CIMSS Satellite Blog
A weblog of meteorological satellite imagery relevant to current weather eventsTue, 14 Feb 2017 21:24:48 +0000en-UShourly1https://wordpress.org/?v=4.7.2Sir Ivan Fire pyroCumulonimbus in New South Wales, Australia
http://cimss.ssec.wisc.edu/goes/blog/archives/23099#respondSun, 12 Feb 2017 15:53:56 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=23099
Himawari-8 0.64 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.4 µm Longwave Infrared Window (bottom) images [click to play animation]
Himawari-8 Visible (0.64 µm), Shortwave Infrared (3.9 µm) and Longwave Infrared Window (10.4 µm) images (above /MP4 ; zoomed-in over fire source region: GIF / MP4) showed wildfires burning in New South Wales, Australia on 12 February 2017. The larger Sir Ivan Fire near Dunedoo produced a pyroCumulonimbus (pyroCb) cloud, which first cooled below the -40ºC Longwave Infrared brightness temperature “pyroCb threshold” at 0530 UTC (-47ºC) and quickly reached its minimum temperature of -56.6ºC at 0540 UTC. An animation of Himawari-8 true-color images is available here(courtesey of Dan Lindsey, RAMMB/CIRA).
Consecutive true-color images from Suomi NPP VIIRS (0402 UTC) and Aqua MODIS (0405 UTC) viewed using RealEarth(below) showed the large smoke plume about 1.5 hours prior to pyroCb development.
Suomi NPP VIIRS and Aqua MODIS true-color images [click to enlarge]
A high fire danger was well-anticipated across this portion of Australia:
http://cimss.ssec.wisc.edu/goes/blog/archives/23099/feed0Northeast US winter storm
http://cimss.ssec.wisc.edu/goes/blog/archives/23082#respondThu, 09 Feb 2017 23:59:23 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=23082
GOES-13 Water Vapor (6.5 µm) images, with surface fronts and MSLP pressure [click to play animation]
A strong winter storm impacted much of the Northeast US on 09 February 2017, dropping up to 24 inches of snow in Maine and producing wind gusts of 70 mph in Massachusetts (WPC storm summary). GOES-13 (GOES-East) Water Vapor (6.5 µm) images with surface fronts and Mean Sea Level Pressure (above) showed the rapid intensification of the mid-latitude cyclone.
GOES-13 Visible (0.63 µm) images, with hourly surface weather symbols [click to play animation]
GOES-13 Visible images (above) and Water Vapor images (below) with hourly surface weather symbols revealed the extent of thunderstorms in the south and heavy snow in the north. A number of sites in New England also reported thundersnow.
GOES-13 Water Vapor (6.5 Âm) images, with hourly surface weather symbols [click to play animation]
Suomi NPP VIIRS Visible (0.64 µm) and infrared Window (11.45 µm) images (below) provided a high-resolution snapshot of the storm at 1708 UTC. Note the areas of banded convective elements both south of the storm center over the Atlantic, and also inland over parts of New England.
Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with surface fronts and MSLP [click to enlarge]
===== 10 February Update =====
Terra and Aqua MODIS false-color RGB images [click to enlarge]
As the storm moved northward over Newfoundland and Labrador in eastern Canada on 10 February, a toggle between Terra (1601 UTC) and Aqua (1743 UTC) MODIS false-color “snow/cloud discrimination” Red/Green/Blue (RGB) images (above) showed the extent of the snow cover (darker shades of red), although supercooled water droplet clouds (shades of white) persisted over many areas at the times of the 2 images. Glaciated ice crystal clouds also appeared as shades of red.
Snowfall totals in the Canadian Maritimes were as high as 38 cm (15 inches).
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/23082/feed0GOES-16 Views of Tornadic Thunderstorms over Louisiana
http://cimss.ssec.wisc.edu/goes/blog/archives/23056#respondTue, 07 Feb 2017 19:41:51 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=23056Severe Weather hit Louisiana on Tuesday 7 February 2017, and the ABI on GOES-16 viewed the convective development. This website includes an animation (also available on YouTube) of the visible imagery (Band 2, 0.64 µm with 0.5-km resolution at the subsatellite point) from ABI during the time period of the strongest tornadoes in and near New Orleans. Click here for an animation that includes views of all 16 ABI Bands.
A comparison of GOES-13 (GOES-East) Visible (0.63 µm) and Infrared Window (10.7 µm) images is shown below, with hourly surface reports and locations of the tornado reports.
