Final Snow Call- Today, and 5:30 update..

This is the map I will use on the air at noon. This bump up in snow total is based on the following:

1. This looks like a repeat of Dec. 5th Storm. that track and strengthening phase while rounding the trough brought this same range.
2. Colder temps mean more fluff in the snow.
3. I see the potential for slightly higher amounts north and a burst near Rt. 50 from DC to AA County.

As of around 5pm, the radar looked very similar to my forecast split. It wasn't exact, but pretty darn close. That heavy band along Rt 50 from DC through the Eastern Shore was in line with my map an hour earlier. I know how a lot of you want to know how much 'at your house', that is why I tried to get more specific. I was impressed with this though, so I'll be tacky and quickly pat myself on the back... I did not account for warm roads and perhaps higher sun angle or thin cloud deck. That explains the wet roads until around 5pm.

Here is the 5:30 image from my place showing 2 inches. It's still coming down, and I feel pretty confident about my forecast verifying in most places.
I'd love to hear how much you got, and even see some pictures. If so, send them to berk@wmar.com, and I'll try to get some on the air in the morning.

More on this storm and Friday's in the post below...

Our Very Own Snow. For Real!

I am postponing the Snowfall Records until tomorrow so I can spend my limited weekend time on tonight's snow. My former radio partner Tony Pann tried convincing me on Friday- but I did not buy it. If you see the TV Graphics page, my outlook map for Sunday (from Friday) showed a chance of rain late... I thought there was a chance that this might even miss us to the south. The snow I had on the map, was back in the mountains. But things change.

Here is the proven NAM model showing the '540' line by this evening. There will be enough moisture as the freezing line catches up to drop some snow. Another shot appears to want to move in New Year's Day. That was my original forecast early last week, and I was talked out of it by Thursday. Well, it's back.
As of this morning, there did not seem to be much grid model support for local snow. This was due to temps being too warm, and the precip departing before was have a chance. However, I do believe we will get cloud temps to cool down enough, but with wet ground and marginal surface temps, here is what I expect locally. If you are local then I will be back on ABC2 Monday morning with the latest. It is a sign of the pattern turning more favorable for us in January. Although it make take until the 2nd week of the month for us to truly make to turn to colder weather for a longer duration.

Major Ice for Some, Others Get None

Fellow weather geeks that have followed the models have seen the trend. The poll at the right reflects the shift to a track farther west. Is all lost? The arctic air has not truly built in here, and the tropical feed into this system will have dramatic warming on the east side. Again, for simplicity, I have been comparing just one model - the GFS - all week to show how elements can change. This also proves my point from earlier this week with that ridiculous snowcast on Tuesday. There are so many models to look at and decipher, many layers of the atmosphere, and text extractions (that won't look pretty here). If I showed it all I would run out of room on this blog- and bore half of you out of here. So let's stick with the basics and continue with the GFS which in fact I think is doing the best job. If you want to discuss other models, you can shoot me an e-mail. I'll try to get back with all of you (but it is the weekend). Here you can see the primary Low still dominant Sunday morning, and slower development of the secondary low. That second low is too close to us, and not off of the coast- which allows the warm flow to dominate. Some areas will get hammered! North/Central PA through central New England will get a major ICE STORM. This may include parts of central MD- but warm air will scream in here Sunday morning. The 'vertical velocities' and tropical support from Olga will produce heavy rain rates and likely thunderstorms... especially for the Eastern Shore. Where the cold air holds longer, moderate icing of 1/2" or more is possible. I think that will be confined west of us.
Even though some sun and warming have taken place today, keep this in mind:

• Low dewpoints will allow for evaporational cooling. The initial precipitation evaporates and drops the temperature to the Wet Bulb level. So when it starts, it will get cooler. At noon BWI was 35F with a dewpoint temp of 19F. That gives a wet bulb near 26F. I don't see us dropping that low, but it should go back below freezing when 'stuff' begins between 4pm and 7pm.
  
• NE winds will lock in that cold air longer farther west and in valleys. While I have a general forecast map, elevation will play a role in ice- in this case, lower levels get more as warm air reaches hill tops first.
• Sunday morning potential for temperatures near 50F with heavy rain in the cities. The may be a sharp boundary with the cold air's last stand. Depending on the actual time and position of 2nd Low, will determine when the wind shifts and cold air filters back in.
• Sunday afternoon: A brief period of snow may be enough to coat the ground, or an inch or so. It's the quick drop in temps that would cause a quick freeze of anything wet.
• Sunday Night's Winds 30-50mph may drop trees and power lines

My First Call- Updated and fixed diagram

Before I get into my 1st call, a reminder that a new Snow Poll is at the right side here. That is your 1st call for total snow at BWI. This includes beginning and end of storm, by Sunday night.
Also, a lot of questions on freezing rain. Here is a great animation explaining winter precipitation. As warm air works in to a storm, it often rides above the ground first, while cold air which is more dense stays at the surface. Depending on how thick the layer of warm air is, and how warm it is will determine:

1. If snowflakes from the clouds melt.
2. If there is a chance to refreeze before reaching the ground.

• Sleet- Melts then refreezes
• Freezing Rain: Falls as rain, freezes on the ground.

