Tuesday, February 3, 2009


MON FEB 3 - 9:45 AM. The next set of 850 mb shortwaves are easy to identify on the map below published by NOAA a little after 8 AM and 8 PM each day I've posted this for those teachers who are conducting a storm followup discussion. Based on wind barb indicators (calculating the flow direction, speed of the shortwave and distance to a location) you can peg the arrival of precipitation down to the hour. The map displays upside down, so you'll have to cut/paste.

As an example, my estimated arrival time for another round of snow showers in the Carolinas would be by noon today, lasting perhaps 4 hours, then tapering off. For the Mid-Atlantic, it looks like a very small embedded shortwave as of 8AM was located in western PA. As of 10:30 AM, it is represented on the surface map as a weak trough, the trailing edge of which should exit central Maryland by noon. If you see your snow intensity increase, then decrease between 10AM and Noon, that's the reason. (Teachers and students: Don't get excited, it's just light snow touched off by the shortwave.) In addition to a weak upper level and surface low in southern Ohio, there was another strong shortwave over central Albany, NY that will take longer to rotate around the 850 mb low. That second wave should arrive over central Maryland by dusk, about the same time as the surface low. These two will touch off another round of light snow during the evening commute, but ending by 7PM. This timing suggests that afternoon or evening activities should be able to go forward as planned.. but ultimately that decision is up to you!

REGARDING AVAILABILITY OF "COMMENTS" AT SCHOOL: Although our evening scientific discussions have been engaging, please do not to pester your friendly neighborhood school Internet security department with requests to unblock the comments. (No, I wasn't contacted by them or are otherwise "in trouble.") They have perfectly valid reasons for leaving things just where they are, and I wholeheartedly support their decision.

Let's just be eternally grateful that educational systems permit this weather news source to be viewed in the first place! You all would agree, having the comments available in school would be a terrible distraction or worse. For true weather enthusiasts, it gives you something to look forward to when you get home: reading the day's comments! If something cataclysmic develops, that information will be posted on the main page. Thank you everyone for your support and understanding!

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