Pyrocumulonimbus clouds in British Columbia, Canada

August 12th, 2017 |

GOES-16 Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images, with hourly surface reports plotted in yellow [click to play animation]

GOES-16 Visible (0.64 µm, top) and Shortwave Infrared (3.9 µm, bottom) images, with hourly surface reports plotted in yellow [click to play animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing*

GOES-16 “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) along with “Red” Visible and “Clean” Infrared Window (10.3 µm) images (below) showed the formation of 3 pyrocumulonimbus( pyroCb) clouds late in the evening on 12 August 2017, within the cluster of ongoing intense wildfires in British Columbia, Canada.

GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with hourly surface reports plotted in yellow [click to play animation]

A toggle between NOAA-18 AVHRR Visible (0.63 µm), Near-Infrared (0.86 µm), Shortwave Infrared (3.9 µm) and Longwave Infrared Window (10.8 µm) images is shown below. The coldest cloud-top IR brightness temperature was -70º C (associated with the northernmost pyroCb).

NOAA-18 Visible (0.63 µm), Shortwave Infrared (3.9 µm) and Longwave Infrared Window (10.3 µm) images, with surface station plots in yellow [click to enlarge]

NOAA-18 Visible (0.63 µm), Shortwave Infrared (3.9 µm) and Longwave Infrared Window (10.3 µm) images, with surface station plots in yellow [click to enlarge]

In a daytime Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image (from RealEarth) with VIIRS-detected fire locations plotted in red (below), a very large pall of exceptionally-dense smoke from the BC fires could be seen drifting northward as far as the Northwest Territories of Canada.

Suomi NPP VIIRS true-color image, with VIIRS-detected fire locations plotted in red [click to enlarge]

Suomi NPP VIIRS true-color image, with VIIRS-detected fire locations plotted in red [click to enlarge]

The Suomi NPP OMPS Aerosol Index (AI) product (below; courtesy of Colin Seftor, SSAI) displayed AI values as high as 17.18 within the thick BC fire smoke pall.

Suomi NPP OMPS Aerosol Index [click to enlarge]

Suomi NPP OMPS Aerosol Index [click to enlarge]

===== 13 August Update =====

Suomi NPP OMPS Aerosol Index product [click to enlarge]

Suomi NPP OMPS Aerosol Index product [click to enlarge]

On 13 August, a maximum OMPS AI value of 39.91 was seen at around 21:13 UTC over the Northwest Territories of Canada (above) — according to Colin Seftor and Mike Fromm (NRL), this value surpassed the highest pyroCb-related AI value ever measured by TOMS or OMI (whose period of record began in 1979).

The north-northeastward transport of BC fire smoke — as well as a prominent increase in smoke from fires across northern Canada and the Prairies — was evident in an animation of daily composites of Suomi NPP VIIRS true-color images from 07-13 August (below).

Daily Suomi NPP VIIRS true-color image composites (07-13 August), with VIIRS-detected fire locations plotted in red [click to play animation]

Daily Suomi NPP VIIRS true-color image composites (07-13 August), with VIIRS-detected fire locations plotted in red [click to play animation]

Cold temperatures in Alaska

January 19th, 2017 |

NOAA-18 AVHRR Infrared Window (10.8 µm) image, with surface air temperatures and corresponding station identifications [click to enlarge]

NOAA-18 AVHRR Infrared Window (10.8 µm) image, with surface air temperatures and corresponding station identifications [click to enlarge]

A NOAA-18 AVHRR Infrared Window (10.8 µm) image (above) showed the signature of cold air (violet colors) settling into river valleys and other low-elevation terrain areas across the cloud-free interior of Alaska at 1916 UTC (10:16 am local time) on 18 January 2017. Note that there was a layer of clouds (warmer cyan colors) over much of the North Slope of Alaska; these clouds were acting to limit strong surface radiational cooling, with resulting surface air temperatures only as cold as the -20s F. This AVHRR image was about 1 hour before the low temperature at Fairbanks International Airport (PAFA) dropped to -51ºF (-46ºC) — the first low of -50ºF or colder at that location since 31 December 1999 (-53ºF). While these were certainly cold temperatures, in general most were several degrees warmer than the daily record lows for 18 January:

