Sunday, March 12, 2017

How Much Snow Monday night and Tuesday??

I'll start with the details and then elaborate for those who care!

New River Valley up 81 to past Roanoke 3 to 6, up to the Blue Ridge.

East of the Blue Ridge - North of Altavista , Cutting north to Farmville , Including Lynchburg 2-4.

Martnsville, Danville, Ect coating to 2 inches.

If this is a Dud: Ending as snow in NRV, LYH and ROA and all Rain southside.

If we over achieve, 4 to 8 NRV, ROA and LYH, 2 to 4 down to Martinsville and Danville.


Discussion:
If this were January, we'd be looking at 6-10 inches region wide, maybe some bonus snows in the north and east areas. It's not too warm, it's just March, mid March at that.

To not overcomplicate my discussion,  we have storms that are phased and unphased, Phase, simply put is when 2 branches of the jet streams, and their upper air energy work together.

Early on, a phase seemed likely, then models moved away from that. Today, they are more phased and the net gain is best snows should be west of the Blue Ridge.

What a phase does is strenghten the low fast enough to cool the air from top to bottom by creating strong vertical motion upwards.  The models currently strengthen the low a little sooner and enough cold is in place along -81 for mostly snow, or rain changing to snow. As the low deepens and pulls east a rapid change over takes place. However, the snow ends pretty quickly after it changes over with maybe 2-3 hours of accumulating snow and then 2-3 hours of light snow and flurries.


Details:
Roaonoke and NRV, a mix of snow, sleet and rain develops late afternoon, changing to all snow in the evening. Snow will be briefly heavy. Snow ends in the pre dawn hours. 3 to 6 on colder surfaces, slushy mess on roads, etc.

Area including Lynchburg: Rain and sleet develop, maybe all rain for a while then changing to snow. Snow could be heavy an hour or three, before ending as 2-3 hours of light snow and flurries. It's gone by sunrise with 2-4 inches falling, mainly grassy areas. The roads will have some slush on them..

Southside. Rain and maybe a little sleet ending as snow, coating to 2 inches.

Crazy talk: In my "weather chats" with various people I've predicted that if the  low deepens to 995mb before Cape Hatteras we see 4-8 in all areas except southside. I still believe that. I think we miss it by 50-75 miles. (AKA, Past the VA/NC border.

More Crazy talk: Pretty good odds school is out Tuesday. Snow will be gone by noon. Gone, as in melted.

Even More Crazy Talk: Winter is hanging on a little after NO winter. May need to blog later about other events.

What can go wrong? If the low is SLOWER deepining, we get some rain ending as lighter snow, but no accumulations to speak of.

If you're up, the snow may rock a couple hours nice big flakes from 10pm to 3am.
Thunder, as the low deepens with both the rain and snow is possible.

Huge event just north of DC. My baby sis lives 20 miles NW of Philly near where I was raised, I think she sees 12-20 inches.

I think that the NWS will go Winter Weather advisory for most areas NOT southside and MAYBE winter storm watches/warnings for Amherst, Bortetourt and Rockbridge Counties.

Doubt I will make another full blog. Thank you for the "ad clicks"of appreciation.

 I will update with model runs, and updates, upgrades and downgrades on social media. Remember you can follow my FB Page, VirginiaWx  me personally, Keith D. Huffman, (do a FR or follow) and/or twitter which is VirginiaWx


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