Super Typhoon Yutu makes landfall on Tinian and Saipan

October 24th, 2018 |

Himawari-8 “Clean Window” Infrared (10.41 µm) Imagery, 0900-1540 UTC on 24 October 2018 (Click to animate)

Himawari-8 Clean Window Infrared (10.41 µm) imagery shows Super Typhoon Yutu poised to hit Tinian and Saipan in the Marianas Islands, to the northeast of Guam. The 0900 UTC Advisory from the Joint Typhoon Warning Center shows a storm with sustained winds of 145 knots, with strengthening forecast. JMA estimates a surface pressure of 905 hPa! (Link)

(Himawari data courtesy JMA and the NWS Pacific Region)

Update: Landfall on Tinian and Saipan occurred just before 1500 UTC; a closer view using 2.5 minute rapid scan Himawari-8 imagery can be seen here (station plot PGSN is Saipan, where reliable observations ceased after 1452 UTC).

Added: From William Straka, CIMSS. NOAA-20 had a fortuitous overpass, almost directly over Tinian at landfall. The Day Night Band Visible (0.7 µm) Imagery (with a full moon) and 11.45 µm infrared imagery is shown below).

NOAA-20 VIIRS Day Night Band visible (0.7 µm) imagery and I05 infrared (11.45 µm) imagery, 1551 UTC on 24 October 2018 (Click to enlarge)

CIMSS helps manage a Direct Broadcast (DB) antenna at the National Weather Service on Guam, and that antenna received both NOAA-20 and GCOM data as the eye was over, or close to, Tinian.  Microwave imagery from The Advanced Microwave Scanning Radiometer 2 (AMSR-2) on JAXA’s GCOM satellite, below, (courtesy Kathy Strabala, CIMSS) at 36.5 GHz and 89.0 GHz, reveals cloud and rainband structures that infrared imagery cannot.  In particular, the 89.0 GHz imagery suggests the formation of an outer eyewall ouside the very compact inner eye.  This typically is the start of an eyewall replacement cycle.

GCOM AMSR-2 imagery at 36.5 and 89.0 GHz, 1601 UTC on 24 October 2018 (Click to enlarge)

The DB antenna also processed data from NOAA-20, the same overpass as shown above, zoomed in over Tinian. The antenna is able to capture data over much of the western Pacific Basin, as the Day Night Band visible image shows below. A true color image from the previous overpass on Guam, 12 hours earlier, during daytime (0311 UTC on 24 October), is here.

NOAA-20 VIIRS Day Night Band visible (0.7 µm) imagery, 1544 UTC on 24 October 2018 (Click to enlarge)

Ferguson Fire in California forms a pyrocumulonimbus cloud

July 15th, 2018 |
GOES-16

GOES-16 “Red” Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

* GOES-17 images shown here are preliminary and non-operational *

The Ferguson Fire in central California produced a pyrocumulonimbus (pyroCb) cloud during the afternoon hours on 15 July 2018. GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed that the high-altitude portion of the pyroCb cloud then drifted northeastward toward the California/Nevada border, where cloud-top infrared brightness temperatures cooled to near -55ºC (orange enhancement) as it crossed the border around 0005 UTC on 16 July.

A comparison of Visible images from GOES-15 (0.63 µm), GOES-17 (0.64 µm) and GOES-16 (0.64 µm) is shown below — with the imagery displayed in the native projection of each satellite. Images from GOES-16/17 are at 5-minute intervals, while images from GOES-15 are every 5-15 minutes depending on the operational scan schedule of that GOES-West satellite. GOES-17 was at its post-launch checkout position of 89.5ºW longitude, so it offered a more direct view of the pyroCb cloud.

Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right) [click to play animation]

Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right) [click to play animation]

A toggle between NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images (below) showed the pyroCb cloud southwest of the California/Nevada border (between Bridgeport KBAN and Mammoth KMMH) at 2327 UTC. In spite of a minimum cloud-top 10.8 µm infrared brightness temperature of -59ºC (red enhancement), note the darker (warmer) appearance of the cloud on the 3.7 µm image — this is due to reflection of solar radiation off the smaller ice particles of the pyroCb anvil. The -59ºC temperature roughly corresponded to an altitude of 13 km or 42.6 kft on the 00 UTC Reno, Nevada rawinsonde report (plot | data)

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

A time lapse of the pyroCb was created by Sierra Fire Watch (below).

Time lapse [click to play YouTube video]

Time lapse [click to play YouTube video]

Hurricane Chris accelerates away from the United States

July 11th, 2018 |

GOES-16 ABI Band 2 (“Red Visible”) Visible (0.64 µm) Imagery, 1852-2117 UTC on 11 July 2018 (Click to animate)

Hurricane Chris is accelerating away from the United States (although it will likely pass very close to Cape Race, Newfoundland Canada). Visible Imagery (GOES-16 ABI Band 2, “Red Visible”, at 0.64 µm), above, from late afternoon on 11 July shows a well-developed storm with a pronounced eye.

Before Sunrise on 11 July 2018, both NOAA-20 and JAXA’s Global Change Observation Mission (GCOM) Satellite overflew the storm at slightly different times.  The VIIRS (Visible Infrared Imaging Radiometer Suite) instrument NOAA-20 samples in the visible and infrared part of the electromagnetic spectrum whereas the AMSR2 Instrument (Advanced Microwave Scanning Radiometer 2) on GCOM samples in the microwave.  Because microwave energy can penetrate clouds, it can be used to estimate rainfall, and the toggle below steps through the Infrared (11.45 µm) and Day Night Band Visible (0.70 µm) from VIIRS (at 0645 UTC) as well as the Convective Precipitation and Surface Rain rate from AMSR2 (at 0618 UTC). 

Lunar illumination is absent  in the Day Night band visible imagery, but Earth glow nevertheless illuminates the eye of the storm;  in addition, two lightning streaks are visible north and east of the center.  Surface Rain and Convective Rain rates show the heaviest rains near the storm center, as expected (NOAA-20 VIIRS and GCOM AMSR2 imagery courtesy William Straka, CIMSS).

VIIRS Infrared (11.45 µm) and Visible (0.70 µm) Day Night Band Visible Imagery, 0645 UTC on 11 July 2018, and GCOM AMSR2 Convective Precipitation and Surface Rain Rate estimates at 0618 UTC on 11 July (Click to enlarge)

Mesoscale Convective Vortex generated by monsoon thunderstorms in Arizona

July 9th, 2018 |

As mentioned by NWS San Diego, monsoon thunderstorms that developed over Arizona spawned a small Mesoscale Convective Vortex (MCV). The animation below shows nighttime GOES-16 (GOES-East) “Clean” Infrared Window (10.3 µm) images, followed by daytime GOES-16 “Red” Visible (0.64 µm) images — the center of the MCV circulation briefly exhibited an “eye-like” appearance just after 16 UTC (south of the California/Mexico border).

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) and “Red” Visible (0.64 µm) images, with hourly plots of surface reports [click to play MP4 animation]

A 1-km resolution NOAA-19 Infrared Window (10.8 µm) image at 1132 UTC (below) showed a more detailed view of the small cluster of thunderstorms responsible for the MCV — the convection produced 0.68″ of rainfall near Yuma KNYZ in far southwestern Arizona, and generated an outflow boundary which produced wind gusts to 46 mph at Thermal, California KTRM (NWS statements).

NOAA-19 AVHRR Infrared Window (10.8 µm) image [click to enlarge]

NOAA-19 AVHRR Infrared Window (10.8 µm) image [click to enlarge]

A toggle between 1-km resolution NOAA-15 and NOAA-18 Visible (0.63 µm) images (below) revealed the emergence of the eye-like MCV center in far northern Baja California (just southeast of Campo, California KCZZ) at 1547 UTC.

NOAA-15 and NOAA-18 Visible (0.63 µm) images [click to enlarge]

NOAA-15 and NOAA-18 Visible (0.63 µm) images [click to enlarge]