Wednesday, January 31, 2007
Wintry Mix Slowly Comes Into Focus
Minor Accumulations Possible, But Not a Sure Bet
Dan Stillman @ 1:05 PM
What we know for sure is that today will be sunny and cold, and tonight and early tomorrow will bring increasing clouds. Beyond that, questions abound with regard to a storm now beginning to develop in the Gulf of Mexico. Will the storm bring light snow by tomorrow afternoon? If so, will the snow mix with sleet, freezing rain or rain tomorrow night? Or will it stay too far south and east to give us much of anything? Our best guess follows, including a look at all the possible scenarios.
Sunny, cold. Breezy and cold early with morning temperatures starting out in the 20s and wind chills in the single digits and teens. Winds should diminish in the afternoon as highs reach the mid 30s. Tonight, increasing clouds and calm winds, lows in the low-to-mid 20s.
Light snow developing by midday? The early part of the day looks fine, with overcast skies and maybe some morning flurries. Temperatures should climb into the low-to-mid 30s by lunchtime.
Light snow could overspread the area from south to north in approximately the 11am-2pm time frame. South and east of town, precipitation intensity could be moderate at times during the afternoon and early evening, with sleet and rain mixing in. Accumulations through rush hour may be limited to an inch or less, but even that could be enough to cause problems on the roads, especially as temperatures drop to near 30 (upper 20s north and west) after dark. Overnight, a second batch of snow, sleet and freezing rain may fall mainly between midnight and 8 am, mixing with plain old rain south and east of town. However, it's not out of the question that this second batch could fizzle. Total accumulations of 1-2" are possible but not definite.
More details on this potential winter event can be found in the Snow Lover's Crystal Ball at the bottom of this post. If the forecast warrants, Josh will have an accumulation map, timeline, schoolcast and more in his post late tonight or early tomorrow.
Lingering flurries and snow showers, temps warming above freezing. After lingering morning clouds and flurries, expect a partly to mostly cloudy day with a chance of afternoon rain or snow showers. It looks like the cold air behind the storm will be delayed, allowing highs to top out in the upper 30s to low 40s. Overnight, breezy and cold with clearing skies and lows in the mid 20s.
Cold. Saturday is shaping up to be mostly sunny, windy and cold with highs in the mid-to-upper 30s. Partly cloudy, breezy and chilly on Saturday night with lows near 20 in town and dipping into the teens in the burbs. Then, breezy and very cold on Superbowl Sunday -- highs in the upper 20s to near 30.
Snow Lover's Crystal Ball 
Next Chance of Accumulating Snow:
Thursday PM-Friday AM
Probability: 50%
Potential Impact:
Commentary: The models, which initially wavered between an inland and coastal track for this storm, have begun to converge on more of a coastal track that would favor snow and ice rather than rain, but there is some question as to whether it might stay too far south and east to produce significant accumulations for the D.C. metro area. It also looks as if the storm may come in two waves. The first wave could produce minimal accumulation during the afternoon and early evening hours on Thursday (but maybe still enough to cause problems for the afternoon rush). The second wave makes a run at us late Thursday night with a mixture of snow, sleet and freezing rain, mixing with just rain south and east of town. But the latest model data indicates the heart of this second batch may skirt to the south and east.
Could the storm be a total bust? Yes, the current trend in the models is for a more southerly and off-the-coast track. If this trend were to continue, we could be left with nothing more than some flurries and a bit of light snow. I'd put the chances of no accumulation at 25%, but with the potential to increase. The most likely scenario is as described above in the forecast section of the post, with total accumulations in the 1-2" range. An inland storm with mostly rain looks to be the least likely scenario.
Today
Sunny, cold. Breezy and cold early with morning temperatures starting out in the 20s and wind chills in the single digits and teens. Winds should diminish in the afternoon as highs reach the mid 30s. Tonight, increasing clouds and calm winds, lows in the low-to-mid 20s.Tomorrow
Light snow developing by midday? The early part of the day looks fine, with overcast skies and maybe some morning flurries. Temperatures should climb into the low-to-mid 30s by lunchtime.Light snow could overspread the area from south to north in approximately the 11am-2pm time frame. South and east of town, precipitation intensity could be moderate at times during the afternoon and early evening, with sleet and rain mixing in. Accumulations through rush hour may be limited to an inch or less, but even that could be enough to cause problems on the roads, especially as temperatures drop to near 30 (upper 20s north and west) after dark. Overnight, a second batch of snow, sleet and freezing rain may fall mainly between midnight and 8 am, mixing with plain old rain south and east of town. However, it's not out of the question that this second batch could fizzle. Total accumulations of 1-2" are possible but not definite.
More details on this potential winter event can be found in the Snow Lover's Crystal Ball at the bottom of this post. If the forecast warrants, Josh will have an accumulation map, timeline, schoolcast and more in his post late tonight or early tomorrow.
Lingering flurries and snow showers, temps warming above freezing. After lingering morning clouds and flurries, expect a partly to mostly cloudy day with a chance of afternoon rain or snow showers. It looks like the cold air behind the storm will be delayed, allowing highs to top out in the upper 30s to low 40s. Overnight, breezy and cold with clearing skies and lows in the mid 20s.The Weekend
Cold. Saturday is shaping up to be mostly sunny, windy and cold with highs in the mid-to-upper 30s. Partly cloudy, breezy and chilly on Saturday night with lows near 20 in town and dipping into the teens in the burbs. Then, breezy and very cold on Superbowl Sunday -- highs in the upper 20s to near 30.Next Chance of Accumulating Snow:
Thursday PM-Friday AM
Probability: 50%
Potential Impact:
Commentary: The models, which initially wavered between an inland and coastal track for this storm, have begun to converge on more of a coastal track that would favor snow and ice rather than rain, but there is some question as to whether it might stay too far south and east to produce significant accumulations for the D.C. metro area. It also looks as if the storm may come in two waves. The first wave could produce minimal accumulation during the afternoon and early evening hours on Thursday (but maybe still enough to cause problems for the afternoon rush). The second wave makes a run at us late Thursday night with a mixture of snow, sleet and freezing rain, mixing with just rain south and east of town. But the latest model data indicates the heart of this second batch may skirt to the south and east.
Could the storm be a total bust? Yes, the current trend in the models is for a more southerly and off-the-coast track. If this trend were to continue, we could be left with nothing more than some flurries and a bit of light snow. I'd put the chances of no accumulation at 25%, but with the potential to increase. The most likely scenario is as described above in the forecast section of the post, with total accumulations in the 1-2" range. An inland storm with mostly rain looks to be the least likely scenario.
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