Summary of the 02-03 March Nor’Easter

March 3rd, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with plots of hourly wind gusts [click to play MP4 animation]

A strong Nor’easter affected much of northeastern portion of the US during 02 March and 03 March 2018. As noted in the previous blog post, the storm produced very strong winds which led to widespread wind damage and power outages. A GOES-16 (GOES-East) Mesoscale Sector was positioned over the storm on 02 March, and “Red” Visible (0.64 µm) images (above) provided a detailed view of the center of circulation over the western Atlantic.

A 2-day animation of GOES-16 Mid-level Water Vapor (6.9 µm) images (below) showed the evolution of the storm as it moved from the Great Lakes to the Atlantic Ocean (surface analyses). A summary of the peak wind gusts and highest snowfall/rainfall totals can be seen here and here.

GOES-16 Mid-level (6.9 µm) images, with plots of hourly wind gusts [click to play MP4 animation]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with plots of hourly wind gusts [click to play MP4 animation]

On 03 March, a vortex was seen to develop in GOES-16 “Red” Visible (0.64 µm) images, just behind the occluded frontal boundary — about 30 minutes after a burst of stronger northeasterly winds (with speeds as high as 58 knots) was analyzed in that region by the Metop ASCAT instrument.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with surface fronts and Metop ASCAT surface scatterometer winds [click to play MP4 animation]

A signature of this vortex was also evident in GOES-16 Low-level Water Vapor (7.3 µm) images (below). A toggle between Visible and Water Vapor images at 1605 UTC is available here.

GOES-16 Mid-level (6.9 µm) images, with surface fronts and Metop ASCAT surface scatterometer winds [click to play animation]

GOES-16 Low-level Water Vapor (7.3 µm) images, with surface fronts and Metop ASCAT surface scatterometer winds [click to play MP4 animation]

Finally, a NOAA-20 VIIRS True-color Red-Green-Blue (RGB) image centered over Lake Erie at 1839 UTC on 03 March (below) showed the fresh snow cover left by the storm as it moved across the Great Lakes on 02 March. Snow can be seen across parts of Lower Michigan, southern Ontario, northern Ohio, and far northwestern Pennsylvania. NOAA-20 is the first of the JPSS series of satellites (note: the data are still considered preliminary and non-operational as the instruments and products are being evaluated and tested).

NOAA-20 True-color RGB image, centered of Lake Erie [click to enlarge]

NOAA-20 VIIRS True-color RGB image, centered of Lake Erie [click to enlarge]

Cyclone Gita in the South Pacific Ocean

February 12th, 2018 |

Himawari-8

Himawari-8 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.4 µm, bottom) images, with hourly plots of surface reports [click to play Animated GIF | MP4 also available]

Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images (above) showed Cyclone Gita as it moved toward Tonga in the South Pacific Ocean during 11 February – 12 February 2018. The tropical cyclone reached Category 4 intensity (ADT | SATCON) near the end of the animation period.

A longer animation of Himawari-8 Infrared images (below) revealed that the center of Gita moved just south of the main island of Tongatapu. Surface observations from Fua’Amotu (NFTF) ended after 0735 UTC.

Himawari-8

Himawari-8 “Clean” Infrared Window (10.4 µm) images, with hourly surface plots [click to play Animated GIF | MP4 also available]

MIMIC-TC morphed microwave imagery (below) showed that Gita underwent an eyewall replacement cycle after moving to the southwest of Tongatapu — a small eyewall was replaced by a larger eyewall, which was very apparent in DMSP SSMIS Microwave (85 GHz) images at 1533 and 1749 UTC.

MIMIC-TC morphed microwave imagery

MIMIC-TC morphed microwave imagery

Metop ASCAT scatterometer surface winds (below) showed Gita around the time that the storm center was just south of Tongatapu at 0850 UTC.

Metop ASCAT scatterometer surface winds [click to enlarge]

Metop ASCAT scatterometer surface winds [click to enlarge]

Detection of low clouds on “Cirrus band” imagery

October 29th, 2017 |

GOES-16 Visible (0.64 µm, top), Cirrus (1.37 µm, middle) and Infrared Window (10.3 µm, bottom) images [click to play animation]

GOES-16 Visible (0.64 µm, top), Cirrus (1.37 µm, middle) and Infrared Window (10.3 µm, bottom) images [click to play animation]

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

The ABI “Cirrus” (1.37 µm) band is centered in a strong water vapor absorption spectral region — therefore it does not routinely sense the lower troposphere, where there is usually substantial amounts of water vapor. Hence, its main application is the detection of higher-altitude cirrus cloud features.

