Thread for 12/14 potential dusting, arctic air, and 12/17 potential slop

[BTRWx]

31 minutes ago, mappy said:

back on topic for a moment

12z NAM = ice I do not want

BWI?

[yoda]

12z GGEM precip meteogram for DCA has 3-4mm of snow and 12mm of freezing rain

[Scarlet Pimpernel]

22 minutes ago, PennQuakerGirl said:

Is there a reason why the GGEM appears to be such an outlier? 

In this case I'm not sure precisely what it might be, but in the past that particular model has been aggressive as I recall (as it is with ice in the current event).  That said, from what I've seen in the discussion here and the bit that I've looked at the other models, they apparently have also shifted a bit more south with the precip.

[DDweatherman]

Would really be nice to see the euro come aboard a bit on QPF/south shift. 

[WinterWxLuvr]

1 minute ago, UVVmet84 said:

Would really be nice to see the euro come aboard a bit on QPF/south shift. 

 

 

[Bob Chill]

3 minutes ago, UVVmet84 said:

Would really be nice to see the euro come aboard a bit on QPF/south shift. 

Considering how much it would have to come south to even remotely resemble CMC/RGEM (or even the gfs for that matter) I don't expect much @ 12z. It might babystep but remain a pretty weak event imo. 

[DDweatherman]

1 minute ago, Bob Chill said:

Considering how much it would have to come south to even remotely resemble CMC/RGEM (or even the gfs for that matter) I don't expect much @ 12z. It might babystep but remain a pretty weak event imo. 

Definitely not expecting much from it. Could see a minor uptick in QPF, or a couple mile jog south, but not expecting anything more. 

[Eskimo Joe]

8 minutes ago, UVVmet84 said:

Would really be nice to see the euro come aboard a bit on QPF/south shift. 

Silly weenie, the Euro only shifts south when it wants to give us 35 and partly sunny.

[WhiteoutMD]

26 minutes ago, Ji said:

isnt their a weenie myth that the canadien model handles CAD the best?

All aboard the JB train (Justin Berk) 

[mappy]

22 minutes ago, BTRWx said:

BWI?

 

[mappy]

GFS sucks

per cobb, maybe 1" snow, followed by .2 of sleet/freezing rain (for westminster)

[high risk]

I mentioned this yesterday, but it still holds today:   the key is with the sfc winds early Saturday.  The NAM and GFS establish 10-15 kt of southerly flow pretty quickly after sunrise which will pull in the warm air fast.    The RGEM keeps the sfc winds in the 3-6 kt category which will make it much tougher to erode the cold air.     Watch the winds at the airports Saturday morning:  if those stronger southerlies are slow to kick in, we're going to stay icy longer.    Regardless, though, as folks here have pointed out, road surfaces are super cold, so this is likely to be a high impact event even if QPF is light.

[Bob Chill]

8 minutes ago, high risk said:

I mentioned this yesterday, but it still holds today:   the key is with the sfc winds early Saturday.  The NAM and GFS establish 10-15 kt of southerly flow pretty quickly after sunrise which will pull in the warm air fast.    The RGEM keeps the sfc winds in the 3-6 kt category which will make it much tougher to erode the cold air.     Watch the winds at the airports Saturday morning:  if those stronger southerlies are slow to kick in, we're going to stay icy longer.    Regardless, though, as folks here have pointed out, road surfaces are super cold, so this is likely to be a high impact event even if QPF is light.

This is a really good point. It's hard to say which is right. I will say that it seems more typical to have light winds with inversions but by 12z it's pretty shallow. The scouring process won't be even S-N either. Protected low lying areas will probably hang tough for a time as usual.

I'm inclined to believe that the GFS and Euro may be a little slow with precip and underdoing intensity. Not saying I think the RGEM/CMC are to be hugged or anything. Just that WAA precip can overcome the column pretty quick. Somewhere in between the Euro/GFS and CMC/RGEM will probably end being closer to reality. 

[Bob Chill]

Euro shifted south a bit with precip between 6-12z. Not a big jump but certainly noticeable and probably around .10 qpf around DC by 12z and around .15 across the northern tier.  An uptick from the 0z run. Larger uptick in qpf from 12-18z. I would guess half is ice or so. Not much to add on the run other than more impacts in general from the 0z run. 

[yoda]

If you want an ice storm and possibly no power for a little while, 12z RGEM is the way to go -- DC is 0.56" all ice.... and there are some numbers approaching 3/4" -- all through 15z SAT

 

 

[Bob Chill]

Looking at the zoomed panels. Almost everybody in our area gets between .4-.6 precip by 18z. The biggest change in the uptick is the area from wincheshter-nova-central MD-baltimore. The 0z run has .2-.4 qpf for that area.

The tricky part is the flip time to plain rain. At the very least it supports the south trend with precip so the euro keeps things interesting. 

[mappy]

Mm, sounds like I need to prepare for some ice tomorrow morning vs snow

[Stormpc]

Where's PSU?

He wrote 100,000 words on this topic the last 5 days and now the trends are better and he is MIA. I would love to see his input as well.

Road surfaces are about as cold as you can get in this region. Add low UV from today's clouds, darkness of night and low dew points spells trouble for late/overnight.

[Superstorm]

Lots of brine on the beltway


Sent from my iPhone using Tapatalk

[Bob Chill]

Just now, mappy said:

Mm, sounds like I need to prepare for some ice tomorrow morning vs snow

The main reason the euro is so light on snowfall is because it starts late. Measurable precip isn't anywhere close by 6z. 

[WxUSAF]

My bar is just some measurable snow/sleet IMBY that's more than 0.1". Not too much to ask for right?

[smokeybandit]

Baltimore area roads were brined yesterday.

[Bob Chill]

1 minute ago, WxUSAF said:

My bar is just some measurable snow/sleet IMBY that's more than 0.1". Not too much to ask for right?

I just want to wake up early and see a wintry scene. No numerical qualification. Just visual. 

I've become a bit more optimistic that this event may pack more punch than I previously thought. Of course it will be short lived but seeing guidance across the board shift a little south with better QPF is encouraging. 

[DDweatherman]

My bus is getting more fuel late in the game. 

[Joshfsu123]

12 minutes ago, Stormpc said:

Where's PSU?

He wrote 100,000 words on this topic the last 5 days and now the trends are better and he is MIA. I would love to see his input as well.

Road surfaces are about as cold as you can get in this region. Add low UV from today's clouds, darkness of night and low dew points spells trouble for late/overnight.

I've seen ice on roadways/sidewalks in downtown DC today walking to work ... from where water has for whatever reason been leaked. So the roads/ground are frozen solid, that's for sure.

[mappy]

12 minutes ago, Bob Chill said:

The main reason the euro is so light on snowfall is because it starts late. Measurable precip isn't anywhere close by 6z. 

Yeah. I saw. I mean, ice is ice, and I shouldn't complain. Wintry precip works for me. Just wondering if I really should prepare for it before going to bed tonight (in case we lose power). Since I'll be one of the last to flip... 

[DDweatherman]

1 minute ago, mappy said:

Yeah. I saw. I mean, ice is ice, and I shouldn't complain. Wintry precip works for me. Just wondering if I really should prepare for it before going to bed tonight (in case we lose power). Since I'll be one of the last to flip... 

We have a couple more runs to figure that out. If 18z Gfs keeps getting wetter then maybe 

[DC2Winston]

FWIW, NWS zone forecast doesn't even mention SN- any longer in 20008 overnight.  Straight to sleet/frz rain.  Nasty.

[H2O]

radar looks great

[H2O]

i'll see myself out