Discussion (and OBS if any) for minor impact (possibly mdt) wintry mix sometime btwn Noon Sun Jan 19-Noon Wed Jan 22. Focused Inauguration Day and 21st

[wdrag]

Modeling for the past several days suggests one or possibly two hazard events for a large portions of the NYC subforum, maybe excluding e LI?  Headline has a large 4 day period for possibilities and cant be sure of anything except that precipitation will occur. 

Fast flow-thread the needle timing in the climatologically coldest time of the year with cold air nearby to draw into whatever low pressure systems approach. 

Hopefully this will not be 30+ pages of less than normal snowfall in CP. Daily CP norms (averaged out) are 0.3"/day. Am suggesting CP has a chance to stick 1-2" sometime in this period as modeling proposes 1/4-3/4" qpf in this time frame with temps at times below freezing.  Ensemble temps tend to favor coldest  temps in this thread periodJan 21-22. 

Most favored area for snow and ice continues as usual inland from I95, especially the I84 corridor (our nw-ne suburbs).

Not looking like a major storm as of this 1/11 starter thread but annoying minor to possibly moderate impact 1-6" amounts of snow and a period of icing, especially interior just west of I95 through the I84 corridor Monday-Tuesday the 20th-21st. Another shot of reinforcing wind driven cold should follow around the 22nd?  

ICE: added EPS ice QPF here with several 12z/00z cycles of the EPS are offering glaze in the interior even near NYC which subdues the EPS expected snowfall.  Ignore the NC ice which occurred earlier today.... and the qpf amounts need to are shaved by maybe 70% for reasonable glaze thickness.

Am aware its fast flow and the lack of blocking could result in a failed thread but so far there is chatter and thought it good to pull the chatter off the January thread into one more focused thread. More snow opportunities Jan 25th onward as already suggested in the Jan thread. 

Added ensemble more conservative snow depth change for back checks on 1/22 to see how much this thread failed. We have to remember that the max snow axis error on multi ensemble agreed max qpf and snowfall can be in error by maybe 200 miles at Day 10.   Graphics cleaned up at 735A/11.

 

 

[NEG NAO]

at least its not the GFS showing it

[wdrag]

13 minutes ago, NEG NAO said:

at least its not the GFS showing it

Glad you posted this.  Somewhat similar to various 12z/00z EC op's the past couple of days.  =

If the GFS smooth rounded base verifies,  it wont do much here after the 19th but I'm thinking we now have two 12z/.11 op runs through 240 hours that have something going on.

Trough might sharpen-warm (ice) but for now we're in the game for something.

Attached image of the smoothed out GFS 5h  still has a dual jet at 5H,  RRQ of the departing core (yellow 120 kt) east of New England over the Bay of Funds and LFQ of the approaching trough in the Miss Valley (115KT GA).  LOTSSSS can go wrong including...too many shortwaves - too closely spaced, or just one event that is wet and then blows colder air over us with no digging trough. 

WPC D7 now expanding qpf in here.  It's going to waffle and so we might know that much more til about Monday or Tuesday of this coming week.  

[NEG NAO]

12Z Euro more or less agrees with 12Z Canadian I like seeing that HP in southeast Canada also...

[wdrag]

First cut Blend of Models through hr 239 without the 1/10 early 11 snowfall. Yesterdays BOM was pretty conservative (underdone) in our NYC forum. 

[psv88]

I generally find the BOM and snow depth maps to grossly underestimate snow totals. I know some people love them but I have never once found them to be very accurate, particularly the snow depth maps 

[wdrag]

53 minutes ago, psv88 said:

I generally find the BOM and snow depth maps to grossly underestimate snow totals. I know some people love them but I have never once found them to be very accurate, particularly the snow depth maps 

I figure they are a D10 start.

 

[wdrag]

Just posting todays D6-10.  Added a comment at 430P that the 12z/11 NAEFS has two distinct events here, one near the 19th (Rain LI), and the other centered near the 21st & that one is colder.  10 days away... plenty will change. 

