Hourly GOES-West imagery from the CSPP Geosphere site, above (direct link to animation), shows the development of a broad Kona Low over the Hawai’ian islands. MIMIC Total Precipitable Water (TPW) fields over the eastern Pacific, below, show a very moist airmass moving into the eastern Hawai’ian islands as the Kona low develops to the west. The OSPO Percent of Normal fields at 1200 UTC on the 29th (here), show values >150% of normal throughout the Hawai’ian island chain. The next few days will be wet in Hawai’i — the entire state is under either Flood Watches or Flood Advisories.

Airmass RGB imagery, below, from GOES-18 shows the dark green coloration that is characteristic of deep tropical moisture to the south of Hawai’i. The developing Kona Low, to the west of Kauai, is surrounded by air rich in potential vorticity, as suggested by the orange tint in the RGB. The developing low is also cut off from the main belt of westerlies that are north of 40^oN Latitude.

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NOAA-20 overflew the Hawai’ian island chain around 0000 and 1200 UTC on 29 November. The near-full Moon on the 29th provided ample illumination for the Day Night Band imagery, shown below. A developing low is obvious to the west of Kauai, and convective clouds associated with rich moisture shown in the MIMIC animation above is apparent over the Hawai’i.

NUCAPS data from two sequential NOAA-20 overpasses can be used to assess how the atmosphere is changing. The toggle below compares NUCAPS’ estimate of 500-mb temperature at 2339 UTC on the 28th and 1210 UTC on the 29th. The -12^oC isotherm moves south during these 12 hours although the -16^oC isotherm retreats northward.

The toggle below compares NUCAPS profiles near 20 N, 166 W. Significant upper-tropospheric cooling is apparent between 2345 UTC on 28 November and 1214 UTC on 29 November!

The 0000 and 1200 UTC soundings at Lihue, below, also show cooling in mid-levels during the 12 hours.

The Direct Broadcast antenna in Honolulu (link) is a useful source for microwave estimates for rainrate derived from polar orbiting satellite for systems affecting Hawai’i. The toggle below shows rainrate from MetopC (0744 UTC) and NOAA-20 (1208 UTC); heavy rain has moved onto the Big Island from the southeast, and it is slowly approaching Kauai from the west

For more information on this wet event, refer to the National Weather Service office in Honolulu.

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10-minute interval GOES-16 (GOES-East) True Color RGB images (source) from 0930-1900 UTC on 13-26 November 2023 (above) showed Iceberg A23a just east-northeast of Joinville Island (at the tip of the Antarctic Peninsula). Although cloud-free periods were scarce during those 14 days, even on most of the cloudy days the silhouette of A23a was evident. During that time, A23a was the largest iceberg in the world (although it was smaller in area than recent icebergs such as A68).

On 2 days in mid-November when cloud cover was at a minimum, a toggle between “Natural Color” RGB images from Landsat-9 (at 1239 UTC on 14 November) and Landsat-8 (at 1233 UTC on 15 November) is shown below (source) — which revealed a small amount of westward drift during that 24-hour period.

While the NOAA-20 VIIRS Sea Ice Temperature derived product at 0000 UTC on 13 November (below) generally displayed values near or just below freezing (medium shades of orange) across much of the surface of A23a, there were some areas across the northern portion of the iceberg that exhibited above-freezing values (darker shades of orange) as warm as 274.4 K or +1.25C (suggesting that some surface melting was occurring).

However, on 27 November GOES-16 True Color RGB images (below) showed that fractures — likely induced by wind stress as an occluded cyclone moved across the area (surface analyses) — began developing within the southern and eastern portions of A23a.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) Day Cloud Phase Distinction RGB images with an overlay of GLM Flash Extent Density (above) showed a glaciating (brighter shades of green) to glaciated (pale shades of yellow) lake effect snow (LES) band streaming inland off Lake Erie on 17 November 2023. There were 4 brief periods of lightning activity seen just south of the Buffalo, New York metro area. Note: since Flash Extent Density (FED) values were relatively low, the maximum value of the default FED colormap range was adjusted to 2.5 (to emphasize peaks within the low-FED areas).

A closer view (below) showed that the FED-indicated lightning activity was centered over the Southtowns (southern suburbs) of Boston — which had received up to 8.5 inches of snow by about 2300 UTC on 27 Novembver.

THUNDERSNOW Lake Erie at Hamburg Beach #NYwx pic.twitter.com/KpRqAXg5Qf

— BuffaloSnowKing (@BuffaloSnowKing) November 27, 2023

Cursor sampling of 2-km resolution GOES-16 CLAVR-x Cloud Top Temperature and Cloud Top Height derived products (below) indicated that the coldest cloud top temperatures within the lightning-producing LES band were in the -18 to -19°C range, with maximum cloud top heights in the 12000-13000 ft range.

During the next several hours, the LES cloud band slowly migrated southward — GOES-16 Nighttime Microphysics RGB images with an overlay of GLM Flash Extent Density (below) suggested that the cloud tops were mixed phase (ice crystals and supercooled water droplets — shades of tan to light brown), which is a necessary condition for charge separation processes within the cloud that lead to lightning production. Another favorable thundersnow factor was a sufficiently high -10°C air temperature level of 1.1 km (reference), as seen in 0000 UTC Buffalo rawinsonde data.

Beginning at 0253 UTC on 28 November, notable bursts of FED lightning activity were seen in the vicinity of Chautauqua County/Dunkirk Airport (KDKK) — which reported a thunderstorm (TS) that lasted from from 0257 UTC to 0312 UTC, and thundersnow (TSSN) at 0306 UTC (below). The surface visibility at that site dropped from 6 miles at 0310 UTC to 1-1/4 mile at 0320 UTC. Thanks to Rick DiMaio (Loyola University) for bringing these KDKK observations to our attention.

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GOES-East fire detection products in RealEarth allow users to assess burning areas across the Continental United States. In the example below, burning appears to be occurring in Lafayette Parish, Louisiana. These fire detections in southern Louisiana are picked up by the GOES scene fire detection and by the GOES fire temperature RGB (purple reddish area). This scene is associated with a fire radiative power (FRP) of 49.6. When adding HRRR smoke model output to the display, users can see that some near-surface smoke may be occurring nearby. However, the HRRR smoke is likely coming from a different location. The GOES scene fire detection is picking up many fires throughout the surrounding area.

Farther north in the state, in Caldwell Parish, the GOES algorithm picks up a fire scene with an even higher fire radiative powers (FRP up to 405.11). When observing with the GOES fire temperature RGB, this scene is even more apparent than the example in Lafayette Parish. However, the HRRR model output does not place any near-surface smoke there. This may be due to the model not receiving the latest satellite data input. (Note that the latest HRRR timestamp is at 1700Z while the GOES products are from 1731Z).

Users can recreate these scenes in RealEarth.

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