Early this morning at around 3:15 AM local time, an EF-0 tornado touched down in Pico Rivera, a community in Los Angeles County, California. It damaged several homes and knocked down numerous trees over the course of its mile-long path. Numerous instances of damaging winds were also reported, as seen on the NOAA SPC Storm Reports page. Fortunately, there were no reports of injuries.

Tornadoes in Los Angeles County are comparatively rare, but not unheard of. This is the 50^th recorded tornado in the county since 1950, and every month of the year has had at least one tornado report. The peak season for LA County tornadoes is winter and spring with more tornadoes recorded in January than any other month; with today’s event, March is now tied for second on that list. The NOAA NCEI Storm Events Database is an invaluable tool for analyses like these.

This particular storm event was driven by an advancing cold front linked to a low pressure system offshore. A steady stream of moist air from the Pacific ensured sufficient moisture to support convection. That is evident in the GOES-18 Band 8 upper level water vapor imagery, which shows a plume of moisture pointed directly at the greater Los Angeles area.

A polar-orbiting overpass at 0930 UTC (2:30 AM local time, approximately 45 minutes before tornadogenesis) provided Gridded NUCAPS observations. The 700-500 mb lapse rate product from Gridded NUCAPS shows lapse rates over LA County to be close to the critical conditionally unstable value of 6.0 C/km, with more unstable air aloft coming onshore from the south. The elevated lifting from the advancing front coupled with the elevated instability was enough to support deep convection.

Forecasters anticipated the potential weather overnight and the GOES-18 mesoscale sector was active for this event, providing images every minute. Since it was nighttime, none of the products that depend on shortwave channels were available, but many interesting things can be discerned from the longwave imagery. The Channel 13 IR window view shows the cold cloud top temperatures associated with the deep, moist convection, while the speckled orange portions of the Night Microphysics RGB help to confirm that the clouds over LA are deep, thick, and moisture-laden. Mesoscale sectors are available in AWIPS, or are freely available to everyone at SSEC RealEarth.

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W-NW winds gusting in excess of 50 mph in the wake of a cold front lofted areas of blowing dust across parts of Texas on 12 March 2025, as seen in GOES-16 (GOES-East) Visible images (above). Blowing dust reduced the visibility to 1-1/2 miles at times along the Interstate 20 corridor in the vicinity of Midland.

Daytime True Color RGB images created using Geo2Grid (below) provided a more distinct view of the blowing dust — and after sunset, Dust RGB images highlighted the airborne dust as shades of magenta.

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A sequence of Suomi-NPP VIIRS Visible images (above) showed the formation of large ice leads in the eastern Beaufort Sea — as well as the growth of a polynya adjacent to the coast near the Alaska/Yukon border — during the 5-day period from 07-11 March 2025.

Suomi-NPP VIIRS Shortwave Infrared images (below) provided a view of the ice leads and polynya during both the nighttime and daytime hours during the 07-11 March period.

Daily composites of Suomi-NPP VIIRS Sea Ice Temperature/Thickness/Age products (source) indicated that the larger ice leads were developing near the gradient of temperature and thickness of old ice in the eastern Beaufort Sea (below).

In spite of lower spatial resolution and a large satellite viewing angle, the more prominent ice leads (as well as the polynya adjacent to the Alaska/Yukon coast) were also apparent in GOES-18 (GOES-West) Visible images from the CSPP GeoSphere site (below).

Comparisons of Ice Stage and Ice Analysis (source) shown below indicated that the 2 largest ice leads and the polynya formed during the 7-day period between 03 March and 10 March.

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Several recent notices have announced that radiosonde-carrying balloon launches to measure the temperature and moisture (and winds) in the atmosphere are suspended due to personnel shortages. There are products available to mitigate this data shortage. NOAA-Unique Combined Atmospheric Processing System (NUCAPS) profiles (training video here) use data from CrIS/ATMS (on NOAA-20/NOAA-21) and IASI/AMSU/MHS (on Metop-C) to create thermodynamic profiles.

Where can these data be accessed? For National Weather Service WFOs, they are available in AWIPS under the ‘Satellite’ tab (and then ‘JPSS Polar’); then look at ‘NUCAPS Sounding Availability’, shown below, and ‘Gridded NUCAPS’. When NUCAPS Sounding Availability is on your screen, you can profiles by clicking on the points. For example, the Sounding Availability plot below shows two different profile locations in far southern coastal Maine; profiles at these two points are shown below as well. The low-level warming one might expect during the day is captured well.

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Gridded NUCAPS fields show values that have been interpolated to a pressure level on a grid. In the animation of 850-mb temperature plotted in AWIPS and shown below, showing a combination of MetopC, NOAA-20 and NOAA-21 fields, the 0^oC isotherm is progressing northward through Maine in the 11 hours shown. The number of observations is far greater than the number of radiosondes that would have launched in this time.

Gridded NUCAPS fields are also available online. The images below show values over the Pacific Ocean (where radiosondes are routinely absent), and they show a stable and dry region arcing toward the Pacific Northwest from the tropics. Perhaps the cloudband in about the same location in the nightmicrophysics RGB (from the CSPPGeosphere site) is related to this NUCAPS-observed feature.

Use gridded NUCAPS when (that is, always!) you need supplemental observations of the troposphere.

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