Wednesday, December 19, 2007
Quiet and Cool to Close Out the Week
Could cold front cause rainy Sunday?
Dan Stillman @ 9:40 AM
When the week began, it looked like a storm system developing to the southwest could bring an active pattern for Thursday and Friday. Instead, confidence is on the rise that the weather will remain rather quiet until a strong cold front impacts the region on Sunday. In the meantime, temperatures will be cool but right around where you'd expect them to be this time of year -- highs in the 40s -- with varying amounts of cloudiness.
Partly to mostly cloudy, mid 40s. We find ourselves in the midst of southerly flow ahead of an approaching cold front. The front and associated flow are rather weak, but will be enough to boost temperatures a bit higher than yesterday, even with partly to mostly cloudy skies. Highs should max out in the mid 40s, with light winds from the south or southwest at 5-10 mph. And a midday sprinkle/flurry or brief rain/snow shower is not out of the question. The front passes through this evening, giving way to mostly clear skies and overnight lows in the low 30s downtown, upper 20s in the burbs.
Partly sunny, mid 40s. There was some concern that an area of low pressure and associated precipitation could approach from the southwest. But it now seems likely that high pressure will fend off any inclement weather. The result should be a partly sunny day with highs in the mid 40s. Overnight, partly cloudy with lows near 30 in town, mid 20s in the burbs.
Pictured: A squall line as seen Sunday afternoon from Oakton, Va. By CapitalWeather.com photographer Kevin Ambrose.
Partly sunny, mid 40s. Earlier in the week, it was thought that the storm to the southwest might skirt us to the south and then redevelop off the coast and threaten the area with precipitation. However, the storm and any redevelopment is now expected to stay south. In its place, high pressure should remain in control, giving us a partly sunny day with highs in the mid 40s. Overnight, it'll be partly cloudy with lows in the upper 20s to mid 30s (suburbs-city), as winter officially begins Saturday at 1:08 a.m.
How close was the DC metro area to experiencing a major ice storm Saturday night? It depends on your perspective. In the grand scheme of things I guess you could say it was a pretty close call, at least for the northern and western suburbs. One thing is for sure -- we were a lot closer to a major ice storm than a blockbuster snowstorm. To get big-time snow accumulations you need cold air at all levels of the atmosphere. In this case, while cold air held strong at the surface north and west of town, temperatures during the heart of the storm were well above freezing in the upper atmosphere. This is the ideal scenario for freezing rain, which occurs when precipitation falls through an above-freezing atmosphere and remains in liquid form until hitting a below-freezing surface, where it freezes on contact.
It's not often that the DC area sees upper-level temperatures as warm as they were Saturday night while the surface is near or below freezing. What prevented the northern and western suburbs from a serious bout with freezing rain was that the cold air at the surface wasn't quite cold enough. Dulles only made it as low as 33 degrees during the storm. Various neighborhood stations in Montgomery County reported temperatures at or slightly below 32, but this wasn't enough to freeze the rain, especially since the ground was still warm from Friday's highs in the low 50s. For the District and points south and east, icing was never really a significant concern, as temperatures for the most part never dropped lower than about 35.
Today
Partly to mostly cloudy, mid 40s. We find ourselves in the midst of southerly flow ahead of an approaching cold front. The front and associated flow are rather weak, but will be enough to boost temperatures a bit higher than yesterday, even with partly to mostly cloudy skies. Highs should max out in the mid 40s, with light winds from the south or southwest at 5-10 mph. And a midday sprinkle/flurry or brief rain/snow shower is not out of the question. The front passes through this evening, giving way to mostly clear skies and overnight lows in the low 30s downtown, upper 20s in the burbs.Thursday
Partly sunny, mid 40s. There was some concern that an area of low pressure and associated precipitation could approach from the southwest. But it now seems likely that high pressure will fend off any inclement weather. The result should be a partly sunny day with highs in the mid 40s. Overnight, partly cloudy with lows near 30 in town, mid 20s in the burbs.Pictured: A squall line as seen Sunday afternoon from Oakton, Va. By CapitalWeather.com photographer Kevin Ambrose.
Partly sunny, mid 40s. Earlier in the week, it was thought that the storm to the southwest might skirt us to the south and then redevelop off the coast and threaten the area with precipitation. However, the storm and any redevelopment is now expected to stay south. In its place, high pressure should remain in control, giving us a partly sunny day with highs in the mid 40s. Overnight, it'll be partly cloudy with lows in the upper 20s to mid 30s (suburbs-city), as winter officially begins Saturday at 1:08 a.m.A Look Ahead
- Saturday is shaping up to be the better day of the weekend, with some clouds (not sure how many right now), maybe a sprinkle or shower, and highs in the mid to upper 40s.
- On Sunday, a sprawling cold front -- stretching up and down the East Coast -- could bring moderate to possibly heavy rains.
Dodged a Bullet?
How close was the DC metro area to experiencing a major ice storm Saturday night? It depends on your perspective. In the grand scheme of things I guess you could say it was a pretty close call, at least for the northern and western suburbs. One thing is for sure -- we were a lot closer to a major ice storm than a blockbuster snowstorm. To get big-time snow accumulations you need cold air at all levels of the atmosphere. In this case, while cold air held strong at the surface north and west of town, temperatures during the heart of the storm were well above freezing in the upper atmosphere. This is the ideal scenario for freezing rain, which occurs when precipitation falls through an above-freezing atmosphere and remains in liquid form until hitting a below-freezing surface, where it freezes on contact.
It's not often that the DC area sees upper-level temperatures as warm as they were Saturday night while the surface is near or below freezing. What prevented the northern and western suburbs from a serious bout with freezing rain was that the cold air at the surface wasn't quite cold enough. Dulles only made it as low as 33 degrees during the storm. Various neighborhood stations in Montgomery County reported temperatures at or slightly below 32, but this wasn't enough to freeze the rain, especially since the ground was still warm from Friday's highs in the low 50s. For the District and points south and east, icing was never really a significant concern, as temperatures for the most part never dropped lower than about 35.
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