“Medicane” in the Mediterranean Sea

October 31st, 2016 |

EUMETSAT Meteosat-10 Infrared Window (10.8 um) images [click to play MP4 animation]

EUMETSAT Meteosat-10 Infrared Window (10.8 um) images [click to play MP4 animation]

A compact tropical-like cyclone (often referred to as a “medicane“) moved across the Mediterranean Sea during the 28-31 October 2016 period. EUMETSAT Meteosat-10 Infrared Window (10.8 um) images (above; also available as a 71 Mbyte animated GIF) showed the system as it developed over the Ionian Sea between Italy and Greece, initially moved southwestward, and then turned to the east where it eventually passed near the Greek island of Crete on 31 October (producing a wind gust to 52 knots at Chania’s Souda Airport LGSA and causing some wind and water damage: media story 1 | media story 2). In addition, a wind gust to 50 knots was seen on a ship report at 12 UTC on 28 October, just to the west of the storm center.

The corresponding EUMETSAT Meteosat-10 Visible (0.64 um) images (below; also available as a 17 Mbyte animated GIF) provided a more detailed look at the structure of the storm during the daylight hours of those 4 days.

EUMETSAT Meteosat-10 Visible (0.64um) images [click to play MP4 animation]

EUMETSAT Meteosat-10 Visible (0.64um) images [click to play MP4 animation]

Daily snapshots of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images viewed using RealEarth are shown below. The hazy signature of blowing dust/sand from northern Africa could be seen within the broad southeast quadrant of the storm circulation.

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

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

There was ample moisture available to fuel convection around the storm, as seen in the MIMIC Total Precipitable Water product (below).

MIMIC Total Precipitable Water product [click to play animation]

MIMIC Total Precipitable Water product [click to play animation]

The surface wind circulation of the medicane was well-sampled on a variety of Metop-A and Metop-B overpasses, using ASCAT plots (below) from this site.

Metop-A and Metop-B ASCAT surface scatterometer winds, 28-31 October [click to play animation]

Metop-A and Metop-B ASCAT surface scatterometer winds, 28-31 October [click to play animation]

Suomi NPP ATMS images (below; courtesy of Derrick Herndon, CIMSS) revealed the areal coverage of the small “warm core” on Channel 8 (54.94 GHz) and Channel 7 (53.596 GHz); a north-to-south oriented vertical cross section showed the depth of the thermal anomaly associated with the medicane.

Suomi NPP ATMS Channel 8 (54.94 GHz) image, 31 October at 0037 UTC [click to enlarge]

Suomi NPP ATMS Channel 8 (54.94 GHz) image, 31 October at 0037 UTC [click to enlarge]

Suomi NPP ATMS Channel 7 (53.596 GHz) image, 31 October at 0037 UTC [click to enlarge]

Suomi NPP ATMS Channel 7 (53.596 GHz) image, 31 October at 0037 UTC [click to enlarge]

 

North-to-south vertical cross section of Suomi NPP ATMS brightness temperature anomaly [click to enlarge]

North-to-south vertical cross section of Suomi NPP ATMS brightness temperature anomaly [click to enlarge]

For additional information, see this blog post from the Capital Weather Gang.

 

Hurricane Nicole

October 13th, 2016 |

Track of Nicole, from 12 UTC on 04 October to 12 UTC on 13 October [click to enlarge]

Track of Nicole, from 12 UTC on 04 October to 12 UTC on 13 October [click to enlarge]

From its inception as a highly-sheared Tropical Storm on 04 October, Nicole moved in an erratic path with small intensity fluctuations for 8 days (above); then a period of intensification began on 12 October, with the storm reaching Category 4 intensity southwest of Bermuda at 03 UTC on 13 October. With ample illumination from the Moon (which was in the Waxing Gibbous phase, at 90% of full) Nicole exhibited a well-defined eye on Suomi NPP VIIRS Day/Night Band (0.7 µm) imagery at 0615 UTC, with cold cloud-top temperatures surrounding the eye on the corresponding VIIRS Infrared Window (11.45 µm) image (below).

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]

As Nicole approached Bermuda, increasing deep-layer wind shear began to impact the storm and weaken it to a Category 3 — and DMSP-17 Microwave (85 GHz) data showed that the eye had become open to the south (below).

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]

The passage of Nicole over Bermuda is shown on GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images spanning the period 1037-1555 UTC (below).

GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images [click to play animation]

As the eye of Nicole passed over Bermuda around 13 UTC, the staff at the Bermuda Weather Service were able to successfully launch a rawinsonde balloon, which reported data as high as the 202 hPa pressure level or 12.2 km altitude — much higher than their previous launch attempts at 06 and 12 UTC (below). The Total Precipitable Water (TPW) value derived from that 15 UTC sounding was 72.5 mm or 2.85 inches, which was in general agreement with that displayed by the MIMIC TPW product. Note that the eye of Nicole did not appear to be directly over Bermuda on the 1300 UTC GOES-13 images — this is due to a combination of parallax and the fact that the eye had a significant southwest-to-northeast tilt with height.

Bermuda rawinsonde reports from 00, 06, 12 and 15 UTC on 13 October [click to enlarge]

Bermuda rawinsonde reports from 00, 06, 12 and 15 UTC on 13 October [click to enlarge]

A sequence of Infrared images from POES and Metop AVHRR (12.0 µm) and Terra MODIS (11.0 µm) during the period 1016 to 1513 UTC is shown below.

POES and Metop AVHRR, and Terra MODIS infrared images [click to enlarge]

POES and Metop AVHRR, and Terra MODIS infrared images [click to enlarge]

Hurricane Matthew: heavy rainfall and flooding across the Southeast and Mid-Atlantic US

October 9th, 2016 |

MIMIC Total Precipitable Water product, from 06 October/04 UTC to 08 October/16 UTC [click to play MP4 animation]

MIMIC Total Precipitable Water product, from 06 October/04 UTC to 08 October/16 UTC [click to play MP4 animation]

Copious amounts of moisture associated with Hurricane Matthew resulted in heavy rainfall (map | text list) and widespread flooding across the Southeast and Mid-Atlantic US during the 07 October to 09 October 2016 period. Hourly images of the MIMIC Total Precipitable Water (TPW) product (above; also available as a 22 Mbyte animated GIF) showed the high TPW values that spread from Florida to the Mid-Atlantic states; all-time record high TPW values were measured via rawinsonde at Jacksonville, Florida and Charleston, South Carolina, with a record high value for the month of October at Newport/Cape Hatteras, North Carolina (Tweet). For more details, see the Weather Underground blog.

Track of Matthew, from 28 September at 12 UTC to 09 October at 18 UTC

Track of Matthew, from 28 September at 12 UTC to 09 October at 18 UTC

Matthew set numerous records for intensity, longevity, and landfall (summary) — an animation of hourly GOES-13 Water Vapor (6.5 µm) images covering the 11-day period from 12 UTC on 28 September to 12 UTC on 09 October is shown below (also available as a large 113 Mbyte animated GIF). The CIMSS Tropical Cyclones site posted GOES-13 Visible (0.63 µm) animations from the individual days of 03 October, 04 October, 05 October, 06 October, 07 October, and 08 October.

GOES-13 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-13 Water Vapor (6.5 µm) images [click to play MP4 animation]

The combination of high winds and flooding led to widespread power outages, with over 2 million homes and businesses without power. A comparison of nighttime Suomi NPP VIIRS Day/Night Band (0.7 µm) images from 28 September (before Mattthew arrived) and 09/10 October (after the passage of Matthew) showed a notable reduction in the glow of city lights in areas with no power (below; images courtesy of William Straka, SSEC). Note that the presence of patchy clouds on all 3 images tended to diffuse or even obscure the appearance of city lights below, depending on the thickness of the cloud layer(s).

Suomi NPP VIIRS Day/Night Band (0.7 µm) images on 28 September, 09 October and 10 October [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) images on 28 September, 09 October and 10 October [click to enlarge]

As clouds cleared in the wake of Hurricane Matthew on 09 October, a Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image at 1859 UTC, viewed using RealEarth (below), revealed patterns of turbidity in the offshore waters of the Atlantic Ocean from Florida to North Carolina; this increased turbidity was a result of high amounts of particles suspended in the water due to a combination of mixing from prolonged high winds and runoff from inland flooding.

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

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

About 8 hours later, a Terra MODIS Sea Surface Temperature (SST) product image at 0243 UTC on 10 October (below) showed a large eddy of warm Gulf Stream water (with a maximum SST value of 85.2º F, darker red color enhancement) surrounding a pocket of cooler water (with a minimum SST value of 78.5º F, darker blue color enhancement) off the coast of South Carolina.

Terra MODIS Sea Surface Temperature product [click to enlarge]

Terra MODIS Sea Surface Temperature product [click to enlarge]

The VIIRS Instrument on Suomi NPP provides data that are used in a River Flood Product (discussed previously on this blog). The product uses three reflective bands (I01, I02, and I03 at 0.64 µm, 0.86 µm and 1.61 µm, respectively) and the infrared window band I05 at 11.45 µm. The image below (courtesy of Sanmei Li at George Mason University) identifies many flooded regions over North Carolina. In particular, the flooding near Goldsboro and Lumberton is identified.

snppviirs_floodmap_south_north_carolina_usa_11oct_2016_18_17

JPSS River Flood product produced with Suomi NPP data, 1817 UTC on 11 October 2016 (Click to enlarge)

A sequence of 1 pre-Matthew (06 September) and 3 post-Matthew (09, 10 and 12 October) Terra/Aqua MODIS false-color RGB images from the SSEC MODIS Today site (below) also helped to highlight areas of flooding (darker shades of blue, especially notable along river valleys) that resulted from the heavy rainfall.

