December 14/15 winter storm threat part II

[OceanStWx]

I'm not worried about the over with these trends.

 

I think everybody (including WFOs) are guilty of this with these SWFEs. As trends go colder initially, we continually ramp up snow. Totals keep going up and up as QPF increase in the cold air mass, and we think there is no stop to that trend.

 

In reality there is only so long it can snow before the dry slot. There is sort of an upper bound to snowfall amounts. We've got a pretty large area of 14+ along the coast there, I feel like that may be too high.

[TauntonBlizzard2013]

RGEM is warmer than 0z too but still implies a good hit in CMA and interior EMA. Thing is this is a multi model multi run increase in torchiness...probably unlikely that it's over right now.

That's what I mean. The warming isn't done.

[wx2fish]

I find it hard to believe we get above freezing. Prob some ZR tho

I agree. Shouldn't cut down on your totals too much.

[phil882]

It will also bring the DS in faster as well.

 

Yes... by the time areas near the coast are warming up above freezing in the warm nose, most of the frontogenesis will be north. You can already see the dry slot progressing in Kentucky. Some of that will fill in as it approaches us, but that represents the end of the major forcing for this event. 

[Clinch Leatherwood]

That's what I mean. The warming isn't done.

 

You should still get a good burst.  I'm hosed, by the time the real heavy stuff moves in it's already flipped here. 

 

Good illustration of what may probably happen (but likely even a little further north than this is illustrating) between 18 and 22 hours.

 

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

[dendrite]

I think everybody (including WFOs) are guilty of this with these SWFEs. As trends go colder initially, we continually ramp up snow. Totals keep going up and up as QPF increase in the cold air mass, and we think there is no stop to that trend.

 

In reality there is only so long it can snow before the dry slot. There is sort of an upper bound to snowfall amounts. We've got a pretty large area of 14+ along the coast there, I feel like that may be too high.

Yeah I was thinking that. I still like a general 8-10" here with spotty 12"s. My frontogenetic band from a few days ago may end up in EFK or YSC.

[MJHUB]

That's what I mean. The warming isn't done.

 

still thinking 4-6 maybe closer to 4 over by you further east. HRRR had about 6 in RI 5 out your way

[weatherwiz]

RGEM is warmer than 0z too but still implies a good hit in CMA and interior EMA.  Thing is this is a multi model multi run increase in torchiness...probably unlikely that it's over right now.

 

Central MA into far NE MA and into southern NH (I have southern NH as my cutoff here as that's the further north I have focused on) will be exceptionally well.  For several days now models have pinned this area for the strongest lift and with WAA working into southern zones and increasing the thermal gradient, that's going to really increase frontogenesis and the areas mentioned will be in a prime spot.  

Making a new map and going to go from 6-9'' in these areas to 9-13''.  While the potential certainly does exist for more I'm still nervous about going higher, especially over a widespread area.  

[NJwinter23]

Easy to see why the short term trends have come in NW when looking at the Water Vapor... That thing is amped up! I'll enjoy my thump before the rain though. Pre-12/15 and with a raging +AO/NAO so far how can one complain.

[OceanStWx]

Yeah I was thinking that. I still like a general 8-10" here with spotty 12"s. My frontogenetic band from a few days ago may end up in EFK or YSC.

 

When most of the lift is in a 6-9 hour window that's about your upper bound. And even then you have to rip 1"/hr for the duration to get there. That's not the easiest thing to do.

 

So for me personally, I like to keep my snowfall forecast a foot or less in these events. If I start cranking out a large area of 15+ I need to take a step back and question whether it can really happen.

[dendrite]

Easy to see why the short term trends have come in NW when looking at the Water Vapor... That thing is amped up! I'll enjoy my thump before the rain though. Pre-12/15 and with a raging +AO/NAO so far how can one complain.

Southern stream s/w...AWT

[TauntonBlizzard2013]

You should still get a good burst. I'm hosed, by the time the real heavy stuff moves in it's already flipped here.

Good illustration of what may probably happen (but likely even a little further north than this is illustrating) between 18 and 22 hours.

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

Verbatim that's a solid 4-6 here. Well see. It's a now cast thing.

We need some good banding, if not were looking at an inch or two.

The rain I think washes it away regardless

[CT Rain]

Yeah I was thinking that. I still like a general 8-10" here with spotty 12"s. My frontogenetic band from a few days ago may end up in EFK or YSC.

It's generally tough to get 12"+ from one of these events. You really need to get in the comma head for the blockbuster totals. I try and not forecast more than a foot of the 700-850 mb lows are to my west ,

[HIPPYVALLEY]

With DP's still running below 0 from here on N there is a lot of dry air to overcome.  Hours of virga for many.

[ctsnowstorm628]

Yeah I was thinking that. I still like a general 8-10" here with spotty 12"s. My frontogenetic band from a few days ago may end up in EFK or YSC.

 Greedy me would not be upset.

