I’ve been working the midnight shift at the office for the last few nights and have found the MODIS and VIIRS RGB imagery particularly useful. I have viewed the imagery each night and even referenced it specifically in my Area Forecast Discussion early on the morning of the 16th.
A swath of dry air wrapping around the base of the closed low could be seen moving into the region, from Louisiana into Mississippi early on the morning of May 16th. While this was apparent in standard 4 km GOES water vapor imagery, the MODIS Airmass RGB certainly showed more detail. This type of imagery also has the ability to delineate airmass of differing characteristics. Notice the warm, moist airmass across much of the Southeast, ahead of and along the cloud shield. The Nighttime Microphysics RGB image valid at the same time below provided more detail of low level clouds upstream and in the local area, which was important for the forecast.
Since it was apparent that some clearing was indeed possible, if not likely for parts of the area during the morning and into the afternoon, I decided to increase my forecast temperatures. With this type of imagery, it is far easier to delineate between cloud types, and makes the forecast process more efficient. I also noticed that much of the cloud cover at the time to our west, particularly over the Arklamiss area, was mostly cirrus clouds.
This morning, the aviation forecaster and I used the imagery to distinguish between cloud types once again.
While an area of deep convection can be seen in northern Alabama (red colors in north central AL), at the time we were actually more concerned about the low clouds and fog impacting our TAF sites. The image above showed that the low stratus were present across much of northern Alabama and prevalent enough to keep IFR conditions in for the MSL TAF. Additionally, a narrow line of clouds stretching from NE Oklahoma to north central Mississippi could be seen in the imagery. This turned out to be a weak, albeit developing baroclinic boundary upon which deep convection resulted in Mississippi. The RGB imagery above essentially make the forecast process much more efficient and were utilized in several aspects of forecasting this morning. We are eager to get this type of imagery in AWIPS II at some point in the near future.