[wdrag]

Also fwiw: I'll be monitoring trends of the EPS freezing rain qpf.  Does it shrink southward due to less qpf, or colder temps (snow), or does it shift west or east implying warming aloft shifting its northward rajectory either up the Apps, or offshore.  Interesting to monitor this far out.  On the 17th morning, I will probably adjust the headline to whatever looks to be a more likely solution than what is threaded now. I hope at that time we're still in the hunt.  I did check snowstorms >4" on LI and the average is 2 or 3/season.  Been awhile.

[LibertyBell]

Just now, wdrag said:

Also fwiw: I'll be monitoring trends of the EPS freezing rain qpf.  Does it shrink southward due to less qpf, or colder temps (snow), or does it shift west or east implying warming aloft shifting its northward rajectory either up the Apps, or offshore.  Interesting to monitor this far out.  On the 17th morning, I will probably adjust the headline to whatever looks to be a more likely solution than what is threaded now. I hope at that time we're still in the hunt.  I did check snowstorms >4" on LI and the average is 2 or 3/season.  Been awhile.

for NYC I think it's three 4" snowstorms a season, one 6" snowstorm a season and an 8" snowstorm every other season.

[wdrag]

Multiple event opportunities 1/19-2/10.. possibly our time to see that elusive 4+?

 

On BOM, I agree w psv88 it seems a little conservative but the BOM gives me a starting point regarding what to think about-investigate--ditto for NWS and decision makers. 

[LibertyBell]

1 hour ago, wdrag said:

Multiple event opportunities 1/19-2/10.. possibly our time to see that elusive 4+?

 

On BOM, I agree w psv88 it seems a little conservative but the BOM gives me a starting point regarding what to think about-investigate--ditto for NWS and decision makers. 

From what you've outlined, Walt, it sounds like more wet 1/19 and more white 1/21 for long island (at least the south shore?)

[WestBabylonWeather]

22 minutes ago, LibertyBell said:

From what you've outlined, Walt, it sounds like more wet 1/19 and more white 1/21 for long island (at least the south shore?)

It would be on brand for Atlanta to have more snow than LI for the upcoming event would it not? 

[Stormlover74]

43 minutes ago, LibertyBell said:

From what you've outlined, Walt, it sounds like more wet 1/19 and more white 1/21 for long island (at least the south shore?)

As long as the gfs isn't right

[Allsnow]

34 minutes ago, Stormlover74 said:

As long as the gfs isn't right

Cutter then dry cold 

[MJO812]

3 hours ago, Allsnow said:

Cutter then dry cold 

And then you have the cmc

[MJO812]

9 minutes ago, MJO812 said:

And then you have the cmc

Not bad at all

[NEG NAO]

0Z Euro is too far off the coast

and 0Z Canadian is inland with mixing issues here

[LibertyBell]

13 hours ago, WestBabylonWeather said:

It would be on brand for Atlanta to have more snow than LI for the upcoming event would it not? 

the way I could see the Deep South getting more snow than us is possibly because the oceans are warming much faster than the land is, so maybe being near the ocean will be bad for snow going forward and it would be better to be in Arkansas or Northern Georgia or in the Carolinas, regardless of latitude.

 

[Stormlover74]

Cmc is decent next Tuesday.  Light to moderate event 

[wdrag]

6 minutes ago, Stormlover74 said:

Cmc is decent next Tuesday.  Light to moderate event 

As Well as 06z EC AI.  Huge difference between rain then cold dry 12z GFS (big diff with its snowy 06z vsn) vs the 12z GGEM.  Unresolved and up in the air for me.   Just have to wait it out.  Still D6-9. 

[Allsnow]

2 minutes ago, wdrag said:

As Well as 06z EC AI.  Huge difference between rain then cold dry 12z GFS (big diff with its snowy 06z vsn) vs the 12z GGEM.  Unresolved and up in the air for me.   Just have to wait it out.  Still D6-9. 

