Ex-hurricane Ophelia over Ireland and the United Kingdom

October 16th, 2017 |

Meteosat-10 Water Vapor (6.25 µm) images, with hourly surface wind gusts (knots) plotted in red [click to play MP4 animation]

Meteosat-10 Water Vapor (6.25 µm) images, with hourly surface wind gusts (knots) plotted in red [click to play MP4 animation]

After reaching Category 3 intensity over the eastern Atlantic Ocean on 14 October, Hurricane Ophelia rapidly underwent transition to an extratropical storm which eventually spread high winds across much of Ireland and the United Kingdom on 16 October 2017. EUMETSAT Meteosat-10 upper-level Water Vapor (6.25 µm) (above) and lower-level Water Vapor (7.35 µm) images (below) revealed the familiar “scorpion tail” signature of a sting jet (reference). Hourly wind gusts (in knots) from primary reporting stations are plotted in red.

Meteosat-10 Water Vapor (7.35 µm) images, with hourly surface wind gusts (knots) plotted in red [click to play MP4 animation]

Meteosat-10 Water Vapor (7.35 µm) images, with hourly surface wind gusts (knots) plotted in red [click to play MP4 animation]

Two sites with notable wind gusts were Cork, Ireland (67 knots at 0930 UTC) and Valley, UK (70 knots at 1500 UT), shown below. In fact, a wind gust of 103 knots (119 mph or 191 km/hour) was reported at the Fastnet Rock Lighthouse off the southwest coast of Ireland.

Time series plot of surface data from Cork, Ireland [click to enlarge]

Time series plot of surface data from Cork, Ireland [click to enlarge]

Time series plot of surface data from Valley, United Kingdom [click to enlarge]

Time series plot of surface data from Valley, United Kingdom [click to enlarge]

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Terra and Aqua MODIS true-color images [click to enlarge]

Terra and Aqua MODIS true-color images [click to enlarge]

In a toggle between Terra MODIS (overpass time around 1159 UTC) and Aqua MODIS (overpass time around 1345 UTC) true-color Red/Green/Blue (RGB) imagery (above), a somewhat hazy appearance was seen over the Irish Sea on the Terra MODIS image. This was due to an airborne plume of sand from the Sahara Desert (UK Met Office story).

In fact, blowing sand was observed about 3 hours later at Isle of Man, from 1520-1620 UTC — during that time period their surface winds gusted to 68 knots (78 mph), and surface visibility was reduced to 2.2 miles (below).

Time series plot of surface data from Isle of Man [click to enlarge]

Time series plot of surface data from Isle of Man [click to enlarge]

Hurricane Harvey makes landfall

August 26th, 2017 |

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

As Hurricane Harvey moved across warm waters in the northwestern Gulf of Mexico (SST | OHC), it continued to intensify (ADT | SATCON) to a Category 4 hurricane just before making landfall (which occurred around 03 UTC on 26 August 2017, or 10 pm local time on 25 August). A GOES-16 Mesoscale Sector had been positioned over Harvey, providing images at 30-second intervals; some of these are shown with “Red” Visible (0.64 µm) images prior to sunset (below). A GOES-16 vs GOES-13 (GOES-East) Visible image comparison is available here.

GOES-16 Visible (0.64 µm) images, with hourly surface ports plotted in yellow (Click to play MP4 animation)

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

Hurricane Harvey had a large eye on GOES-16 “Clean” Infrared Window (10.3 µm) images at landfall, which persisted — albeit becoming smaller with time — for many hours after it moved inland (below). A longer-term animation of 5-minute GOES-16 Infrared Window images (covering the period 23-27 August) is available here.

GOES-16

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

A sequence of 4 Infrared Window images, from Suomi NPP VIIRS and Terra/Aqua MODIS, covering the period 0419-0851 UTC (below) showed the shrinking eye and the erratic path of Harvey once it moved inland.

Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) Infrared Window images [click to enlarge]

Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) Infrared Window images [click to enlarge]

A recap of the torrential rainfall amounts and maximum wind gusts caused by Hurricane Harvey can be seen in the WPC Storm Summary.

