The video embedded above shows GOES-13 Water Vapor imagery each hour for all of June. Water vapor imagery (6.5 µm) is handy for tracking features in the atmosphere, and various circulations are plain in the animation, including Tropical Storm Bill and Pacific Hurricanes Blanca and Carlos. The 10.7 µm window channel animation is shown below.

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The 2015 Wildfire Season is off to a quick start in Alaska (continuing an observed trend). This map (from this site) shows more than 300 active fires over Alaska at 2000 UTC on 29 June 2015. This graph (from the Alaska Climate Info Facebook page) compares early burn acreage in 2015 to that in 2004 (the year with the most acreage burned — see this graph, courtesy of Uma Bhatt, University of Alaska-Fairbanks).

Soumi NPP VIIRS 3.74 µm infrared imagery from early morning on 29 June 2015 (top) shows numerous wildfire hot spots (dark black pixels) in the region surrounding the Yukon River (the middle portion of the imagery, south of Kotzebue Sound). VIIRS visible imagery from the same time, above, shows an extensive pall of smoke over much of central Alaska.

Meanwhile, thick smoke from fires burning over northern Canada (comparison of VIIRS visible and shortwave IR images from 28 June) was drifting southward over central portions of the Lower 48 states. The smoke plume on 28 June (above) was fairly narrow; however, a much broader and thicker plume was seen moving south on 29 June (GOES visible imagery below, then MODIS/VIIRS true-color RGB imagery as displayed using the SSEC RealEarth web map server). SSEC MODIS Today true-color imagery of this smoke plume is also available here. Pilot reports placed the lower and upper bounds of the thick smoke at 5000 and 17500 feet, with flight visibilities as low as 2 miles at 5000 feet. Some of the smoke subsided to the surface in southeastern South Dakota, restricting the surface visibility at Sioux Falls to 5 miles and raising the Air Quality Index there into the Unhealthy category. In fact, the smoke was so thick over far eastern South Dakota that it had the effect of reducing surface heating and slowing the rise of afternoon temperatures, such that convective temperatures were not being reached and probabilities of precipitation had to be scaled back:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
356 PM CDT MON JUN 29 2015

.SHORT TERM…(THIS EVENING THROUGH TUESDAY)
ISSUED AT 356 PM CDT MON JUN 29 2015

IN ADDITION…THICK PLUME OF SMOKE CONTINUES TO DRIFT SOUTHWARD IMPACTING NEARLY ALL OF THE FORECAST AREA…BUT MOST   NOTABLE ALONG AND EAST OF THE JAMES RIVER VALLEY. BECAUSE OF THIS…AFTERNOON TEMPERATURES ARE ABOUT 2 TO 4 DEGREES
COOLER THAN FORECAST AND WE ARE HAVING A HECK OF A TIME REACHING OUR CONVECTIVE TEMPERATURE. THEREFORE LOWERED THE LATE AFTERNOON AND EVENING POPS IN OUR EASTERN ZONES TO ONLY SLIGHT CHANCE POPS. BUT EVEN THOSE MAY BE TOO HIGH AND IF NOTHING DEVELOPS OVER THE NEXT COUPLE OF HOURS…THEY MAY NEED TO BE REMOVED ENTIRELY.

Daytime detection of smoke plumes is not difficult with visible (or true-color) imagery. At night, however, smoke detection is a challenge. The VIIRS Day/Night Band on Suomi NPP can detect smoke when Lunar Illumination is high (although detection is limited to one or sometimes two passes per night). Smoke is otherwise mostly transparent to infrared channels on the GOES Imager. Websites such as the NOAA/NESDIS IDEA and the GASP are helpful; however, the GASP product uses single-channel (visible) detection only.

Visible imagery from GOES-15, below, highlights the expansive region covered by smoke over northern Canada. Note that the smoke becomes less distinct with time as the sun rises higher in the sky, because forward scattering of visible light by smoke particles is more effective than backward scattering.

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Advisories on Tropical Storm Bill were initiated when the system organized and intensified off the coast of Texas at 03 UTC on 16 June 2015 (GOES-13 IR image animation). Bill moved inland during the afternoon hours on 16 June, as can be seen in a comparison of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images at 1916 UTC (above).

Late in the day on 17 June, the general appearance of downgraded Tropical Depression Bill on GOES-13 6.5 µm water vapor channel imagery (below) began to suggest that the system might be undergoing an extratropical transition (intrusion of dry air in the southern quadrant, along with a blosominig comma head signature on the northern quadrant) — but Bill maintained sufficient tropical characteristics to continue being named a tropical depression.

The circulation of TD Bill maintained its identity on satellite imagery as the storm remained over land for the next 3+ days, curving northeastward and moving across the Ohio River Valley region. Slow-moving TD Bill dropped over 12 inches of rain at some locations in Texas and Oklahoma, with amounts exceeding 8 inches in Missouri and 6 inches in Indiana (WPC storm total rainfall totals), before being designated a post-tropical feature at 21 UTC on 20 June (WPC advisories).

The history of Bill can be followed in a multi-day animation of GOES-13 10.7 µm IR channel imagery (above); in addition, the lower-tropospheric circulation of Bill can be followed using the CIMSS 850 hPa relative vorticity product (below).

As the post-tropical remnants of Bill emerged over the Atlantic Ocean early in the day on 21 June, it still appeared to be associated with an arc of deep convection as seen on a comparison of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images at 1742 UTC (below). A similar comparison of Terra MODIS visible and IR images at 1514 UTC can be seen here.

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An explosion occurred along a natural gas pipeline near Lindenau, Texas just after 01 UTC on 15 June 2015 (8:00 pm local time on 14 June). The thermal signature or “hot spot” of the resulting fire was detected on both GOES-15 (GOES-West) and GOES-13 (GOES-East)  3.9 µm shortwave IR imagery (above; click image play animation). The images have overlays of surface reporting stations (yellow), Interstate highways (cyan), and primary highways (gray). The relatively small but very hot fire exhibited IR brightness temperatures as high as 341.1 K on GOES-13 and 340.0 K on GOES-15, which is close to the saturation temperature for the 3.9 µm detectors on those satellites. Since GOES-13 was in Rapid Scan Operations (RSO) mode at the time, the fire hot spot was first detected by that satellite (at 0107 UTC) — and the IR brightness temperature remained at 341.0 K for another 40 minutes after initial detection (0115 to 0155 UTC).

A subtle signature of the fire’s smoke plume (lighter gray enhancement) could be seen moving northwestward and then northward away from the fire hot spot. On the 0125 UTC GOES-13 shortwave IR image (below), and overlay of the CRAS model winds showed them turning from southeastward at the surface (in agreement with regional METAR surface reports) to southerly at an altitude of 3 km, suggesting that the smoke plume may have reached that height.

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