Bomb cyclone makes landfall along the Oregon/California coast

November 26th, 2019 |

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images, with 3-hourly plots of surface fronts [click to play animation | MP4]

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images, with surface fronts plotted in cyan and buoy locations plotted in red [click to play animation | MP4]

A sequence of GOES-17 (GOES-West) Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (above) showed the evolution of a bomb cyclone (surface analyses: WPC | OPC) that made landfall along the Oregon/California coast just after sunset on 26 November 2019. The storm produced wind gusts of 106 mph in southwestern Oregon and 70 mph in northwestern California.

GOES-17 “Red” Visible (0.64 µm) images of the storm are shown below — the Mean Sea Level Pressure anomaly was 4-5 sigma below the climatological mean as the rapidly-deepening midlatitude cyclone made landfall. Similarly, 925 hPa wind speed anomaly was 3-5 sigma above the climatological mean. The system had transitioned to a warm seclusion phase by 00 UTC, as seen in a comparison of Visible and Water Vapor images at that time.

GOES-17 "Red" Visible (0.64 µm) images, with 3-hourly plots of surface fronts [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) images, with surface fronts plotted in cyan and buoy locations plotted in red [click to play animation | MP4]

A GOES-17 Mesoscale Domain Sector was positioned over the region, providing Visible images at 1-minute intervals (below).

GOES-17

GOES-17 “Red” Visible (0.64 µm) images, with hourly plots of surface wind barbs and gusts in knots [click to play animation | MP4]

A larger-scale view of the entire GOES-17 Mesoscale Domain Sector is shown below, using Visible images from the AOS site.

GOES-17 "Red" Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-km resolution NOAA-15 AVHRR Shortwave Infrared (3.7 µm) imagery at 0217 UTC (below) showed the center of circulation just off the Oregon/California coast. At that time, winds were gusting to 50 knots at Crescent City, California (KCEC).

NOAA-15 AVHRR Shortwave Infrared (3.7 µm) image at 0217 UTC [click to enlarge]

NOAA-15 AVHRR Shortwave Infrared (3.7 µm) image at 0217 UTC, with plots of 02 UTC surface reports (cyan/yellow) and wind gusts (in knots, red) [click to enlarge]

A time series of surface data from Crescent City, California (below) showed the period when the air pressure dropped to 973.4 hPa (28.74 inches) — setting a new all-time low pressure record for the state of California. In addition, new low pressure records for the month of November were set at Medford, Oregon (981.4 hPa / 28.98 inches) and at Eureka, California (984.8 hPa / 29.08 inches).

Time series of surface data at Crescent City, California [click to enlarge]

Time series of surface data at Crescent City, California [click to enlarge]

Air pressure at the offshore buoy 8 miles NW of Crescent City (46027) dropped to 971.7 hPa (28.69 inches) at 0350 UTC (below).

Plots of Wind Speed (blue), Wind Gust (red) and Air Pressure (green) from Buoy 46027

Plots of Wind Speed (blue), Wind Gust (red) and Air Pressure (green) from Buoy 46027


Potential Vorticity anomaly approaching Baja California and Southern California

November 5th, 2019 |

GOES-17 Upper-level Water Vapor (6.2 µm), Mid-level Water Vapor (6.9 µm) and Air Mass RGB images, with and without contours of PV1.5 pressure [click to play animation |MP4]

GOES-17 Upper-level Water Vapor (6.2 µm), Mid-level Water Vapor (6.9 µm) and Air Mass RGB images, with and without contours of PV1.5 pressure [click to play animation |MP4]

GOES-17 (GOES-West) Upper-level Water Vapor (6.2 µm), Mid-level Water Vapor (6.9 µm) and Air Mass RGB images (above) displayed the signature of dry, ozone-rich air associated with a Potential Vorticity (PV) anomaly approaching Baja California and Southern California on 05 November 2019. The “dynamic tropopause” — taken to be the pressure of the PV1.5 surface — descended to the 500 hPa level within this PV anomaly.

A GOES-17 Water Vapor image with plots of available NOAA-20 NUCAPS soundings (below) is labeled with sounding points within the core of the PV anomaly (Point 1) and within the core of the driest air (Point 2).

