3/12/12 Bring on the Warmth.. (Unless you like snow)

The winds that drive the weather patterns has decided to take a Spring Break vacation into Eastern Canada for the next 10 days. If you like mild spring like weather, then you are in luck. If you were looking for lots of snow, well, you may need to head out west.

Unlike this past winters jet stream which featured a zonal flow across the US. This jet is more pronounced and will usher in warmth from the south into much of the Eastern US.

A warm air bubble will form over the Eastern US for the next 10-12 days, allowing above normal temperatures for most areas. The only issue is that on the eastern end, the stream may fluctuate back and forth some. This means that the Northeast US may see more variation in the weather than areas directly under the bubble of High pressure.

 The warmest day of 2012 so far will happen today across most of New England, with many places reaching 70. A west wind will help bring temperatures up**.  Areas along the extreme Atlantic coast will see temperatures a few degrees cooler and the Cape and the Islands will be coolest as the wind blows over the 42 degree water temperature.

A wide variation is expected in temperatures across Southern New England today. A west wind will help bring temperatures into the 70s, but along the immediate coastline it will be 5-8 degrees cooler and out on the Cape and Islands temperatures will stay in the 50s.

A storm system over the upper mid west will push through on Tuesday with some clouds and a few showers, but it will weaken as it approaches New England.

Technical Meteorological Note: Adiabatic Lapse Rates!

The reason it will be warm in Boston today has to do with the Berkshire and Green Mountains in the west.  As a west wind rises over the mountains, it will cool somewhat.  However as that air flows down off of the mountains, it will compress and warm up (notice how when you put air in a tire, it gets warm) in a perfect atmosphere, the air will warm 5 1/2 degrees F for every 1000 feet lost in elevation when the air is dry.  Today the wind is set up perfectly from the west to come off of the higher elevations of these ancient mountain ranges to warm the air to the east.  (Typically a warm wind for Boston comes from the SW, and therefore there is little in the way of compression and the warming is primarily transported from the heating of the landmass from the south)  Note:  The 42 degree water ocean temperature will keep extreme coastal areas cooler today, as the wind is light today. If the wind were say above 10-15 mph, it would force itself and overtake the cold air.