Viewing Fall lightning with RealEarth

October 21st, 2021 |

Cooler temperatures across the Midwest don’t come without some severe weather. Yesterday evening and last night, a system brought rain and lightning to parts of Iowa, Minnesota, Wisconsin, Illinois, and Michigan, moving over Ohio by Thursday morning. RealEarth, a web-based visualization platform developed at UW-Madison, can display data from GOES-16 to monitor such events. RealEarth’s data archives usually go back at least 24-hours which provides temporal context to weather events.

RealEarth is a free data discovery and visualization platform developed at SSEC/CIMSS at the University of Wisconsin-Madison. It is available at realearth.ssec.wisc.edu.

A 24-hour animation every hour from RealEarth (time in UTC) showing GOES-16 ABI Band 13 with the purple areas representing lightning. More specifically, the purple areas depict Flash Extent Density from the Geostationary Lightning Mapper (GLM) also aboard GOES-16.

Eruption of Manam in Papua New Guinea

October 19th, 2021 |

Himawari-8 True Color RGB images [click to play animated GIF | MP4]

The Manam volcano in Papua New Guinea erupted around 2200 UTC on 19 October 2021. JMA Himawari-8 True Color RGB images created using Geo2Grid (above) showed lower- to middle-altitude ash clouds (shades of tan to brown) moving westward and northward, while the main eruptive cloud — composed of a mixture of ash, SO2 and ice particles — spread out at high altitudes to the east and north. (Side note: brief flashes of sun glint off some of the island rivers were also seen.)  

Retrieved values of Ash Height from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) indicated that the Manam eruption cloud reached maximum altitudes within the 16-18 km range. 

Himawari-8 Ash Height [click to play animated GIF | MP4]

GOES-17 Fog/Low Stratus (FLS) product availability in AWIPS

October 18th, 2021 |

GOES-17 MVFR Probability over the PACUS Sector [click to play animation]

The suite of Fog/Low Stratus (FLS) products derived using GOES-17 (GOES-West) data within the PACUS Sector (above) became available via the Satellite Broadcast Network (SBN) for AWIPS on 18 October 2021. Two examples are shown below: one centered over Oregon, and the other centered over the Big Island of Hawai’i. The 4 products are Marginal Visual Flight Rules (MVFR, cloud ceiling 1000 to 3000 feet above ground level and/or visibility 3 to 5 miles) Probability, Instrument Flight Rules (IFR, cloud ceiling 500 feet to less than 1000 feet and/or visibility 1 to less than 3 miles) Probability, Low Instrument Flight Rules (LIFR, cloud ceiling less than 500 feet and/or visibility less than 1 mile) Probability and Cloud Thickness. 

GOES-17 MVFR Probability (top left), IFR Probability (top right), Low IFR Probability (bottom left) and Low Cloud Thickness (bottom right) [click to play animation]

GOES-17 MVFR Probability (top left), IFR Probability (top right), Low IFR Probability (bottom left) and Low Cloud Thickness (bottom right) [click to play animation] 

GOES-17 FLS products are also being produced by CIMSS over the Alaska region (below) — which are being distributed via an LDM feed.

GOES-17 MVFR Probability (top left), IFR Probability (top right), Low IFR Probability (bottom left) and Low Cloud Thickness (bottom right) [click to play animation]

A library of FLS applications can be found on the GOES-R Fog Product Examples site, and FLS Forecaster Training is available here.

Using NUCAPS to diagnose threats in a region of Enhanced/Moderate risk

October 13th, 2021 |
GOES-16 Low-Level water vapor infrared imagery (Band 10, 7.34 µm) at 1931 UTC on 12 October 2021 (Click to enlarge). NOAA-20 NUCAPS Sounding Availability points are indicated as colored dots. METAR plots are also included.

The Storm Prediction Center in Norman issued a convective outlook on 12 October 2021 that included a large area of Enhanced Risk over western Kansas and Oklahoma, noting the expected development of a strong low-level jet creating favorable shear profiles for supercells. (SPC increased the threat to a Moderate Risk for a small part of southwestern Kansas and parts of the Oklahoma and Texas panhandles at 2000 UTC). The Band 10 low-level water vapor image above, from 1931 UTC. An initial round of convection is moving eastward over central Kansas. Did that convection stabilize the atmosphere? NUCAPS profiles can give information on that, information that is not dependent on numerical model simulations.

The plot below, taken from RealEarth, shows the Lifted Index computed from NUCAPS soundings blended with MADIS surface observations. The greatest instability, shaded in red, lies along the Kansas/Colorado border, and it extends to the southeast along the western Oklahoma/north Texas border. (Click here to see surface-based CAPE at the same time).

NUCAPS/MADIS Surface-based Lifted Index, 1952 UTC on 12 October 2021 (Click to enlarge)

What do individual profiles show? 20 different profiles over southwestern Kansas are in the stepped animation below. Steep mid-level lapse rates (greater than 8 K/km) are indicated in the soundings, and Most Unstable Convective Available Potential Energy (MUCAPE) values persist in the lower troposphere. It also appears that moisture is pooling along the Kansas/Colorado border: precipitable water values from two soundings (at 38.42 N/102.60 N and 38.04 N /101.89 W) and are greater than surrounding values. So: instability is present, and moisture is available. Model-independent information like this can help a forecaster during the wait for initiation.

GOES-16 Day Cloud Phase Distinction image at 1931 UTC, along with NUCAPS Sounding Availability plots. Individual profiles as indicated are shown in the inset; values from those soundings are shown in the grey box in upper left (Click to enlarge)

It can be time-consuming in AWIPS to look through multiple soundings (the Pop-up SkewT functionality can be helpful, but for subtle changes in precipitable water, or in lapse rate, that use is limited). Gridded NUCAPS fields are available in AWIPS, and also online. The 700-500 mb lapse rate, shown below, from this website, diagnoses the steep lapse rates that were present (perhaps to be expected given the suggestion of an elevated mixed layer in the water vapor imagery at the top of this blog post!)

Lapse Rate (700-500 mb) diagnosed from NOAA-20 NUCAPS, 1949 UTC on 12 October 2021 (Click to enlarge)

So what happened with this event? Convection developed along the Colorado/Kansas border, and spawned severe weather over western Kansas, western Oklahoma, and western Texas. GOES-16 clean window infrared imagery (10.3 µm), below, shown on top of the Level 2 stability Lifted index product, shows the instability and the development of the convection (Click here for a Band 13 animation only).

GOES-16 clean window infrared imagery (Band 13, 10.3 µm) and Level 2 Derived Stability Index (Lifted Index, clear sky only) from 2201 UTC on 12 October 2021 through 0646 UTC on 13 October 2021 (Click to enlarge).