Hurricane Hermine

September 1st, 2016

GOES-13 Visible (0.63 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

GOES-13 Visible (0.63 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

Hermine was upgraded to a Hurricane over the Gulf of Mexico around 20 UTC on 01 September 2016. GOES-13 (GOES-East) Visible (0.63 µm) images (above) showed improvement in the appearance of curved banding structures around the eye late in the day. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes. Note that Hurricane Hermine developed from Tropical Invest 99L, which was sampled by 1-minute GOES-14 imagery beginning on 25 August; unfortunately, the 1-minute Super Rapid Scan Operations for GOES-R (SRSO-R) test period ended at 1115 UTC on 29 August (however, imaging of the evolution of Tropical Depression 9 to Hurricane Hermine continued at 15-minute intervals).

The corresponding GOES-13 Infrared Window (10.7 µm) images (below) revealed the eventual formation of a distinct eye, with bursts of convection exhibiting cloud-top IR brightness temperatures in the -75º to -80º C range (shades of white to violet pixels) in the western and southern semicircles of the eyewall region. Hermine became the first hurricane to make landfall in Florida since Wilma in 2005.

GOES-13 Infrared Window (10.7 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with surface/buoy/ship reports plotted in yellow [click to play animation]

A Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image visualized using RealEarth (below) provided a detailed view of the curved banding around the western and southern portion of the eye.

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

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

A comparison of DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images around 2315 UTC (below) depicted a much larger eye presentation on microwave vs infrared — the microwave image showed the curved banding structure around an eye that was still not well-organized.

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

While Hermine passed over waters exhibiting warm Sea Surface Temperature values in the eastern Gulf of Mexico, the Ocean Heat Content values were only modest (below).

Sea Surface Temperature and Ocean Heat Content values [click to enlarge]

Sea Surface Temperature and Ocean Heat Content values [click to enlarge]

The high values of Total Precipitable Water (TPW) associated with Hermine were evident on hourly composites of morphed TPW from MIRS sensors (below). Rainfall amounts exceeded 22 inches in Florida (WPC storm summary)

Morphed Total Precipitable Water derived from MIRS sensors [click to play animation]

Morphed Total Precipitable Water derived from MIRS sensors [click to play animation]


===== Post-landfall Update, 02 September =====
 

Suomi-NPP overflew Hermine shortly after 0700 UTC on 02 September, after its 0530 UTC landfall near St. Mars FL. The toggle below shows the VIIRS 0.7 µm Day/Night Band and the 11.45 µm Infrared Window imagery. Both show the asymmetric nature of the storm. Rain and clouds extend quite a distance to the south and east of the storm, but not far to the west. The infrared imagery shows cold cloud tops surrounding the storm center southeast of Tallahassee, with very cold cloud tops also over Tampa FL and near Savannah GA with bands associated with the storm. Cloud detail is missing in the Day/Night Band image because of the lack of lunar illumination — a New Moon occurred early on 01 September — however, high-altitude mesospheric airglow waves (references: 1 | 2 | 3) can be seen off the east coast of Florida and Georgia, excited by Hermine’s bands of strong thunderstorms.

Suomi NPP Day/Night Band Visible (0.70 µm) and Infrared Window (11.45 µm) images at 0723 UTC on 2 September [click to enlarge]

Suomi NPP Day/Night Band Visible (0.70 µm) and Infrared Window (11.45 µm) images at 0723 UTC on 2 September [click to enlarge]

A toggle between before-landfall (0319 UTC Terra MODIS) and after-landfall (0814 UTC POES AVHRR) Infrared images, below, shows the expected trend of warming cloud-top IR brightness temperatures and a consolidation into a more compact storm circulation.

11.0 µm Terra MODIS (0319 UTC) and 12.0 µm POES AVHRR (0814 UTC) Infrared images [click to enlarge]

11.0 µm Terra MODIS (0319 UTC) and 12.0 µm POES AVHRR (0814 UTC) Infrared images [click to enlarge]

===== 03 September Update =====

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]

A toggle between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0707 UTC on 03 September (above; courtesy of William Straka, SSEC) showed that Hermine — still being classified as a Tropical Storm — continued to produce mesospheric airglow waves as it moved off the East Coast of the US. Numerous bright white streaks were also evident on the Day/Night Band image, due to cloud illumination from intense lightning activity.

During the following daylight hours of 03 September, GOES-13 (GOES-East) Visible (0.63 µm) images (below: also available as an MP4 animation) showed the circulation of post-tropical cyclone Hermine. In eastern North Carolina, winds gusts as high as 80 mph were recorded, with rainfall amounts as great as 8.54 inches (NWS Newport/Morehead City); the storm also produced a few tornadoes (SPC Storm Reports). In southeastern Virginia, winds gusted to 73 mph (NWS Wakefield). A few of the heavier rainfall amounts for individual states are listed here.

GOES-13 Visible (0.63 µm) images, with surface and buoy wind barbs plotted in yellow and wind gusts (knots) plotted in red [click to play animation]

GOES-13 Visible (0.63 µm) images, with surface and buoy wind barbs plotted in yellow and wind gusts (knots) plotted in red [click to play animation]

A Suomi NPP VIIRS true-color image visualized using RealEarth (below) showed the clouds associated with Hermine at 1827 UTC.

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

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

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]

GOES-14 SRSO-R: pyrocumulus clouds over the Rey Fire in California

August 22nd, 2016

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images [click to play MP4 animation]

The GOES-14 satellite was in SRSO-R mode on 22 August 2016, providing images at 1-minute intervals over the western United States. A 3-panel comparison of Visible (0.63 µm), Shortwave Infrared (3.9 µm) and Infrared Window (10.7 µm) images (above; also available as a large 110 Mbyte animated GIF) showed that there were multiple bursts of pyrocumulus (pyroCu) clouds over the Rey Fire in southern California — while the bulk of the smoke was being transported westward over the offshore waters of the Pacific Ocean, smoke that was ejected to higher altitudes by the pyroCu clouds sent a plume of smoke drifting to the southeast.

The nearby Vandenberg rawinsonde data profile (below) suggests that the pyroCu clouds vertically lofted smoke to an altitude of at least 6.7 km (the 449 mb pressure level), where winds shifted to a northwesterly direction. However, since the pyroCu cloud-top IR brightness temperatures never even made it to -20º C (cyan color enhancement on the bottom panels), the smoke probably wasn’t much higher than the 6.7 km altitude (sounding data).

Vandenberg Air Force Base rawinsonde report [click to enlarge]

Vandenberg Air Force Base rawinsonde report [click to enlarge]

A comparison of Suomi NPP VIIRS true-color and false-color Red/Green/Blue (RGB) images displayed using RealEarth (below) showed the dense plume of smoke drifting westward away from the active fire area (brighter shades of pink on the false-color image), along with a pyroCu cloud over the fire and the early stage of the southeastward-moving smoke plume aloft.

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Suomi NPP VIIRS true-color and false-color images [click to enlarge]

Deep cyclone over Hudson Bay

August 11th, 2016

GOES-13 Water Vapor (6.5 µm) images, with hourly surface observations [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with hourly surface observations [click to play animation]

GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above) showed the intensification of a strong cyclone over Hudson Bay, Canada during the 09 August – 10 August 2016 period; the cyclone deepened to a central pressure of 980 hPa (28.94″ of mercury) at 06 UTC on 10 August.

Daily composites of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images visualized using RealEarth (below) showed the storm on 08, 09 and 10 August.

Suomi NPP VIIRS true-color RGB images [click to enlarge]

Suomi NPP VIIRS true-color RGB images [click to enlarge]