Sunday, January 25, 2009


REVISION: MON JAN 26 - 2:45 PM. Moistening atmosphere today will permit overnight arrival of light snow, forcing many Maryland school districts to close Tue. Continued mix of freezing rain and snow into Wednesday is a near guarantee that students in Baltimore County receive a 5 day weekend. Please post your observations of the evening news roundup and we will have a lively discussion later this evening as I am out until 7PM.

UPDATE: MON JAN 26 - 7:45 AM. A complex winter storm will affect the Mid-Atlantic region starting early Tuesday and continuing into Wednesday night. Watches were extended overnight to include most of Maryland, southern and southeastern PA. The present concerns for members of the school community in the Baltimore/Mid-Atlantic Metro region:

1. ARRIVAL TIME: Confusion abounds on exactly what is the time of onset Tuesday. NWS currently has the winter storm watch starting tomorrow night, but light snow could arrive Tuesday morning, creating tremendous logistical problems for school districts having to announce early dismissals. The excessive inconsistency between media outlets and weather agencies sending a mixed message to students, parents and teachers alike.

The current GFS projection for 7AM Tuesday shows moisture arriving across the area. The reality is, you'll see just flurries or less heading out to your car or bus Tuesday morning, as the steady moisture does not arrive until mid-morning or later. Educators know their districts will wait for "ground truth" to make a decision, and I highly doubt ANY districts will close outright on hope that the forecast verifies, they've been burned before on that. The critical factor will be evaporative cooling and how quickly the air saturates to allow the snow forming above 5000 feet to reach the ground. If the column saturates quickly enough, light snow should break out by 9AM and just keep on coming. Bottom line: For tomorrow, elementary schools especially should prepare for a repeat of the February 13, 2007..uh, what shall we call it...? um, the "incident."

2. PRECIPITATION: Will arrive in waves and vary with intensity, duration and type. As the low center shown on HPC maps approaches, snow will give way to sleet then freezing rain. Remember everyone, I have been saying ALL ALONG THIS WOULD NOT BE PRIMARILY SNOW for Maryland. That honor is reserved for our Pennsylvania readers. Introducing frozen precip reduces overall accumulations, so my early estimate is an average of 3 inches south of the PA-MD line, which includes snow and ice totals. North of the PA line, and from Carroll County west, greater than 3 inches is possible. Details on exact amounts/locations later.

3. SCHOOLS: Tuesday's problems are clear. As for Wednesday, remember precip will be cranking overnight, making it difficult for road crews to keep up. Even with only 2-3" on the ground, sleet/freezing rain mixing in the early morning, makes the case for most schools from Montgomery County north to close. Howard and Anne Arundel counties may be close to the rain/snow battleground, and their potential impacts will be refined as the event nears. Delays on Thursday are such a wild card at this point I am not going to speculate until the storm is underway.

CONCLUSION: This is already turning into "weather-whiplash" as you can plainly see totally conflicting forecasts from every media outlet available. This is due in part to some meteorologists/TV networks unwilling to make a bold call for fear of retribution, the available data is too much in flux, and there is often too much data to digest which leads to a less-refined forecast. My approach is to rely first on sound verifiable data and observations, then see if the computer models are projected along similar lines. Suffice to say, the next 72 hours will be replete with weather pandemonium among students, teachers, parents and the general public. For those hoping on a little mid-week break, climatology and upper level dynamics are on your side my friend, regardless of what the computers and their prognosticators may say. So my final word for today is: PREPARATION. The storm is on the way, and if you are hoping for wintry precipitation and a day off, I believe you'll be satisfied with the outcome.

Not again? Photo of an early dismissal in March 2005 at a midwestern school district.

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