Tropical Storm Michael

October 7th, 2018 |

GOES-16 "Clean" Infrared Window (10.3 µm) images [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images (above) showed deep convection associated with Tropical Depression 14 east of Belize and the Yucatan Peninsula of Mexico early in the day on 07 October 2018. There was a large area of cloud-top infrared brightness temperatures in the -80ºC to -89ºC range (shades of purple), with isolated small pockets of -90ºC or colder (yellow enhancement).

1-minute GOES-16 “Red” Visible (0.64 µm) images from the UW-AOS site (below) showed numerous convective overshooting tops.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

At 1655 UTC the system was upgraded to Tropical Storm Michael — 1-minute GOES-16 Infrared images (below) showed that deep convection persisted in the eastern semicircle of Michael during the remainder of the day.

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play MP4 animation]

A hint of the elongated low-level circulation could be seen just west of the deep convection on late-day GOES-16 Visible images (below).

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

===== 08 October Update =====

NOAA-20 VIIRS Day/Night Band (0.7 µm), Infrared Window (11.45 µm) and ATMS Microwave (88 GHz) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm), Infrared Window (11.45 µm) and ATMS Microwave (88 GHz) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm), Infrared Window (11.45 µm) and ATMS Microwave (88 GHz) images at 0721 UTC (above; courtesy of William Straka, CIMSS) indicated that a well-defined convective band was wrapping around the eastern, northern and northwestern portions of the storm center (with some bright lightning streaks showing up on the DNB image in the southeastern segment of this convective band).

In a comparison of DMSP-18 SSMIS Microwave (86 GHz) and GOES-16 Infrared Window (10.3 µm) images at or shortly after 1115 UTC (below), the Microwave imagery showed a very large eye beneath the convective clusters.

DMSP-18 SSMIS Microwave (86 GHz) and GOES-16 Infrared Window (10.3 µm) images [click to enlarge]

DMSP-18 SSMIS Microwave (86 GHz) and GOES-16 Infrared Window (10.3 µm) images [click to enlarge]

Michael was upgraded to a Category 1 hurricane at 15 UTC; 1-minute GOES-16 “Red” Visible (0.64 µm) images (below) revealed abundant deep convection around the core of the storm during the 3 hours leading up to that time.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play MP4 animation]

Michael had been moving over very warm water since forming on 06 October; analyses of Ocean Heat Content and Sea Surface Temperature (below) showed that while the hurricane was forecast to briefly pass over a region of lower OHC in the far southeastern Gulf of Mexico, the remainder of its journey across the Gulf would be over water possessing modest amounts of OHC and warm SST values of 29-30ºC.

Ocean Heat Content and Sea Surface Temperature analyses, with past and forecast tracks of Michael [click to enlarge]

Ocean Heat Content and Sea Surface Temperature analyses, with past and forecast tracks of Michael [click to enlarge]

Similarly, a relatively cloud-free Terra MODIS Sea Surface Temperature product from 0343 UTC on 06 October (below) showed SST values of 84-85ºF (darker red colors) along much of the forecast path of Hurricane Michael (issued at 2100 UTC on 08 October).

Terra MODIS Sea Surface Temperature product (0343 UTC on 06 October) with Hurricane Michael forecast positions issued at 2100 UTC on 08 October [click to enlarge]

Terra MODIS Sea Surface Temperature product (0343 UTC on 06 October) with forecast positions of Hurricane Michael issued at 2100 UTC on 08 October [click to enlarge]

Hurricane Michael

September 6th, 2012 |
GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

Hurricane Michael became the first Category 3 hurricane of the 2012 Atlantic Basin season on 06 September. GOES-13 0.63 µm visible channel images (above) and GOES-13 10.7 µm IR channel images (below) from the CIMSS Tropical Cyclones site showed that Michael displayed a well-defined eye.

GOES-13 10.7 µm IR channel images

GOES-13 10.7 µm IR channel images

A comparison of 375-meter resolution Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images (below) offered a more detailed view of the eye structure at 15:42 UTC.

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

 

Hurricane Force low off the US East Coast

April 2nd, 2019 |

GOES-16 "Red" Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed a cluster of deep convection just to the north of the center of a rapidly-intensifying midlatitude cyclone (surface analyses) off the coast of North Carolina on 02 April 2019. In addition, convection was later seen developing along the north-south cloud band marking the leading edge of the cyclone’s cold front. The rapid deepening of this hurricane force low easily met the criteria of a bomb cyclone — its central pressure dropped 20 hPa in just 12 hours (from 1004 hPa at 18 UTC on 02 April to 984 hPa at 06 UTC on 03 April).

