Leaning Toward Cool and Wet Still

As the last days of August and summer come to a close, long range forecasts out to 10days (even 14 days) are pointing toward a continuation of the cooler and wetter trends of late. This pattern has been with us, with few interruptions, since the beginning of July. It is the result of a flow at the jet stream level which has been out of the northwest allowing cool fronts to slip southward at regular intervals. By my count, we have had nearly twenty "FROPA"'s (FROntal PAssages) since June 1st. Would you like to try counting these? Go to: http://www.hpc.ncep.noaa.gov/dailywxmap/

A pattern like this could also be cool and dry but the timing between fronts and the exact trajectory of the jet is allowing moisture and instability to build ahead of these systems and hence showers and storms can more easily develop. A review of the storms and rain of August 19/20 can be found here. If this pattern were more "amplified" (more north to south), we would still get the cool (likely even cooler) but the fronts would probably pass through "dry".

Ted Keller
Senior Meteorologist
KOLR/KSFX-TV
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