Monday, February 20, 2012

Post storm wrap up

Wow, what an event!

It was a forecasting challenge but in the end just was a fun storm to be a part of. It's clear the highlight of the storm was between 5 and 6 PM where .22 liquid fell at the airport in Lynchburg. That was likely a tad above 10-1 ratios, so maybe as much as 2.5 inches fell that hour. I was out with my middle son making a snowman and sledding and it seemed every time we didn't move the sled, 5 minutes later it had a quarter inch on it.

In Lynchburg proper, we really lasted in the meat of the band longer than other locations in our area with another .10 an hour between 7 and 9 pm. Here's a view of the LYH obs--



My forecast overall- I'll give it a B. Had I held to my original map, I'd say that was an A. Using models as guidance can be very tricky. As the event was approaching it was clear there would be a 2 part event-- event one was the first push of moisture and it seemed it would have incredible "frontogensis" -- two airmasses collide into each other. In this case, it was the moisture from the sub tropical jet hitting the cold air sliding in from the north. This part of the event was decent- general 1-4 inches region wide but that wasn't the main show. The model data was much stronger on this in the 2 days before the event until that last second jog south in the models. 

The second part was caused by the mid level circulations-- 850 and 700 MB low. These are harder to forecast as their tracks are not as exact and where the best banding set up would be somewhat difficult to pinpoint. The late night model runs Saturday night pushed them down closer to the VA/NC border. My concern was we'd about get next to nothing (especially far east) from round one and round two would be more intense to our south. 

Round one went as expected and round two slide north vs the model data. About 6.5 inches of the snow in Lynchburg was from that second round associated with the mid level low. 

Here are some regional totals-- many are incomplete. If you check the time stamp, anything that is before midnight or so isn't the entire storm. 


I expect the LYH total to be 8 or 8.1 (current report is 7.7 but it's incomplete) Roanoke is 5.5, Blacksburg is 6.8 and Danville is 3. 

Enjoy the snow today-- 45 for a high today, 55 tomorrow and 60s by Thursday! It will all be melted by late tomorrow except the plow piles. 

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