NOAA-18 AVHRR Infrared Window (10.8 µm) image centered on Bettles (PABT), with surface air temperatures and corresponding station identifications [click to enlarge]

NOAA-18 AVHRR Infrared Window (10.8 µm) image centered on Bettles (PABT), with surface air temperatures and corresponding station identifications [click to enlarge]

Closer views centered on Bettles (above) and on Tanana (below) further highlighted the influence of terrain on the pattern of surface infrared brightness temperatures.

NOAA-18 AVHRR Infrared Window (10.8 µm) image centered on Tanana (PATA), with surface air temperatures and corresponding station identifications [click to enlarge]

NOAA-18 AVHRR Infrared Window (10.8 µm) image centered on Tanana (PATA), with surface air temperatures and corresponding station identifications [click to enlarge]

A comparison of re-mapped 1-km resolution NOAA-18 and “4-km” resolution GOES-15 (GOES-West) Infrared Window imagery (below) demonstrated the spatial resolution advantage of “Low Earth Orbit” (Polar-orbiting) satellites over Geostationary satellites, especially for high-latitude regions such as Alaska. As this plot shows, the true spatial resolution of a “4-km” GOES-15 Infrared image pixel over the interior of Alaska — where that satellite’s viewing angle or “zenith angle” from the Equator is about 74 degrees — is actually closer to 16 km. For the “2-km” Infrared imagery that will be provided by the GOES-R series ABI instrument, the spatial resolution over the interior of Alaska will be closer to 8 km.

NOAA-18 vs GOES-15 Infrared Window images [click to enlarge]

NOAA-18 vs GOES-15 Infrared Window images [click to enlarge]

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NOAA-19 AVHRR Infrared Window (10.8 µm) image, with surface air temperatures and corresponding station identifications [click to enlarge]

NOAA-19 AVHRR Infrared Window (10.8 µm) image, with surface air temperatures and corresponding station identifications [click to enlarge]

The cold continued across much of Alaska on 19 January, as seen on a NOAA-19 AVHRR Infrared Window (10.8 µm) image at 1519 UTC or 4:19 am local time (above). However with a lack of cloud cover over the central portion of the North Slope, surface air temperatures were much colder (in the -40s F) compared to the -20s F that were seen there on the previous day.

NOAA-19 AVHRR Infrared Window (10.8 µm) image centered on Bettles (PABT), with surface air temperatures and corresponding station identifications [click to enlarge

NOAA-19 AVHRR Infrared Window (10.8 µm) image centered on Bettles (PABT), with surface air temperatures and corresponding station identifications [click to enlarge]

As was shown on the previous day, closer views centered on Bettles (above) and on Tanana (below) further highlighted the influence of terrain on the pattern of surface infrared brightness temperatures. On this day a layer of clouds (highlighted by the warmer cyan colors) covered the far eastern portion of the Tanana image below — note that surface temperatures in the Fairbanks area beneath these clouds were only as cold as the -30s F. Farther to the west, which remained cloud-free, the minimum temperature at Tanana was -59ºF.

NOAA-19 AVHRR Infrared Window (10.8 µm) images centered on Tanana (PATA), with surface air temperatures and corresponding station identifications [click to enlarge]

NOAA-19 AVHRR Infrared Window (10.8 µm) images centered on Tanana (PATA), with surface air temperatures and corresponding station identifications [click to enlarge]

Time series plots of surface weather conditions at Fairbanks, Tanana and Bettles during the 18-19 January period are shown below. Note that the surface visibility was periodically restricted 1 statute mile or less, due to ice fog, at all 3 locations.

