As seen on the Cyclone Phailin (02B) track map from the CIMSS Tropical Cyclones site (above), the storm formed near the northern Adaman Islands on 09 October 2013. As Phailin tracked northwestward across the Bay of Bengal, it underwent a period of rapid intensification on 10 October, as indicated by the Automated Dvorak Technique (ADT) intensity estimate plot (below). Phailin reached Category 5 intensity near the middle of the day on 10 October.

McIDAS images of EUMETSAT Meteosat-7 11.5 µm IR channel data (below; click image to play animation) showed the expansive area of very cold cloud tops exhibited by Phailin, with IR brightness temperatures in the -80 to -90º C range (violet to darker purple color enhnahcement).

A McIDAS-V image of 375-meter resolution Suomi NPP VIIRS 11.45 µm IR channel data (below; courtesy of William Straka, CIMSS) offered a more detailed look at the structure of the eye and eyewall region of Phailin at 11:43 UTC on 11 October.

DMSP SSMI/S 85 GHz microwave data (below) suggested that Phailin was undergoing an eyewall replacement cycle prior to landfall, which likely accounts for its drop in intensity to a Category 4 storm (Phailin warning text issued at 15 UTC on 12 October).

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A sequence of images of the satellite-wind-derived 850 hPa relative vorticity product at 6-hour intervals covering the period 04 October to 09 October 2013 (above; click image to play animation) showed that the vorticity associated with Tropical Storm Karen over the Gulf of Mexico on 04 October could be followed northeastward as the storm made the transition to an extratropical low as it movved inland and interacted with a frontal boundary, then eventually organizing into a slow-moving coastal low along the US East Coast.

A comparison of 1-km resolution MODIS 0.65 µm visible channel, 11.0 µm IR channel, and 6.7 µm water vapor channel images (below) showed the organization of the coastal low at 18:10 UTC on 09 October, which featured deep offshore  convection with IR cloud-top temperatures as cold as -75º C.

===== 10 October Update =====

A comparison of 1-km resolution Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images at 17:59 UTC on 10 October (below) revealed that some strong convective elements had moved inland over southeastern Virginia and northeastern North Carolina, producing heavy rainfall.

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The “De Luz” wildfire began to burn at the Camp Pendleton Marine Corps Base in southern California around 19:45 UTC or 12:45 PM on 05 October 2013. The fire burned over 2200 acres and forced evacuations of some housing and a hospital (InciWeb). McIDAS images of GOES-13 (GOES-East) 0.63 µm visible channel data (above; click image to play animation) showed the smoke plume as it drifted quickly southwestward due to strong Santa Ana winds.

A 2-panel comparison of GOES-13 0.63 µm visible channel and 3.9 µm shortwave IR channel images (below; click image to play animation) revealed that the fire “hot spot” (red color enhancement on the shortwave IR images) was detected about 30 minutes prior to the time when a smoke plume became obvious on the visible images.

The fire growth slowed that evening as temperatures began to cool down and the strong Santa Ana winds gradually subsided, but fire continued to burn into the night — a small fire hot spot (yellow to orange color enhancement) was still evident on a Suomi NPP VIIRS 3.74 µm shortwave IR channel image at 09:18 UTC or 2:18 AM local time (below).

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An unusually intense (by early October standards) mid-latitude cyclone produced a variety of weather extremes across the parts of the north-central US during the 04 October to 05 October 2013 period. In the cold sector of the storm system, western South Dakota received record-breaking snowfall and prolonged blizzard conditions, with widespread power outages and livestock losses being two of the major impacts. The early evolution of the storm could be seen on 4-km resolution GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above). Surface weather symbols (including precipitation type) are also plotted on the water vapor images. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode during much of this time, providing images as frequently as every 5-10 minutes.

In the warm sector of the storm system, severe thunderstorms produced numerous tornadoes and hail as large as 2.75 inches in diameter (SPC storm reports), primarily across eastern Nebraska into Iowa. A very large tornado produced EF-4 damage in the Wayne, Nebraska area — the development of this storm could be seen on 1-km resolution 0.63 µm visible channel images (above) and 4-km resolution 10.7 µm IR channel images (below) from the GOES-15 (GOES-West) and GOES-13 (GOES-East) satellite perspectives. Wayne (station identifier KLCG) is located in the center of the visible and IR images; note that the hourly plotted weather observations for Wayne disappeared after 22 UTC, due to the fact that the airport weather instruments were damaged by the tornado.

GOES-13 0.63 µm visible channel images with overlays of the corresponding University of Wisconsin GOES-13 IR Cloud Top Cooling Rate (CTCR) product (below) indicated that CTCR values exceeded 30 degrees Kelvin per 15 minutes (darker blue color enhancement) at 20:45 UTC as the thunderstorm that produced the Wayne tornado was rapidly developing in northeastern Nebraska.

===== 07 October Update =====

High spatial resolution imagery from Low Earth Orbit (LEO) or “polar-orbiting” satellites can be useful for post-case analysis — with this particular storm, helping to determine the areal coverage of the resulting snowfall, and identifying a tornado damage path.

Once the large cloud shield associated with the storm system moved eastward, a comparison of 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images from 06 October (above) showed the widespread area of snow cover (which appeared as darker shades of red on the RGB image) over the western third of South Dakota as well as adjacent portions of Wyoming, Nebraska, North Dakota, and Montana. Terrain had an important influence in both the amount and the coverage of snowfall — it is especially interesting to note the areas of bare ground (shades of cyan in the RGB image) immediately downwind (south and southwest) of the Black Hills, where downsloping winds helped keep the precipitation type as rain (AWIPS-2 animation including topography). Aided by upslope flow, as much as 58 inches of snowfall was reported in the northern Black Hills of South Dakota. Note that much of the Black Hills appear darker on the visible and false-color images, due to the high density of coniferous trees — but there was still significant snow cover on the ground.

In addition, a comparison of before (28 September) and after (07 October) 250-meter resolution MODIS true-color RGB images from the SSEC MODIS Today site (below) revealed the southwest-to-northeast oriented damage path from the large tornado which produced EF-4 damage in the Wayne, Nebraska area (NWS Omaha news story).

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