The most extreme I have seen was in Danbury, CT with rain at 19F. A few years ago we have drizzle at 21F in front of ABC2 Studios.

Being my day off, this will be brief... The models have been all over the place. There general idea I see is slower with the development of the coastal Low. This will make for a longer duration event. Considering the Coastal Low synopsis, it also means a better chance that we have an ice storm. Calling total snow will be tough since I still think we will see it on the bookends - both beginning and end of the storm Sunday evening. All snow line will be well to the north - highlighted in white. Most likely we get between 1/2 and 3 inches (north) of snow then change to sleet/freezing rain quickly after dark. This coastal Low during Sunday should bring us back to snow around noon. Depending on the strength and position we could pick up a few inches on the back side before ending. There is model support for the warm air to get in with temps in the upper 40s Sunday morning. I don't fully agree with that. Cold air damming usually is tough to break west of the bay. That is why I-95 or the bay often ends up as the dividing line. The cold air gets banked up just east of the mountains. Its possible that Frederick and Carroll counties have much more ice than Frostburg which will likely turn to rain closer to the primary low. Again this is 'roughly' what I see right now. It could all change with just a shift 50-100 miles on tonight's models. One thing to look out for is how cold it gets tonight. If we end up low to mid 20s before the clouds roll in, it will hold us lower at the onset. Updated at 3:30pm: It should be noted that storms like to set footprints for themselves. In this case the snow or ice pack can lock in the freezing air. But something that should not get left out is the wind on the back side of this storm..GALE FORCE in the metro areas throughout the region. That means if there is ice on trees, etc., it will be a major problem. Still thinking just north and west - as typical.
I'll get back Saturday morning. This whole event will also determine if I have to get back to work myself this weekend, so I have a personal investment here.

You win! The Early Snowmap and another model.

The 1st Snow Poll is now closed. I was surprised at the response to not show the early map, yet then final surge just barely won 54 to 50. 20 of you would rather wait until after the storm. Well, here it is, but small enough for those of you who don't want to see it. THIS IS NOT MY FORECAST! I don't know this forecaster, but it came from an Accuweather forecaster on Tuesday. It shows Baltimore in the 3"-6" range. I'm curious to see if he has changed his outlook since then. Again, if you click the image, you may have trouble backing up here. Copy URL and paste back in browser - sorry.
I am off work on Friday I will make my first call here during lunch time. I have posted a new Snow Poll at the right. Here you can share you're best 1st guess of total snow (not including ice, etc) for the Baltimore area. This does not include the northern snow-burbs, but the official report at the airport on Sunday night. I'll run another one on Saturday as well to see if you change your mind.

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More Model Support. Here is a 75 Hr forecast from the SREF my buddy Tony Pann sent me. This is for Sunday afternoon and holds the morning GFS idea. Notices the coastal Low over DE, and MD is on the back side. This looks like the primary, with no occlusion or transfer. This would be in response to a strong block to our north. I'm sure the message boards are lit up this evening with renewed hope.

Falling Temps, Flying Leaves, and Flakes

Today: Blustery! What is the true definition of that? I usually consider it when the wind comes in bursts, surges, and makes it feel colder. Today would fit. As temperatures struggle the reach 40F, it will feel like the 20s. How about the snow as well. Following a few streamers from Lake Erie down into Dixie is tough. I did mention it on the air yesterday, but did not want to push it too much. Unfortunately enough did fall to coast the ground in northern Baltimore County and Carroll County. The roads were salted this morning due to icy spots. These flurries and snow showers will continue until mid day, but be isolated. You can ABC2's StormCenter Doppler in my Weather Graphics Page. But that isn't really the story today is it?
Tomorrow it will snow. For all of us. This is the model output for the NAM (North American Model), an upgrade from the former ETA, and has a tendency to overdue precipitation. I am using it, because the other images don't do a good job highlighting this clipper.
Two things to consider: First, when a clipper passes to our south, we often get the high end or more of snow. When it passes just north, we get much less or nothing. Second, there is cold air support for all snow. The general rule of thumb is 10 to 1. So multiply these numbers by 10 for an idea of snowfall.
From overnight the range of liquid equivalent forecasts for Baltimore are:
NAM:0.27"
GFS: .16"
*NGM:0.09" (but that only goes out until Wednesday at 7pm. I will update these numbers by noon)
My general call is for 1-2 inches of snow. The timing will be afternoon through midnight. That means the evening commute could be slippery as roads tend to accumulate snow when the sun gets low between 3pm and 4pm. It should end overnight, but if we get wet afternoon roads to ice up, then Thursday may warrant a school delay. December 5th recent snow history and video of my LIVE coverage from WBAL tomorrow.