Taking a closer look at various regions and features, we will begin with the Northeast US at 0610 UTC (below). One item of interest was the narrow fingers of valley fog that were forming in parts of Pennsylvania and New York, where strong radiational cooling under cloud-free skies was allowing the surface air temperatures to cool into the 30s and 40s F.Over the Southeast US at 0749 UTC (below), ample illumination by the Full Moon provided a very detailed nighttime view of the tops of numerous thunderstorms that had developed along and ahead of a cold frontal boundary (surface analysis). Note the appearance of several bright white areas at the tops of some thunderstorms, a signature of cloud illumination by intense lightning activity. In addition, temperatures ahead of the cold front were unusually warm for 25 December — for example, new records for the warmest low temperature for the date were set at both Mobile, Alabama and Pensacola, Florida (with 75º F and 71º F, respectively). Farther to the north, a DNB image centered over South Dakota (below) showed a great deal of variability in snow cover across that area; the effect of deeper snow cover on surface air temperatures could also be seen in the surface observations at that time, with the colder readings generally coinciding with sites having snow on the ground. Even farther to the north, it could be seen that ice covered a significant portion of Hudson Bay, Canada (below). In southern parts of Hudson Bay where open water still existed, numerous “lake effect” cloud bands could be seen due the northwesterly flow of very cold arctic air across the water. A DNB image centered over the Western US at 0930 UTC (below) revealed features such as snow pack over the higher terrain of the Sierra Nevada in California (where temperatures at the time ranged from 55º F in the desert at Needles KEED to 1º F in the mountains at South Lake Tahoe KTVL), and a variety of open-cell and closed-cell convection over the adjacent offshore waters of the Pacific Ocean. Finally, a DNB image centered over Alaska and the Yukon Territory of Canada at 1111 UTC (below) showed widespread snow cover over the cloud-free interior regions, with the thick cloud shield from a Gulf of Alaska storm moving over southwestern and southcentral Alaska. Very cold surface air temperatures at or below -30º F could be seen at a number of sites in the interior areas, with -42º F being reported at the time in Arctic Village, Alaska PARC (their minimum temperature later dropped to -45º F).
The terminator was also seen on GOES-15 (GOES-West) Visible (0.63 µm, 1-km resolution) images (below), albeit a few hours later. Note that areas of northern Canada and northern Alaska remain dark during the entire day; for example, at Barrow (the northernmost city in Alaska), their polar night — the period with no sunlight — lasts about 65 days, from mid-November to late January.For a global perspective, we can examine Himawari-8 true-color Red/Green/Blue (RGB) images (below), which cover the period before, during, and after the 0448 UTC solstice time — the animation pauses briefly on the 0450 UTC image, nearest the time of the solstice (also available as longer MP4 movie file). One feature that stands out quite prominently (due to a favorable forward scattering angle) is the dense haze covering much of the Indian subcontinent and the adjacent offshore waters. These images were generated using an update (version 2) of the Simple Hybrid Contrast Stretch (SHCS) method, which uses the AHI 0.86 µm band to “boost” the green of the 0.51 µm band, and stretches each of the 3 color components (R/G/B) on both the dark and light ends. Similar full-disk true-color images will be available every 5 minutes from the ABI instrument on GOES-R. The Himawari-8 data was provided by JMA and acquired via NOAA/NESDIS/STAR; the SSEC Data Center served the AHI data via McIDAS ADDE, and McIDAS-X was used for the processing.
— Mike Johnson (@wall_cloud) December 15, 2015
HUNDREDS OF TREES DOWN NORTH OF ZOAR. (GRB)
NUMEROUS TREES DOWN OF 1 FOOT DIAMETER AND GREATER. TRACK WAS APPROXIMATELY 1/4 MILE IN LENGTH AND 125 YARDS WIDE (MQT)
Terra MODIS data on 09 June 2007 (in the image above, at left) showed a tornado scar (much longer than 1/4 mile in length) running southwest-to-northeast through heavily forested Menominee County into Langlade County and then Oconto County in northeast Wisconsin. Terra MODIS True-Color imagery from 15 July 2015 (also in the image above, at right) (cropped from imagery at the MODIS Today website), shows that a scar persists more than 8 years later! (This persistent scar has been mentioned before on this blog here in 2009 and here in 2011).
Landsat-8 overflew northeast Wisconsin on 15 July 2015, at nearly the same time as the Terra MODIS imagery above, and those views, captured via SSEC‘s RealEarth are shown below. The scar is more evident in the shortwave infrared (Band 6, 1.61 µm) than the visible (Band 3, 0.56 µm) because the shortwave infrared channel is more sensitive to changes in vegetation. Lakes are also far more apparent in the 1.61 µm imagery because water absorbs 1.61 µm radiation; little is scattered back to the satellite for detection and water therefore appears black.