Surface weather conditions at Fairbanks [click to enlarge]

Surface weather conditions at Fairbanks [click to enlarge]

Surface weather conditions at Tanana [click to enlarge]

Surface weather conditions at Tanana [click to enlarge]

Surface weather conditions at Bettles [click to enlarge]

Surface weather conditions at Bettles [click to enlarge]

Severe Weather in the Pacific Northwest

October 15th, 2016 |

Window Channel Infrared imagery from COMS-1 (10.8 µm) and GOES-15 (10.7 µm), every 6 hours from 1200 UTC on 7 October through 1800 UTC on 15 October [click to animate]

Infrared Window Channel imagery from COMS-1 (10.8 µm) and GOES-15 (10.7 µm), every 6 hours from 1200 UTC on 7 October through 1800 UTC on 15 October [click to animate]

Strong moisture-laden storms caused abundant precipitation and severe weather over the Pacific Northwest from 13-15 October 2016. The animation above shows two storms making landfall in the Pacific Northwest, one on 13-14 October and a second, on 15 October, which was a storm that originated from the remnants of Typhoon Songda. On 11-12 October, Super Typhoon Songda was recurving, subsequently racing towards the west coast of the United States, and making landfall as a strengthening extratropical cyclone on 15 October. The animation above uses two different satellites (COMS-1 and GOES-15), and includes a seam between the two views because the spectral characteristics of the two infrared window bands are not identical.

Daily precipitation from the Advanced Hydrologic Prediction Center from 13-15 October is shown here, with a weekly total shown below. A large area of precipitation exceeding 6 inches is apparent in the higher terrain.

ahps_7dprecip_15oct_1200

7-day Precipitation Totals ending 1200 UTC on 15 October 2016 (Click to enlarge)

The precipitation amounts were aided by the very moist airmass that accompanied the storms. Total Precipitable Water, shown below, from this site that manipulates data from here, shows the moisture. A larger-scale view that traces the moisture back to the time when Songda first reached typhoon intensity over the West Pacific is available here.

Total Precipitable Water, 12-15 October 2016 [Click to animate]

The strong storm before the one spawned by the remnants of Songda produced an EF2-rated tornado in Manzanita Oregon (YouTube Compilation; SPC Storm Reports; Blog post with damage picture) on 14 October 2016. GOES-15 Visible Imagery, below, shows a storm with overshooting tops moving over northwestern Oregon at the time of the tornado. (GOES-15 was performing a full-disk scan from 15:00-15:26 UTC, so 15-imagery was not available as the tornado moved ashore; the Advanced Baseline Imager on GOES-R will produce CONUS Imagery every 5 minutes in addition to Full-Disk Imagery every 15 minutes). The overshoots are especially apparent in the 1500 and 1530 UTC Images. GOES-13 provided a visible image at about the time of the tornado touchdown, but at a very oblique angle. The cirrus shield of the thunderstorm anvil is apparent, however.

GOES-15 Visible (0.62 µm) imagery, 1445, 1500 and 1530 UTC on 14 October. The Red Square indicates the tornado location [Click to animate]

GOES-15 Infrared Window (10.7 µm) imagery around the time of the severe weather in Oregon, below — which includes locations of SPC storm reports of tornadoes (red) and damaging winds (cyan) — also showed evidence of cold overshooting tops (the coldest clouds tops were around -50º C, yellow enhancement). An infrared image animation showing only the clouds is available here. NOAA-18 flew over the Oregon coast at 1427 UTC, and the AVHRR 12 µm Infrared image showed the parent thunderstorm offshore, upstream of Manzanita (larger-scale view).

GOES-15 Infrared Window (10.7 µm) imagery, 1400-1800 UTC on 14 October [Click to animate]

The Portland, Oregon NWS office issued 10 tornado warnings on 14 October — a record number for a single day.

