GOES-15 (GOES-West) and GOES-13 (GOES-East) Visible (0.63 µm) and Shortwave infrared (3.9 µm) images (above; click to play animation; also available as an MP4 movie file) showed the smoke plume and “hot spot” (dark black to red pixels) associated with a large and fast-burning grass fire in north-central Colorado on the afternoon of 18 September 2015. The smoke plume was more apparent in the GOES-13 visible images, due a more favorable “forward scattering” sun-satellite geometry. The fire burned an estimated 12,669 acres, and dense smoke forced the closure of Interstate 76 for about an hour in the afternoon.

On the following day, the fire burn scar could be seen in a comparison of Suomi NPP VIIRS  true-color and false-color images from the SSEC RealEarth site (below).

Due to the darker color and the lack of vegetation, the grass fire burn scar also exhibited a much warmer signature on the Terra MODIS Land Surface Temperature (LST) product (below) — LST values were as high as 112º F (darker orange color enhancement) within the burn scar, compared to LST values in the 80s and 90s F in surounding areas.

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Tropical Depression Nine in the Atlantic Ocean, above, shows characteristics of a heavily sheared storm (longer sunrise-to-sunset animations: gif | mp4). The low-level circulation is displaced south and west of the strongest convection (which is vigorous enough to produce occasional overshooting tops, below, as shown on this page).

Metop-B overflew Tropical Depression Nine’s circulation just after 1300 UTC on 17 September (Orbital tracks for Metop-B are here). The image below shows a circulation with 20-30 knot winds displaced to the south and west of cold 10.7 µm brightness temperatures indicating high cloud tops detected by the GOES-13 Imager.

Total Precipitable Water images from MIMIC (above) suggest the circulation of Tropical Depression Nine is on the northern edge of deep moisture in the Intertropical Convergence Zone. Its projected path to the north and west is towards dryer air. The projected path (below) does take the storm towards warmer waters; however, it also moves it towards a region of even higher deep-layer wind shear (plots below were taken from the CIMSS Tropical Cyclones site). Only the warmer waters argue that this storm will persist; everything else suggests a struggle to survive. Several tropical cyclones this season have succumbed to wind shear while over the tropical Atlantic. Tropical Depression Nine may add to that total.

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Some locations in southern California received record daily precipitation on 15 September 2015. A time series plot of weather conditions for Los Angeles International Airport is shown above; the 1.80 inches of rainfall received there made it the wettest September day on record.

As mentioned in the NWS Los Angeles record event report, the moisture source for this heavy rainfall event was the remnants of Hurricane Linda (storm path); the MIMIC Total Precipitable Water product covering the period 06-15 September (below) showed the evolution of the moisture associated with Linda, which originally tapped rich moisture from the Intertropical Convergence Zone (ITCZ).

A closer look at the MIMIC Total Preciptable Water product (below) showed how the moisture was becoming more concentrated just offshore, in advance of an approaching upper level trough and a decaying surface cold front.

GOES-15 Infrared (10.7 µm) images (below) revealed that the cloud-top IR brightness temperatures were actually quite warm (> -20º C) over coastal southern California during the period of the heavy rainfall event.

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The Aurora Forecast shown above was issued on the night of 08 September 2015 by the NOAA Space Weather Prediction Center, with the accompanying text:

Following the G2 (moderate) geomagnetic storms from last night, observations of the solar wind at the ACE spacecraft near L1 indicate the potential again this evening for more activity. G1 (minor) conditions have already been observed by the global network of ground-based near real-time magnetometers. A forecast warning for G2 has been issue from 09/0500 – 09/1000 UTC (1am to 6am EST). These could be some prime hours to possibly see the Aurora in the northern most regions of the lower 48 states.

A composite of Suomi NPP VIIRS Day/Night Band (0.7 µm) images viewed using the SSEC RealEarth web map server (above) showed the bright and complex signature of the aurora borealis across southern Canada and the northern United States during the subsequent nighttime hours. Two of the individual Day/Night Band image swaths as viewed using AWIPS-2 are shown below.

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