Wildfires in Texas

April 15th, 2011 |
GOES-13 0.63 µm visible channel images (click image to play animation)

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

Large wildfires continued to burn out of control across much of Texas on 15 April 2010. McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed the growth of a number of very long smoke plumes which were fanned out by strong northerly and northwesterly winds in the wake of a cold frontal passage. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO), providing images as frequently as every 5-10 minutes.

MODIS true color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below; displayed using Google Earth) also showed that a significant dust plume aloft was spreading out southeastward across the region. The blowing dust exhibited a distinct light brown color, in contrast to the light gray color of the smoke plumes.

MODIS true color Red/Green/Blue (RGB) images (displayed using Google Earth)

MODIS true color Red/Green/Blue (RGB) images (displayed using Google Earth)

AWIPS images of POES AVHRR 3.7 µm shortwave IR and 10.8 µm IR window data from the previous evening (below) showed the very large size of some of the fire “hot spots” (black to red to yellow color enhancement on the shortwave IR image) — as well as the fact that some of the fires were so hot that they even exhibited a dark black hot spot signature of the 10.8 µm IR window channel image.

POES AVHRR 3.7 µm shortwave IR + 10.8 µm IR window images

POES AVHRR 3.7 µm shortwave IR + 10.8 µm IR window images

CIMSS participation in GOES-R Proving Ground activities includes making a variety of POES AVHRR images and products available for National Weather Service offices to add to their local AWIPS workstations.

Von Karman vortices south of the Aleutian Islands

April 14th, 2011 |

 

POES AVHRR 0.86 µm visible channel images

POES AVHRR 0.86 µm visible channel images

AWIPS images of POES AVHRR 0.86 µm visible channel data (above) revealed a pair of von Karman vortices streaming southward from the Aleutian Islands of Alaska on 14 April 2011. In this 2-image comparison, note that the cloud features were moving, but the ice in the Bering Sea remained stationary.

An overlay of MADIS low-level atmospheric motion vectors (or “cloud-tracked winds”) indicated that northerly winds across the region were generally in the 20-30 knot range (below).

POES AVHRR visible images + MADIS atmospheric motion vector winds

POES AVHRR visible images + MADIS atmospheric motion vector winds

POES AVHRR Cloud Top Temperature product

POES AVHRR Cloud Top Temperature product

The corresponding POES AVHRR Cloud Top Temperature (CTT) product images (above) indicated that CTT values for these von Karman vortex features were generally in the -10 to -15º C range, while POES AVHRR Cloud Top Height (CTH) product images (below) showed that the tops of the clouds were  around 1-2 km.

POES AVHRR Cloud Top Height products

POES AVHRR Cloud Top Height products

Widespread fires continue in eastern Kansas; resultant smoke pall aloft over Missouri

April 13th, 2011 |

 

POES AVHRR 3.7 µm shortwave IR image

POES AVHRR 3.7 µm shortwave IR image

An AWIPS image of POES AVHRR 3.7 µm shortwave IR data (above) revealed a large number of fire “hot spots” (black to red to yellow pixels) across much of eastern Kansas on 12 April 2011. The majority of these were grassland fires.

On the following day (13 April 2011), a well-defined area of dense smoke aloft could be seen stretching from Missouri into southwestwen Iowa on a MODIS 0.65 µm visible channel image (below).

MODIS 6.5 µm visible channel image

MODIS 6.5 µm visible channel image

====================================

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

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

GOES-13 0.63 µm visible images (above; click image to play animation) showed that the dense smoke feature moved very little during the day. An overlay of NAM12 850 mb winds (below) indicated that light southwesterly winds in the morning transitioned to a more organized southeasterly flow as a low-level cyclonic circulation moved southward across Nebraska into Kansas.

GOES-13 visible images + NAM12 850 mb winds

GOES-13 visible images + NAM12 850 mb winds

A MODIS true color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below; displayed using Google Earth) provided a better view of the smoke pall aloft as the northern end wrapped around the low-level cyclonic circulation.

MODIS true color RGB image (displayed using Google Earth)

MODIS true color RGB image (displayed using Google Earth)

MODIS Aerosol Optical Depth (AOD) products from the IDEA site (below) showed very high ADO values  (orange to red color enhancement) associated with this smoke feature.

MODIS Aerosol Optical Depth (AOD) products

MODIS Aerosol Optical Depth (AOD) products

Record April tornado outbreak in Wisconsin

April 10th, 2011 |

Supercell thunderstorms developed along and ahead of an advancing cold frontal boundary and moved rapidly eastward across parts of northern and central Wisconsin on 10 April 2011. These severe storms produced  widespread damaging winds, large hail (up to 3.0 inches in diameter), and a significant number tornadoes (see: NWS La Crosse | NWS Green Bay | NWS Milwaukee | SPC Storm Reports). With 11 tornadoes confirmed so far, this was the largest single-day April tornado outbreak on record in Wisconsin.

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

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

McIDAS images of GOES-13 0.65 µm visible channel data (above; click image to play animation; also available as a QuickTime movie) showed a number of overshooting tops associated with these severe thunderstorms. The corresponding GOES-13 10.7 µm IR images (below; click image to play animation; also available as a QuickTime movie) showed the cold cloud top IR brightness temperatures (as cold as -67º C at 01:33 UTC), as well as a few enhanced-v and cold/warm couplet signatures.

GOES-13 10.7 µm IR images (click image to play animation)

GOES-13 10.7 µm IR images (click image to play animation)

A comparison of a 1-km resolution NOAA-15 AVHRR 10.8 µm IR image with the corresponding 4-km resolution GOES-13 10.7 µm IR image at 21:33 UTC (below) demonstrates the advantage of higher spatial resolution to aid in the detection of enhanced-v and cold/warm thermal couplet storm top signatures, as well as a more accurate depiction of the coldest cloud top IR brightness temperatures associated with the more vigorous overshooting tops (-71º C on the NOAA-15 AVHRR IR image, compared to -58º C on the GOES-13 IR image).

NOAA-15 AVHRR 10.8 µm IR and GOES-13 10.7 µm IR images at 21:33 UTC

NOAA-15 AVHRR 10.8 µm IR and GOES-13 10.7 µm IR images at 21:33 UTC

An AWIPS GOES-13 0.65 µm visible image at 23:45 UTC (below) was particularly interesting — a few overshooting tops could be seen over central Wisconsin, as well as long shadows being cast upon the hazy boundary layer by a narrow line of developing convection to the southwest. Cloud-to-ground lightning strikes and storm reports (damaging winds, large hail, and tornadoes) are also overlaid on the visible image.

GOES-13 0.63 µm visible image + cloud-to-ground lightning strikes + storm reports

GOES-13 0.63 µm visible image + cloud-to-ground lightning strikes + storm reports

In an effort to try and locate a satellite signature of the damage path of the EF3-rated tornado that moved from Hamburg to Merrill to Gleason in north-central Wisconsin, a comparison of 250-meter resolution MODIS true color images from 10 April (a few hours before the tornado) and 12 April (2 days after the tornado) were used (below). However, the lack of a deep snow cover or dense vegetation in this area made it very difficult to identify the tornado damage path. Note that on 10 April — the day of the tornado outbreak — there still was some light snow cover just to the northwest of the tornado track, with some sites reporting 2-3 inches of snow remaining on the ground that morning.

MODIS true color images on 10 April and 12 April (displayed using Google Earth)

MODIS true color images on 10 April and 12 April (displayed using Google Earth)