 

GOES Sounder data can be used to created Derived Product Imagery (DPI) estimates of instability parameters (for example), and many are shown at this site. The GOES-13 Sounder has been offline for about a year after having suffered an anomaly back in November 2015, when the filter wheel became frozen, but the GOES-15 Sounder (and the GOES-14 Sounder) continue to operate. The animation below of GOES-15 Sounder Lifted Index shows values as low as -4ºC upstream of the Oregon Coast for many hours before the tornado; as such, it was a valuable situational awareness tool.

goes_sounder_dpi_14oct2016_1100_1700step

GOES-15 Sounder DPI Estimates of Lifted Index, 1100-1700 UTC on 14 October 2016 (Click to enlarge)

NOAA/CIMSS ProbSevere is a probabilistic estimate that a given thunderstorm will produce severe weather in the next 60 minutes. The animation below shows ProbSevere polygons overlain over radar from 1501 UTC (when the first ProbSevere polygon appeared around the radar cell that ultimately was tornadic) through 1521 UTC. Values from the ProbSevere output are below:

 

TIME PS CAPE SHR MESH GRW GLA FLSHRATE COMMENTS
1501 11% 1048 39.3 0.00 str str 0 fl/min Satellite from 1245/1241
1503 32% 1056 39.7 0.37 str str 0 fl/min Satellite from 1245/1241
1505 32% 1031 39.4 0.37 str str 0 fl/min Satellite from 1245/1241
1507 29% 1013 38.7 0.37 str str 3 fl/min Satellite from 1245/1241
1509 47% 974 37.9 0.62 str str 3 fl/min Satellite from 1245/1241
1511 47% 962 37.6 0.62 str str 3 fl/min Satellite from 1245/1241
1513 32% 745 33.1 0.52 str str 10 fl/min Satellite from 1245/1241
1515 34% 897 35.9 0.52 str str 1 fl/min Satellite from 1245/1241
1517 10% 887 35.7 0.52 N/A N/A 2 fl/min
1519 8% 762 33.6 0.54 N/A N/A 4 fl/min
1521 7% 737 33.1 0.49 N/A N/A 2 fl/min
realearthprobsevere_14october2016_1501_1521anim

NOAA/CIMSS ProbSevere output in RealEarth, 1501-1521 UTC on 14 October 2016 (Click to animate)

The Sounder also has a 9.6 µm “ozone absorption band”, and another example of GOES Sounder DPI is Total Column Ozone, shown below. Immediately evident is the sharp gradient in ozone (yellow to green color enhancement) located just north of the polar jet axis that was rounding the base of a large upper-level low (500 hPa analyses). The GOES-R ABI instrument also has a 9.6 µm band that is sensitive to ozone; however, there are no current plans to produce operationally a similar Total Column Ozone product.

 

GOES-15 Sounder Total Column Ozone DPI [click to animate]

GOES-15 Sounder Total Column Ozone DPI [click to animate]

Suomi NPP Day/Night Band Visible (0.70 µm) Image, 1057 UTC on 14 October 2016, Green Arrow points to Manzanita OR [click to enlarge]

Suomi NPP Day/Night Band Visible (0.70 µm) Image, 1057 UTC on 14 October 2016, Green Arrow points to Manzanita OR [click to enlarge]

Suomi NPP overflew the Pacific Northwest about 4 hours before the severe weather was observed at Manzanita. The Day/Night Visible Image above, courtesy of Jorel Torres at CIRA (Jorel also supplied the NUCAPS Sounding Imagery below), shows a well-developed storm offshore with thunderstorms off the West Coast of the United States (Click here for an image without the Green Arrow). Multiple overshooting tops can be discerned in the imagery.

