GOES-15/GOES-13 6.5 µm water vapor channel images (click to play animation)

Flooding rains have occurred over south Texas during the past two days, and the animation of GOES water vapor imagery, above, and of MIMIC Total Precipitable Water, below, shows two airstreams moving moisture into that region. The GOES-15/GOES-13 Water Vapor image animation, above, shows upper-level moisture moving in from the tropical Pacific south of Mexico (much of it likely outflow from Tropical Storm Octave). MIMIC Total Precipitable Water animation (available from this site), below, shows a concomitant lower-level moisture source, the Gulf of Mexico. Plots at 925 mb, and 850 mb, show moist, easterly flow around a High centered over the mid-Mississippi valley. As a result, total precipitable water values exceeded 200% of normal over a wide region. (Blended Total Precipitable Water products are available here). The high values of Total Precipitable Water persist into the day on 14 October. (Link, analysis from SPC).

MIMIC Total Precipitable Water (click to play animation)

VIIRS 11.45 µm IR image (click to enlarge)

A Suomi-NPP VIIRS 11.45 µm IR image from late in the day on 13 October (above) showed strong convection near Laredo, TX, with very cold cloud tops (brightness temperature values over Mexico are as cold as -92º C!). Applying a different color enhancement, a comparison of this 1-km resolution VIIRS IR image at 20:11 UTC with the corresponding 4-km resolution GOES-13 10.7 µm IR image (below) highlights two advantages of polar orbiter imagery over geostationary imagery: (1) with the higher spatial resolution, the magnitude of the coldest overshooting cloud tops can be assessed: the -92º C minimum cloud-top IR brightness temperature on the VIIRS image was 14º C colder than the -78º C value seen on the GOES-13 image, and (2) with the minimal parallax error of polar orbiter imagery, the exact location of such cloud-top features can be more accurately determined.

Suomi NPP VIIRS 11.45 µm IR and GOES-13 10.7 µm IR channel images

The result of the strong convection near 2100 UTC, and from other convection apparent in the water vapor animation at top, was a broad region of heavy rains, (obtained from this site) shown below. Some of these rains fell over regions of Texas in drought (as shown here), so where damage was minimal, the heavy rains could be considered beneficial.

24-hour precipitation over Texas valid 1200 UTC 14 October from this site (click to enlarge)

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Track of Cyclone Phailin

As seen on the Cyclone Phailin (02B) track map from the CIMSS Tropical Cyclones site (above), the storm formed near the northern Adaman Islands on 09 October 2013. As Phailin tracked northwestward across the Bay of Bengal, it underwent a period of rapid intensification on 10 October, as indicated by the Automated Dvorak Technique (ADT) intensity estimate plot (below). Phailin reached Category 5 intensity near the middle of the day on 10 October.

Automated Dvorak Technique (ADT) intensity estimate plot

McIDAS images of EUMETSAT Meteosat-7 11.5 µm IR channel data (below; click image to play animation) showed the expansive area of very cold cloud tops exhibited by Phailin, with IR brightness temperatures in the -80 to -90º C range (violet to darker purple color enhnahcement).

EUMETSAT Meteosat-7 11.5 µm IR channel images (click to play animation)

A McIDAS-V image of 375-meter resolution Suomi NPP VIIRS 11.45 µm IR channel data (below; courtesy of William Straka, CIMSS) offered a more detailed look at the structure of the eye and eyewall region of Phailin at 11:43 UTC on 11 October.

Suomi NPP VIIRS 11.45 µm IR channel image

DMSP SSMI/S 85 GHz microwave data (below) suggested that Phailin was undergoing an eyewall replacement cycle prior to landfall, which likely accounts for its drop in intensity to a Category 4 storm (Phailin warning text issued at 15 UTC on 12 October).

DMSP SSMI/S 85 GHz brightness temperature

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850-hPa relative vorticity product (click image to play animation)

A sequence of images of the satellite-wind-derived 850 hPa relative vorticity product at 6-hour intervals covering the period 04 October to 09 October 2013 (above; click image to play animation) showed that the vorticity associated with Tropical Storm Karen over the Gulf of Mexico on 04 October could be followed northeastward as the storm made the transition to an extratropical low as it movved inland and interacted with a frontal boundary, then eventually organizing into a slow-moving coastal low along the US East Coast.

A comparison of 1-km resolution MODIS 0.65 µm visible channel, 11.0 µm IR channel, and 6.7 µm water vapor channel images (below) showed the organization of the coastal low at 18:10 UTC on 09 October, which featured deep offshore  convection with IR cloud-top temperatures as cold as -75º C.

MODIS 0.65 µm visible channel, 11.0 µm IR channel, and 6.7 µm water vapor channel images (09 October)

===== 10 October Update =====

A comparison of 1-km resolution Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images at 17:59 UTC on 10 October (below) revealed that some strong convective elements had moved inland over southeastern Virginia and northeastern North Carolina, producing heavy rainfall.

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR chanel images (10 October)

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GOES-13 0.63 µm visible channel images (click to play animation)

The “De Luz” wildfire began to burn at the Camp Pendleton Marine Corps Base in southern California around 19:45 UTC or 12:45 PM on 05 October 2013. The fire burned over 2200 acres and forced evacuations of some housing and a hospital (InciWeb). McIDAS images of GOES-13 (GOES-East) 0.63 µm visible channel data (above; click image to play animation) showed the smoke plume as it drifted quickly southwestward due to strong Santa Ana winds.

A 2-panel comparison of GOES-13 0.63 µm visible channel and 3.9 µm shortwave IR channel images (below; click image to play animation) revealed that the fire “hot spot” (red color enhancement on the shortwave IR images) was detected about 30 minutes prior to the time when a smoke plume became obvious on the visible images.

GOES-13 0.63 µm visible (left panel) and 3.9 µm shortwave IR (right panel) images (click to play animation)

The fire growth slowed that evening as temperatures began to cool down and the strong Santa Ana winds gradually subsided, but fire continued to burn into the night — a small fire hot spot (yellow to orange color enhancement) was still evident on a Suomi NPP VIIRS 3.74 µm shortwave IR channel image at 09:18 UTC or 2:18 AM local time (below).

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