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

During the pre-dawn hours of 30 August 2010, AWIPS images of the 1-km resolution MODIS and the 4-km resolution GOES-13 fog/stratus product at around 07 UTC  (above) demonstrated the importance of spatial resolution in displaying the location of narrow fingers of river valley fog features across parts of the northeastern US.

About 2.5 hours later, a similar comparison between the 1-km resolution AVHRR and the 4-km resolution GOES-13 fog/stratus products (below) showed that the GOES-13 image was overwhelmed with a widespread “false fog/stratus signal” problem, which made the AVHRR image all the more valuable at that particular time.

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

View only this post Read Less

GOES-13 10.7 µm IR images

GOES-13 10.7 µm IR images (above) and 0.63 µm visible images (below) from the CIMSS Tropical Cyclones site showed Hurricane Earl after the storm reached Category 1 intensity on 29 August 2010. A Central Dense Overcast (CDO) could be seen developing in the images as Earl approached the Leeward Islands.

GOES-13 0.63 µm visible images + surface reports

A comparison of 85 GHz microwave images at 11:02 UTC and 17:23 UTC (below) revealed the increasing organization of banded convective elements around the center of the hurricane.

SSMI/S-16 and AMSR-E 85 GHz microwave images

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

GOES-15 0.63 µm visible images

As a part of the GOES-15 Post Launch Science Test, the satellite was placed into Rapid Scan Operations (RSO) mode, providing images periodically at 5-minute intervals. GOES-15 0.63 µm visible images (above; also available as a QuickTime movie) and 10.7 µm IR images (below; also available as a QuickTime movie) showed two distinct convective bursts that were developing within the CDO region (the 15 UTC and 18 UTC positions of the center of Earl are marked on the images). The coldest cloud top IR brightness temperatures were -86º C (darker violet color enhancement) at 16:15 UTC and again at 19:25 UTC.

The far eastern portion of the island of Guadeloupe can be seen mapped in dark blue along the lower left edge of the GOES-15 images.

GOES-15 10.7 µm IR images

Be sure to check out the PREDICT Field Experiment Blog for additional insights on other tropical cyclone activity in the Atlantic basin.

View only this post Read Less

Morphed Integrated Microwave Imagery at CIMSS (MIMIC) product

An animation of the Morphed Integrated Microwave Imagery at CIMSS (MIMIC) product (above) revealed that Hurricane Danielle (which had intensified into a Category 4 storm) was undergoing an Eyewall Replacement Cycle (ERC) during the 27 August – 28 August 2010 period. Note how the smaller inner eyewall deteriorated and became replaced by a much larger outer eyewall during the ERC process.

Following the ERC, GOES-13 10.7 µm IR images from the CIMSS Tropical Cyclones site (below) showed Danielle beginning the recurvature process after weakening to a Category 2 storm.

GOES-13 10.7 µm IR images

Even though Hurricane Danielle was quite far from the US East Coast (below), long period ocean swells and increasing onshore winds were creating dangerous rip currents along much of the nearshore waters and beaches from Florida to the Mid-Atlantic states.

GOES-13 10.7 µm IR image

Be sure to check out the PREDICT Field Experiment Blog for additional insights on other tropical cyclone activity in the Atlantic basin.

View only this post Read Less

The infrared imagery from Friday morning, 27 August, shows three separate tropical systems — in various stages of development — over the Atlantic Ocean, with a fourth system poised to move out into the tropical Atlantic from Africa. Meteosat imagery shows a fifth system moving westward over central Africa (These images are available at the University of Wisconsin SSEC‘s Geostationary Image Browser).

Hurricane Danielle, above, as seen by GOES-15 (Click here for a longer loop from GOES-13) is a mature Category IV storm over the central Atlantic, with well developed outflow in an environment characterized by warm sea-surface temperatures and small vertical wind shear. The cold cloud tops surrounding the mostly cloud-free eye have brightness temperatures in the 195-200 K range. GOES-15 IR Imagery shows similar temperatures.

Tropical Storm Earl, above, is in an environment not as conducive to development as Danielle. Analyses from the CIMSS Tropical Weather Web Page show a storm track that has recently passed over cooler ocean water. More importantly, Earl is surrounded by dry Saharan Air and that dry air is suppressing some of the convective activity needed to fuel system development. Analyses for Total Precipitable Water (taken from this site) also show Earl entraining dry air. However, the projected path of Earl is towards a warmer sea surface in a more moisture-rich environment, so intensification is forecast.

In contrast the Earl, the disturbance off the coast of Africa, above, as viewed from GOES-12, is over a region of warm water, and is south of dry air with origins over the Sahara. Shear values over the storm are low, so intensification should occur.

The next names in the list for the Atlantic are Fiona, Gaston and Hermine. For the latest on these storms, visit the National Hurricane Center website.

(Added: Dan Lindsey at CIRA notes the similarity to 1995. Here is an image from 2345 UTC on 29 August 1995 showing a similar line-up of storms across the tropical Atlantic).

View only this post Read Less