Strong early-season storm in the North Pacific

September 23rd, 2014
GOES-15 6.5 µm IR channel images (click to play animation)

GOES-15 6.5 µm IR channel images (click to play animation)

The GOES-15 6.5 µm water vapor channel imagery above showed the development and evolution of a strong mid-latitude cyclone in the eastern North Pacific Basin during the 21-23 September 2014 time period; of particular interest was the development of strong subsidence behind the storm (depicted by brighter shades of yellow), and also a second jet starting to approach the storm from the west (as evidenced by increasing cold cloud tops in the base of the trough at the end of the animation). A closer view of the storm using AWIPS II imagery is available here. The strong storm had access to abundant sub-tropical moisture, as depicted in the MIMIC Total Precipitable Water animation below.

MIMIC Total Precipitable Water (click to enlarge)

MIMIC Total Precipitable Water (click to enlarge)

The ASCAT Scatterometer that flies on METOP gives routine observations of surface winds over the ocean. A large area of storm-force winds (in red) was depicted in the image below (from 0630 UTC on 23 September), overlain on the GOES-15 Water Vapor imagery.

 GOES-15 6.5 µm water vapor channel image and ASCAT winds, 0630 UTC on 23 September (click to enlarge)

GOES-15 6.5 µm water vapor channel image and ASCAT winds, 0630 UTC on 23 September (click to enlarge)

A comparison of 4-km resolution GOES-15 6.5 µm and 1-km resolution Aqua MODIS 6.7 µm water vapor channel images at 11:30 UTC, below, demonstrated the benefit of higher spatial resolution for providing a more accurate display of the water vapor gradients and various small-scale features (such as transverse banding associated with cold clouds to the north of the storm), along with the polar-orbiter image elimination of geostationary parallax error for more more precise feature location.

GOES-15 6.5 µm and Aqua MODIS 6.7 µm water vapor channel images

GOES-15 6.5 µm and Aqua MODIS 6.7 µm water vapor channel images

The GOES sounder Total Column Ozone product, below, showed an increase in ozone values (350-380 Dobson Units, darker green to lighter green color enhancement) as the tropopause was lowered in the vicinity of the deepening mid-latitude cyclone.

GOES sounder Total Column Ozone product (click to play animation)

GOES sounder Total Column Ozone product (click to play animation)

A Suomi NPP VIIRS true-color image from the SSEC RealEarth web map server, below, provided a good view of the lower-level clouds associated with the storm.

Suomi NPP VIIRS true-color image

Suomi NPP VIIRS true-color image

For a more detailed analysis of this event from the Ocean Prediction Center perspective, see the Satellite Liaison Blog.

Hurricane Odile

September 15th, 2014
Advanced Dvorak Technique (ADT) plot for Hurricane Odile

Advanced Dvorak Technique (ADT) plot for Hurricane Odile

A time series plot of the Advanced Dvorak Technique (ADT) intensity estimate for Hurricane Odile (above) showed that the tropical cyclone went through a period of rapid intensification on 14 September 2014, reaching Category 4 on the Saffir-Simpson hurricane scale as it moved northwestward toward the southern tip of Baja California (Odile track map).

McIDAS images of GOES-15 10.7 µm IR channel data covering the 13-15 September period (below; click image to play animated GIF; also available as an MP4 movie file) showed Odile from the period of rapid intensification on the 14th to landfall on the 15th. Odile made landfall near Cabo San Lucas around 04:45 UTC on 15 September, with an estimated intensity of 110 knots — this ties with Hurricane Olivia (1967) as the strongest hurricane to make landfall in Baja California Sur during the modern satellite era.

GOES-15 10.7 µm IR channel images (click to play animated GIF)

GOES-15 10.7 µm IR channel images (click to play animated GIF)

Several hours prior to landfall, a comparison of GOES-15 10.7 µm IR and DMSP SSMIS 85 GHz microwave images from the CIMSS Tropical Cyclones site (below) indicated that Odile had a large outer eyewall at that particular point in time.

