As we are in full preparation mode in the DC/Baltimore area, I thought I would share a couple very interesting VIIRS images with you, courtesy of CIMSS at the University of Wisconsin-Madison and NASA SPoRT, through a joint project with JPSS. Sandy’s track forecast hasn’t changed much and I think I’ve covered the threats in the last few posts. Now let’s focus on where we are as of the last 24 hours.
The VIIRS RGB Air Mass image above from yesterday shows the very high resolution of the VIIRS instrument when analyzing a complex storm such as Sandy. Everything to the right of the red line is very dry air at high altitude that is cutting into Sandy’s tropical environment. What is the source region for this dry air? Believe it or not, it is most likely due to stratospheric dry air from an old upper low in the Western Caribbean that got tangled up with Sandy. The dry air is introduced through something called a tropopause fold. All this means is that this feature introduces a non-tropical air mass into a tropical air mass, hence the hybrid, half-storm look on satellite.
Much like yesterday morning, the image above is the day-night band on the Suomi NPP VIIRS instrument. Again, this is the middle of the night and the “day-time like” image is courtesy of our full moon. See the city lights along the East Coast? Absolutely amazing what this satellite can provide to forecasters! A special thank you again to Liam Gumley of CIMSS/SSEC/University of Wisconsin-Madison for working on this in early morning hours this morning!
The final image today shows a close-up view of the day-night band and infrared image (click on image for short animation) with surface pressures and buoy observations overlaid. The details provided by these two bands will be able to assist forecasters in detecting minute storm-structure and environmental changes, even though it comes from a polar orbiting satellite. We don’t get many passes over the U.S. by this satellite per day, but an image like this could be critical in helping the forecaster detect these changes.
I will try to post again later today with a more detailed breakdown of the large scale environment affecting Sandy. Thanks for reading!