GOES-17 Upper-level Water Vapor (6.2 µm) images, with plots of available NOAA-20 NUCAPS soundings [click to enlarge]

GOES-17 Upper-level Water Vapor (6.2 µm) images, with plots of available NOAA-20 NUCAPS soundings [click to enlarge]

The NUCAPS sounding profiles for Point 1 and Point 2 are shown below. The middle/upper troposphere was quite dry at both locations.

NUCAPS sounding profile for Point 1 [click to enlarge]

NUCAPS sounding profile for Point 1 [click to enlarge]

NUCAPS sounding profile for Point 2 [click to enlarge]

NUCAPS sounding profile for Point 2 [click to enlarge]

Easy Fire in Southern California

October 30th, 2019 |

GOES-17 Shortwave Infrared (3.9 µm) and “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-17 Shortwave Infrared (3.9 µm) and “Red” Visible (0.64 µm) images [click to play animation | MP4]

As northeast Santa Ana winds began to increase before sunrise on 30 October 2019, 1-minute Mesoscale Domain Sector GOES-17 (GOES-West) Shortwave Infrared (3.9 µm) and “Red” Visible (0.64 µm) images (above) showed the sudden onset of a thermal anomaly (cluster of  hot 3.9 µm pixels) — associated with the Easy Fire northwest of Los Angeles — which occurred at 1308-1309 UTC (6:08-6:09 AM local time). After sunrise, the narrow wind-driven smoke plume was seen in the Visible imagery.

A comparison of 3 consecutive VIIRS Shortwave Infrared (3.74 µm) images from Suomi NPP and NOAA-20 with the corresponding GOES-17 Shortwave Infrared (3.9 µm) images (below) demonstrated the advantage of polar orbiter imagery for providing a more accurate depiction of the size and location of a fire. Note: the color enhancements are different for the Suomi NPP/NOAA-20 vs GOES-17 images, since there are differences between shortwave infrared detectors on the VIIRS and ABI instruments.

3.74 µm Shortwave Infrared images from Suomi NPP and NOAA-20 compared with the corresponding GOES-17 3.9 µm images [click to enlarge]

3.74 µm Shortwave Infrared images from Suomi NPP and NOAA-20 compared with the corresponding GOES-17 3.9 µm images [click to enlarge]

Stereoscopic views of the Kincade Fire in California

October 30th, 2019 |

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery on 24 October 2019, 1500-2350 UTC (Click to animate)

GOES-16 and GOES-17 satellite imagery can be remapped and combined to create stereoscopic imagery. To achieve the 3-dimensional effect, cross your eyes until three scenes are visible, and focus on the middle image.  You can also achieve this by placing a finger halfway between your eyes and the screen, and focusing on your finger, then focusing on the image behind.  (Here’s a website that might help).  The imagery above, from 24 October 2019, shows high clouds rotating anti-cyclonically above the smoke produced from the Kincade Fire (previous blog posts on this fire are here and here). The smoke plume extended far out into the Pacific Ocean. A Full-resolution image animation is shown below.

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery on 24 October 2019, 1500-2350 UTC (Click to animate)

Animations for 25 October, 26 October, 27 October, 28 October and 29 October are shown below, in order.

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery from 1500 UTC on 25 October 2019 to 0050 UTC on 26 October 2019 (Click to animate)

On the 25th and 26th of October, prevailing winds moved smoke into the Bay Area.  On both days, the fire appeared less vigorous in the visible imagery than on the 24th, at top, or on the 27th;  at least, it appeared to be producing less smoke.

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery from 1500 UTC on 26 October 2019 to 0050 UTC on 27 October 2019 (Click to animate)

On the 27th, below, the fire resembled the scene on 24 October, with a large smoke plume extending far southwest into the Pacific Ocean.

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery from 1500 UTC to 2350 UTC on 27 October 2019 (Click to animate)

On the 28th, below, smoke generation has decreased, and the smoke pall appears over the Bay Area again. A full-resolution version is available here.

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery from 1500 UTC to 2350 UTC on 28 October 2019 (Click to animate)

The scene on the 29th, below (Full resolution available here) is shown below. The smoke plume is extensive.

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery from 1500 UTC to on 29 October 2019 to 0050 UTC on 30 October 2019 (Click to animate)

How did the smoke plume change from day to day? The animation below shows data at 2350 UTC on 24-29 October.

GOES-16 (left) and GOES-17 (right) visible (0.64 µm) imagery at 2350 UTC from 24 to 29 October 2019 (Click to enlarge)