Detection of River Flooding in Alaska

August 31st, 2016 |
Google Maps of west central Alaska, the JPSS River Flood Product and Landsat-8 False Color Imagery, 30 August 2016 [click to enlarge]

Google Maps of west central Alaska, the JPSS River Flood Product and Landsat-8 False Color Imagery, 30 August 2016 [click to enlarge]

Swampy conditions near the meandering Innoko River, a tributary to the Yukon River in Alaska, have been diagnosed by the JPSS River Flood Product near the Innoko’s mouth on the Yukon. (August has been very wet over parts of Alaska) A timely Landsat-8 overpass, in clear skies, on 30 August 2016 allows for excellent validation of the Flood Product. The animation above (using Images from RealEarth) cycles between the Google Maps terrain and satellite views of the region, the JPSS Flood Product (developed by a group led by Sanmei Li at George Mason University, which product uses reflective channels on JPSS (I01, I02, and I03, 0.64 µm, 0.86 µm and 1.61 µm, respectively) and I05, the 11.45 µm channel) and the Landsat-8 False Color overpass. Diagnosed floods in the JPSS Product are distinctly captured in the Landsat-8 False Color product.

Three Tropical Cyclones in the Atlantic Basin

August 29th, 2016 |

GOES-13 Water Vapor Infrared (6.5 µm) Imagery, 2345 UTC 23 August - 1945 UTC 29 August [click to animate]

GOES-13 Water Vapor Infrared (6.5 µm) Imagery, 2345 UTC 23 August – 1945 UTC 29 August [click to animate]

The hourly water vapor animation above over the Atlantic Basin shows the evolution of a strong tropical wave that moved through the Greater Antilles during the week of 23-29 August 2016. (GOES-14 viewed this system on 25 August and 28 August). There are many areas of convection, including Hurricane Gaston, which storm enters the domain from the east. Gaston is no threat to land, however.

Of more interest to the United States are Tropical Depression #8, a small system just southeast of Cape Hatteras, represented as a circular cluster of thunderstorms at the end of the animation, and Tropical Depression #9 near western Cuba. (Click here for an annotated water vapor imagery identifying the storms) Tropical Depression #9 has emerged from the system discussed here. Interests along the coast of North Carolina and Virginia should pay close attention to forecasts on Tropical Depression #8, and those on the Gulf Coast from Louisiana eastward should monitor Tropical Depression #9. For the latest information, see the webpages of the National Hurricane Center.

MIMIC Total Precipitable Water, below, for the 72 hours ending at 1800 UTC on 29 August (from this site), shows that Tropical Depression #8 and Hurricane Gaston, are near regions of dry air that might influence their evolution. In contrast, Tropical Depression #9 is embedded within an atmosphere rich in moisture.

The next two names for tropical cyclones in the Atlantic are Hermine and Ian.

Total Precipitable Water, 1900 UTC 26 August - 1800 UTC 29 August 2016 [click to enlarge]

Total Precipitable Water, 1900 UTC 26 August – 1800 UTC 29 August 2016 [click to enlarge]

Typhoon Lionrock in the West Pacific

August 27th, 2016 |

Track of Typhoon Lionrock [click to enlarge]

Track of Typhoon Lionrock [click to enlarge]

Typhoon Lionrock (12W) in the West Pacific Ocean briefly intensified to Category 4 during the northeastward motion segment of its rather unusual track (above) — the intensity estimate from the Advanced Dvorak Technique peaked at 112.4 knots from 2140 UTC on 26 August to 0630 UTC on 27 August (plot | text).

During this period of intensification, 2.5 minute interval rapid-scan Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images (below; also available as a large 85 Mbyte animated GIF) revealed complex patterns of cloud-top radial and transverse banding. Surface mesoscale vortices were also seen at times within the open eye feature.

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

A few hours later, the Category 3 intensity typhoon continued to exhibit a well-defined eye structure in both DMSP-15 SSMI Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images around 18 UTC (below).

DMSP-15 SSMI Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

DMSP-15 SSMI Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

During the nighttime hours preceding the intensification to Category 4, a comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (below; courtesy of William Straka, SSEC) showed the eye of Lionrock at 1631 UTC on 26 August.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

===== 28 August Update =====

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play MP4 animation]

Typhoon Lionrock again intensified to a Category 4 storm on 28 August; a comparison of 2.5 minute interval rapid-scan Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images is shown above (also available as a large 68 Mbyte animated GIF).

323 reindeer killed by lightning in Norway

August 26th, 2016 |

GFS model fields of surface pressure, 6-hour precipitation, 850 hPa temperature, and 10-m wind [click to play animation]

GFS model fields of surface pressure, 6-hour precipitation, 850 hPa temperature, and 10-m wind [click to play animation]

GFS model fields from this site (above) showed a relatively compact storm that was deepening as it moved northeastward across southern and central Norway on 26 August 2016.

EUMETSAT Meteosat-10 Visible (0.75 µm) and Infrared Window (10.8 µm) images (below; also available as an MP4 animation) revealed the development of thunderstorms over southern Norway during the 0900-1300 UTC period. Cloud-to-ground lightning from one of these storms is believed to have killed 323 reindeer near the southeastern corner of the Hardangervidda National Park (which is located in the center of the visible and infrared satellite images).

Meteosat-10 Visible (0.75 µm, top) and Infrared Window (10.8 µm, bottom) images, with surface reports plotted in cyan [click to play animation]

Meteosat-10 Visible (0.75 µm, top) and Infrared Window (10.8 µm, bottom) images, with surface reports plotted in cyan [click to play animation]

The coldest cloud-top infrared brightness temperatures of the thunderstorms on the 1100 UTC image was -51º C, which corresponded to an altitude of around 10.5 km on the 1200 UTC Ørland rawinsonde report (below) — looking at the individual sounding profiles, Ørland to the north of Hardangervidda was still in the moist convective environment near the center of the storm system, while Stavanger to the south began to show the drier air aloft in the wake of the northeastward-moving storm.

Rawinsonde data from Stavanger and Orland, Norway [click to enlarge]

Rawinsonde data from Stavanger and Orland, Norway [click to enlarge]

A composite of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image swaths as viewed using RealEarth (below) showed the widespread thunderstorms across southern Norway on the earlier (eastern) 1103 UTC overpass, while the later (western) 1243 UTC overpass showed the effects of the mid-level drier air that was beginning to overspread the region as the center of the parent storm system moved northeast.

Suomi NPP VIIRS true-color image swaths [click to enlarge]

Suomi NPP VIIRS true-color image swaths [click to enlarge]