Yellowstone Park 7-30-13

Some  meadow streams here are doing fairly well with respect to water flow. Fall River Basin streams and the Gibbon River are amongst these.  The Lamar River and other northeast corner streams are not so lucky with flows considerably below normal.  So fish early, fish late really applies there. For all these your best chances will be days with enough cumulus clouds to threaten thunder showers.  Cumulus clouds indicate  increased relative humidity, and this helps much in aquatic insect hatches.  Drier air of those bright days means these insects will dry out more quickly allowing shorter time to mate and lay eggs, so they have evolved to hatch in bigger numbers when relative humidity increases.  This coupled with good water flows (such as in Fall River Basin streams) hints at when and where to find best fishing success during these hot dry days.  All this really does not apply to terrestrial insects, but add the active aquatic insects (speckled duns are in case in the waters given above) and you have a better chance at good fishing!