Severe turbulence over coastal South Carolina

November 15th, 2019 |

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of pilot reports and SIGMET boundaries [click to play animation | MP4]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with pilot reports of turbulence and SIGMET boundaries [click to play animation | MP4]

GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) images (above) revealed the presence of elongated W-E oriented billow clouds, many of which exhibited small-scale ripples that were oriented N-S along the billow cloud tops, over coastal areas of South Carolina and North Carolina on 15 November 2019. An initial SIGMET (November 1) was issued covering airspace over Georgia and South Carolina — Severe Turbulence (plotted in red) was reported at 41,000 feet and at 35,000 feet. A second SIGMET (November 2) was later issued covering airspace over South Carolina and North Carolina.

The same GOES-16 Water Vapor images which include isotachs of RAP40 model maximum wind (at any level) are shown below — most of the Moderate to Severe turbulence reports were occurring within the speed gradient along the poleward (left) edge of a SW-NE oriented jet stream flowing parallel to the coast.

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of pilot reports, SIGMET boundaries, and isotachs of RAP40 model maximum wind [click to play animation | MP4]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with pilot reports of turbulence, SIGMET boundaries, and isotachs of RAP40 model maximum wind [click to play animation | MP4]

More detailed views of the billow-top ripples were provided by a Terra MODIS Visible image at 1600 UTC, and NOAA-20 VIIRS True Color Red-Green-Blue (RGB) and Infrared images as visualized using RealEarth (below).

Terra MODIS Visible (0.65 µm) image, with plots of pilot reports and SIGMET boundaries [click to enlarge]

Terra MODIS Visible (0.65 µm) image, with pilot reports of turbulence and SIGMET boundaries [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images, with pilot reports of turbulence [click to enlarge]

NOAA-20 VIIRS True Color RGB and Infrared Window (11.45 µm) images, with pilot reports of turbulence [click to enlarge]

Lake-effect, river-effect and bay-effect cloud bands producing snowfall

November 13th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm), “Clean” Infrared Window (10.35 µm) and Day Cloud Phase Distinction RGB images on 07 November [click to play animation | MP4]

During the course of multiple intrusions of arctic air across the Lower 48 states during early November 2019, a variety of lake-effect, river-effect and bay-effect cloud features were generated — many of which produced varying intensities of snowfall. GOES-16 (GOES-East) “Red” Visible (0.64 µm), “Clean:” Infrared Window (10.35 µm) and Day Cloud Phase Distinction Red-Green-Blue (RGB) images on 07 November (above) showed lake-effect clouds streaming south-southeastward across Lake Superior. The Day Cloud Phase Distinction RGB images (in tandem with the Infrared images) helped to highlight which cloud features had glaciated and were therefore more capable of producing moderate to heavy lake-effect snow; the dominant band yielded 5-10 inches of snowfall in the central part of northern Michigan.

On 11 November, GOES-16 Nighttime Microphysics RGB images (below) displayed lake-effect clouds originating from the still-unfrozen waters of Fort Peck Lake in northeastern Montana — these clouds did produce a brief period of light snowfall downstream at Glendive (KGDV). On this particular morning, the lowest temperature in the US occurred in north-central Montana, with -30ºF reported north of Rudyard.

GOES-16 Nighttime Cloud Phase Distinction RGB images on 11 November [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB images on 11 November [click to play animation | MP4]

On 12 November, cold air moving southward across the Lower Mississippi Valley produced horizontal convective roll clouds which were evident in GOES-16 Nighttime Microphysics RGB and subsequent Visible images after sunrise (below) — one of these narrow cloud bands was likely enhanced by latent heat fluxes as it passed over the comparatively-warm waters of the Mississippi River, and produced accumulating snowfall in downtown Memphis. Note that since Memphis International Airport KMEM was located just east of the cloud band, no accumulating snow was reported there (only a brief snow flurry around 1430 UTC).

GOES-16 Nighttime Microphysics RGB and "Red" Visible (0.64 µm) images on 12 November [click to play animation | MP4]

GOES-16 Nighttime Microphysics RGB and “Red” Visible (0.64 µm) images on 12 November [click to play animation | MP4]

Aqua MODIS Sea Surface Temperature values along parts of the Mississippi River were as warm as the mid-40s F (below).

MODIS Sea Surface Temperature product at 1848 UTC on 12 November; rivers are plotted in red [click to enlarge]

Aqua MODIS Sea Surface Temperature product at 1848 UTC on 12 November; rivers are plotted in red [click to enlarge]


On 13 November, as the cold air was moving off the US East Coast, GOES-16 Infrared images (below) revealed bay-effect cloud plumes which developed over Chesapeake Bay and Delaware Bay — the Chesapeake Bay plume produced brief periods of light snow at Oceana Naval Air Station in Virginia Beach KNTU from 06-10 UTC (and possibly contributed to snowfall farther south at Elizabeth City, North Carolina KECG).

GOES-16 "Clean" Infrared Window (10.35 µm) images on 12 November [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images on 12 November [click to play animation | MP4]

Terra MODIS Sea Surface Temperature values in Chesapeake Bay and Delaware Bay were in the lower to middle 50s F where the bay-effect cloud plumes were originating (below).