AI EC has the event Sunday night into Monday 

[wdrag]

9 minutes ago, Allsnow said:

AI EC has the event Sunday night into Monday 

Yes... I hope that's acceptable for the thread window.  All I want to see is NYC get 1-2" snow in that 4 day window.  How this evolves is for me unknown, but I wouldn't rule out the 19th.

I think folks outside AMWX have gotten too confident on what will happen in that 4 day period (I see some folks saying no way snow on Monday in VA)..  I think this is a mistake.  Yesterday I saw a NYC 10- day dry. now they have precip D8 and 10. 

The 12z/12 GFS probably did one of its common errors, latching onto the front end short wave as primary...  there is a little too much troughing hanging back in the Miss Valley Monday morning imo, to deny a second wave ...  that's where it may become a thread the needle where we might be on the northern fringe.  

Just my perception. so early and we're seeing the run-run variability and the wind shield wiper N-S.  

I think its best we consider ensembles as primary guidance beyond D6, and use their trends right now NOT JUST  cycle to cycle but maybe a trend over 4 cycles.  

Only 1 cycle  trend (so this could fail)  on the 12z GEFS, a touch of snow on the ground BOS-NYC-DC (less than 1/2")  and an inch is ensembled close to I95 Sunday night. 

Others have posted their observation that if there is a vast difference in modeling, something jogs everything into much greater consensus around D5. 

For me, I wait it out. 12z/12 Canadian (maybe its not right but I wont count it out yet) has a large difference in the jet pattern in the northern-southwest USA... offering a connection to a sw USA short wave Monday morning. Both models seem to have dual 5H jet core structure. I monitor. 

[Allsnow]

12z euro will probably show something for the 20th 

[Stormlover74]

3 minutes ago, Allsnow said:

12z euro will probably show something for the 20th 

Yep very nice

[MJO812]

3 minutes ago, Allsnow said:

12z euro will probably show something for the 20th 

 

[Allsnow]

Just now, Stormlover74 said:

Yep very nice

Exactly like the AI at 06z 

[Allsnow]

Another threat loading up for mid week. Please be correct 

[Stormlover74]

4 minutes ago, Allsnow said:

Another threat loading up for mid week. Please be correct 

Destroys the Carolinas. My parents would get a foot 

[EastonSN+]

34 minutes ago, wdrag said:

Yes... I hope that's acceptable for the thread window.  All I want to see is NYC get 1-2" snow in that 4 day window.  How this evolves is for me unknown, but I wouldn't rule out the 19th.

I think folks outside AMWX have gotten too confident on what will happen in that 4 day period (I see some folks saying no way snow on Monday in VA)..  I think this is a mistake.  Yesterday I saw a NYC 10- day dry. now they have precip D8 and 10. 

The 12z/12 GFS probably did one of its common errors, latching onto the front end short wave as primary...  there is a little too much troughing hanging back in the Miss Valley Monday morning imo, to deny a second wave ...  that's where it may become a thread the needle where we might be on the northern fringe.  

Just my perception. so early and we're seeing the run-run variability and the wind shield wiper N-S.  

I think its best we consider ensembles as primary guidance beyond D6, and use their trends right now NOT JUST  cycle to cycle but maybe a trend over 4 cycles.  

Only 1 cycle  trend (so this could fail)  on the 12z GEFS, a touch of snow on the ground BOS-NYC-DC (less than 1/2")  and an inch is ensembled close to I95 Sunday night. 

Others have posted their observation that if there is a vast difference in modeling, something jogs everything into much greater consensus around D5. 

For me, I wait it out. 12z/12 Canadian (maybe its not right but I wont count it out yet) has a large difference in the jet pattern in the northern-southwest USA... offering a connection to a sw USA short wave Monday morning. Both models seem to have dual 5H jet core structure. I monitor. 

Good afternoon Walt. I posted any other thread how the GFS weekend/lost the cutter and has moved a little Southeast with the wave. Looks like the euro weekend/lost the cutter as well. It's plausible this Southeast trend/weakening of the northern low continues.