[OceanStWx]

It's generally tough to get 12"+ from one of these events. You really need to get in the comma head for the blockbuster totals. I try and not forecast more than a foot of the 700-850 mb lows are to my west ,

 

That's basically what I tried to do last evening. Tighten up our snowfall totals to get rid of some of those high outliers. Keep the ranges below 14".

[TheSnowman]

Corey is having the first melt down if the season

Try having to live in the Lifetime Long Battlezone of Northern RI where you go from 8-12 predictions for days to wake up to 4-6 because the Low Pressure wants to Agaaain only give big snows to Snow Country. Then you'll see.

I I'd consider the Lifetime Battlzone in between SENH - ORH - HFD & BOS - PVD - New Haven. You live below that you Have to Accept you're gonna suck a lot. But inside it it is heart attack city.

[OceanStWx]

With DP's still running below 0 from here on N there is a lot of dry air to overcome.  Hours of virga for many.

 

Initially it will be some virga, but with this lift it will saturate quickly. Most people will flip from --SN to SN/+SN very quickly.

[Tropopause_Fold]

GFS still has a big slug of intense mid-level VVs south of LI at 6z...and it's already pinging across the southern half of SNE (at least).  so there is going to be a good deal of mix before the dryslot, imo. 

[MJHUB]

Verbatim that's a solid 4-6 here. Well see. It's a now cast thing.

We need some good banding, if not were looking at an inch or two.

The rain I think washes it away regardless

box new map increased the 4-6 zone south and east cut back the rest of the map tho

[dendrite]

It's generally tough to get 12"+ from one of these events. You really need to get in the comma head for the blockbuster totals. I try and not forecast more than a foot of the 700-850 mb lows are to my west ,

Yeah we all talked about that the other night. It can happen, but it's pretty rare to rack up a foot plus with the mid level lows well to our west.

 

We're going to be piling up lower ratio snows on top of the early fluff too. 6hrly measurements will account for the fluff, but if you measure at 12z or at the end, most of those high ratios will be compacted down.

[CT Rain]

GFS still has a big slug of intense mid-level VVs south of LI at 6z...and it's already pinging across the southern half of SNE (at least). so there is going to be a good deal of mix before the dryslot, imo.

I don't understand why red taggers don't focus on the positives? It's a snowy December day in deep deep winter!

[Digityman]

GYX upping the irons

StormTotalSnowFcst-1.png

 

When is that from?  Meaning, is that the most up to date forecast?

If so, a few of us are sitting right outside that 14-18" zone that goes from Portland south along the coast.

 

[Clinch Leatherwood]

GFS still has a big slug of intense mid-level VVs south of LI at 6z...and it's already pinging across the southern half of SNE (at least).  so there is going to be a good deal of mix before the dryslot, imo. 

 

RGEM is the same way.  A lot of us have already flipped before the most intense stuff moves in.  Eh...1-3" still seems good, glad I wasn't expecting more.

[CT Rain]

Yeah we all talked about that the other night. It can happen, but it's pretty rare to rack up a foot plus with the mid level lows well to our west.

We're going to be piling up lower ratio snows on top of the early fluff too. 6hrly measurements will account for the fluff, but if you measure at 12z or at the end, most of those high ratios will be compacted down.

Yeah 6 hourly measurements will be quite a bit different than 12z depth.

[SlantStickers Anonymous]

I imagine roads are going to be garbage Sunday morning, 6" of snow packed with sleet and rain by the time many wake up. How rapid does the refreeze occur?

Also I could imagine some drainage issues for areas that switch to heavy rain, half a foot of snow packed over storm drains and rock hard top soil could lead to quite a bit of ponding.

[weatherMA]

Should be fun up here. Since I was home in January, and went home for the Feb Blizz, (plus got completely screwed on other storms like getting 5" while Dendrite 20 miles south gets 12") this should be my biggest storm since being up here. I was amazed when I saw how warm everything trended, but not really a worry up here. Game on!

[Cold Miser]

Off to basketball then soccer then Xmas party at 3:00. All with snow falling and temps in the low teens. Thank God for iPhones

Right.  Because none of what you mentioned doing would be able to happen without your personal slave driver device.

[PineHillsWx]

I imagine roads are going to be garbage Sunday morning, 6" of snow packed with sleet and rain by the time many wake up. How rapid does the refreeze occur?

First storm of the season so the plow drivers will be out in force and ready to make some OT money before the holidays. They will have little traffic to contend with in the wee hours of the morning. The main roads will be fine tomorrow....pavement.  Amazes me that people still stock up on food, gas etc for a run of the mill storm that is going to last around 12 hours. It borders on embarrassing....

[TauntonBlizzard2013]

box new map increased the 4-6 zone south and east cut back the rest of the map tho

I agree with cutting back the map in general.

Not sure I agree with extending 4-6 for all Bristol and Plymouth counties. I would take that and run though