The GOES-13 satellite was brought out of on-orbit storage on 27 January 2010 — and a comparison of the 19 channels of the sounder instrument on GOES-12 and GOES-13 (above) shows an improvement in the noise characteristics that were beginning to plague the GOES-12 sounder in late 2009.

The imager instruments on GOES-12 (above) and GOES-13 (below) share the same 5 channels (1 visible and 4 InfraRed). However, the GOES-13 satellite has improved Image Navigation and Registration (INR), which eliminates a great deal of the image-to-image wobble that is often seen with GOES-12. In addition, larger batteries aboard the spacecraft allow GOES-13 to continue to operate through the Spring and Fall season “eclipse periods” (when the satellite is in the Earth’s shadow and the solar panels cannot generate the power needed to operate the various instrument packages).

GOES-13 (launched in May 2006, with a Post Launch Test conducted in December 2006) will replace GOES-12 (launched in July 2001) as the operational GOES-East satellite on 14 April 2010. At that point, GOES-12 will then be moved to a new position at 60º West Longitude to support South American operations. More information on the transition of GOES-13 into operations is available from the NOAA/NESDIS Satellite Services Division.

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A series of powerful storms affected the southwestern US during the 18-23 January 2010 period, which resulted in record rainfall and snowfall in parts of northern Arizona. Flagstaff recorded 54.2 inches of snow, which was their 2nd largest storm total snowfall on record. A 250-meter resolution MODIS true color image from the SSEC MODIS Today site (above) showed the coverage of snow across the higher elevations of northern Arizona on 25 January 2010.

On the following day, a comparison of AWIPS images of the MODIS visible channel and a false-color Red/Green/Blue (RGB) image (below) shows that most of the bright features seen on the visible were snow cover (which shows up as darker pink features on the false color image).

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A cyclone off the mid-Atlantic coast was quickly transitioning to the occluded stage on the morning of 22 January 2010 (above). As the cyclone (in its mature stage) was just beginning to move out over the offshore waters of the Atlantic Ocean, winds gusted to 51 knots at buoy 41025 (Diamond Shoals NC) around 07 UTC and 37 knots at buoy 44014 (64 miles east of Virginia Beach VA) around 11 UTC.

The evolution of a classic “dry swirl” signature was seen on AWIPS images of the 4-km resolution GOES-12 6.5 µm water vapor channel (below) — this dry swirl water vapor signature is a tell-tale sign that a cyclone has reached occlusion (and is often seen with systems over the open oceans).

The appearance of an subtle elongated filament structure on the water vapor imagery (exiting the Georgia / South Carolina coast after about 10 UTC, to the southwest of the occluding cyclone) suggested the presence of a northeastward-propagating jet streak. A plot of 1-hourly MADIS satellite-derived water vapor atmospheric motion vectors (below) revealed one target with a velocity of 151 knots in the general vicinity of the thin filament signature — this wind speed was significantly higher than the 100-110 knots that was initialized by the GFS40 model over that particular area.

McIDAS images of the 1-km resolution GOES-12 visible channel data (below) showed finer details in the low-level cloud structure, as well as the formation of convective bursts near the circulation center toward the end of the animation.

A comparison of 1-km resolution NOAA-17 AVHRR visible channel and 10.8 µm IR channel images at 14:10 UTC (below) showed the cloud structures around the time that the dry swirl signature was becoming more well-defined on the GOES-12 water vapor imagery.

The AVHRR Cloud Top Temperature (CTT) product (below) indicated that CTT values were as cold as -70º C (black color enhancement) prior to the cyclone transitioning to the occluded stage.

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GOES-11 (GOES-West) visible channel images (above) displayed an unusually large area of open-cell cumulus clouds across the North Pacific Ocean on 20 January 2010. This type of open-cell mesoscale convective cloud pattern is a signature of strong instability (via boundary layer cold air advection over relatively warmer waters) in an environment of cyclonic flow. These cloud patterns tend to be fairly shallow, as indicated by their relatively warm appearance on IR imagery (below) — and the presence of open cell convection usually indicates that winds within the marine boundary layer are greater than about 25 knots.

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On the following day (21 January 2010), the cold front marking the leading edge of the cold air advection had moved south of 20º N latitude — and GOES-11 visible images (above) showed the formation of a large area of closed-cell stratocumulus clouds to the northeast of the Hawaiian Islands. This type of closed-cell convection often forms in regions of anticyclonic flow, as confirmed by the GFS360 surface wind field (below) — and stronger subsidence causes the cumulus cloud features to flatten out and form stratocumulus clouds beneath the subsidence inversion. Also note the “barrier effect” of the Hawaiian Islands on the marine boundary layer stratocumulus, as well as the formation of lee cloud lines downwind of the islands.

As a deep cyclone approached the California coast on 21 January, a number of all-time minimum pressure records were set across the state. A MODIS false color Red/Green/Blue (RGB) image (below) shows the extensive cloudiness associated with this storm; on this RBG image supercooled clouds appear as white features, while glaciated clouds take on more of a lighter pink color. Snow cover shows up as darker pink areas (such as those over northern Nevada and southern Oregon/Idaho).

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