Strong jet streak over the Lower 48 states

February 17th, 2019 |


GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of Derived Motion Winds [click to play animation | MP4]

GOES-16 Upper-level Water Vapor (6.2 µm) images, with plots of Derived Motion Winds [click to play animation | MP4]

An unusually strong jet streak was located over the Lower 48 states on 17 February 2019. GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) images with plots of 6.2 µm Derived Motion Winds (above) showed numerous tracked targets along and south of the jet axis — within the jet streak exit region over the Mid-Atlantic states, some velocity values were as high as 181 knots (below).

GOES-16 Upper-level Water Vapor (6.2 µm) image, with plots of Derived Motion Winds at 0002 UTC [click to enlarge]

GOES-16 Upper-level Water Vapor (6.2 µm) image, with plots of Derived Motion Winds at 0002 UTC [click to enlarge]

A plot of rawinsonde data from Lincoln, Illinois at 00 UTC (below) showed wind speeds as high as 190 knots at a pressure of 231 hPa. The 250 hPa wind speed of 184.7 knots set both a daily and an all-time record speed for that pressure level (the old all-time record was 175 knots for a sounding on 10 Dec at 00 UTC).

Plot of 00 UTC rawinsonde data from Lincoln, Illinois [click to enlarge]

Plot of 00 UTC rawinsonde data from Lincoln, Illinois [click to enlarge]

GOES-16 Air Mass RGB images from the AOS site (below) provided a classic portrayal of the green hues of warm/moist tropical air south of and the orange/red hues of cold/dry polar air north of this strong jet stream.

GOES-16 Air Mass RGB images [click to play animation | MP4]

GOES-16 Air Mass RGB images [click to play animation | MP4]

===== 18 February Update =====

GOES-17 "Red" Visible (0.64 µm) and Near-Infrared "Snow/Ice (1.61 µm) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice (1.61 µm) images [click to play animation | MP4]

The large southward dip of the polar jet stream — evident in the GOES-16 Air Mass RGB images from the previous day — brought cold air into the Desert Southwest, resulting in snowfall at lower-elevation locations such as Las Vegas, Nevada. GOES-17 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice (1.61 µm) images (above) revealed snow on the ground in the Las Vegas area — much of which quickly melted with increased surface heating after sunrise. Snow cover is a good absorber of radiation at the 1.61 µm wavelength, so it appeared as darker shades of gray on the Snow/Ice images; the distribution of the heavier snowfall amounts (which naturally melted more slowly) was influenced by the topography of the area. This snowfall forced the closure of Interstate 15 from Las Vegas to the Nevada/California border for several hours due to icy pavement and multiple traffic accidents.

The snow cover was apparent in Visible imagery from 4 GOES (below) — GOES-17 (GOES-West), GOES-15 (the backup GOES-West), GOES-16 (GOES-East) and GOES-13 (the backup GOES-East, which had been brought out of storage for annual maintenance activities).

Visible images from GOES-17, GOES-15, GOES-15 and GOES-13 [click to play animation | MP4]

Visible images from GOES-17, GOES-15, GOES-15 and GOES-13 [click to play animation | MP4]


Seattle, Washington as viewed by 4 GOES

February 13th, 2019 |

Visible images, centered at Seattle, from (left to right) GOES-17, GOES-15, GOES-16 and GOES-13 [click to play animation | MP4]

Visible images, centered at Seattle, from (left to right) GOES-17, GOES-15, GOES-16 and GOES-13 [click to play animation | MP4]

The GOES-13 satellite was brought out of storage for annual maintenance activities on 13 February 2019 — allowing for a unique view of the Seattle, Washington area from that satellite as well as GOES-15, GOES-16 (GOES-East) and GOES-17 (GOES-West). After receiving significant snowfall during the previous several days, snowcover was abundant across that region. The brighter-white snow-covered mountain peaks south and southeast of Seattle (especially that of Mount Rainier) were also apparent on visible imagery from all 4 satellites.

Note that visible images from the older GOES-13/GOES-15 are not as bright as those from the newer GOES-16/GOES-17 — performance of visible detectors on the previous generation of satellites degraded over time, while the new GOES-R series benefits from on-orbit calibration of the visible detectors to mitigate this effect.

