GOES-S (named GOES-17 once it reached geostationary orbit) was launched on 01 March 2018. Beginning at 1800 UTC on 12 February 2019, it became the operational GOES-West satellite (replacing GOES-15, which was launched in March 2010). The period of transition to operational status is shown on Full Disk images of “Red” Visible (0.64 µm) and Mid-level Water Vapor (6.9 µm) images (above).

In an animation of GOES-17 images from the 16 ABI spectral bands, centered on the Big Island of Hawai’i (below), an increase in cumulus clouds was evident in the Visible and Near-Infrared bands (1-6) along with a warming signature of the island summits (Mauna Kea and Mauna Loa) in the Infrared bands (7-16) as daytime heating increased during the morning hours. Weighting functions for all of the Infrared bands which are not strongly affected by water vapor absorption (7, and 11-16) have peaks at/near the surface — and the presence of dry air within the middle troposphere shifted the three Water Vapor band (8-10) weighting functions downward to allow some of the island summit thermal signature to be sensed. This dry air aloft (and a lack of cirrus clouds over the island) also enabled the summits to be sensed by the 1.37 µm Near-Infrared “Cirrus” band (4).

A comparison of all 16 ABI bands from GOES-17 covering most of Alaska and the adjacent Bering Sea is shown below.

In the animation below (source), GOES-17 and GOES-16 (GOES-East) Longwave Infrared (11.2 µm) images have been combined and displayed in a Mollweide projection. This shows the broad area of coverage provided by the current GOES constellation, which reaches from far eastern Australia to far western Europe and Africa.

Although the GOES-17 ABI instrument experiences a nocturnal Loop Heat Pipe (LHP) cooling problem (also discussed here) — which increases around the time of the Spring and Autumn equinox —  the issue only affects the emitted Longwave Infrared spectral bands (bands 08-16), and only for periods lasting as long as a few hours (peaking daily around 1300-1330 UTC). Trends of the Focal Plane Module (FPM) temperature of the ABI instrument can be monitored at this site — and examples of Band 09 (6.9 µm Water Vapor) imagery from 11 February are shown below. Note how the images return to normal after the peak FPM temperatures cool from around 97 K to around 80 K. More information on the daily variation of FPM temperatures throughout the year is available here, here and here.

The LHP cooling issue affects various ABI spectral bands to differing degrees, with the Band 14 (11.2 µm Longwave Infrared) imagery being the least impacted — this can be seen in a Full Disk animation covering the same time period (below).

GOES-17 and GOES-15 will operate in tandem from their respective locations of 137.2º West and 128º West longitude through early July 2019 — so GOES-15 imagery can be used during times when GOES-17 is adversely affected by the LHP cooling issue.

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

1-minute Mesoscale Domain Sector GOES-17 “Red” Visible (0.64 µm) images from the AOS site (above) showed the distinct circulation of a strong midlatitude cyclone (surface analyses) that was centered just north of Hawai’i on 10 February 2019. The pressure gradient associated with this storm produced strong winds across the island chain. Wave heights to 38.4 feet were recorded at Buoy 51208 near Kaua’i, with wind gusts to 57 knots at Buoy 51001 northwest of Kauwa’i.

Here's a brief overview of some of the highest wind speeds and other impacts we experience over the weekend. Unsettled weather looks to stick around though the rest of the week with breezy trades. See https://t.co/fUefWa9aTA for the full forecast #hiwx pic.twitter.com/24Qi1fnxAJ

— NWSHonolulu (@NWSHonolulu) February 13, 2019

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (below) revealed the presence of numerous lee waves which extended hundreds of miles downwind of the islands — most notable were those emanating from Kauwa’i.

Derived Motion Winds calculated using GOES-15 (GOES-West) Water Vapor (6.5 µm) imagery from the CIMSS Tropical Cyclones site (below) showed targets with velocites of 150-160 knots just north of Hawai’i at 09 UTC and 12 UTC.

GOES-17 Air Mass RGB images (below) showed the orange to red hues signifying a lowered tropopause and increased stratospheric ozone within the atmospheric column as the storm evolved during the 09-10 February time period.

Suomi NPP VIIRS True Color and Infrared Window (11.45 µm) images at 23 UTC as viewed using RealEarth are shown below.

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Very cold surface air temperatures occurred in northeastern Montana and northwestern North Dakota on the morning of 08 February 2019 — with official lows of -50ºF near Antelope and Four Buttes in Montana and -47ºF at Bottineau in North Dakota (and according to MesoWest, -49ºF was registered at a Department of Transportation site west of Crosby in far northwestern North Dakota). GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images (above) revealed surface brightness temperatures across those areas were as cold as -47ºC (-53ºF).

A sequence of VIIRS Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 (below) showed similar surface brightness temperatures, with some pixels as cold as -48ºC (-54ºF). The color enhancement applied to the VIIRS images is the same as that used on the GOES-16 images above, with the red colors beginning at the -40ºC breakpoint (violets begin at -50ºC). While there is not a direct correspondence between satellite-sensed surface infrared brightness temperatures and air temperatures measured in an above-ground instrument shelter, with improving satellite spatial resolution the difference is often within 1-3ºC (or 2-5ºF).

Highs & lows from across the area today. The cold spots this morning were the stations 13 mi. NNW of Four Buttes & 2 mi. WSW of Antelope, both checking in at -50!

The "warm" spots this afternoon were 16 mi. NNE of Mosby at 15, & 5 mi. west of Landusky at 14. #mtwx #cold #brrr pic.twitter.com/UCPScKGS7b

— NWS Glasgow (@NWSGlasgow) February 9, 2019

The all-time record low minimum for any @NDAWNmesonet set at Hofflund this morning was a -47.3?F (-44.0?C) reading looking at the raw data, so there was no rounding down to get to -47?. #impressive

— Daryl Ritchison (@DarylRitchison) February 8, 2019

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

Transient pockets of cloud-top waves were evident on GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (above) north of Hawai’i on 06 February 2019. Some of the waves were located along the tops of convective cloud features, while others appeared to be randomly distributed.

Plots of rawinsonde data from Lihue, Hawai’i (below) showed that winds within the middle to upper troposphere had a general westerly component — so these mesoscale cloud-top wave features were oriented perpendicular to the flow.

There was only 1 pilot report of turbulence within the broad region exhibiting these waves, occurring at 2304 UTC at an altitude of 33,000 feet — and this appeared to coincide with a discrete wave packet that was propagating eastward (below).

While the more robust wave packets could also be seen in GOES-17 “Clean” Infrared Window (10.3 µm) images (below), their complete areal coverage was more obvious in the Water Vapor imagery — particularly where the wave features were more subtle.

Aviation advisories for Significant Weather (SIGWX) had been issued for that region (below), which included a Moderate risk for Clear Air Turbulence (CAT) from 28,000-39,000 feet and the possibility of isolated/embedded Cumulonimbus (CB) clouds with tops to 38,000 feet, along with a west-northwest high-level jet stream from 290º at 90 knots. The pilot report of turbulence at 33,000 feet included winds from 261º at 81 knots.

The cloud-top waves were also seen in a sequence of VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP, viewed using RealEarth (below).

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