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PHS information adds small-scale variability to initial fields

Polar Hyperspectral Data (PHS) can be married to ABI data via Data Fusion, and that data that exploits the high spectral resolution of Polar Hyperspectral Data (from IASI and CrIS data on Metop and JPSS satellites, respectively) and the high spatial/temporal resolution of ABI data can be assimilated into a... Read More

WRF model fields (4-km resolution) of MUCAPE at 00h in a simulation that starts at 1800 UTC on 23 May 2024; the toggle compares WRF runs with and without PHS data within the initial fields (Click to enlarge)

Polar Hyperspectral Data (PHS) can be married to ABI data via Data Fusion, and that data that exploits the high spectral resolution of Polar Hyperspectral Data (from IASI and CrIS data on Metop and JPSS satellites, respectively) and the high spatial/temporal resolution of ABI data can be assimilated into a numerical model. The toggle above compares MUCAPE fields at 0000 UTC from an 1800 UTC 23 May 2024 initialization (more output from this day is shown in this blog post) created with and without PHS data. A similar toggle that compares 0-1 km Bulk Shear (with and without PHS data) is below. In both fields, the PHS data has introduced low-level variability that should better reflect the actual distribution of thermodynamics as measured by the sounders on the LEO satellites.

WRF model fields (4-km resolution) of 0-1 km Bulk Shear at 00h in a simulation that starts at 1800 UTC on 23 May 2024; the toggle compares WRF runs with and without PHS data within the initial fields (Click to enlarge)

Does the better representation of thermodynamic variability (and variability in dynamics) translate in this case to a better forecast. In the previous blog post, the WRF simulation with PHS data starting at 1600 UTC and 1700 UTC did show better convective initiation times than the HRRR simulation that did not benefit from the inclusion of PHS data (i.e, this figure, and this one, respectively). The 4-h forecast valid at 2200 UTC (that compares 4-km WRF with PHS data and 3-km HRRR data, here, shows better initialization in the WRF with PHS data). The toggle below compares 4-h forecasts from a 4-km WRF model initialized at 1800 UTC, and valid at 2200 UTC; one simulation includes assimilated PHS data, and one does not. The initiation of convection is not substantially different in the model runs initialized at 1800 UTC. The higher spatial variability for this case at this time does not lead to a better forecast of initiation as was apparent in the earlier model runs described in this blog post.

WRF model fields (4-km resolution) of Surface fields including Composite Reflectivity at 04h in a simulation that starts at 1800 UTC on 23 May 2024; the toggle compares WRF runs with and without PHS data within the initial fields (Click to enlarge)

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Hail swath near Willard, New Mexico

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Day Cloud Phase Distinction RGB images (above) showed clusters of slow-moving thunderstorms across Torrance County in central New Mexico on 19 June 2024. In addition to generating strong winds and heavy rainfall, these storms were also prolific hail-producers — most notably, there was one Local Storm Report of 2.00-inch diameter hail that lasted for 1.5... Read More

1-minute GOES-18 Day Cloud Phase Distinction RGB images, from 2000 UTC on 19 June to 0019 UTC on 20 June; Interstates and State Highways are plotted in violet [click to play animated GIF| MP4]

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Day Cloud Phase Distinction RGB images (above) showed clusters of slow-moving thunderstorms across Torrance County in central New Mexico on 19 June 2024. In addition to generating strong winds and heavy rainfall, these storms were also prolific hail-producers — most notably, there was one Local Storm Report of 2.00-inch diameter hail that lasted for 1.5 hours and accumulated to a depth of 6 inches (9 miles southeast of Willard).

Parts of the northwest-to-southeast oriented swath of hail accumulation near Willard were evident through occasional breaks in the clouds — exhibiting varying shades of green, such as was seen at 2005 UTC, 2250 UTC, 2305 UTC and 0006 UTC. The hail swath appeared to have crossed State Highway 60, which jogs west-to-east across Torrance County (passing through Willard).

