Winter Examiner Poll

Here is one of the few cases early voting can be good and fair. As I shifted my blog to Examiner.com, there are still some limitations. I am using this spot for a Winter Season Snow Poll - At the right. What do you you think about this season? The poll will end Wednesday morning, and I will post the results on Examiner. I will also spend at least 1 day each week on the seasonal forecasts. Check back for Wednesday Winter Outlooks.
The chart at the right is of a wild 10 year period we just had with the top 1 and 2 and bottom 3 and 4 seasons on record. We've had dramatic swings in both directions.
Note:
2005-2006 = 19.5"
2006-2007 = 11.0"
2007-2008 = 8.5"

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.