Using NUCAPS profiles before Pyrocumulus events

September 11th, 2022 |
GOES-17 True-color imagery, 2101 UTC 10 September to 0106 UTC on 11 September

A CSPP Geosphere mp4 animation from late on 10 September, above (link), shows the development of a pyrocumulus cloud at the south edge of the Cedar Creek fire complex in Oregon (previously discussed here, here and here). The animation above starts at 2101 UTC, shortly after a NOAA-20 overpass above the region. NUCAPS profiles over the regions can define the thermodynamics to help forecasters determine is pyrocumulus clouds might develop. The Green points in the sounding availability plots, below, denote retrievals that converged to a solution using both microwave and infrared data from the ATMS and CrIS instruments, respectively. This includes the profiles near the very warm Cedar Creek fire pixels in east-central Oregon. (Here is a zoomed-in view over the fire with GOES-17 FDCA Fire Power observations; note the two different regions of active fire).

GOES-17 Band 7 (3.9 µm) imagery at 2020 UTC on 10 September 2022 along with NUCAPS Sounding Availability plots (Click to enlarge)

The animation below steps through 3 NUCAPS profiles near the fire. A dry atmosphere is apparent, but note also the very steep lapse rates. If convection develops, aided by the heat of the fire, there is little to inhibit its growth to the tropopause.

NUCAPS profiles east, over and west of the Cedar Creek fire, ca. 2050 UTC on 10 September 2022 (Click to enlarge)

NUCAPS profiles can be gridded to provide horizontal fields of thermodynamic variables. The lapse rate computed from 850 and 500 mb temperatures, below, also shows very steep lapse rates (note that portions of Oregon are at/above 850 mb and no data are available).

GOES-17 Band 7 (3.9 µm) imagery along with NUCAPS gridded lapse rates (850-500 mb), ca. 2030 UTC on 10 September 2022 (Click to enlarge)

One things that happens when a Pyrocumulus develops: the cloud is trackable (in contrast to any surrounding smoke). The CSPP Geosphere animation below (link) shows the Night Microphysics (at night) and True-Color (during the day) — the cloud can be tracked until is dissipates near dawn, and the true-color imagery the next day shows the smoke associated with the pyrocumulus has also moved to the east. Note also in the animation how the active fires show up in the GOES-17 Night Microphysics as different shades of magenta.

Hourly imagery from CSPP Geosphere, 2206 10 September 2022 – 1706 UTC on 11 September 2022

Although infrared imagery is challenged to view smoke at night, as suggested in the animation above, the VIIRS Day Night band sees it (if there is sufficient illumination by the Moon). That was the case early on 11 September, as shown below (in an image taken from the VIIRS Today website). Both the light signature from fires are apparent as is the smoke plume from the pyrocumulus.

NOAA-20 Day Night Band visible (0.7 µm) imagery over Oregon, ca. 1100 UTC on 11 September 2022 (click to enlarge)

AWIPS Satellite imagery in this blog post were created using the TOWR-S AWIPS. Thank you!

Pyrocumulonimbus clouds in Oregon, Idaho and California

September 10th, 2022 |

An extended period of hot temperatures across much of the western US — where drought conditions were widespread — helped set the stage for large wildfires which produced several pyrocumulonimbus (pyroCb) clouds in parts of Oregon, Idaho and California during the 07-10 September 2022 period.

===== 07 September =====

GOES-18 Day Land Cloud Fire RGB images [click to play animated GIF | MP4]

GOES-18 (GOES-West) Day Land Cloud Fire RGB images (above) displayed numerous wildfires (clusters of red pixels) from far eastern Oregon into Idaho on 07 September 2022. Three of the larger fires — one in Oregon and two in Idaho — produced one or more pulses of pyroCb clouds during the day.

1-minute GOES-18 True Color RGB images visualized using CSPP GeoSphere (below) showed the smoke-laden cloud tops (shades of tan) associated with some of the pyroCb pulses from the eastern Oregon and central Idaho wildfires.

GOES-18 True Color RGB images [click to play MP4 animation]

4-panel displays of 1-minute Mesoscale Domain Sector GOES-18 Day Land Cloud Fire RGB, Shortwave Infrared (3.9µm), “Clean” Infrared Window (10.35 µm) and Cloud Top Temperature (below) provided a closer view of a vigorous pyroCb produced by the Moose Fire in far eastern Idaho (near the Montana border). During that time period, the maximum surface 3.9 µm infrared brightness temperature of the fire signature reached 137.88oC (the saturation temperature of GOES-18 ABI Band 7 detectors). The coldest pyroCb cloud-top 10.35 µm infrared brightness temperatures were -52oC, while the coldest Cloud Top Temperature derived product values were around -56oC.

GOES-18 Day Land Cloud Fire RGB (top left), Shortwave Infrared (3.9 µm, top right), Infrared Window (10.35 µm, bottom left) and Cloud Top Temperature (bottom right) [click to play animated GIF | MP4]

===== 08 September =====

GOES-17 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.35 µm, bottom) [click to play animated GIF | MP4]

1-minute GOES-17 (which resumed duty as GOES-West as of 1601 UTC on 08 September) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed a “marginal” pyroCb produced by the Mosquito Fire in California on 08 September 2022, whose coldest cloud-top 10.35 µm infrared brightness temperature reached -39oC (just shy of the -40oC threshold of pyroCb classification) — however, the Cloud Top Temperature derived product (not shown) did reach -42oC.