GOES-13 0.63 µm Visible (top) and 10.7 µm Infrared Window images (bottom), with hourly surface reports in yellow and locations of the tornado reports in cyan.
Suomi NPP overflew the convection shortly after the tornadoes were on the ground in Louisiana, and images from the three spectral bands shown below, 11.45 µm, 0.64 µm and 1.61 µm show a mature convective system with overshooting tops over the Gulf Coast states and the Gulf of Mexico. The 1.61 µm Snow Ice band helps in the discrimination between cloud tops comprised of water droplets (bright white) vs. cloud tops comprised of ice crystals (grey); the ABI on GOES-16 has a similar band.
Suomi NPP VIIRS Imagery from 1924 UTC on 07 February 2017. Infrared Window (11.45 µm), Visible (0.64 µm) and Snow/Ice (1.61 µm) bands are shown. (Click to enlarge)
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/23056/feed0Shamal Wind event across the Arabian Peninsula
http://cimss.ssec.wisc.edu/goes/blog/archives/23063#respondSun, 05 Feb 2017 21:40:14 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=23063
Daily composites of Suomi NPP VIIRS true-color images [click to play animation]
A Shamal Wind event affected the Persian Gulf and the Arabian Peninsula during the first few days of February 2017, as a strong cold front moved southward across the region. Daily composites of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images (source: RealEarth) during the 31 January – 05 February period (above) showed blowing dust eventually moving off the coast of Yemen and Oman and across the Gulf of Aden and the Arabian Sea (note the cold frontal arc clouds on 03 February). The strong Shamal winds on 03 February forced a suspension in the Dubai Desert Classic golf tournament the cancellation of Stage 4 of the Tour of Dubai bicycle race (Dubai meteorogram).
The cold air associated with the Shamal wind was especially evident at locations along the Persian Gulf during the 01-04 February period (below) — for example, the daily maximum temperature at Abu Dhabi in the United Arab Emirates on 01 February was 31ºC (88ºF), while it was only 18ºC (64ºF) on 03 February. At Doha in Qatar, their minimum temperature was 9ºC (48ºF) — their all-time minimum is 4ºC (39ºF). Snow fell in the Oman / United Arab Emirates border lands, with 10 cm (3.9 inches) reported at Jabal Jais. In addition to Abu Dhabi, blowing dust/sand also restricted surface visibility to 2 miles or less at locations such as Abumusa Island and Fujairah.
Daily composites of Suomi NPP VIIRS true-color images, with METAR surface observations [click to enlarge]
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/23063/feed0Tule fog in California
http://cimss.ssec.wisc.edu/goes/blog/archives/23023#respondTue, 31 Jan 2017 23:59:07 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=23023
The tweet shown above was issued by the NWS forecast office in Hanford, California — using an image of the GOES-15 Low Instrument Flight Rules (LIFR) Probability, a component of the GOES-R Fog/low stratus suite of products — to illustrate where areas of dense Tule fog persisted into the morning hours on 31 January 2017.
AWIPS II images of the GOES-15 Marginal Visual Flight Rules (MVFR) product (below) showed the increase in areal coverage of Tule fog beginning at 0600 UTC (10 pm local time on 30January); the fog eventually dissipated by 2030 UTC (12:30 pm local time) on 31 January. Note that Lemoore Naval Air Station (identifier KNLC) reported freezing fog at 14 UTC (their surface air temperature had dropped to 31º F that hour). In addition, some of the higher MVFR Probability values were seen farther to the north, along the Interstate 5 corridor between Stockton (KSCK) and Sacramento (KSAC) — numerous traffic accidents and school delays were attributed to the Tule fog on this day.
GOES-15 MVFR Probability product [click to play animation]
GOES-15 MVFR Probability and Aqua MODIS Infrared Brightness Temperature Difference (BTD) products [click to enlarge]
Legacy infrared Brightness Temperature Difference (BTD) products are limited in their ability to accurately detect fog/low stratus features if high-level cirrus clouds are present overhead. This is demonstrated in comparisons of GOES-15 MVFR Probability and BTD products from Aqua MODIS (above) and Suomi NPP VIIRS (below). Again, note the Interstate-5 corridor between Stockton and Sacramento, where the extent of the fog was not well-depicted on the BTD images (even using high spatial resolution polar-orbiter MODIS and VIIRS data).
