WARM ADVECTION - Fancy Term, Obvious results

Warm Advection. It is a term I harp on over and over again, and you will probably be bored of it by the time we are through. However, it produces 90% of the precipitation here in New England. Directly related to "Isentropic Lift", it is simply the warming of the atmosphere (relative to the atmosphere above, not relative to the ground) producing uplifting currents of air, which in turn can produce rain or snow. When coupled with "positive vorticity advection", another fancy term, but a very real producer of precipitation (twisting in the atmosphere that is increasing) - the two team up to give us snow. Many meteorologists on TV especially in OTHER cities nowadays do not use these raw upper level elements to forecast precipitation but instead rely on how much precipitation is actually churned out by the computer models.

Saturday evenings weather event is tied to warm advection , with a little bit of the "PVA" thrown in for good measure. On the chart left, if you click on it, you will see what looks a bit like a surface weather map, but is actually a map from 5,000 ft. above. The area where the winds (following along the pressure, or "height" lines) are blowing across the temperature gradient (the colored lines) from warmer to colder is the warm advection area. . . I have circled it, and we are nearing the end of our event on Saturday evening. Now, we also usually get a last burst of precipitation right under the 850mb Low pressure system which is just about on top of us at that time. Many of the weaker systems that blew by earlier this week were MISSING this warm advection component. West of here, the mountains tend to do okay milking precipitation out of other situations, such as winds coming in from the west after the storm has moved by when upper air low pressure moves by, but the mountains rob us here along the coast of that precipitation, which is why warm advection is so key to MOST , not all, but MOST of our precipitation in Eastern New England.