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Tropical Storm Alberto in the southern Gulf of Mexico

MIMIC Total Precipitable Water fields from 15 June through 19 June 2024, above, show a broad cyclonic circulation over Central America and adjacent waters (the Central American Gyre). On 18 June, shown below in an animation from the CSPP Geosphere site, the convection in this gyre was diffuse and unorganized (although the... Read More

MIMIC Total Preciptable Water fields, 0000 UTC on 15 June – 1800 UTC on 19 June 2024 (Click to enlarge)

MIMIC Total Precipitable Water fields from 15 June through 19 June 2024, above, show a broad cyclonic circulation over Central America and adjacent waters (the Central American Gyre). On 18 June, shown below in an animation from the CSPP Geosphere site, the convection in this gyre was diffuse and unorganized (although the National Hurricane Center initiated Potential Tropical Cyclone advisories on the system at 2100 UTC on the 17th.

True-Color imagery from GOES-16 Full Disk scanning, 1300-1700 UTC on 18 June 2025. A brief period of Night Microphysics imagery is apparent at the start of the animation

By 1500 UTC on 19 June, the system had acquired sufficient convection near its center, and had become organized enough to achieve Tropical Storm status, and the first named storm of the 2024 Atlantic Season, Alberto, was named. The Geosphere animation below, from 1300-1700 UTC on 19 June (that is, 24 hours after the animation above), shows the increase in convection over the southern Gulf of Mexico.

True-Color imagery from GOES-16 Full Disk scanning, 1300-1700 UTC on 19 June 2025. A brief period of Night Microphysics imagery is apparent at the start of the animation

The shear over the western Gulf of Mexico became much more favorable for tropical storm development between 1800 UTC on 18 June and 1800 UTC on 19 June 2024, that is, it has decreased, as shown below (imagery taken from here).

850-200 mb wind shear, 1800 UT on 18 and 19 June 2024 (Click to enlarge)

The projected path of Alberto is westward into Mexico, as shown in the image below showing the favorable shear values and warm Sea-surface Temperatures. Slow strengthening is forecast.

SST and Wind Shear Analysis over Tropical Storm Alberto, 1800 UTC on 19 June 2024 (Click to enlarge)

Although the storm center is forecast to move into Mexico, the very moist airmass surrounding the system is affecting (and will continue to affect) much of coastal and southern Texas. Tropical Storm warnings are in place from Galveston southward to Mexico, and Flash Flood Warnings have also been raised. A Flood Watch is in effect for Texas south of San Antonio. For more information on Alberto, refer to the National Hurricane Center website.

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Large Haboob over New Mexico and parts of Mexico

Starting on June 19, 2024, there was a large haboob (“wall of dust”) over New Mexico and nearby regions. This was captured by both GOES-18 (1-min “mesoscale”) and GOES-16 (5-min “Contiguous U.S.”) ABI imagery. What is shown is the CIMSS true color composite imagery during the day and the “dust” RGB at... Read More

Starting on June 19, 2024, there was a large haboob (“wall of dust”) over New Mexico and nearby regions. This was captured by both GOES-18 (1-min “mesoscale”) and GOES-16 (5-min “Contiguous U.S.”) ABI imagery. What is shown is the CIMSS true color composite imagery during the day and the “dust” RGB at night. Both animations run from approximately 21 UTC on June 19 to 04 UTC on June 20th, 2024.

NOAA’s GOES-18 (GOES-West) ABI imagery (CIMSS true color and the dust RGB).

Similar loop as above, but as seen from NOAA’s GOES-East.

NOAA’s GOES-16 (GOES-East) ABI imagery (CIMSS true color and the dust RGB). Click to Play.

H/T

The imagery was generated with the geo2grid software. The data was accessed via the UW/SSEC Data Services. T. Schmit works for NOAA/NESDIS/STAR and is stationed in Madison, WI.

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