The Lightning Imaging Sensor (LIS) that flies on the International Space Station (ISS) observed about 20 individual flashes in about a minute to the east of Japan on 1 February 2023, as shown in the animation above. Himawari-9 Band 13 clean window infrared (10.41 µm) imagery, below, bracketing the lightning observation times above shows a developing storm system moving out over the Pacific — the comma head of the system is over southern Hokkaido Island. Convective development can be inferred between 35^o and 40^o N off the coast of Honshu.

Did this system intensify, as one might expect given the presence of lightning? It did. The imagery below, from this site, shows the storm forecast to strengthen from 999 hPa at 0600 UTC to 989 hPa at 1800 UTC on 1 February. LIS data, though infrequent, can give useful information about convection.

View only this post Read Less

JMA Himawari-9 False Color RGB images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed plumes of SO2 (brighter shades of cyan) drifting northward, westward and southeastward from the East Epi submarine volcano, following its eruption on 01 February 2023 (local time).  The differences in SO2 transport were due to directional wind shear with height. No signatures of significant concentrations of volcanic ash were seen in other types of multispectral satellite imagery.

View only this post Read Less

Using a combined LEO/GEO approach, ABI and VIIRS retrievals are used to estimate flooding from a satellite perspective. Individual flood products from VIIRS and ABI (or AHI, depending on location) are blended to create the NOAA LEO/GEO Flood Mapping Product.

An example is shown below over the Sacramento, California region. Recent rains in California caused flooding in much of the state, including regions near the state’s capital, Sacramento, particularly along the Sacramento River. RealEarth provides a 14-day archive of the NOAA LEO/GEO Flood Mapping Product (listed as River Flood: Joint ABI/VIIRS), which is available on a daily basis. The product is an estimate of surface flooded water fractions, and can be obstructed by cloud cover as seen in the frame from 1-29-2023. While the area looks heavily flooded, it is important to note that many of these regions are actually agricultural rice farms that intentionally flood surface areas.

A flood gauge monitored by the USGS shows a decline in water levels over the past week in Sutter County, CA, just north of Sacramento and along the Sacramento River.

You can generate the RealEarth LEO/GEO Flood Product animation on your own or investigate other flood sites by visiting the RealEarth webpage.

View only this post Read Less

SAR data are being acquired over American Samoa for the next several weeks. SAR data from a Sentinel-1A overpass at 0553 UTC on 31 January, shown above (from this website), shows mostly light winds, mostly less than 10 m/s. The Normalized Radar Cross Section (NRCS) data can be used to view any ice contamination in the wind speed image. Ice can cause very strong reflection of the SAR signal that will be misinterpreted as strong winds. If significant ice is present in any convective tower, it will have a feathery appearance in the NRCS data.

SAR netcdf files can also be imported into AWIPS, and the toggle below compares GOES-18 Band 13 imagery and SAR data at the same time. On this day it is challenging to relate the small increases in wind apparent in the SAR imagery to Band 13 satellite imagery.

---

MetopB overflew the Samoan Islands shortly after 0900 UTC (link), and Advanced Scatterometer (ASCAT) winds from that platform also show weak winds. MetopC ASCAT winds from 0831 and 1011 UTC show light winds as well.

Thanks to the NOAA Office of Observations and NOAA/NESDIS/STAR SMCD and SOCD for arranging these observations.

---

The Special Collection actually started on 30 January, and two RADARSAT collections occurred, one at 0544 (Wind Analaysis is here; NRCS is here) and one at 1647 UTC (Wind Analysis ; NRCS). Toggles of the two image pairs are shown below.

The 1647 UTC wind speed analysis includes regions where contamination by thick ice in clouds is likely occurring. That is, those very strong wind values (nearly 50 knots!) centered near 16.25 S and 171.5 W are not true surface winds speeds, but arise because of strong reflection from thick ice within convective clouds in that vicinity. (The ice features have a feathery look in the NRCS fields). GOES-18 Band 13 imagery over that region, below, shows abundant deep convection. The GOES-18 Cloud Phase product (here) indicated ice clouds over the convection, but only within certain regions of the convection was the ice thick enough to reflect enough SAR radiation to affect the derived wind speeds.

View only this post Read Less