Smoke from fires in Quebec, Canada

May 31st, 2010

POES AVHRR visible + showrtwave IR images

POES AVHRR 0.63 µm visible + 3.7 µm shortwave IR images

Large wildfires began to burn in parts of Quebec, Canada during the last few days of May 2010. AWIPS images of  1-km resolution POES AVHRR 0.63 µm visible channel and  3.7 µm shortwave IR channel data (above) revealed several clusters of hot pixels (yellow to red pixels) associated with active fires on 29 May 2010, with large smoke plumes drifting southeastward.

On the following day (30 May), a 1-km resolution MODIS 0.65 µm visible image (below) showed the large smoke plumes that continued to drift to the southeast.

MODIS 0.65 µm visible image

MODIS 0.65 µm visible image

An animation of 4-km resolution GOES-13 3.7 µm shotwave IR images (below) showed the flare-up of active fire hot spots (yellow to red color enhancement) during the daytime hours on 30 May.

GOES-13 3.9 µm shortwave IR images

GOES-13 3.9 µm shortwave IR images

GOES-13 0.63 µm visible channel images (below) depicted the very long smoke plume that had drifted across the northeastern US and out across the adjacent waters of the Atlantic Ocean on 31 May. This thick smoke was reducing visibility and causing air quality problems across parts of New England on that day.

GOES-13 0.63 µm visible images

GOES-13 0.63 µm visible images

This smoke plume was also very apparent on a MODIS Red/Green/Blue (RGB) image, created  using bands 1/4/3 (below).

MODIS true color RGB image (using bands 1/4/3)

MODIS true color RGB image (using bands 1/4/3)

Undular bore feature off the coast of Maine

May 26th, 2010

GOES-13 0.63 µm visible images (color enhanced)

GOES-13 0.63 µm visible images (color enhanced)

We received the following in an email from Dan St. Jean at the NWS forecast office in Gray/Portland Maine, who also supplied us with an animation of color-enhanced GOES-13 0.63 µm visible images (above) from 26 May 2010:

A backdoor cold front was moving southwestward down the Maine coast, while some significant convection (at the start of the loop) was moving southward along the extreme eastern coast of Maine. It's hard to say why and exactly where, but the activity appeared to throw a gravity wave ahead of it moving just ahead of the cold front. Anyway I thought you might find this worth a closer look as we rarely see these crisp wave features up here.

The visible images reveal the closely-spaced packet of wave clouds that marked the southwestward propagation of the gravity wave or “undular bore” — thanks for the heads-up on this interesting feature Dan!

Another view of the wave clouds can be seen on a Red/Green/Blue (RGB) false color image using NOAA-15 AVHRR channels 01/02/04 (below). In this particular RGB image combination, low clouds have more of a yellow tint, while colder, higher-topped clouds appear brighter white.

NOAA-15 AVHRR false color RGB image (using channels 01/02/04)

NOAA-15 AVHRR false color RGB image (using channels 01/02/04)

An AWIPS image of the MODIS Sea Surface Temperature (SST) product (below) showed that the initial convective outflow boundary likely moved over an area of cooler offshore waters (SST values generally in the middle 40s to lower 50s F, blue to cyan colors) — with a stronger marine boundary layer inversion over the colder waters, the gravity wave / undular bore feature might have been able to become more well-defined as it was ducted toward the southwest.

MODIS Sea Surface Temperature (SST) product

MODIS Sea Surface Temperature (SST) product

Great Lakes advection fog features

May 25th, 2010
POES AVHRR Sea Surface Temperatre (SST) product

POES AVHRR Sea Surface Temperatre (SST) product

During 24 May25 May 2010, a northward flux of unseasonably warm (daily high temperatures in the 80s and 90s F) and humid (dew points in the middle 60s to low 70s F) air moved northward across the Great Lakes region. However, an AWIPS image of the POES AVHRR Sea Surface Temperature (SST) product (above) showed that SST values were still in the upper 30s to low 40s F over much of Lake Superior and the upper 40s to low 50s F over much of Lake Michigan.

The cold water temperatures caused the surface air to cool to saturation, with widespread advection fog developing over a great deal of Lake Superior and Lake Michigan. A 250-meter resolution MODIS Red/Green/Blue (RGB) image created using Bands 1/4/3 (below) revealed an interesting pattern of “shock waves” in the lake fog as the southeasterly flow was interacting with the coastline of parts of eastern Wisconsin.

MODIS true color RGB image (created using Bands 1/4/3)

MODIS true color RGB image (created using Bands 1/4/3)

During the subsequent overnight hours, a comparison of the 4-km resolution GOES-13 fog/stratus product with the corresponding 1-km resolution MODIS fog/stratus product (below) demonstrated how the improvement in spatial resolution was an aid to more accurately locating the exact boundaries of the fog over western Lake Superior and the inland areas in the vicinity of Duluth, Minnesota (station identifier KDLH).

4km resolution GOES-13 fog/stratus product + 1-km resolution MODIS fog/stratus product

4km resolution GOES-13 fog/stratus product + 1-km resolution MODIS fog/stratus product

With arrival of daylight on the morning of 25 May, an animation of GOES-13 0.63 µm visible channel images (below) showed how the lake fog features were affecting various inland portions of northeastern Minnesota at different times.

GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

Gulf of Mexico oil slick update

May 24th, 2010
MODIS true color (Bands 1/4/3) and false color (Bands 7/2/1) RGB images

MODIS true color (Bands 1/4/3) and false color (Bands 7/2/1) RGB images

A comparison of 250-meter resolution MODIS Red/Green/Blue (RGB) true color (using Bands 1/4/3) and false color (using Bands 7/2/1) images from the SSEC MODIS Today site (above) showed the main portion of the surface oil slick in the northern Gulf of Mexico on 24 May 2010. This was Day 34 following the deadly explosion on the offshore oil rig Deepwater Horizon, and the damaged underwater wellhead continued to discharge more than 5,000 barrels of oil per day.

A day later, MODIS true color and false color images from 25 May 2010 (below) continued to exhibit a distinct signature of the surface oil slick.

MODIS true color (using Bands 1/4/3) and false color (using bands 7/2/1) images

MODIS true color (using Bands 1/4/3) and false color (using bands 7/2/1) images