Elliot Abrams

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Warmer Air Advances, But How Far?

May 05, 2014; 7:17 AM

Monday Morning

Cool air dominates the Northeast while a heat wave is unfolding in the Central Plains. As we go through the week, an upper air trough from just off the West Coast will move to the Rockies and then the Plains. A ridge now over the Upper Mississippi Valley will reach the East Coast Friday night. The position of the upper air ridge axis will be important later this week because it determines how far the very warm air will progress. In a true warm sector, where the air is uniformly warm, the flow at ground level is parallel to the flow aloft. That will be the case west of the ridge axis (or crest). Downstream from there the surface flow may be from the southwest but the flow aloft is from the northwest. When the wind changes in that way with elevation, it is called a veering wind. In such cases, it is becoming warmer, but may not yet be anywhere near as warm as in the warm sector I mentioned earlier. It is in the contested zone where we look for clouds, showers and thunderstorms. This video forecast extends through next weekend.

The sun must be low in the sky for rainbows to appear, when showers move east of your location and the sun comes out, a rainbow often appears. Here's a partial rainbow I saw Saturday evening.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

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About This Blog

Elliot Abrams
Elliot Abrams from AccuWeather.com offers this Northeast Weather Blog for the U.S. with regular updates on NE weather from a leading forecaster and meteorologist.