Blowing dust in southern Bolivia

July 4th, 2020 |

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) showed plumes of blowing dust originating from dry river beds along portions of the Río Grande O Guapay and Río Parapetí in southern Bolivia on 04 July 2020. Strong northerly winds developed across that region, just east of the axis of a deepening trough of low pressure.

VIIRS True Color RGB images from Suomi NPP and NOAA-20 as visualized using RealEarth (below) provided a more detailed view at the blowing dust plumes.

VIIRS True Color RGB images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB images from Suomi NPP and NOAA-20 [click to enlarge]

A plot of surface report data from Viro Viru International Airport, Santa Cruz de la Sierra — located not far to the north of the blowing dust plumes — showed northerly winds gusting as high as 36 knots (41 mph) at 20 UTC (below).

Plot of surface report data from Viro Viru International Airport [click to enlarge]

Plot of surface report data from Viro Viru International Airport [click to enlarge]

Thanks to Santiago Gassó for pointing out these dust features.

Fancy some time on the Lake? ACSPO SSTs show the warmest (and coolest) waters

July 1st, 2020 |

ACSPO Lake Surface Temperatures over Lakes Erie and Ontario, early morning on 01 July 2020 (Click to enlarge)

Advanced Clear-Sky Processing of Oceans (ACSPO) Sea Surface Temperatures (SSTs or, in this case, Lake Surface Temperatures, LSTs) are available via an LDM feed from CIMSS for insertion into AWIPS.  Clear skies over the lower Great Lakes (Erie and Ontario) for the morning overpasses of Suomi NPP (orbit paths, from this site) and NOAA-20 (orbit paths, from this site), toggled above, allow for an accurate depiction of lake surface temperatures.  Warmest Lake Erie temperatures are in the western part of the lake (mid-70s), with low 70s along the southern shore of the lake.  Surface temperatures are in the upper 60s on the Ontario side of the lake, with the exception of warm temperatures in Long Point Bay.

In Lake Ontario, temperatures are warmest over the southwest part of the Lake (almost 70!) and coolest along the north shore (low/mid 60s).  Note that the region that is warmest does have a different signal in the True Color imagery, below, cropped from an experimental CIMSS website (VIIRS Today).

NOAA-20 True Color imagery over western Lake Ontario, 30 June 2020 (click to enlarge)

Actinoform clouds near Hawai’i

June 30th, 2020 |

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) revealed 3 cyclonically-rotating actinoform cloud structures that were moving west-southwestward toward the Hawaiian Islands on 30 June 2020 (surface analyses).

A closer look at the northernmost actinoform feature showed it moving over Buoy 51000 (located northeast of Hawai’i) around 04 UTC on 01 July — there was somewhat of an increase in 1-minute wind speeds and wind gusts as it approached, but no obvious perturbation was seen in the air pressure (it appeared to have arrived during the typical ~12-hourly drop in pressure).

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

A sequence of 3 hourly (at 0010, 0110 and 0210 UTC) panoramic camera views from Buoy 51000 (below) suggested that there were rain showers reaching the ocean surface beneath one of the actinoform’s radial arms at 0210 UTC (GOES-17 Visible image).

Sequence of 3 hourly (at 0010, 0110 and 0210 UTC) panoramic camera views from Buoy 51000 [click to enlarge]

Sequence of 3 hourly panoramic camera views from Buoy 51000, at 0010, 0110 and 0210 UTC [click to enlarge]

True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) VIIRS images from NOAA-20 and Suomi NPP as visualized using RealEarth (below) provided a detailed view of 2 of the actinoform clouds. The radial arms that comprised the cloud features remained within the marine boundary layer, so they exhibited fairly warm cloud-top infrared brightness temperatures.

True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

Plots of rawinsonde data from Hilo, Hawai’i (below) indicated that the marine boundary layer was strongly capped by a temperature inversion at an altitude of 1.3-1.5 km (where the air temperature was around +15ºC — which was very close to the minimum cloud-top infrared brightness temperatures exhibited by the actinoform clouds).

Plots of rawinsonde data from Hilo, Hawai'i [click to enlarge]

Plots of rawinsonde data from Hilo, Hawai’i [click to enlarge]

Other examples of actinoform clouds have been shown in May 2019, March 2008, March 2007 and June 1997.

Thunderstorms affecting American Samoa

June 20th, 2020 |

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (above) showed thunderstorms beginning to increase in areal coverage north of and in the vicinity of American Samoa on 20 June 2020, as a surface trough north of the islands began to move southward.

To monitor the flash flooding potential of these thunderstorms, a GOES-17 (GOES-West) Mesoscale Domain Sector was positioned over the American Samoa region — which provided “Clean” Infrared Window (10.35 µm) images at 1-minute intervals (below). Some of these storms exhibited minimum cloud-top infrared brightness temperatures around -80ºC (black enhancement), producing heavy rainfall (over 6 inches in 9 hours) and strong winds (gusting to 60 mph) according to the NWS Pago Pago compilation of local storm reports.

GOES-17 "Clean" Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-17 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]