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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Himawari-9 Infrared Imagery, above, shows Mawar as it develops and eye and strenghtens to Super Typhoon status. The animation above shows a well-developed symmetric storm with good outflow from all quadrants. The eye is seemingly in steady state from about 0300-0900 UTC, after which time its size shrinks. The 0600 UTC update from the Joint Typhoon Warning Center reported a central pressure near 923 mb. Based on the analysis of heat content in the ocean (from the SSEC Tropical Weather Website), below, Mawar is close to its maximum strength.

The DPRINT product (formerly called Open-AIIR), a Machine-Learning tool that estimates winds based on satellite presentation, available at the SSEC Tropical Weather Website, suggests a peak in intensity occurred around 1000 or 1100 UTC on 23 May. However, Mawar remains a Super Typhoon. Microwave observations of the eyewall structure (here), can be used to monitor the possibility of an Eyewall Replacement Cycle (ERC), which cycle will be responsible for short-time period variations in typhoon strength from now through landfall on/near Guam. Such cycles are challenging to predict in advance.

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The RCM-2 satellite made another overpass over Mawar, this time at 0830 UTC on 23 May (previous SAR Observations are discussed here and here). The image below compares the SAR observations with the Target Himawari Band 13 (Clean Window, 10.4 µm) image. The strongest SAR winds are not completely encircling the eye. All Mawar SAR observations/analyses can be accessed here.

Waves at Ipan, southeast of Guam, shown below, have increased to 16 feet. Significant coastal flooding is expected on Guam with this storm.

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Current forecasts have the path of Mawar bisecting the island of Guam. Refer to the National Weather Service Guam Forecast office website for more information (Local statements from the Guam forecast office are here). Other information is available at the JTWC and Tokyo RSMC.

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Update, 1700 UTC on 23 May

The satellite presentation of Mawar has degraded, and the eye is no longer so striking in satellite imagery. The animation below runs from 0634 UTC, when the eye is distinct, through 1657 UTC on 23 May.

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