) north of the diagnosed Total Precipitable Water maximum over Illinois and Iowa (link), i.e., in the gradient of Total Precipitable Water.

GOES-16: wildfires in southern California

July 8th, 2017 |

GOES-16 Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images, with hourly surface plots [click to play MP4 animation]

GOES-16 Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images, with hourly surface plots [click to play MP4 animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

As southern California experienced a record-setting heatwave, 2 large wildfires were burning in San Luis Obispo and Santa Barbara counties on 08 July 2017: the Alamo Fire and the Whittier Fire. GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the smoke plumes and hot spots (red pixels) associated with these 2 fires.

The dense smoke plumes also exhibited a signature on the Near-Infrared “Cirrus” (1.37 µm) images (below), even though they were not composed of ice crystals (note that 10.3 µm Infrared Window brightness temperatures of the smoke plumes were warmer than -20º C, cyan color enhancement, the entire day). This example demonstrates that in a dry atmosphere, the “Cirrus” imagery will also be able to detect the presence of any airborne particles that are efficient scatterers of light (which includes smoke, dust and volcanic ash).

GOES-16 Visible (0.64 µm, left), Near-Infrared Cirrus (1.38 µm, center) and Infrared Window (10.3 µm, right) images, with station identifiers plotted in yellow [click to play MP4 animation]

GOES-16 Visible (0.64 µm, left), Near-Infrared Cirrus (1.37 µm, center) and Infrared Window (10.3 µm, right) images, with station identifiers plotted in yellow [click to play MP4 animation]

During  the nighttime prior to sunrise, with the benefit of ample illumination from a Full Moon, a long smoke plume streaming southwestward from the Alamo Fire was clearly seen on Suomi NPP VIIRS Day/Night Band (0.7 µm) imagery at 0910 UTC or 2:10 am local time (below). A very bright glow — larger than that of some nearby city lights — was co-located with the large hot spot on the corresponding Shortwave Infrared (3.74 µm) image.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images [click to enlarge]