SPC Storm Reports from 5 April 2022 note a Tornado hit Allendale SC shortly before 2000 UTC. The animation above shows the ProbSevere (version 2 — available online here) display prior to and just after the tornado. NOAA/CIMSS ProbSevere identifies and tracks the radar feature associated with this tornadic storm. ProbSevere is designed to give forecasters more confidence in warning issuance. ProbSevere in this case highlights the radar object associated with model fields and satellite/radar observations that are most suggestive of a storm supporting tornadogenesis — note that ProbSevere values in adjacent cells are smaller. A meteorogram of this radar object, shown below (and available here), shows the ProbSevere components, and also ProbHail/ProbWind/ProbTor/Probsevere values, for both versions 2 and 3. ProbSevere values increased at around 1930 UTC. ProbSevere v3 values generally are smaller than ProbSevere v2 values; ProbSevere v3 will be demonstrated this year at the Hazardous Weather Testbed (HWT) this year. (Click here to view the Charleston, SC (KCLX) radar at 1958 UTC; a pronounced hook is apparent)

This tornadic cell stood out in the visible imagery. GOES-16 Mesoscale Sector #2 on 5 April included portions of South Carolina. The mp4 animation below, from the CSPP Geosphere site, (this direct link to the animation will be valid for a bit less than a week) shows the tornadic cell erupting at around 1930 UTC near the Georgia/South Carolina border.

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Observations — satellite and radar — both showed the obvious storm. How did short-range guidance perform? A Polar Hyperspectral modeling system — also to be demonstrated at the Hazardous Weather Testbed — produces hourly 18-hour forecasts with initial fields influenced by Sounder Data from the Polar Orbiting satellites Suomi-NPP, NOAA-20, Metop-B and Metop-C. Infrared sounder (CrIS on Suomi/NPP and IASI on Metop) and Microwave sounder (ATMS on Suomi/NPP, AMSU/MHS on Metop) data can produce a more accurate initialization of the moisture distribution in atmosphere. The forecast initialized at 1200 UTC for Lifted Index and Significant Tornado Parameter, valid at 18, 19 and 20 UTC — that is, 6-h, 7-h and 8-h forecasts, below, shows increasing instability before the tornado in Allendale.

The model runs initialized at 1700, 1800 and 1900 UTC, showing fields from initialization through 0000 UTC on 6 April 2022, are shown below. Note that the area with a Significant Tornado Parameter signal is mostly confined to southeastern South Carolina — that is, near the coast. Storm reports show that severe weather was mostly near the coast as well.

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These fields are also available in AWIPS via an LDM feed (in preparation for HWT). The 3 images below show changes in the 2000 UTC forecast (from the model initialized at 1400, 1600 and 1700 UTC). The trend towards higher Significant Tornado Parameter over southeastern South Carolina is obvious. Note that Allendale’s location is shown.

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Added: the GLM on GOES-16 saw a dramatic increase in Flash Extent Density with the tornadic storm starting around 1925 UTC on 5 April. (Click here to see a slower animation from 1920 – 1930 UTC)

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Probability of Moderate or Greater (MOG) Turbulence is a Machine-Learning product that uses satellite imagery (Band 13 — the clean window infrared channel at 10.3 µm — over the GOES-West domain; GOES-16 Probabilities use both Band 13 and the upper-level water vapor imagery — Band 8 at 6.19 µm; training on this product is available here) and GFS estimates of tropospheric stability. The animation above (from this website) shows an axis of maximum probabilities to the northeast of Hawai’i. Two pilot reports of turbulence are plotted in that axis, one near 0910 UTC, one near 1000 UTC.

The upper-level water vapor imagery associated with this feature is shown below. The GOES-17 upper-level water vapor imagery displayed below is showing the effects of the poor functionality of the Loop Heat Pipe (you can investigate more on this topic here). In this animation, that effect is manifest by flickering in the image (that is especially noteable around 11 UTC). The overnight imagery should degrade further in the next few days before recovering later in May.

GOES-17 MOG Turbulence Probability is available in AWIPS, as shown below. The product is produced from the Full Disk Imagery, that is, with a 10-minute cadence.

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The CIMSS Weighting Function website can gauge from what level the information sensed in the upper-level water imagery emerges. The image below, using 0000 UTC GFS data, suggests the information is originating around 300 mb.

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GOES-16 (GOES-East) Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (above) showed deep tropospheric waves moving over the Gulf of Mexico on 04 April 2022. Waves propagating west-southwestward were initiated by thunderstorms — but no distinct forcing mechanism was apparent for the wave that was moving northwestward.  

Also included in the animation is an overlay of the CIMSS Moderate or Greater (MOG) Turbulence Probability product — values were very low in areas where the wave features were seen, but were high in the immediate vicinity of a small cluster of thunderstorms (until those storms rapidly dissipated). In this case, there were no pilot reports of turbulence with any of the wave features or the small short-lived cluster of thunderstorms.

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MIMIC (Morphed Integrated Microwave Imagery at CIMSS) estimates of Total Precipitable Water, above, and available in real time here, and archived here, show two cyclonic rotations on the poleward side of the deep moisture of the Intertropical Convergence Zone in the western Pacific. These two circulations are areas of interest to the Joint Typhoon Warning Center, as shown below. At the end of the animation, one circulation (tropical invest 94W) is about to move over the Phillippines. A second feature at the end of the animation is near 10^o N, 150^o E.

You can also view assessments of total column precipitable water (and TPW in pre-defined layers) as measured by NOAA-20 CrIS/ATMS sensors and produced by HEAP software that produces NUCAPS profiles. This SPoRT site displays gridded swaths of precipitable water, and they’re aggregated below in a loop. The latest esimates of layer Relative Humidity are shown below that. The middle-/upper-troposphere over Guam is quite dry!

What does Himawari-8 show over the region? As noted in this blog post, it’s a straightforward task to automatically acquire Himawari data via cron on any unix machine. Daily animations can then be produced, and strung together as shown below in an mp4 (Click here for the animated gif) spanning 01 through 03 April 2022. The convection associated with Invest 94W is obvious early in the animation before its convection collapses. The rotation associated with Invest 95W is apparent to the southeast of Guam at the end of the animation, but the system is poorly organized.

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Why have these systems not developed further? The toggle below shows a mapping of shear and SSTs centered on Invest 95W (click here for a basin-wide analysis of Shear, taken from the SSEC Tropical Weather Website). Given that the atmosphere has low shear, and sea-surface temperatures are warm, it’s possible that dry air to the north has helped prevent organization. The low latitude — between 5^o and 10^o N — might also be a factor.

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