GOES-15 MVFR Probability and Suomi NPP VIIRS infrared Brightness Temperature Difference (BTD) products [click to enlarge]
Daylight images of GOES-15 Visible (0.63 µm) data (below) showed the dissipation of the Tule fog during the 1600-2200 UTC (8 am – 2 pm local time) period. The brighter white snow pack in the higher elevations of the Sierra Nevada was also very evident in the upper right portion of the satellite scene.
GOES-15 Visible (0.63 µm) images [click to play animation]
One ingredient contributing to this Tule fog event was moist soil, from precipitation (as much as 150-200% of normal at some locations in the Central Valley) that had been received during the previous 14-day period (below).
Total liquid precipitation and Percent of normal precipitation for the 14-day period ending on 31 January 2017 [click to enlarge]
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/23023/feed0First Imagery from Himawari-9
http://cimss.ssec.wisc.edu/goes/blog/archives/23042#respondTue, 24 Jan 2017 14:54:38 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=23042
Visible Band 3 (0.64) Full Disk Imagery from Himawari-9 at 0240 UTC on 24 January 2017 [click to enlarge]
The Japanese Meteorological Agency (JMA) has released the first imagery from the Advanced Himawari Imager (AHI) on Himawari-9. The image above, from 0240 UTC on 24 January 2017, is from Band 3 (the “Red” Band) that detects reflected solar radiation near 0.64 µm in the visible part of the electromagnetic spectrum. This band has the highest spatial resolution of the 16 AHI channels: 0.5 km at the sub-satellite point. (A similar image from Himawari-8 at 0250 UTC on 24 January 2017 is here; Himawari-8 does not produce imagery at 0240 UTC or 1440 UTC; satellite housekeeping occurs at those times).
Additional Himawari-9 band imagery from 0240 UTC on 24 January 2017 is available here. All imagery courtesy of JMA.
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/23042/feed0Cold temperatures in Alaska
http://cimss.ssec.wisc.edu/goes/blog/archives/23008#respondThu, 19 Jan 2017 20:59:30 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=23008
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 (warmercyan 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]
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]
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-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]
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 bythe 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]
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 Tanana [click to enlarge]
Surface weather conditions at Bettles [click to enlarge]
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/23008/feed0Atmospheric river events bring heavy precipitation to California
http://cimss.ssec.wisc.edu/goes/blog/archives/22992#respondFri, 13 Jan 2017 23:59:31 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=22992
MIMIC Total Precipatable Water product [click to play MP4 animation]
Terra MODIS Visible (0.65 µm) and Near-Infrared “Snow/Ice” (2.1 µm) images [click to enlarge]
A relatively cloud-free day on 13 January provided a good view of the Sacramento Valley and San Francisco Bay regions. A comparison of Terra MODIS Visible (0.65 µm) and Near-Infrared “Snow/Ice” (2.1 µm) images (above) showed that snow cover in the higher terrain of the Coastal Ranges and the Sierra Nevada appeared darker in the Snow/Ice band image (since snow and ice are strong absorbers of radiation at the 2.1 µm wavelength) — but water is an even stronger absorber, and therefore appeared even darker (which allowed the areas of flooding along the Sacramento River and its tributaries to be easily identified). A similar type of 1.6 µm Near-Infrared “Snow/Ice” Band imagery will be available from the ABI instrument on the GOES-R series, beginning with GOES-16.
Better detail of the flooded areas of the Sacramento River and its tributaries was seen in 250-meter resolution false-color Red/Green/Blue (RGB) imagery from the MODIS Today site — water appears as darker shades of blue, while snow appears as shades of cyan (in contrast to supercooled water droplet clouds, which appear as shades of white). In the corresponding MODIS true-color image, rivers and bays with high amounts of turbidity (tan shades) were evident; the offshore flow of sediment from a few rivers could also be seen.
Terra MODIS true-color and false-color RGB images [click to enlarge]
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/22992/feed0Portland, Oregon heavy snow event
http://cimss.ssec.wisc.edu/goes/blog/archives/22965#respondWed, 11 Jan 2017 23:59:41 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=22965
GOES-15 Infrared Window (10.7 µm) images, with hourly reports of surface weather type [click to play animation]
A surface low moving inland (3-hourly surface analyses) helped to produce widespread rain and snow across much of Oregon and southern Washington during the 10 January – 11 January 2017 period. 4-km resolution GOES-15 (GOES-West) Infrared images (above) and Water Vapor images (below) showed the development of a deformation band that helped to focus and prolong moderate to heavy snowfall over the Portland, Oregon area (accumulations | historical perspective). The GOES-15 images are centered at Portland International Airport (station identifier KPDX).
