It is premature to post a snow map until Sunday morning in the Washington Region as until the exact track is pinned down we have precipitation type issues (where does the rain/snow line set up) during the event.
For those of you north and west of Washington and Baltimore the latest forecast modeling is still showing a significant snow storm. For those of you south and east, this could still wind up being a significant storm.
The latest European operational model from overnight brings the “540 line” right into the District, meaning if this latest operational is correct (I will remind you that many of the ensembles keep the “540 line” south and east of Washington) the northern and western suburbs receive the heaviest snowfall accumulations while areas south and east get slop (wet snow) going over to a mix and ending as light snow.
Latest 00z operational European model showing 2am Tuesday (Monday night):
- Notice the 540 line (blue line labeled 540)… that is the “rain/snow” line.
Latest 00z operational European model showing 8am Tuesday:
- “540 line” could make it all the way to Baltimore and Dulles, of course in these areas the “damage will have been done” during the overnight when heavy snow would have already accumulated in these areas with snow-covered roadways.
Latest 00z operational European model showing Noon Tuesday:
- Storm is pulling away and colder air is rushing in as winds have now shifted to the north-north-west but the high-march sun angle is now helping to warm the atmosphere and best lift is now in the Philadelphia Area.
Here is what has people pulling their hair out this morning:
- So if last night’s latest operation model (the images I just showed you above) are absolutely 100% accurate in track (that’s a far stretch of the imagination)… this is how much snow could fall (notice how the southern and eastern outer suburbs get shafted while the northern and western suburbs are having a snow party)
Okay so now some of you (and I know who you are) are immediately jumping to the conclusion that “it’s over” … “Tim is forecasting a bust”. I am not forecasting a bust, I am saying that until we have an exact track ironed out… any shift back to the east even by as little as 25 miles is going to bring significant snowfall back into areas south and east of 95. We simply do not know. Let me show you what I mean by looking at the latest Ensembles:
Latest European showing probability of 3″ or more:
- Please notice the 70 to 80 percent probability of 3″ or more in locations that the latest operational showed zero accumulation… (southern Maryland for example) … now you can see my point (I hope).
Latest European showing probability of 6″ or more:
Let’s take a look at the latest suggested track from the European Ensembles:
- Here was yesterday’s European Ensemble showing potential locations of where the Nor’easter will be sitting at 8AM Tuesday with some of the “L’s” in eastern North Carolina and others just offshore.
- The exact track is going to have significant impacts on how much snow falls in our area. Any track further east keeps the boundary layer (850mb) at or below freezing.
Here is the last night’s latest forecast ensemble from the European:
- The entire DC Metropolitan Region is still in the “game” for significant snow… that is the bottom line.
European Snowfall Accumulation Potential (based on the latest Ensembles)
Yesterday’s 12z run:
Last night’s 00z run:
- Not a lot of change within the ensemble mean… good news for now.
Let’s look at the latest Global Forecast System (GFS) Ensembles
GFS Ensemble showing precipitation type and track around 2AM Tuesday:
- Notice how some have heavy snow in our southern and eastern immediate burbs while others show a mix.
The image below shows the latest GFS Ensemble showing potential Snowfall accumulation:
For my faithful Snow plow operator followers, the DC Area airport hubs finally issued a travel advisory yesterday for Tuesday so people are all scrambling to change flights to Monday.
If you are a snow plow operator north and west of Baltimore or DC … it’s safe to say that right now your services are certainly going to be needed.
If you plow snow in southern Maryland, Fredericksburg or the northern Neck of Virginia … I’d at least be ready as one operation run is meaningless until we start seeing the ensembles shifting to a rainy solution south and east of DC.