Terra MODIS Sea Surface Temperature product and Visible (0.65 µm) image at 1613 UTC [click to enlarge]

Terra MODIS Sea Surface Temperature product and Visible (0.65 µm) image at 1613 UTC [click to enlarge]

Kincade Fire in Northern California

October 24th, 2019 |

GOES-17 multi-panel images showing all 16 ABI spectral bands [click to play animation | MP4]

GOES-17 multi-panel images showing all 16 ABI spectral bands [click to play animation | MP4]

1-minute interval (and 30-second interval, beginning at 0730 UTC) Mesoscale Domain Sector GOES-17 (GOES-West) multi-panel images showing all 16 ABI spectral bands (above) revealed the hot thermal signature of the Kincade Fire in Northern California on 24 October 2019. The fire thermal anomaly first became evident in Shortwave Infrared and Near-Infrared imagery at 0421 UTC or 9:21 PM PDT on 23 October (0421 UTC image | 6-minute animation). A weather station close to the fire (Healdsburg Hills) recorded winds gusting to 76 mph less than 2 hours after the fire started; at that time, the Relative Humidity was only 11%. Above-normal temperatures were also present across that region of California, with Downtown Oakland setting a daily record high of 89ºF.

At times the fire’s hot thermal emissions were detected by 13 of the 16 spectral bands — including very subtle signatures in the “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and “Cirrus” (1.38 µm), and Low-level Water Vapor (7.34 µm) bands (below). The hottest Shortwave Infrared (3.9 µm) brightness temperature observed was 138.7ºC (411.9 K), which is the saturation temperature for those ABI detectors.

Since overlapping 1-minute GOES-17 Mesoscale Sectors provided 30-second Visible images, the westward transport of dense smoke from the fire source could be followed in great temporal and spatial detail (below). Note that a ship about 50 miles offshore reported smoke at 18 UTC. Just south of the dense plume, smoke was being reported at Santa Rosa — but the surface visibility remained at 10 miles.

GOES-17

GOES-17 “Red” Visible (0.64 µm) images, with surface reports plotted in yellow [click to play animation | MP4]

A larger-scale view using the GOES-17 CIMSS Natural Color Red-Green-Blue (RGB) product (below) indicated that smoke had been transported about 400 miles offshore by 20 UTC.

GOES-17 CIMSS Natural Color RGB images [click to play animation | MP4]

GOES-17 CIMSS Natural Color RGB images [click to play animation | MP4]

A toggle between Terra MODIS True Color and False Color RGB images from the MODIS Today site (below) provided a more detailed view of the smoke plume and the thermal anomaly (shades of pink to red) associated with the large Kincade Fire (as well as the much smaller Muir Fire near the coast, north of San Francisco).

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

Terra MODIS True Color and False Color RGB images at 1826 UTC [click to enlarge]

A comparison of Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images at 0900 and 2023 UTC (below) showed the expansion of the fire’s thermal anomaly (red to black pixels) during that ~11.5 hour period.

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images at 0900 and 2023 UTC [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.74 µm) images at 0900 and 2023 UTC; the solid violet line west of the fire is California Highway 101. [click to enlarge]

Severe weather in Minnesota and Wisconsin

July 19th, 2019 |

GOES-16 "Red" Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the development and propagation of a Mesoscale Convective System (MCS) that produced hail up to 3.0 inches in diameter in Minnesota and wind gusts to 84 mph and a few tornadoes in Wisconsin (SPC Storm Reports | NWS Twin Cities | MN DNR | NWS Green Bay) on 19 July 2019. Numerous overshooting tops and widespread storm-top gravity waves were evident in the imagery, along with a few Above-Anvil Cirrus Plume features extending northeastward from some of the overshooting tops around sunset. Also notable were the inflow feeder bands that were streaming northward into the southern flank of the MCS across Minnesota.

A comparison of GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (below) revealed cloud-top infrared brightness temperatures as cold as -86ºC over northwestern Wisconsin.

GOES-16

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play MP4 animation]

As the MCS persisted into the subsequent nighttime hours, GOES-16 Infrared images (below) showed the large canopy of cold cloud tops, with infrared brightness temperatures of -80ºC or colder (violet pixels).  Some of the embedded storms exhibited well-defined Enhanced-V storm top signatures (for example, at 2219 UTC).

GOES-16

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

===== 22 July Update =====

Terra MODIS True Color RGB images, 11 July vs 22 July [click to enlarge]

Terra MODIS True Color RGB images, 11 July vs 22 July [click to enlarge]

A comparison of Terra MODIS True Color Red-Green-Blue (RGB) images from 11 July and 22 July (above) showed the subtle NW-SE oriented swath of downed trees across northeastern Wisconsin. A 14 July vs 22 July comparison as viewed using RealEarth is shown below — the swath extended from approximately Pickerel to Mountain.

14 July and 22 July Terra MODIS True Color RGB images [click to enlarge]

Terra MODIS True Color RGB images, 14 July vs 22 July [click to enlarge]

In 22 July Terra MODIS images displayed using AWIPS (below), the swath of downed trees was brighter (more reflective) in the Near-Infrared “Snow/Ice” (1.61 µm), warmer (darker shades of orange to red) in the Shortwave Infrared (3.7 µm) and Land Surface Temperature, and lighter shades of green in the Normalized Difference Vegetation Index.

Terra MODIS Visible (0.65 µm), Near-Infrared "Snow/Ice" (1.61 µm), Shortwave Infrared (3.7 µm), Land Surface Temperature and Normalized Difference Vegetation Index images on 22 July [click to enlarge]

Terra MODIS Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.7 µm), Land Surface Temperature and Normalized Difference Vegetation Index images on 22 July [click to enlarge]

The swath of downed trees was also seen in GOES-16 Normalized Difference Vegetation Index images (below), showing up as a darker shade of green with that product’s default enhancement.

GOES-16 Normalized Difference Vegetation Index images [click to play animation]

GOES-16 Normalized Difference Vegetation Index images on 22 July [click to play animation]