Gap flow in the Strait of Juan de Fuca

The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing.  Users bear all responsibility for inspecting the data prior to use and for the manner in which the data are utilized.

On the morning of 18 July 2017, low-level clouds moved eastward through the Strait of Juan de Fuca.  This can be seen in the GOES-16 Nighttime Microphysics RGB product:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/18jul17/nmp&loop_speed_ms=60

Recall in this RGB product, low clouds are depicted in the aqua color (before sunrise), which is moving eastward.  After sunrise, there is a reflected component to the 3.9 micron band, therefore its recommended to only make use of this product at night.  After sunrise we may make use of the visible imagery:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/18jul17/vis&loop_speed_ms=60

Note the speed of the eastward moving low-level clouds appears to be faster than other low-level clouds in the region.  This is due to gap flow through the Strait of Juan de Fuca, a well known topic of research.

One method to make for a smooth transition in your loop between nighttime and daytime is to make use of the image combination in AWIPS and make use of visible imagery for the daylight hours.  Here is a different example of gap flow through the Strait of Juan de Fuca that makes use of the fog product at night:

http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=training/visit/loops/26jul17&loop_speed_ms=60

Like the nighttime microphysics product, this product also makes use of the 3.9 micron band.  Once sunlight is introduced with any product that involves the 3.9 micron band, it may change the interpretation of the product which is why it is recommended for nighttime use only.  In this loop, the visible imagery becomes clear after sunrise but we still see a bit of the fog product which you may adjust with the alpha setting in your color table editor on AWIPS.

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