Wildfire burning in Greenland

August 4th, 2017 |
GOES-16 Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images [click to play animation]

GOES-16 Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images [click to play animation]

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

GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above; a zoomed-in version is available here) displayed a subtle hazy signature of a smoke plume along with an intermittent “hot spot” (darker black pixels) associated with  a small fire — located near the center of the cyan circle — that was burning close to the southwest coast of Greenland on 01 August 2017. The approximate latitude/longitude coordinates of the fire were 67.87º N / 51.48º W, a location about halfway between Ilulissat (station identifier BGJN) and Kangerlussuaq (station identifier BGSF) and about halfway between the western edge of the Greenland Ice Sheet and the west coast .

Closer views using daily composites of 250-meter resolution Terra and Aqua MODIS true-color Red/Green/Blue (RGB) images (from 30 July to 04 August), sourced from RealEarth (below) indicated that the fire may have started close to 1540 UTC on 31 July — when a small white smoke and/or cloud feature (just north of the cursor) was seen at the fire source location on the Terra image (overpass time). The Aqua overpass time was around 1600 UTC.

Daily composites of Terra MODIS true-color RGB images, from 30 July to 04 August [click to enlarge]

Daily composites of Terra MODIS true-color RGB images, from 30 July to 04 August [click to enlarge]

Daily composites of Aqua MODIS true-color RGB images, from 30 July to 04 August [click to enlarge]

Daily composites of Aqua MODIS true-color RGB images, from 30 July to 04 August [click to enlarge]

Similar daily composite RGB images from Suomi NPP VIIRS (31 July to 04 August) are shown below. Note that the initial fire signature was not seen on the 31 May VIIRS image, due to the earlier overpass time  (1513 UTC) of the Suomi NPP satellite.

Daily composites Suomi NPP VIIRS true-color RGB images,.from 31 July to 04 August [click to enlarge]

Daily composites of Suomi NPP VIIRS true-color RGB images,.from 31 July to 04 August [click to enlarge]

On 03 August, a 1507 UTC overpass of the Landsat-8 satellite provided a 30-meter resolution Operational Land Imager (OLI) false-color RGB image of the fire (below). This was the same day that a pilot took photos of the fire, as reported on the Wildfire Today site.

Landsat-8 false-color RGB image [click to enlarge]

Landsat-8 OLI false-color RGB image [click to enlarge]

A comparison of one “before” (27 July) and two “after” (03 and 05 August) Landsat-8 OLI false-color RGB images (below) showed differences in smoke plume transport as the wind direction changed.

Landsat-8 false-color images on 27 July, 03 August and 05 August [click to enlarge]

Landsat-8 OLI false-color images on 27 July, 03 August and 05 August [click to enlarge]

It is possible that this “natural fire” is similar to the Smoking Hills type of spontaneous combustion that has been observed in the Canadian Arctic (thanks to Ray Hoff, retired UMBC Professor of Physics, for that tip).

Credit to Mark Ruminski (NOAA/NESDIS) for first bringing this interesting event to our attention.

===== 09 August Update =====

The animations of daily Terra and Aqua true-color RGB images (below) have been extended to 09 August and 08 August, respectively.

Daily composites of Terra MODIS true-color RGB images, from 30 July to 09 August [click to enlarge]

Daily composites of Terra MODIS true-color RGB images, from 30 July to 09 August [click to enlarge]

Daily composites of Aqua MODIS true-color RGB images, from 30 July to 08 August [click to enlarge]

Daily composites of Aqua MODIS true-color RGB images, from 30 July to 08 August [click to enlarge]

Suomi NPP VIIRS true-color RGB images from 04-09 August (below) include VIIRS-detected fire locations plotted in red. The 09 August image showed that smoke from the fire had drifted west-southwestward over the adjacent offshore waters of Davis Strait.

Daily composites of Suomi NPP VIIRS true-color RGB images, from 04-09 August, with fire detection points plotted in red [click to enlarge]

Daily composites of Suomi NPP VIIRS true-color RGB images, from 04-09 August, with fire detection points plotted in red [click to enlarge]

===== 12 August Update =====

Landsat-8 OLI false-color images on 03, 05 and 12 August [click to enlarge]

Landsat-8 OLI false-color images on 03, 05 and 12 August [click to enlarge]

Another overpass of Landsat-8 on 12 August provided a glimpse of the fire burn scar, which appeared as a darker hue of reddish-brown. Note that the fire had burned eastward to the coast, during a day when stronger westerly winds prevailed.

Related sites:

NASA Earth Observatory

NPR

ESA Space in Images

AGU EOS

 

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).