The NOAA/CIMSS ProbSevere team created a tool to help forecasters monitor the time tendency of lightning potential at a static point. The static points in the map below are mostly civilian airports and army airfields throughout the U.S. From the ProbSevere LightningCast website, a user can toggle on the “Lightning meteograms” layer from the menu on the left (Figure 1). The user can then click a location (red dots) and finally click the link in the pop-up window. This will bring up a new website with different time series (Figure 2 [static link]).

From this page, a user can quickly see how the probability of lightning has been changing (computed by LightningCast), as well as the observed lightning tendencies from GOES-East and GOES-West GLM, and Earth Networks Inc™. LightningCast probabilities are computed on the 5-minute and 1-minute scans for both GOES-East and GOES-West (when applicable). The 1-min scans will be displayed when the location is covered by a mesoscale sector. Users can change the location of meteograms (top left) as well as the time frame (top right). Data from recent days will be archived. The flash rates from GLM and ENI are aggregated within 5- and 10-mile radii of the location and within the previous 5 minutes.

Forecasters can use this to monitor lightning for aviation purposes or nearby large outdoor events. For instance, forecasters are surely monitoring for lightning at the Masters Golf Tournament in Augusta, GA today. LightningCast probabilities have been steadily increasing for nearly an hour, and lightning was observed within 5 miles of Augusta Regional airfield (Figure 3). Augusta Regional is about 10 miles southwest of Augusta National Golf Course.

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A sequence of 1-minute Mesoscale Domain Sector GOES-18 (GOES-West) images from all 16 ABI spectral bands (above) displayed reflectance and/or thermal signatures of the SpaceX Falcon-9 rocket booster as the Intelsat-40e/TEMPO Mission was launched from Cape Canaveral Space Force Station in Florida at 0430 UTC on 07 April 2023.

A subtle reflectance was even detected in Band 02 (“Red” Visible) imagery at 0430 UTC and 0431 UTC (below).

A stepped sequence of images from spectral bands 02-06 at 0430 UTC is shown below.

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The recent bouts of severe weather (See this blog post about the 31 March outbreak, or this one about the 4 April outbreak) over the central United States mean an opportunity to compare Numerical Model output from models that are initialized with temperature/moisture profiles derived from Polar Hyperspectral Soundings (using both infrared and microwave data from CrIS/ATMS or IASI/AMSU/MHS) to models that have not assimilated such data. Does the addition of the observations of temperature and moisture profiles observed by NOAA-20/NOAA-21 or MetopB/MetopC lead to a better prediction of convective weather? As happened in 2022, this Polar Hyperspectral Modeling System (PHSnMWnABI, or just PHS for short) will be demonstrated at SPC’s Hazardous Weather Testbed. The blog post will show a few examples of differences between PHS-enhanced modeling output, and a separate modeling system not so enhanced.

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Significant Tornado Parameter (STP) can be computed from HRRR model output and from PHS/WRF model output, and that field, overlain with severe weather reports, is shown below at hourly intervals for the 31 March – 1 April severe weather event. There is good correpondence between the severe weather reports and the STP fields, moreso especially with PHS-enhanced WRF model over Iowa and Illinois at 2100, 2200, 2300, 0000 and 0100 UTC. (These fields show average values of 9 separate forecasts valid at the time shown, that is, the average of a 1-h forecast, a 2-h forecast, a 3-h forecast…, and a 9-h forecast valid at the time shown).

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Consider the toggle below that compares HRRR model output (without PHS input) and WRF model output (with PHS input). There is a pronounced difference in the predicted radar reflectivity in this 3-h forecast to the west of Chicago (NWS WFO outlines are shown on that map). The 1700 UTC radar, below (source), shows better agreement with the PHS model, although an argument could be made that the PHS model is overpredicting the precipitation on this day.

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A comparison of the average STP from different forecasts enhanced by PHS observations and forecasts that do not assimilate PHS data is shown below for the same event, but at 0000 UTC on 5 April 2023. (Here’s the same figure for 1500 UTC on the 4th, and 0900 UTC on the 5th). In general, STP values are greater in the WRF run that starts with assimilated moisture and temperature observations from Hyperspectral Soundings.

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More results from this modeling system will be shown in the coming weeks. Imagery in this blog post is courtesy Qi Zhang, CIMSS. Model output from this system is available online here.

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Himawari-9 Airmass RGB imagery, below, from 0000 on 4 April through 1200 UTC on 6 April 2023 (created using geo2grid) show a transition from a deep tropical airmass (deep green in the RGB with embedded clouds that are white) over the southern Marianas islands to one that is a bit dryer (more orange in the RGB). A meteorogram for the A. B. Won Pat International Airport on Guam, below, shows the transition that started around 1800 UTC on 4 April. In particular, the pressure increased from 1008 mb to around 1010 mb; winds shifted to northeast and then east (and strengthened); dewpoint temperatures dropped a couple degrees (^oF). Guam is at 13.4° N; this airmass penetrated very deep into the tropics.

What other satellite products showed this change? The Night Microphysics RGB, below, also shows a boundary moving south over the southern Marianas islands. As with the airmass RGB above, the boundary does not appear to move very far south of Guam.

Advanced Scatterometer (ASCAT) imagery from MetopB and MetopC (originally from this website, and combined into one image at this website that shows the most recent 1-week animation) also shows the expansion southward of strong northeasterly winds. On 3 April 2023, winds around Guam are light from the east or southeast. By 5 April 2023, strong northeasterly winds have expanded southward over the Marianas Islands.

ASCAT winds ca. 1200 UTC on 6 April 2023, shown below, indicate strong convergence over Guam.

Gridded NUCAPS fields (available at this site) also show the stark differences across the Marianas Islands from north to south. The animation below shows 850-700 mb lapse rates (more stable over the northern Marianas), 400-200 mb lapse rates (more stable over the northern Marianas), Total Precipitable water (dryer over the northern Marianas) and 850-mb Temperatures (cooler over the northern Marianas). NUCAPS data can give very useful information within data voids (like the Western Pacific Ocean!)

MIMIC Total Precipitable Water fields over the western Pacific Ocean (from this site and archived here), below, from 0000 UTC on 1 April through 1200 UTC 6 April, show the dramatic southward motion of dry air over the northern Marianas that extend northeastward from Guam (at 13.4° N, 144.8° E).

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Sandwich product imagery from this JMA website (scraped daily), below, shows parts of the western Pacific from 0000 UTC on 1 April through 5 April 2023. The storm responsible for dragging a front across the Marianas is apparent in the imagery starting around 3 April.

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