The primary convective cluster began to exhibit a large amount of lightning after 1830 UTC, as seen in plots of GOES-16 GLM Groups (below). To the east of this intensifying convection, one ship report at 18 UTC included winds from the east at 50 knots — in addition, a moderate to heavy shower of hail was being reported and their surface visibility was restricted to 1.25 miles (18 UTC surface analysis).

GOES-16 "Red" Visible (0.64 µm) images, with GLM Groups and surface wind gusts plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with GLM Groups and surface wind gusts plotted in red [click to play animation | MP4

There were several factors pointing to the development of a sting jet with this storm, as discussed here and here. GOES-16 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (below) revealed distinct areas of warming/drying (darker shades of yellow to orange) that possibly highlighted rapidly-descending air associated with a sting jet (for example, on the 1946 UTC images).

GOES-16 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images [click to play animation | MP4]

GOES-16 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images [click to play animation | MP4]

After 23 UTC, GOES-16 “Clean” Infrared Window (10.3 µm) images (below) portrayed the formation of a large eye-like feature indicative of a warm seclusion (00 UTC surface analysis). Lightning activity remained very high during that time.

GOES-16 "Clean" Infrared Window (10.3 µm) images [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.3 µm) images [click to play animation | MP4]


A comparison between 1-km resolution Terra MODIS Infrared Window (11.0 µm) imagery at 0237 UTC with an Aqua MODIS Sea Surface Temperature product at 1755 UTC on the following afternoon (below) showed that the storm intensified and formed the large eye-like feature over the northern portion of the axis of warmest Gulf Stream water (where SST values were in the 70-76ºF range).

Terra and Aqua MODIS Infrared Window (11.0 µm) images from 0237 UTC and 0649 UTC, along with the Aqua MODIS Sea Surface Temperature product at 1755 UTC [click to enlarge]

Terra MODIS Infrared Window (11.0 µm) image at 0237 UTC, along with the 1755 UTC Aqua MODIS Sea Surface Temperature product [click to enlarge]

With a nighttime overpass of the NOAA-20 satellite at 0651 UTC, the eye-like feature was apparent in VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images (below). Although the Moon was in the Waning Crescent phase (at only 8% of Full), that illumination with the aid of airglow was sufficient to provide a useful “visible image at night” using the Day/Night Band; a streak of bright pixels was due to intense lightning activity within a line of thunderstorms just ahead of the cold front. Note: the NOAA-20 images are incorrectly labeled as Suomi NPP.

NOAA-20 VIIRS Infrared Window (11.45 µµ) and Day/Night Band (0.7 µm) images [click to enlarge]

NOAA-20 VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images, with an overlay of the 06 UTC surface analysis [click to enlarge]

Hurricane Lane

August 22nd, 2018 |

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images (above; courtesy of William Straka, CIMSS) showed the eye of Hurricane Lane in the central Pacific Ocean at 1208 UTC on 22 August 2018, a few hours after it reached Category 5 intensity (SATCON). Surface mesovortices were evident within the eye, and storm-top gravity waves were seen propagating west-southwestward away from the eyewall.

 

GOES-15 (GOES-West) Infrared Window (10.7 µm) images (below) revealed a significant amount of trochoidal motion as Lane moved northwestward during the 21 August – 22 August period. The storm weakened somewhat to Category 4 intensity as of 15 UTC on 22 August.

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

Hurricane Lane was near the limb of the Full Disk view of both Himawari-8 and GOES-17, as seen in a comparison of “Red” Visible (0.64 µm) images from the two satellittes (below).

* GOES-17 images shown here are preliminary and non-operational *

“Red” Visible (0.64 µm) images from Himawari-8 (left) and GOES-17 (right) [click to play animation | MP4]

DMSP-16/17 SSMIS Microwave (85 GHz) images from the CIMSS Tropical Cyclones site are shown  below.

DMSP-16 SSMIS Microwave (85 GHz) image at 1411 UTC [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) image at 1411 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1717 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1717 UTC [click to enlarge]

Since forming as Tropical Depression 14E on 14 August. Lane had been moving westward over water having only modest Ocean Heat Content but Sea Surface Temperature values of 27-28ºC (below).

