GOES-19 (Preliminary/Non-operational) Day Cloud Phase Distinction RGB images (above) — created using Geo2Grid — displayed supercooled “lake effect” clouds (shades of white) streaming southeast off Lake Sakakawea in northwestern North Dakota on 25th November 2024. A smaller cloud plume was also seen streaming southeast off Devils Lake in northeastern North Dakota. Existing snow cover appeared as shades of green in the RGB images, with bare ground appearing as shades of blue.

GOES-16 (GOES-East) Near-Infrared “Snow/Ice” (1.61 µm) images (below) included 15-minute plots of METAR surface reports — which showed brief periods of light snow at Hazen (KHZE) and Bismarck (KBIS). Snow cover appeared as darker shades of gray to black in the Snow/Ice imagery. Note the cold air — having temperatures in the single digits to teens F — that was flowing across the still-unfrozen reservoirs of the Missouri River (in addition to Devils Lake). Water surface temperatures on Lake Sakakawea were in the middle to upper 40s F.

Lake effect clouds near Devils Lake today, with even a few flurries underneath!#ndwx @NWSGrandForks pic.twitter.com/yymtTRqsIt

— Dillon Vogt (@DillonvWx) November 25, 2024

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GOES-West imagery centered over the Samoan Islands, shown above in an animation, shows a region of rich moisture surrounding those islands (purple in the enhancement, which suggests values or 2-2.2″), but the islands themselves are within a dry pocket (TPW values closer to 1.7″, orange/rust in the enhancement used). Total Precipitable Water derived from Microwave data, below (from the MIMIC website), shows similar values, including the local minimum over Samoa. A benefit with microwave observations of atmospheric moisture (compared to ABI) is the ability to detect values in the presence of clouds.

Pago Pago airport does have an upper-air station. However, hydrogen generation difficulties at that site in the past months have meant that balloon launches are limited, and one did not occur at 1200 UTC on 25 November. However, NOAA-20 overflew the region shortly thereafter and NUCAPS soundings can estimate the thermodynamic profile. The plot below shows where profiles are available; green points signify profiles for which the infrared retrieval converged to a solution, typically in regions of mostly clear skies (as might be inferred from the GOES-18 imagery above!)

The toggle below shows two NUCAPS profiles, one just west of Tutuila (at 14.2^oS, 171.5^oW) and one 6 points to the south (at 16.55^oS, 171.5^oW). Note the larger values of TPW in the more southerly sounding, consistent with what is discussed above. Otherwise, the profiles are quite similar.

Level 2 products also include clear-sky measures of instability, such as Lifted Index and Convective Available Potential Energy (CAPE). The Lifted Index field below shows pockets of stability (blue in the enhancement used) surrounded by minor instability (yellow in the enhancement) surrounding the Samoan Islands.

CAPE values (scaled from 0-400 J/kg) similarly show relatively weak regions of stability and instability surrounding the Samoan islands.

The TPW fields, and the Derived Stability Indices, do have similarities as might be expected. The toggles below compare TPW, LI an CAPE at 0300 and at 1300. Interestingly, the strong values of CAPE at the eastern edge of the domain at 0300 UTC seemingly have no echo in the other fields. In other regions (north of the Samoan Islands, for example), minima in CAPE and relative stability in Lifted Index occur where local minima in TPW exist. This case demonstrates how one stability index might not give the same information as another; make sure you have access to both!

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The (anti-clockwise) motion of the cloud features above suggests that an anticylone is present over the islands The animation below includes GOES-West derived motion wind vectors computed from Band 9 (mid-level water vapor, 6.95 µm) infrared images. The wind vectors are from near 350 mb, which height is determined by matching the Band 9 brightness temperature to GFS model temperatures.

Level 2 Products, especially in regions — like the South Pacific Ocean — where conventional data are lacking, can give a forecaster needed insight into how the atmosphere might evolve with time.