Using a spare rooftop antenna, staff at the SSEC Data Center were able to ingest and process this data from GOES-13 (in addition to the other 3 GOES satellites). GOES-13 will be placed back into storage on 25 February 2019.

A toggle between larger-scale images using the 5 spectral bands of the GOES-13 Imager are shown below.

GOES-13 Visible (0.63 µm), Shortwave Infrared (3.9 µm), Water Vapor (6.5 µm), Infrared Window (10.7 µm) and Infrared CO2 Absorption (13.3 µm) images at 2015 UTC [click to enlarge]

GOES-13 Visible (0.63 µm), Shortwave Infrared (3.9 µm), Water Vapor (6.5 µm), Infrared Window (10.7 µm) and Infrared CO2 Absorption (13.3 µm) images at 2015 UTC [click to enlarge]

Final Full Disk images from GOES-13

January 8th, 2018 |

As discussed in this blog post, GOES-13 — launched in May 2006, with a Post Launch Test in December 2006 — served as GOES-East from 2010 to 2017. Image dissemination was terminated on 08 January 2018; the satellite will then begin drifting on 10 January to its storage location at 60º  West longitude. Shown below are the final Full Disk Visible (0.63 µm), Water Vapor (6.5 µm) and Infrared Window (10.7 µm) images broadcast by GOES-13 at 1445 UTC.

GOES-13 Visible (0.63 µm) image [click to enlarge]

GOES-13 Visible (0.63 µm) image [click to enlarge]

GOES-13 Water Vapor (6.5 µm) image [click to enlarge]

GOES-13 Water Vapor (6.5 µm) image [click to enlarge]

GOES-13 Infrared Window (10.7 µm) image [click to enlarge]

GOES-13 Infrared Window (10.7 µm) image [click to enlarge]

Ice floes in Chesapeake Bay

January 7th, 2018 |

Landsat-8 false-color RGB image [click to enlarge]

Landsat-8 false-color RGB image [click to enlarge]

In the wake of the explosive cyclogenesis off the East Coast of the US on 04 January 2018, very cold air began to spread across much of the eastern half of the Lower 48 states. Focusing on the Hampton Roads area of southeastern Virginia, satellite imagery began to show the formation of ice in the rivers and bays. On 06 January, a 30-meter resolution Landsat-8 false-color Red-Green-Blue (RGB) image viewed using RealEarth (above) revealed some of this ice — in particular, long narrow ice floes (snow and ice appear as shades of cyan) that likely emerged from the Back River (northeast of Hampton) and were drifting northward and southward just off the coast of the Virginia Peninsula.

On the following day (07 January), 250-meter resolution Terra MODIS true-color and false-color RGB images from the MODIS Today site (below) showed that a larger V-shaped ice floe was located just southeast of the Peninsula, with its vertex pointed toward the Hampton Roads Bridge-Tunnel (HRBT). Snow and ice also appear as shades of cyan in the MODIS false-color image.

Terra MODIS true-color and false-color RGB images [click to enlarge]

Terra MODIS true-color and false-color RGB images [click to enlarge]

07 January also happened to be the last full day of imagery to be broadcast by the GOES-13 satellite — a comparison of 1-minute Mesoscale Sector GOES-16 (GOES-East) Visible (0.64 µm) and 15-30 minute interval GOES-13 Visible (0.63 µm) images (below) showed that the V-shaped ice floe continued to drift southwestward toward the HRBT. However, it was difficult to tell whether the ice feature made it over and past the tunnel; even with the improved GOES-16 Visible spatial resolution (0.5 km at satellite sub-point, compared to 1.0 km for GOES-13) and the 1-minute rapid image scans, the ice floe became harder to track during the afternoon hours before high clouds began to overspread the region.

"GOES-16

GOES-16 Visible (0.64 µm, left) and GOES-13 Visible (0.63 µm, right) images, with hourly surface air temperatures (ºF) plotted in yellow [click to play MP4 animation]

However, a close examination of Suomi NPP VIIRS true-color and false-color images at 1826 UTC (below) indicated that some of the ice had indeed moved westward past Fort Monroe (on the far southeastern tip of the Peninsula) and over/past the HRBT.

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

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

On the topic of cold temperatures in southeastern Virginia, a new daily record low of -3 ºF was set at Richmond on the morning of 07 January, and at Norfolk new daily record low and record low maximum temperatures were set (10 ºF and 23 ºF, respectively).