Track of Hurricane Lane, with maps of Ocean Heat Content and Sea Surface Temperature [click to enlarge]

Track of Hurricane Lane, with maps of Ocean Heat Content and Sea Surface Temperature [click to enlarge]

===== 23 August Update =====

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1150 UTC [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1150 UTC [click to enlarge]

Hurricane Lane remained at Category 4 intensity during the early hours of 23 August — however, the satellite presentation began to deteriorate as the eye became cloud-filled as seen in toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 at 1150 UTC (above) and Suomi NPP at 1240 UTC (below). An interesting narrow “warm trench” signature became very pronounced within the northwestern quadrant of Lane on the later Suomi NPP Infrared image.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1240 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1240 UTC [click to enlarge]

GOES-15 Visible (0.63 µm, left) and Infrared Window (10.7 µm, right) images, with hourly plots of data from Buoy 51002 [click to play animation | MP4]

GOES-15 Visible (0.63 µm, left) and Infrared Window (10.7 µm, right) images, with hourly plots of data from Buoy 51002 [click to play animation | MP4]

GOES-15 Visible (0.63 µm) and Infrared Window (10.7 µm) images after sunrise (above) showed that the eye of Lane moved over Buoy 51002 — located about 200 miles southwest of the Big Island of Hawai’i — just after 19 UTC (below). The peak wind gust measured by the buoy was 93 knots or 107 mph ay 1830 UTC; the lowest wind and air pressure values were recorded while in the eye from 1930-2110 UTC.

Plot of wind speed/gust and air pressure data from Buoy 51002

Plot of wind speed/gust and air pressure data from Buoy 51002

At 1703 UTC Buoy 51002 was located just west of the eye, beneath strong convection of the eyewall as seen on a DMSP-17 SSMIS Microwave (85 GHz) image (below).

DMSP-17 SSMIS Microwave (85 GHz) image at 1703 UTC, with and without plots of buoy data [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1703 UTC, with and without plots of buoy data [click to enlarge]

A Suomi NPP VIIRS Day/Night Band (0.7 µm) image at 2334 UTC or 1:34 pm HST on 23 August is shown below.

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

===== 24 August Update =====

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

A Suomi NPP VIIRS Day/Night Band (0.7 µm) image (above) showed Category 3 Hurricane Lane at 1211 UTC or 2:11 am HST on 24 August. Thin tendrils of high-altitude transverse banding can be seen along the western and northern periphery of the storm.

GOES-15 Infrared Window (10.7 µm) images (below) showed the development of the transverse banding as Lane eventually weakened to a Category 1 storm during the course of the day; a rapid warming of the cloud-top infrared brightness temperatures began around 2100 UTC. Even though the Ocean Heat Content and Sea Surface Temperature in the waters immediately west of Hawai’i were still fairly high, the hurricane was moving into an environment of increasingly unfavorable deep-layer wind shear which acted to decouple the low-level and mid-level circulations and hasten the weakening process.

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

GOES-15 Infrared Window (10.7 µm) images [click to play animation | MP4]

GOES-15 Visible (0.63 µm) images (below) provided a slightly closer look at the storm during the daylight hours.

GOES-15 Visible (0.63 µm) images [click to play animation | MP4]

GOES-15 Visible (0.63 µm) images [click to play animation | MP4]

A dramatic difference was seen between Suomi NPP VIIRS Day/Night Band images at 1211 UTC and 2315 UTC (below), as Lane weakened from a Category 3 to a Category 1 hurricane in this 11-hour period.In spite of the rapid weakening, very heavy rainfall continued across much of the State, with 24-hour amounts exceeding 20 inches at some locations on the Big Island of Hawai’i. Note that the Low-Level Circulation Center (LLCC) of Lane had become exposed on the later 2315 UTC image (in spite of a thin veil of cirrus overhead), and was located to the southwest of the rapidly-dissipating convection that was closer to the islands.

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

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

===== 25 August Update =====

On the islands, the highest wind gust associated with Lane was 74 mph — and storm total rainfall amounts greater than 50 inches were recorded, with Hilo setting a record 3-day accumulation of 31.85 inches and a record 4-day accumulation of 36.76 inches. Rainfall rates on the Big Island exceeded 19 inches in 24 hours on 23 July.

Time series of surface reports from Hilo, Hawai'i [click to enlarge]

Time series of surface reports from Hilo, Hawai’i [click to enlarge]

Hourly images of the MIMIC Total Precipitable Water (TPW) product during the period 22-25 August (below) showed the circulation of Lane transporting high amounts of moisture across the Hawaiian Islands. TPW values of 60 mm (2.4 inches) or more were also seen in rawinsonde data from Hilo on many of these days.

MIMIC Total Precipitable Water product during 22-25 August [click to play animation | MP4]

MIMIC Total Precipitable Water product during 22-25 August [click to play animation | MP4]

A toggle between Suomi NPP VIIRS Day/Night Band images from 24 August / 2315 UTC and 25 August / 1152 UTC (below) showed a slow north/northwestward motion of the exposed LLCC of what had further weakened to Tropical Storm Lane.

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

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