Winter Storm Nor'easter

This weekend a strong Winter Storm will affect millions of people in a system known to many as a nor’easter. This storm is called such because of its northeasterly track and a strong low-pressure system that forms off of the Atlantic Coast and feeds moisture and cold air in. This storm seems like it will mostly affect the Northeast and Northern Mid-Atlantic areas along with regions farther west and north of the DC metro area. This does not mean that impacts will not be present, as this storm could bring a variety of precipitation types: rain, freezing rain, sleet and snow.

Most models are presenting a warmer outlook to the storm than initially forecasted which will favor more rain closer to the DC and along the I-95 corridor with a chance of freezing rain and sleet and more snow to the west especially along the I-81 corridor. 

I will be providing a timeline for this storm as it approaches and begins to form this evening into tonight and eventually moving out of the region by mid-morning tomorrow. Also, I will try to give an accurate forecast for snowfall/sleet/ice totals, though this could remain a challenge due to the fact that road conditions, surface temperature and precipitation type could play a major factor in the true impact of this storm

Friday Afternoon: The storm will arrive a little after 4pm and will begin as rain. Temperatures will be steady in the high 30s, but dropping quickly as sundown approaches. Winds out of the south at 5-10mph. Do not be surprised if you see flakes even in the early evening due to dew points being below freezing

Friday Evening: By the evening, the surface temperature will have dropped enough for sleet and mixed precipitation to start. Do not be surprised if snow begins at this time, but it looks more and more likely due to an inversion in the upper atmosphere that snow accumulation at this time will be minimal at best. Temperatures will be slightly above freezing at this point, with winds shifting to out of the SE.

Friday Night (10pm-1am)-This is the trickiest point of the storm with the most uncertainty with it; mostly due to the fact that the temperature around the region is supposed to be 32, or freezing. This means that a variety of precipitation forms could be present at different areas throughout the DC metro. This is also the time where freezing rain will begin to be a factor. Freezing rain is when rain falls from the sky and freezes on contact to the surface. This produces the highest impact for travel and surfaces. This is also going to be the heaviest of precipitation for the storm.

Saturday early (1am-5am)-At this point of the storm, precipitation could shift back to rain, freezing rain will continue or there could be a shift towards some flakes. All of this has to do with what is going on just above the surface. It is looking more and more that warm air will cause a cold rain rather than snowfall and that amounts of accumulation will be minimal at best. Temperatures around this point will remain steady at 32 or even rise just above before sunrise.  

Saturday morning (5am-9am)-By this point, as a few stray snow showers may linger, but no additional accumulation will be likely. Temperatures will be rising quickly after sunrise, which means the chance of mixed precipitation drops significantly after 7am. Winds will pick up out of the Northwest gusting 15-20mph. The storm may linger until mid-morning, though the majority of the precipitation will have moved to the north and east.

Saturday mid-day-Cloudy skies, cold and raw outside with gusty winds, though it should clear by mid to late afternoon. Highs near 40. Winds gusting 20-25mph out of the Northwest.

Total accumulation for the DC Metro area: Coating to a half inch of mixed precipitation with a chance of >.05 inches of freezing rain.

Source: Capital Weather Gang @captialweather

Impact: Low (though may be higher), if the roads are well treated this storm should be no problem. Though I would not suggest being out around the time where the heaviest of precipitation will be passing 10-1am.

Stay safe out there GMU!!

-James Luehrs

Winter Storm Surprises the DMV - January 6, 2015

The D.C. Metropolitan area experienced it’s first glimpse of winter this morning as snow blanketed the region. This clipper was predicted to produce snow totals around 1-2 inches with more snow in the northern and western suburbs, but this clipper over performed and brought with it up to 5 inches in some areas. The storm began around 5 A.M. this morning. The snow continued to fall until about noon before it began to taper off. The official snowfall total at Reagan National Airport was 2.4 inches.

This storm was caused by a weak area of low pressure called an Alberta clipper.  “Alberta clippers” are storms that have a tendency to dive south from central Canada and then cross southeast through the northern Plains. The clipper then travels through the Ohio Valley and into the Atlantic Ocean.  Clippers differ from coastal lows (nor’ easters) because they are relatively weak regions of low pressure. Since they are quick and lack oceanic moisture, they generally do not produce a lot of snow. Clippers usually produce only a dusting to an inch of snow.

With this storm brought a messy morning commute.  The Virginia Department of Transportation (VDOT) prepared with over 500 plows on the road. VDOT also began pretreating the roads last night. Although VDOT was prepared, many side streets were not plowed and were hard to navigate through this morning.

With only a couple inches in the forecast, many school systems decided to open on time today, most notably Fairfax County Public Schools (FCPS). Many people took to social media to express their frustration. At one point, “#closefcps” was trending worldwide. FCPS later released a statement apologizing for opening schools this morning.  The roads did begin to clear up the afternoon as temperatures rose slightly, making the afternoon commute a little less hectic.

For those who did get to stay home and enjoy the snow, it was quite a pretty scene outside. The storm produced a fluffy snow, which results from very cold associated air mass and low moisture content air. This type of snow is not the best for building snowmen and making snowballs, but it is easy to shovel.

The snow should stick around for a few days because temperatures are about to plummet. The high for Wednesday is around 28 degrees with wind chills in the single digits.  This cold pattern is going to continue for the rest of the week.  The good news (or bad news, depending on if you like snow) is that the rest of the week should remain sunny.  However, I advise everyone to remain cautious if you plan on heading out tonight or tomorrow morning, as many side roads have still not been treated. With temperatures dropping quickly, these roads will quickly become slick again.