NUCAPS Soundings are produced from the Cross-Track Infrared Sounder (CrIS, with 1300+ channels of information) and the Advanced Technology Microwave Sounder (ATMS, with 22 channels) that are present on Suomi NPP (in addition to the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument that provides the Day/Night band imagery). The image below shows the location of NUCAPS Soundings — the color coding of the points is such that Green points have passed Quality Control, whereas yellow points denote sounding for which the Infrared Sounding retrieval has failed to converge and Red points denote soundings for which both Infrared and Microwave sounding retrievals have failed to converge).

Suomi NPP Day/Night Band Visible Image, 1057 UTC on 14 October 2016, with NUCAPS Sounding Locations indicated.  The Green Circle shows the location of the Sounding below [click to enlarge]

Suomi NPP Day/Night Band Visible Image, 1057 UTC on 14 October 2016, with NUCAPS Sounding Locations indicated. The Green Circle shows the location of the Sounding below; Refer to the text for the Dot Color meaning [click to enlarge]

NUCAPS Soundings can give valuable information at times other than those associated with radiosonde launches (0000 and 1200 UTC, typically), and over a broad region. The point highlighted above, between the occluded storm and the coast, shows very steep mid-level lapse rates that suggest convective development is likely.

NUCAPS Sounding, location as shown by the Green Circle in the figure above. [click to enlarge]

NUCAPS Sounding, location as shown by the Green Circle in the figure above [click to enlarge]

The imagery below shows soundings a bit farther south, near convection that looks supercellular. The NUCAPS Soundings there suggest very steep mid-level lapse rates.

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Hurricane Nicole

October 13th, 2016 |

Track of Nicole, from 12 UTC on 04 October to 12 UTC on 13 October [click to enlarge]

Track of Nicole, from 12 UTC on 04 October to 12 UTC on 13 October [click to enlarge]

From its inception as a highly-sheared Tropical Storm on 04 October, Nicole moved in an erratic path with small intensity fluctuations for 8 days (above); then a period of intensification began on 12 October, with the storm reaching Category 4 intensity southwest of Bermuda at 03 UTC on 13 October. With ample illumination from the Moon (which was in the Waxing Gibbous phase, at 90% of full) Nicole exhibited a well-defined eye on Suomi NPP VIIRS Day/Night Band (0.7 µm) imagery at 0615 UTC, with cold cloud-top temperatures surrounding the eye on the corresponding VIIRS Infrared Window (11.45 µm) image (below).

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

As Nicole approached Bermuda, increasing deep-layer wind shear began to impact the storm and weaken it to a Category 3 — and DMSP-17 Microwave (85 GHz) data showed that the eye had become open to the south (below).

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) and GOES-13 Infrared Window (10.7 µm) images [click to enlarge]

The passage of Nicole over Bermuda is shown on GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images spanning the period 1037-1555 UTC (below).

GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) and Infrared Window (10.7 µm) images [click to play animation]

As the eye of Nicole passed over Bermuda around 13 UTC, the staff at the Bermuda Weather Service were able to successfully launch a rawinsonde balloon, which reported data as high as the 202 hPa pressure level or 12.2 km altitude — much higher than their previous launch attempts at 06 and 12 UTC (below). The Total Precipitable Water (TPW) value derived from that 15 UTC sounding was 72.5 mm or 2.85 inches, which was in general agreement with that displayed by the MIMIC TPW product. Note that the eye of Nicole did not appear to be directly over Bermuda on the 1300 UTC GOES-13 images — this is due to a combination of parallax and the fact that the eye had a significant southwest-to-northeast tilt with height.

Bermuda rawinsonde reports from 00, 06, 12 and 15 UTC on 13 October [click to enlarge]

Bermuda rawinsonde reports from 00, 06, 12 and 15 UTC on 13 October [click to enlarge]

A sequence of Infrared images from POES and Metop AVHRR (12.0 µm) and Terra MODIS (11.0 µm) during the period 1016 to 1513 UTC is shown below.

POES and Metop AVHRR, and Terra MODIS infrared images [click to enlarge]

POES and Metop AVHRR, and Terra MODIS infrared images [click to enlarge]