1-minute GOES-17 True Color RGB images (below) displayed the smoke-laden (shades of tan) cloud top of this “marginal pyroCb”.

GOES-17 True Color RGB images [click to play MP4 animation]

===== 10 September =====

As discussed in this blog post, the Cedar Creek Fire in Oregon had been producing a large smoke plume during the day on 09 September — and this trend continued into the overnight hours, as shown by a Suomi-NPP VIIRS Day/Night Band (0.7 µm) image valid at 1020 UTC on 10 September (below). Ample illumination by a Full Moon provided an excellent example of the “visible image at night” capability of the Day/Night Band (DNB).

Suomi-NPP VIIRS Day/Night Band (0.7 µm) image, valid at 1020 UTC on 10 September [click to enlarge]

In a closer view of of the Cedar Creek Fire, a toggle between the corresponding Suomi-NPP VIIRS DNB and Shortwave Infrared images (below) displayed the bright nighttime glow of the more active individual fires (as well as the dense smoke plume drifting northwestward) in the DNB image — and the thermal signature of fires along the northwestern perimeter was evident in the Shortwave Infrared image, even though the dense smoke plume was overhead.

Suomi-NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (11.45 µm) images, valid at 1020 UTC on 10 September [click to enlarge]

During the subsequent daytime hours, a sequence of 1-minute GOES-17 Day Land Cloud Fire RGB, Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.35 µm) and Cloud Top Temperature product (below) showed that the Cedar Creek Fire produced a pyroCb cloud late in the day on 10 September 2022. During that particular time period, the maximum surface 3.9 µm infrared brightness temperature of the fire signature reached 138.71oC (the saturation temperature of GOES-17 ABI Band 7 detectors). The coldest cloud-top 10.35 µm infrared brightness temperature was -45oC, while the coldest Cloud Top Temperature derived product value was -49oC.

Sequence of GOES-17 Day Land Cloud Fire RGB, Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.35 µm) and Cloud Top Temperature product [click to play animated GIF | MP4]

1-minute GOES-17 True Color RGB images (below) showed the Cedar Creek Fire pyroCb rising through and towering above the large pall of lower-altitude smoke.

GOES-17 True Color RGB images [click to play MP4 animation]

During the following overnight hours, a toggle between Suomi-NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (11.45 µm) images valid at 1002 UTC (below) revealed that the nighttime glow and thermal signature of larger active fires along the perimeter of the Cedar Creek Fire were still apparent, in spite of dense smoke that lingered over the area and high clouds that were beginning to move overhead from the west.

Suomi-NPP VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (11.45 µm) images, valid at 1002 UTC on 11 September [click to enlarge]

Wildfires in Idaho

September 4th, 2022 |

GOES-18 Fire Temperature RGB images, with GOES-17 Fire Detection and Characterization Algorithm products [click to play animated GIF | MP4]

Overlapping 1-minute Mesoscale Domain Sectors provided 30-second GOES-18 (GOES-West) Fire Temperature RGB images, along with GOES-17 Fire Detection and Characterization Algorithm (FDCA) products (above) — which showed thermal signatures of the larger Ross Fork Fire and the smaller Wildhorse Fire in southern Idaho on 04 September 2022. The Wildhorse Fire caused a closure of US Highway 20, just west of Hill City, for a period of 12 hours.

The Ross Fork Fire burned very hot, with Shortwave Infrared (3.9 µm) infrared brightness temperatures reaching 137.88ºC (the saturation temperature of GOES-18 ABI Band 7 detectors). For those hottest fire pixels, occasionally FDCA parameters (Fire Temperature, Fire Power, Fire Area and Fire Mask) were generated and displayable via AWIPS cursor sampling (below).

GOES-18 Fire Temperature RGB image, with GOES-17 FDCA cursor values for a Processed Fire [click to enlarge]

Note, however, that FDCA parameters were not displayable in AWIPS for Cloudy Fires (fires with partial obscuration by pyrocumulus clouds and/or optically-thick smoke) or for Saturated Fires (below). Part of this issue is related to the fact that the peak GOES-18 3.9 µm temperature (137.88ºC) was slightly lower than the peak 3.9 µm value for GOES-16/-17 (138.71ºC).

GOES-18 Fire Temperature RGB image, with GOES-17 FDCA cursor values for a Saturated Fire [click to enlarge]

 

GOES-18 Fire Temperature RGB image, with GOES-17 FDCA cursor values for a Cloudy Fire [click to enlarge]

Cedar Creek Fire in Oregon

September 2nd, 2022 |

GOES-18 Day Land Cloud Fire RGB (top left), GOES-18 Shortwave Infrared (3.9 µm, top right), GOES-17 Fire Power (bottom left) and GOES-17 Fire Temperature (bottom right) [click to play animated GIF | MP4]

GOES-18 (GOES-West) Day Land Cloud Fire RGB and Shortwave Infrared (3.9 µm) images along with GOES-17 Fire Power and Fire Temperature products (above) displayed characteristics associated with the Cedar Creek Fire in Oregon on 02 September 2022. The peak 3.9 µm infrared brightness temperature reached 137.88ºC, with Fire Power values exceeding 2000 MW and Fire Temperature values exceeding 1200 K. The Fire Power and Fire Temperature products are components of the Fire Detection and Characterization Algorithm (FDCA).

GOES-18 True Color RGB images created using CSPP GeoSphere (below) showed the large smoke plume produced by this wildfire, which spread north-northeastward across Washington State during the day.

GOES-18 True Color RGB images [click to play MP4 animation]