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Bipolar weather with sun today and rain Monday

Yesterday’s winds have calmed as a high pressure dome is now centered over the Mid-Atlantic states. The absence of wind, low dewpoints, and a clear sky overnight all combined to allow temperatures to plummet to 34 degrees at both Shannon Airport and the UMW weather station. With strong April sunshine this afternoon Fredericksburg will just make it to the 60 degree mark, a couple of degrees below average for this date. But with continued light winds it will likely feel warmer this afternoon than yesterday.

Tonight, however, the nice weather will deteriorate to the point where Monday will begin with rain by the breakfast hour…and LOTS of rain is expected all day. A low pressure center now located over Louisiana will move up the Ohio valley and drag plenty of moisture northward from the Gulf of Mexico source region. A weather parameter known as “Precipitable Water” (“PWATS” in weather geek speak) will rise to almost two inches which basically translates into heavy rain as shown in this Weather Prediction Center forecast graphic: qpf day2

The track of heavy rain west of the mountains represents the forecast path of the low pressure center. The track that crosses over the ‘Burg is the result of the Gulf moisture riding up and over cooler air at the surface, which tends to squeeze out atmospheric moisture very efficiently. The city and surrounding areas will see well over an inch of rain between Monday and Tuesday morning.

Part of the surface structure of the low pressure center includes a warm front that will push northward up the East Coast. Unfortunately for the ‘Burg that boundary will remain south of the city during the day Monday, allowing easterly winds to bring in cooler air off the Atlantic. The official NWS Sterling forecast high temperature for Fredericksburg is 55 degrees tomorrow but the thermometer may struggle to climb above the 50 degree point. This setup is another variant of the **%(%$$$** cold air damming wedge that continually messes up forecasts.

Enjoy today’s spring weather and sunshine, and then pull out the rain gear and jackets to start out the work week Monday!!

Permalink: http://news.fredericksburg.com/weather/2014/04/06/bipolar-weather-with-sun-today-and-rain-monday/

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