From the ABC 7 Weather team

Archive for category Forecast Discussion March 2015

Thursday Snow: Impact, Timing, Totals, and Could it Change?

March 4, 2015 - 07:58 AM
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Here we go again. It seems every week in February and now into March we've had school closings, delays and disruptive snow or ice. A winter storm warning is now in effect for most of our area Thursday. 

Winter Storm Warning

Today is a dreary one with nothing but plain old rain. Temperatures will warm up and help melt our leftover snow. The changes will start overnight. Cold air will advance into the region and meet up with the stream of moisture that stretches all the way from the Northeast to Mexico! 

Water Vapor Satellite NOAA

Here is a timeline of the transition and when we expect snow across the region. It will start happening while you are sleeping. Areas north and west could wake up to a little snow on the ground, but don't be shocked if it's not accumulating yet until around sun up in the metro. Longer south of town.

Rain to Snow Timeline

The heaviest snow will be in the morning through midday. It tapers off late afternoon/early evening. Snowfall totals will range with the heaviest snow north of D.C. and lighter amounts to the south. Here is the latest Stormwatch7 forecast.  

Stormwatch7 Snow Forecast

COULD IT CHANGE? 

Yes. The key thing to watch is how quickly cold air rushes in tomorrow and how much moisture will still be in place when that happens. A prolonged period of sleet or wintry mix would require us to shave down the numbers.  At the same time, snow bands will likely set up somewhere across the region and could bring a slightly higher burst for bigger numbers. Our forecast reflects the most likely totals and why we always give you a range of numbers. If you are "shopping around" comparing forecasts, make sure you note that source. There are a lot of maps floating around on social media from people that do not have a meteorology background. No matter the numbers, the impact will be significant. School closings are likely. Government closing.. probably. You can check the latest on this link. Travel will be bad through much of the day Thursday with snow covered roads and poor visibility at times. Flights will get cancelled. The later in the day your flight, the more likely you will get out as snow should ease late day or early evening.  If you are winter weary, check out our 7day forecast!  A nice break over the weekend into next week.

 

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Another Round of Wintry Weather

March 2, 2015 - 10:27 AM
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Alright March – stop it. This is where we should begin to look forward to spring: days are getting longer, next Sunday Daylight Saving Time begins, it is actually the begin of meteorological spring, etc. However, you give us one day this week that will feel like spring-wedged between days that we have winter weather activity. C’mon March!

This week will be a roller coaster ride so get ready. The forecast is subject to change (as always) but I want to give you an outline of what to expect. The reason for the change is that there are a lot of timing issues that we will have to watch. For example – how much ice could we accumulate on Tuesday evening before warm air takes over? That is an example of just one of the questions we have this week but bear with me and just keep an eye on the forecast. Here is what you can expect in the very least.

After some decent melting through the day on Monday as temperatures climb through the 40s, we will once again have some icy spots tonight with overnight lows forecast to drop into the teens and 20s. We will start off on the mostly clear side tonight with high pressure slipping east from the Midwest. However, clouds will be on the increase towards daybreak Tuesday.

TUESDAY

A Winter Weather Advisory is in effect from Tuesday morning through the evening hours across the D.C. area. This is to cover the potential for light icing through the day. It may actually start as a brief period of snow and sleet before changing to freezing rain.

Winter Weather Advisory in effect for the entire D.C. area Tuesday


The first half of Tuesday looks fine (besides some morning icy spots). Temperatures will move into the mid-30s through the day ahead of our next system. A warm front will slide in from the south and west through Tuesday night as high pressure scoots off the Mid Atlantic coast.

NOAA

There will be plenty of clouds around and cold air in place at the surface. Precipitation will begin to fall from the southwest to the northeast after the lunch hour into the early afternoon. It looks to start off as maybe some snow but a quick transition to sleet and freezing rain.

Warm air will eventually filter in from the south and west but the question remains: when can that warm air win out at the surface? At that point, we will begin to see a transition to rain as temperatures actually go up Tuesday night into Wednesday. However, at this point, expect some icy accumulation for the evening commute on Tuesday.  

 

Probability of .01" or more of ice accumulation through 1a.m. Wednesday

WEDNESDAY

This is the most spring like day we will experience this week. Temperatures will shoot into the 50s as the D.C. region will be in the warm sector. However, there will be some scattered rain showers around throughout the day. There could be a decent amount of rain coming down in areas so we will have to watch for potential localized flooding throughout the region as the snow pack that is left begins to melt. I do not expect widespread flooding but at least the potential for again, some more localized flooding.

River Flood Outlook


WEDNESDAY NIGHT INTO THURSDAY

A strong cold front will then slowly move through the region and cold air will begin to move back in from the north and west. An area of low pressure will form and ride along the front after it sweeps through our region and sags to the south and east of the D.C. area. This will give us a chance of some wet snow Wednesday night into Thursday morning.

In fact, there could be some accumulating snow around by Thursday morning. Temperatures on Thursday will only rebound into the lower 30s, not far off from our overnight low on Wednesday night of around 30 degrees. Any snow will move out during the morning with arctic high pressure pushing in. Expect a breezy day on Thursday as winds pick up.

High pressure will stick around Friday and Saturday giving us sunshine and gradually warming temperatures. Plan ahead and keep it here for the latest forecast as we continue to tweak it! 

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