However, in areas of the atmosphere characterized by low amounts of total precipitable water, the Cirrus band can sense clouds (and other features, such as blowing dust) in the lower troposphere. Such was the case on 29 October 2017, when a ribbon of dry air resided over the northern Gulf of Mexico in the wake of a strong cold frontal passage; low-level stratocumulus clouds were very apparent on GOES-16 Cirrus band images (above). Also of note: cloud features associated with Tropical Storm Philippe could be seen east of Florida.

The three GOES-16 Water Vapor bands (Upper-level 6.2 µm, Mid-level 6.9 µm and Lower-level 7.3 µm) highlighted the pocket of dry air that was moving across the northern Gulf of Mexico on that day (below).

GOES-16 Upper-level Water Vapor (6.2 µm, top), Mid-level Water Vapor (6.9 µm, middle) and Lower-level Water Vapor (7.3 µm, bottom) images [click to play animation]

GOES-16 Upper-level Water Vapor (6.2 µm, top), Mid-level Water Vapor (6.9 µm, middle) and Lower-level Water Vapor (7.3 µm, bottom) images [click to play animation]

The MODIS instrument on Terra and Aqua has a 1.37 µm Cirrus band as well; 1619 UTC Terra images (below) also revealed the stratocumulus clouds (especially those over the northeastern Gulf, where the driest air resided). Conversely, note how the low cloud features of Philippe were not seen on the Cirrus image, since abundant moisture within the tropical air mass east of Florida attenuated 1.37 µm wavelength radiation originating from the lower atmosphere.

In addition, the VIIRS instrument — on Suomi NPP, and the upcoming JPSS series — has a 1.37 µm Cirrus band.

Terra MODIS visible (0.65 µm), Cirrus (1.375 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Terra MODIS visible (0.65 µm), Cirrus (1.375 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Hourly images of the MIMIC Total Precipitable Water product (below) showed the ribbon of very dry air (TPW values less than 10 mm or 0.4 inch) sinking southward over the northern Gulf of Mexico. This TPW product uses microwave data from POES, Metop and Suomi NPP satellites (description).

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2017/10/tpw_17z.png

MIMIC Total Precipitable Water images [click to play animation]

Tropical Storm Nate forms near Nicaragua

October 5th, 2017 |

GOES-16 ABI Band 2 Visible (0.64 µm) Imagery, 1127 – 1324 UTC on 5 October 2017 (Click to animate)

GOES-16 Visible Imagery, above, shows convection (imagery at 1-minute intervals) surrounding Tropical Storm Nate, just onshore in northeastern Nicaragua.

GOES-16 ABI “Clean Window” Infrared (10.3 µm) Imagery, 4 October 2017 at 2300 UTC through 1130 UTC on 5 October 2017 (Click to animate)

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

The Tropical Depression (#16) in the western Caribbean Sea has strengthened to become a minimal Tropical Storm, acquiring the name Nate. The animation from GOES-16, above, shows disorganized convection over the entire basin, stretching into the Pacific Ocean south of central America. (The sheared remains of Pacific Tropical Storm Ramon are also present south of Mexico). The animation below, from 0000-1300 UTC on 5 October 2017, shows the mid-level Water Vapor Infrared Imagery (6.95 µm) from GOES-16. Convection develops over the center of Nate, over Nicaragua, at the end of the animation.

GOES-16 ABI “Mid-Level Water Vapor” Infrared (6.95 µm) Imagery, 0000-1300 UTC on 5 October 2017 (Click to animate)

Microwave Imagery, below, from SSMI/S at around 1000 UTC on 5 October, (from this site) suggests that Nate is centered very near the coast of Nicaragua. Nate is forecast to move north into the Gulf of Mexico; its path through the northwest Caribbean suggests strengthening is possible if Nate remains far enough from land. Very warm water is present in the northwest Caribbean; that warmth extends to great depth as shown by this plot of Oceanic Heat Content; that warmth extends into the central Gulf of Mexico.

85 GHz Brightness Temperatures, 1000 UTC on 5 October 2017 (Click to enlarge)

Nate formed at a time when the Moon was Full. Thus, Suomi NPP Day Night Band Visible Imagery showed excellent illumination. The image below is from 0627 UTC on 5 October.

Suomi NPP Day Night Band Visible (0.7 µm) Imagery, 0627 UTC on 5 October 2017 (Click to enlarge)

Total Precipitable Water in advance of Nate is plentiful, as shown in the loop below (from this site). There is dry air over the continental United States, however, associated with a strong High Pressure System. Easterly winds south of that system are apparent in Scatterometer winds from early in the morning on 5 October.

MIMIC Morphed Total Precipitable Water, 1200 UTC 4 October – 1100 UTC 5 October 2017 (Click to enlarge)