Target Sector (2.5-minute interval) JMA Himawari-9 Visible and Infrared images (above) covered the period +/- 2 hours when Super Typhoon Mawar reached Category 5 intensity at 0600 UTC on 25 May 2023. Mesovortices within the eye were evident in Visible imagery, with the eye exhibiting a “stadium effect” geometry (two signatures that are often associated with intense tropical cyclones).

A DMSP-17 SSMIS Microwave (85 GHz) image at 0911 UTC from the CIMSS Tropical Cyclones site (above) showed Mawar to the west of Guam, with a well-defined, completely closed eyewall along with a spiral band wrapping into the storm center from the south. Later in the day, Mawar further intensified to 155 knots at 1800 UTC (JTWC advisory | ADT | SATCON | D-MINT | D-PRINT) — and a DMSP-18 SSMIS Microwave image at 1905 UTC (below) revealed a distinct pair of spiral bands.

As also mentioned in this blog post, a Suomi-NPP VIIRS Day/Night Band (0.7 µm) image valid at 1655 UTC (below) revealed mesospheric airglow waves (reference) radiating hundreds of miles northward through westward away from Mawar — these vertically-propagating gravity waves were generated by deep convection within Mawar’s eyewall.

A long animation of Himawari-9 “Clean” Infrared Window (10.4 µm) images (below) showed that the eye of Mawar exhibited a small amount of trochoidal motion during the day.

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Typhoon Mawar wobbled north during the day on 24 May and moved through the Rota channel between the islands of Guam to the south and Rota to the north, as shown in the animation of Himawari-9 Target Sector Band 3 (Visible, 0.64 µm) imagery above. The track path from the Joint Typhoon Warning Center, below, shows the 0900 UTC position just north of Ritidian Point on Guam. Typhoon conditions are widespread over Guam however with widespread heavy rain, winds and lightning.

Waves at the Ritidian Buoy exceeded 28 feet in height!

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There is a Direct Broadcast antenna at the forecast office in Guam, and it collected imagery during the storm. The image below, from MetopB, shows 12 µm brightness temperatures at 1205 UTC on 24 May 2023. At this time, typhoon winds continued to affect the island although the center of the eye was

NOAA-20 overflew the storm shortly after 0300 UTC on 24 May 2023, and the Day Night band imagery from that pass is shown below. At that time, the storm was still east of Guam.

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From a NOAA Email: The first in-person Satellite Proving Ground experiment at the Hazardous Weather Testbed (HWT) in Norman OK since 2019 is underway! We have 7 NWS forecasters helping to evaluate 5 products that involve satellite data, focusing specifically on severe storms and their environment. One of the products being evaluated is output from a model that has been initialized with assimilated Polar Hyperspectral Soundings (both infrared and microwave) from NOAA-20 and NOAA-21 and from MetopB and MetopC. Forecaster-developed blog posts on the various products, including PHSnMWnABI model output (PHS for short) can be found at this site: https://goesrhwt.blogspot.com. Model output for HWT is within AWIPS, but it is also available online here.

Consider the GOES-16 Clean Window Infrared (Band 13, 10.3 µm) image below from 2200 UTC on 23 May 2023 (the color bar has been altered from the default; the coldest cloud top temperature is -80^oC rather than the default -109^oC). The strongest convection is over eastern New Mexico, but scattered convection is occurring throughout the state, and it also spreads into west Texas.

Three-hour forecasts from the 1900 UTC model run are designed to alert a forecaster to regions where significant weather might occur. That is, it is a short-range situational awareness tool. Because of the addition of temperature and moisture information from the Polar Orbiters (likely MetopB/MetopC for this time), a more accurate initialization is likely. What kind of information can be viewed?

The toggle below compares the Band 13 infrared imagery to low-level storm-relative helicity in the 0-3 km layer. The agreement between the two images varies. The strongest convection over eastern New Mexico and over west Texas has a good counterpart in the helicity fields. Weaker convection through the central part of New Mexico also has corresponding signals in the helicity field. It’s not a perfect one-to-one relationship however.

Model composite reflectivity fields, below, suggest that the modeled storm in west-central Texas is the most vigorous at this timestep.

A comparison of the two radar fields at 2200 UTC, observed and simulated, is below. Both show active and more widespread convection over eastern New Mexico and west Texas, with scattered convection over the rest of New Mexico.

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The in-person HWT Experiment runs through Friday 26 May. After a one-week break (that includes Memorial Day), two remote weeks occur, from 5-9 June and from 12-16 June.

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When NOAA-20 flew over the eastern half of Typhoon Mawar at 1500 UTC on 23 May 2023, broken cloudiness to the south and east of the storm allowed for successful infrared retrievals. What did those three retrievals indicated in the toggle above show?

Retrieval 1, below, showed a very warm upper-tropospheric atmosphere; -30^oC temperatures nearly at 31000 feet! The very warm upper troposphere calls to mind the warmth with Typhoon Soulik in 2018; Soulik’s eye was so large that a successful retrieval occurred within the eye (link) and -30^oC was at 34000 feet!

Soundings at Points 2 and 3 are not quite so warm; -30^oC is “just” at 30000 feet.

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Even if NOAA-20 overflies a strong tropical cyclone with abundant clouds, it’s possible that partial clearing on the periphery of the storm can help diagnose atmospheric thermodynamics there.

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Suomi NPP overflew Mawar at 1552 UTC on 23 May, and mesospheric gravity waves are evident in this Day Night Band imagery, below, radiating out from the storm center.

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