Tropical Storm Andrea

June 5th, 2013
GOES-14 10.7 µm IR images + wind shear and tropical overshooting tops

GOES-14 10.7 µm IR images + wind shear and tropical overshooting tops

Tropical Storm Andrea (the first Atlantic Basin tropical cyclone of the 2013 season) formed in the eastern Gulf of Mexico on 05 June 2013. GOES-14 10.7 µm IR images from the CIMSS Tropical Cyclones site (above) showed that the center of Andrea was located along the western edge of deep convection, which exhibited numerous Tropical Overshooting Tops. Andrea was forecast to move northeastward into an environment characterized by increasing values of deep layer wind shear, so rapid intensification was not anticipated.

Due to partial obscuration by high clouds from the deep convection, the low-level center of circulation was difficult to identify on McIDAS images of GOES-14 0.63 µm visible channel data (below; click image to play animation).

GOES-14 0.63 µm visible channel images (click image to play animation)

GOES-14 0.63 µm visible channel images (click image to play animation)

Early in the day, an AWIPS comparison of 1-km resolution MODIS 11.0 µm IR and 4-km resolution GOES-14 10.7 µm IR images (below) demonstrated that the higher spatial resolution data was able to display the small yet very cold areas of tropical overshooting tops — the coldest IR brightness temperatures seen on the MODIS image were -87º C (violet color enhancement), compared to -78º C (lighter gray color enhancement) on the corresponding GOES-14 IR image.

MODIS 11.0 µm IR channel and GOES-14 10.7 µm IR channel images

MODIS 11.0 µm IR channel and GOES-14 10.7 µm IR channel images

===== 06 June Update =====

POES AVHRR 12.0 µm IR channel and 0.85 µm visible channel images

POES AVHRR 12.0 µm IR channel and 0.85 µm visible channel images

1-km resolution POES AVHRR 12.0 µm IR channel and 0.86 µm visible channel images (above) showed Andrea off the west coast of Florida at 15:05 UTC. There was some suggestion of a closed eye beginning to form on the visible image.

1-km resolution GOES-14 0.63 µm visible channel images (below; click image to play animation) revealed that the center of circulation became more well-defined as the tropical storm made landfall around 21:40 UTC (5:40 PM local time) near Steinhatchee, Florida. Maximum sustained winds at landfall were estimated to be 65 mph.

GOES-14 0.63 µm visible channel images (click image to play animation)

GOES-14 0.63 µm visible channel images (click image to play animation)

Update on GOES-13

June 3rd, 2013

Special update: GOES-13 is scheduled to become the operational GOES-East on June 6, 2013 at approximately 1545 UTC. Link.

Special update #2:GOES-13 will become the operational GOES-East Satellite no sooner than Monday 10 June 2013 Link.

GOES-13 will become operational GOES-East at approximately 1545 UTC on Monday June 10. Link.

(Update on the GOES-13 Sounder can be found at the bottom of the blog post)

GOES-13 Imager Channels from 1445 UTC on 3 June 2013 (click image to play animation)

GOES-13 Imager Channels from 1445 UTC on 3 June 2013 (click image to play animation)

GOES-13 suffered an anomaly in May, and GOES-14 has been standing in for GOES-13 since May 23rd. (Click here to read about a possible cause of the anomaly) Testing of GOES-13 has shown that the Imager continues to send quality imagery, as shown in the animation of Full-Disk imagery above.

GOES-13 and GOES-14 6.5 µm Sounder Channels from 1346 UTC on 31 May 2013

GOES-13 and GOES-14 6.5 µm Sounder Channels from 1346 UTC on 31 May 2013

The Sounder, at present, is being outgassed (and there is therefore no current Sounder data; the sounder is off during outgassing); it is possible that after outgassing, the GOES-13 imagery will be as clean as GOES-14. Imagery before outgassing showed significant differences in noise levels between the two instruments. An outgas was also performed last year to reduce noise in the sounder observations (that outgas was of shorter duration).

GOES-14 10.7 µm Imager showing change in CONUS sector footprint

GOES-14 10.7 µm Imager showing change in CONUS sector footprint

GOES-14 remains the operational GOES-East image until further notice. The CONUS sector has been expanded to the east to include Puerto Rico in more operational scans. Imagery above shows the coverage before and after the eastward expansion of the CONUS sector.

NOAA/NESDIS continues distributing updates on the GOES satellites. Announcements can also be found here.

Update: June 6 2013:

GOES-13 4.4 µm Sounder from before (top) and after (bottom) outgassing.  Standard deviation of imagery as shown

GOES-13 4.4 µm Sounder from before (top) and after (bottom) outgassing. Standard deviation of imagery as shown

An outgas was performed to “clean” the sounder instrument, and it was successful. Above are images from Sounder band 15 (4.4 µm) before (top) and after (bottom) the outgas. Note that the standard deviation of the image has dropped. The Noise Index in the figure below (from this website) also shows a dramatic change for the better after the outgas. (Image below courtesy of Fangfang Yu, NOAA/NESDIS).

