The phrase "a cool snap" is correct and usable in written English.
It can be used to describe a sudden drop in temperature, often referring to a brief period of cooler weather.
Example: "After weeks of warm weather, we experienced a cool snap that brought a refreshing change to the summer heat."
Alternatives: "a chilly spell" or "a brief cold wave".
We look at everything though an Instagram filter, spend our nights trying to create a cool snap story and have learned to condense our most profound thoughts into 140 character tweets.
Photographs were taken with a Cool SNAP digital camera.
A Cool Snap FX cooled CCD camera (Roper Scientific) controlled by SimplePCI (Compix Inc).
Samples were observed with a DMR Leica microscope and images were captured with a Cool Snap HQ camera (Roper Scientific).
The results were examined using a DM400B Leica epifluorescence microscope connected to a Cool Snap camera (Roper).
Images were captured with a cool SNAP K4 CCD camera (Photometrics, Tucscon, AZ) and archived with home-made software.
The measurements were performed using a Photon Technology International (PTI) (Birmingham, NJ) photomultiplier based system mounted on an Olympus IX71 microscope, equipped with a DeltaRAM excitation light source, or with a Ratiomaster 5 Imaging System (PTI) equipped with a Cool-snap HQ2 (Roper) Camera.
Images were captured with a Cool-Snap digital camera (Roper Scientific Photometrics, Tucson AZ).
Cell images were performed by a microscope Nikon Eclipse TE-2000S (Nikon, Florence, Italy) equipped with a cool-snap camera (see Supplementary Information).
Stained sections were mounted in 80% glycerol and images captured on a Nikon Eclipse 6600 upright compound microscope using a Cool-Snap Pro true color camera.
Fluorescence micrographs were obtained with a Cool-Snap-Pro colour camera (Media Cybernetics, Finchampstead, Berkshire, UK) and image processing software (Image Pro Plus 4.5) linked to a Nikon Eclipse E800 microscope.
