Subtropical storm Melissa

By Sheldon Kusselson and Dan Bikos

Subtropical storm Melissa exists off the Eastern coastline of the U.S. on 10-11 October 2019, as GOES-16 visible imagery on 11 October shows:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/11Oct19/vis&loop_speed_ms=60

note the lack of deep convection over the center of the circulation, however convection does exist north and northeast of the center at this time.

Another perspective on this storm can be seen on the Advected Layer Precipitable Water (ALPW) product:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/11Oct19/ALPW&loop_speed_ms=200

The ALPW product depicts precipitable water in 4 layers.

Upper left (Surface to 850 mb), Upper right (850 to 700 mb), Lower left (700 to 500 mb), Lower right (500 to 300 mb).

Note the advection of subtropical moisture from two distinct areas in the Atlantic at the two lowest layers and at least one of the two highest layers. Dry areas are probably the blocks to the low off the East Coast.

The storm has brought rainfall from coastal New Jersey to Massachusetts, the moisture associated with this rainfall can also be viewed in a Total Precipitable Water (TPW) product. Here we show the experimental merged TPW product which makes use of observations from both microwave instruments on multiple polar orbiting satellites and the GOES-16 ABI:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/11Oct19/merged_TPW&loop_speed_ms=200