Terra and Aqua MODIS false-color images, from 06 September and 09, 10 and 12 October 2016 [click to enlarge]

Terra and Aqua MODIS false-color images, from 06 September and 09, 10 and 12 October 2016 [click to enlarge]

Hurricane Matthew makes landfall in western Haiti, then eastern Cuba

October 4th, 2016 |

GOES-13 Visible (0.63 µm) Imagery, 1045-1245 UTC on 4 October 2016 (Click to enlarge)

Hurricane Matthew has made landfall in western Haiti. The rocking animation (click here for a straight animation) above shows the cloud-filled eye of the storm crossing the Tiburon Peninsula. The storm’s center is forecast to remain largely over water as it moves through the Windward Passage between Cuba and Hispaniola.

A closer look using a 2-panel comparison of GOES-13 Visible (0.63  µm) and Infrared Window (10.7 µm) images, below, shows the deteriorating satellite presentation following interaction with the topography of the islands. The GOES-13 satellite was in Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes.

GOES-13 0.63 µm Visible (left) and 10.7 µm Infrared Window (right) images [Click to play animation]

GOES-13 0.63 µm Visible (left) and 10.7 µm Infrared Window (right) images [Click to play animation]

NOAA-18 overflew the region around 1130 UTC while the eye was on land, and the toggle below shows Visible (0.64 µm) and Infrared Window Channel (10.8 µm) imagery from 1130 UTC. The cloud-filled eye is distinct in the infrared image at that time, but a sequence of POES AVHRR Infrared (12.0 µm) images showed the rapid deterioration shortly after landfall (as was seen in the GOES-13 images above).

NOAA-18 AVHRR Visible (0.64 µm) and Infrared (10.8 µm) Imagery, 1130 UTC on 4 October 2016 (Click to enlarge)

A toggle between 1215 UTC GOES-13 Infrared Window (10.7 µm) and 1217 UTC DMSP-18 SSMIS Microwave (85 GHz) images from the CIMSS Tropical Cyclones site, below, revealed that a well-defined eye was still evident in the microwave data.

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]

Aqua overflew Matthew shortly after 1800 UTC on 4 October, and the toggle below shows the 1-km visible (0.65 µm) and the 1-km ‘Cirrus Channel’ (1.38 µm). The Cirrus Channel detects radiation at a wavelength where very strong absorption by water vapor is occurring; only high clouds are detected with this channel, and the toggle between the Cirrus Channel and the Visible nicely outlines the cirrus canopy of the storm. The Advanced Baseline Imager (ABI) on GOES-R also includes a Cirrus Channel.

Aqua MODIS Visible (0.65 µm) and

Aqua MODIS Visible (0.65 µm) and “Cirrus Channel” (1.38 µm) at 1832 UTC on 4 October 2016 [Click to enlarge]

Meanwhile, to the northeast of Matthew, in the tropical Atlantic, Tropical Storm Nicole has formed. The animation of visible imagery from GOES-13, below, shows a sheared storm; the low-level circulation is west of the deepest convection. It’s unlikely that Nicole will intensify much under such sheared conditions. Cirrus outflow from Matthew is evident at the south and west of Nicole.

GOES-13 Visible (0.63 um) images [click to play animation]

GOES-13 Visible (0.63 um) images [click to play animation]

ASCAT on METOP-A sampled both storms in its morning overpass over the western Atlantic, as shown below. The maximum scatterometer-derived wind speeds were 60 knots with Matthew and 40 knots for Julia.

GOES-13 Visible (0.63 µm) image, with Metop-AASCAT winds [Click to enlarge]

GOES-13 Visible (0.63 µm) image, with Metop-AASCAT winds [Click to enlarge]

Late in the day on 04 October, Category 4 Hurricane Mathew made a second landfall along the far eastern tip of Cuba. As seen in the image toggle below, in spite of a ragged appearance on GOES-13  Infrared Window (10.7 µm) imagery, a distinct eye was still seen using DMSP-18 SSMIS Microwave (85 GHz) data.

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]

GOES-13 Infrared Window (10.7 µm) and DMSP-18 SSMIS Microwave (85 GHz) images [Click to enlarge]