Noise Index from GOES-13 4.4 µm Sounder channel from various timeframes

Noise Index from GOES-13 4.4 µm Sounder channel from various timeframes

Severe weather in the Oklahoma City area

May 31st, 2013
GOES-14 sounder Convective Available Potential Energy (CAPE) product (click image to play animation)

GOES-14 sounder Convective Available Potential Energy (CAPE) product (click image to play animation)

Only 11 days after the devastating EF-5 tornado that struck Moore, Oklahoma, another round of severe weather brought tornadoes (including the EF-5 El Reno tornado) large hail (up to 2.5 inches in diameter), damaging winds (gusts as high as 87 mph), and heavy rain that led to flash flooding to the Oklahoma City area on 31 May 2013 (SPC storm reports| NWS Norman summary). AWIPS images of the 10-km resolution GOES-14 sounder Convective Available Potential Energy (CAPE) derived product (above; click image to play animation) showed the trend of rapid destabilization across the region during the hours leading up to convective initiation — widespread CAPE values in the 5000-6000 J/kg range were seen (lighter purple color enhancement).

Once convective initiation began the storm growth was explosive, as revealed by McIDAS images of 1-km resolution GOES-14 0.63 µm visible channel data (below; click image to play animation; also available as a QuickTime movie). The GOES-14 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-10 minutes. Complex storm-top structures were evident in the visible imagery, including numerous overshooting tops and anvil gravity waves. In addition, later in the animation a smoke plume can be seen approaching from the west (originating from a large fire that was burning in New Mexico). OKC denotes the location of Oklahoma City.

GOES-14 0.63 µm visible channel images (click image to play animation)

GOES-14 0.63 µm visible channel images (click image to play animation)

Not long after the first large thunderstorms began to develop west of Oklahoma City, a 1-km resolution POES AVHRR 12.0 µm IR channel image (below) displayed cloud-top IR brightness temperatures as cold as -78º C at 21:51 UTC or 4:51 PM local time (shortly before the first report of 1.25-inch diameter hail at 21:59 UTC). A 1-km resolution AVHRR vs 4-km resolution GOES-14 IR image comparison demonstrated two important advantages of polar-orbiter satellite imagery: (1) more accurate depiction of the coldest overshooting tops (-78º C on AVHRR, vs -64º C on with GOES-14), and (2) limited parallax error, helping to more accurately determine the true location of the overshooting tops.

POES AVHRR 12.0 µm IR channel image

POES AVHRR 12.0 µm IR channel image

AWIPS image combinations of GOES-14 10.7 µm IR channel data with overlays of Cloud Top Cooling (CTC) Rate and Overstooting Top (OT) Detection products (below; click image to play animation) showed the following: (1) the first region of significant CTC that was flagged with the newly-developing Oklahoma City storm was at 21:15 UTC, with a CTC rate of -8.8º C compared to the previous GOES-14 IR image; (2) the CTC rate increased to -26.9º C for the following 21:25 UTC IR image; (3) the CTC rate jumped to a remarkable -60.2º C for the following 21:32 UTC IR image (an indicator of the explosive rate of storm development); (4) OT detection icons began to appear once GOES-14 IR images exhibited IR brightness temperature values of -60º C and colder (beginning at 21:55 UTC).

GOES-14 10.7 µm IR image + Cloud Top Cooling Rate and Overshooting Top Detection products (click image to play animation)

GOES-14 10.7 µm IR image + Cloud Top Cooling Rate and Overshooting Top Detection products (click image to play animation)

===== 02 June Update =====

A comparison of before/after (14 May/02 June) 250-meter resolution true-color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below) showed the damage path from the 31 May El Reno, Oklahoma tornado. The lakes and rivers appear brighter on the 02 June image due to sun glint off the bodies of water (the sun-satellite geometry was different than it was on 14 May).

Before/after (14 May/02 June) MODIS true-color Red/Green/Blue (RGB) images

Before/after (14 May/02 June) MODIS true-color Red/Green/Blue (RGB) images

The tornado damage path is also highlighted on the 02 June MODIS true-color RGB image, viewed using Google Earth (below).

MODIS true-color RGB image (viewed using Google Earth)

MODIS true-color RGB image (viewed using Google Earth)

Hurricane Barbara

May 29th, 2013
GOES-14 0.63 µm visible channel images (click image to play animation)

GOES-14 0.63 µm visible channel images (click image to play animation)

McIDAS images of GOES-14 0.63 µm visible channel data (above; click image to play animation) showed Tropical Storm Barbara as it intensified to Category 1 hurricane shortly before making landfall along the coast of the Gulf of Tehuantepec in southeastern Mexico on 29 May 2013. Since reliable records began for the Eastern Pacific Basin in 1966, Hurricane Barbara was the second-earliest hurricane landfall, as well as the easternmost landfall location.

An AWIPS image of ASCAT surface scatterometer winds overlaid on a GOES IR image (below) depicted a maximum wind speed of 53 knots at 16:01 UTC (while Barbara was still at tropical storm intensity).

ASCAT surface scatterometer winds

ASCAT surface scatterometer winds

A 375-meter resolution Suomi NPP VIIRS 11.45 µm IR image at 19:35 UTC (below) showed the very cold cloud-top IR brightness temperatures (primarily in the -80 to -90 C range, enhanced with varying shades of violet) associated with convective clusters around the center of Hurricane Barbara as the storm was making landfall along the Mexican coast.

Suomi NPP VIIRS 11.45 µm IR image

Suomi NPP VIIRS 11.45 µm IR image

 ===== 30 May Update =====

GOES-14 0.63 µm visible channel images (below; click image to play animation) seem to suggest that the low-level circulation of Barbara remained intact after crossing the rugged terrain of southern Mexico, and emerged into the Gulf of Mexico on 30 May. The GOES-14 satellite had been placed into Rapid Scan Operations (RSO), providing images as frequently as every 5-10 minutes.

GOES-14 0.63 µm visible channel images (click image to play animation)

GOES-14 0.63 µm visible channel images (click image to play animation)