GOES-15 Water Vapor (6.5 µm) images, with hourly reports of surface weather type [click to play animation]
1-km resolution GOES-15 Visible (0.63 µm) images (below) during the last few hours of daylight on 10 January revealed the shadowing and textured signature of numerous embedded convective elements moving inland, which were helping to enhance precipitation rates (and even produce thundersnow at a few locations, a phenomenon which is very unusual for the Pacific Northwest).
GOES-15 Visible (0.63 µm) images, with hourly reports of surface weather type [click to play animation]
===== 12 January Update =====
As clouds cleared in the wake of the storm, a comparison of 375-meter resolution Suomi NPP VIIRS true-color and false-color Red/Green/Blue (RGB) images viewed using RealEarth(below) revealed the extent of the snow cover; snow appears as shades of cyan in the false-color image, in contrast to clouds which appear as shades of white. [Note: with 5 inches of snow remaining on the ground, a new record low temperature was set in Portland on 13 January]
Suomi NPP VIIRS true-color and false-color RGB images [click to enlarge]
The fresh snowfall was also apparent in a 30-meter resolution Landsat-8 false-color RGB image (below) along the south face of Mount Hood (located about 98 miles or 158 km east of Portland). The ski slopes of Timberline Lodge and Mount Hood Meadows received 13-14 inches of new snow during this event; the snow base depth at Timberline was greater than the average amount for this time of year.
Landsat-8 false-color RGB image [click to play zoom-in animation]
]]>http://cimss.ssec.wisc.edu/goes/blog/archives/22965/feed0Oil well fire in Utah
http://cimss.ssec.wisc.edu/goes/blog/archives/22944#respondFri, 06 Jan 2017 23:59:12 +0000http://cimss.ssec.wisc.edu/goes/blog/?p=22944
GOES-15 Visible (0.63 µm) images, with hourly surface reports [click to play animation]
GOES-15 (GOES-West) Visible (0.63 µm) images (above) showed a small, short-lived black cloud that formed south/southwest of Vernal (station identifier KVEL) in northeastern Utah on 06 January 2017. This feature was the result of a fire at an oil well site (media report | well location) that apparently started around 11:30 am local time (1830 UTC); the black cloud from the burning oil tanks — which was first apparent on the 1930 UTC visible image — stood out well against the snow-covered ground. The initial northwestward transport of the smoke plume was consistent with lower-tropospheric winds in Grand Junction, Colorado rawinsonde data at 07 January/00 UTC, which showed southeasterly winds as high as 784 hPa (2185 meters or 7169 feet above ground level). The sounding profile also showed that this height was the top of a well-defined temperature inversion, which acted as a cap to prevent the smoke from reaching higher altitudes (photo).
GOES-13 (GOES-East) Visible (0.63 µm) images (below) also displayed the dark smoke plume. The viewing angles from the 2 satellites were similar (~53 degrees from GOES-15 vs ~57 degrees from GOES-13), but the time sampling was slightly better from GOES-15 (due to the extra “SUB-CONUS” scan images at :11 and :41 minutes nearly every hour). Image frequency will be even better with the GOES-R series of satellites (beginning with GOES-16), with routine scans every 5 minutes; the visible image spatial resolution will also be improved (to 0.5 km, vs 1.0 km with the current GOES).
GOES-13 Visible (0.63 µm) images, with hourly surface reports [click to play animation]
MODIS Visible (0.645 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images from a 2036 UTC overpass of the Aqua satellite (below) showed the black smoke cloud in the Visible, but there was no evidence of a fire “hot spot” in the Shortwave Infrared (the media report indicated that the fire was extinguished about 2 hours after it started, which would have been around or just before the time of the MODIS images). On the Infrared Window image, the smoke plume actually did exhibit a slightly colder (darker blue color enhancement) signature, which is unusual since conventional fire and wildfire smoke is normally transparent to thermal radiation.
Aqua MODIS Visible (0.645 µm) and Shortwave Infrared (3.7 µm) images at 2036 UTC [click to enlarge]
A view of the 250-meter resolution Aqua MODIS true-color Red/Green/Blue (RGB) image from the MODIS Today site is shown below.
Aqua MODIS true-color image at 2036 UTC [click to enlarge]