At 1500 UTC today, the Set Point temperature on the cryocooler was re-set to a cooler temperature (the effect of the warmer Set Point temperature is discussed here: Bands 10 and 12 had more lines of missing data related to the warming of the satellite by the Sun). The cryocooler works to reduce the thermal load on the satellite, but during seasonal peak heating (see the figure on Page 5 in this document), it is unable to counteract fully the effects of the malfunctioning Loop Heat Pipe on GOES-17.

The figure below compares Focal Plane Temperatures on 16 April (with the warmer Set Point temperature) and 19 April (during which day the cooler Set Point Temperature was re-implemented). (More comparison imagery is at this website; imagery for Band 10 on 16 April is here; from 19 April is here) Note how the brightness temperature difference between GOES-16 and GOES-17 is very different (one might say noisy) on 16 April, and on 19 April until about 1530 UTC, after which point it stabilizes at less than about 0.25K warmer for GOES-17. The change in the Focal Plane Module (FPM) Temperature is also apparent: The FPM is about 3K cooler than on 16 April starting around 1500 UTC on 19 April. This is because of the change in the Set Point on the cryocooler that occurred at that time.

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Oceans such as the South Pacific can be a large data void. NOAA-20 NUCAPS profiles can be an important data source to define the state of the atmosphere. The image above shows NUCAPS Sounding Availability from the overnight pass over American Samoa; the largest island of American Samoa, Tutuila, is just west of 170^oW in image above. There are green circles just north and just south of Tutuila, signifying locations of NUCAPS profiles associated with successful retrievals. The toggle below compares those two profiles with the 1200 UTC rawinsonde launch (NSTU) from Pago Pago. Good agreement is apparent, although the NUCAPS profiles are smoother.

The environment is somewhat dry. This is confirmed by a MIMIC Total Precipitable water mapping, shown below (for 1200 UTC on 19 April 2022) in an image taken from here. The Samoan islands are between two bands of moisture.

NUCAPS profiles give useful information, but it can be cumbersome to view all individual profiles sequentially. Gridded fields of various properties are available in AWIPS (and online here and here). The toggle below shows a larger view than the topmost image, and it compares gridded Temperature fields at 950 mb, and the 950-700 mb lapse rate. Over the Samoan islands, 950-mb temperatures are faily uniform around 23^o C, with “cooler” temperatures (closer to 21^o C) just to the northeast. Lapse rates are stable: between 4 and 5 ^oC/km. As you might expect given the relative dryness and stability, shower chances over American Samoa for 19 April are low.

Use NUCAPS when your weather is approaching from a region void of conventional data.

Imagery in this blog post was in part from the NOAA/TOWR-S instance of AWIPS in the Cloud. Thank you!

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The month-long animation above shows the Himawari-8 Sandwich Product (daytime, blending visible band 3 (0.64 µm) and Band 13 (10.41 µm); and nighttime: Infrared only (Band 13, 10.41 µm) ) for the period from 16 March 2021 through 16 April 2021 over the Pacific Island (1) sector from this site, courtesy of JMA. How has the tropical western Pacific changed over this month? During the first week, mid-latitude extratropical fronts move west to east across the northern part of the domain, brushing the northern Marianas Islands. The monsoon trough over the southern part of the domain shows a lot of activity from the start of an animation, although some periods show more activity than others (25-28 March is quiescent compared to times before and after). A cyclonic circulation moves westward to the south of Guam on 31 March/1 April. Then a stronger impulse moves into the domain from the east on 2-3 April. By 7 April, this tropical storm is south of Guam moving towards the northwest where it becomes Typhoon Malakas. An obvious eye is apparent in that system as it recurves to the west of Guam on 12-13 April. By the end of the animation (17 April), the system has lifted to the north/east of this domain, and the sector has only scattered convection.

Note in particular as the animation occurs how the region of Sun glint has shifted northward. Northern Hemisphere Spring is ongoing.

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GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in white [click to play animated GIF | MP4]

Overlapping 1-minute Mesoscale Sectors provided 30-second GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images (above) — with time-matched plots of SPC Storm Reports — of thunderstorms that produced straight-line wind damage and hail as large as 4.25 inches in diameter across far southern Missouri and northeastern Arkansas after sunset on 15 April 2022. These storms intensified in the vicinity of a warm front that become quasi-stationary across the area (surface analyses). Following a storm damage survey (NWS Little Rock PNS), it was determined that damage at the reported tornado locations was caused by straight-line winds and wind-driven large hail.

Around the time of the first tornado/wind damage report (below), an area of warmer cloud-top infrared brightness temperatures (shades of orange) began to appear immediately downwind (southeast) of the cold overshooting top (cluster of black pixels) — suggesting the presence of an Above-Anvil Cirrus Plume (reference | VISIT training).

GOES-16 “Clean” Infrared Window (10.35 µm) image at 0030 UTC, with time-matched SPC Storm Report plotted in white [clic to enlarge]

The coldest GOES-16 cloud-top infrared brightness temperatures were around -70^oC, which was about 10^oC colder than the tropopause / equilibrium level temperature, as seen in a plot (source) of 00 UTC rawinsonde data from Little Rock, Arkansas (below).

Plot of rawinsonde data from Little Rock, Arkansas at 00 UTC on 16 April 2022 [click to enlarge]

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