GOES-14 10.7 µm IR channel image and DMSP SSMIS 85 GHz microwave image

GOES-14 10.7 µm IR channel image and DMSP SSMIS 85 GHz microwave image

Even after several hours of traversing the rugged terrain of the Baja California peninsula, Odile continued to maintain hurricane intensity; the faint signature of an eye could still be seen on AWIPS II images of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel data at 22:34 UTC on 15 September (below).

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

Record rainfall and flooding in Arizona

September 8th, 2014
GOES-15 10.7 µm IR channel images (click to play animation)

GOES-15 10.7 µm IR channel images (click to play animation)

McIDAS images of 4-km resolution GOES-15 10.7 µm IR channel data (above; click image to play animation; also available as an MP4 movie file) showed the merger of two large mesoscale convective systems (MCS) which produced an all-time record maximum calendar day precipitation amount of 3.29 inches at Phoenix Sky Harbor Airport (PHX) on 08 September 2014. Some locations in the Phoenix area received in excess of 5 inches of rainfall (NWS Phoenix event summary).

An AWIPS-II image of 375-meter resolution Suomi NPP VIIRS 11.45 µm IR channel data (below) showed the MCS pair at 09:07 UTC or 3:07 AM local time —  this was prior to the merger, and the southeastern storm exhibited a minimum cloud-top IR brightness temperature of -84º C (purple color enhancement), which was much colder than the -71º C seen with the northwestern storm. At the onset of the heavy thunderstorms at PHX, southerly to southeasterly winds  — likely outflow from the southeastern MCS — gusted as high as 31 knots (36 mph) and visibility was reduced to 0.8 mile (surface reports: text | graph).

Suomi NPP VIIRS 11.45 µm IR channel image

Suomi NPP VIIRS 11.45 µm IR channel image

As the circulation of former-Hurricane Norbert continued to spin over the Pacific Ocean west of Baja California, deep tropical moisture kept working its way farther inland — GOES sounder Total Precipitable Water (TPW) values in excess of 50-60 mm (2.0 to 2.4 inches) were eventually seen across the southwestern half of Arizona (below; click image to play animation).

GOES sounder Total Precipitable Water derived product images (click to play animation)

GOES sounder Total Precipitable Water derived product images (click to play animation)

The Blended Total Precipitable Water product (below; click image to play animation) also showed values of 50-60 mm working their way into southwestern Arizona during the 06-08 September period.

Blended Total Precipitable Water product (click to play animation)

Blended Total Precipitable Water product (click to play animation)

The Percent of Normal TPW product (below; click image to play animation) indicated that these TPW values were in excess of 200% of normal (yellow color enhancement) over large portions of the Desert Southwest. On the morning of 08 September, the TPW value of 2.03 inches derived from rawinsonde data at Tucson, Arizona set a record high for the month of September at that location.

Percent of Normal TPW product (click to play animation)

Percent of Normal TPW product (click to play animation)

Happy Camp Fire in northern California

September 3rd, 2014
GOES-15 0.63 µm visible channel images (click to play animation)

GOES-15 0.63 µm visible channel images (click to play animation)

After being started by lightning on 11 August, the Happy Camp Fire Complex (Inciweb) continued to burn in far northern California on 03 September 2014. McIDAS images of GOES-15 (GOES-West) 0.63 µm visible channel data (above; click image to play animation) initially revealed the smoke which had settled into the area valleys during the previous night, and then showed a new smoke plume which drifted southwestward off the coast, then turned to the left and moved southward along the adjacent nearshore waters.  The smoke moved over Arcata/Eureka airport (KACV), at one point reducing the surface visibility to 6 miles.

As the fie continued to burn into the following night, an AWIPS II image of Suomi NPP VIIRS 3.74 shortwave IR channel data at 10:21 UTC (3:21 AM local time) showed the cluster of fire hot spots (black to yellow to red pixels), while the corresponding VIIRS 0.7 µm Day/Night Band image showed that the bright glow of the fire complex was as large and as intense as that from many of the larger cities in the region.

Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images

Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images