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The distinct hot thermal signature (black to yellow to red pixels) of a new fissure eruption between Stóra-Skógfell and Sýlingarfell on the Reykjanes Peninsula in southwestern Iceland was apparent in 10-minute Full Disk scan GOES-16 (GOES-East) Shortwave Infrared (3.9 µm) images during the 20th-24th November 2024 period (above). Station identifier BIRK is Reykjavik Airport, and BIKF is Keflavik International Airport. The fissure eruption began at 2314 UTC on 20th November, with the first GOES-16 thermal signature appearing at 2320 UTC.

A 30-meter resolution Landsat-9 Natural Color image (source) provided a detailed view of the lava flow’s hot thermal signature (brighter shades of red) at 1252 UTC on 24th November (below). A hazy volcanic plume could be seen drifting to the south-southwest.

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GOES-18 airmass RGB imagery, above (created using geo2grid software), shows the development of a hurricane-force low to the west of Washington and Oregon on the 19th of November. The orange and purple colors in the RGB suggest a significant intrusion of stratospheric air. That air is rich in ozone, and there are satellite observations that can highlight the ozone signal. NUCAPS profiles include information on trace gases, and the image below (from the JSTAR Mapper) shows the ozone distribution on 19 November.

Suomi-NPP also includes the Ozone Mapping and Profiling Suite (OMPS) instrument — available here at NASA Worldview. The animation of OMPS Column Ozone, below (from this source), shows the motion of ozone-rich air from over Alaska on the 17th to the Gulf of Alaska/northeast Pacific Ocean on the 19th.

The evolution of the system is also apparent in the water vapor infrared imagery (GOES-18, Band 8, 6.19 µm) below. Cyclogenesis is rapid on the 19th as an impulse drops southward from Alaska.

GCOM-W1 overflew the strong system at 2112 UTC on 19 November, and the AMSR-2 winds (derived with GAASP software and available here) are shown below. Winds in excess of 64 knots (that is, hurricane-force) are shown west of Washington and Oregon.

SMAP winds (source, also available here), below, at 0101 UTC on 20 November, also show the strong winds with this potent system.

Metop-B and Metop-C both carry the Advanced Scatterometer (ASCAT), and winds from those two satellites above this system are shown below. As with the other microwave-derived windspeeds shown above, the strong winds separate from the center and also with wind features to the south and to the northeast of the center are prominent.

MetopC ASCAT winds are also in AWIPS, and the toggle below shows the fields overlain on top of Band 13 clean window infrared imagery. Two of the plots show all the ASCAT wind barbs; this allows a user to see at a glance the wind distributions. For more information on ASCAT winds, click here.

VIIRS Day Night Band visible (0.7 µm) imagery, below, at 0934 and 0958 UTC show the system illuminated with a waning gibbous 3/4 crescent moon. Winds observed at the buoys at this time were in the 30-40 knot range.

What were near-shore buoys showing? The toggle below (using plots from this website) shows observations at Buoy 46132 (South Brooks), 46206 (La Perouse Bank), 46087 (at the mouth of the Strait of Juan de Fuca), 46041 (Cape Elizabeth), 46029 (Columbia River Bar) (This figure shows the locations of most of the buoys, you can also see the locations here). The buoys showed wind gusts in excess of 50 knots, and sustained winds close to 35 knots.

Buoy 46005, at 46^oN, 131^oW, showed a pressure near 28″ of mercury (near 945 mb) and gusts exceeding 60 knots before failing.

A closer view of GOES-18 Water Vapor images (above) revealed the distinct circulation associated with this rapidly intensifying low — whose center passed near Buoy 46005 (which recorded a wind gust of 64 knots at 2120 UTC, after which it stopped reporting).

NOAA-21 and NOAA-20 VIIRS Day/Night Band images that included a plot of the final 2100 UTC Buoy 46005 observation (below) showed the center of the low passing just west of the buoy.

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