Two Mdt to high impact events NYC subforum; wknd Jan 6-7 Incl OBS, and mid week Jan 9-10 (incl OBS). Total water equiv by 00z/11 general 2", possibly 6" includes snow-ice mainly interior. RVR flood potential increases Jan 10 and beyond. Damaging wind.

[wdrag]

49 minutes ago, HVSnowLover said:

I certainly don't take the nam seriously but the euro, gfs, and rgem are not that bad for most of the subforum away from the immediate coast. Only the CMC seems like a complete whiff SE of I287.

Watch CMC trends... it tends to run warmer than NAM. HRRR ag 48 hours tends to run warm and then as we trend close toT0 it should cool.  Those two models are my overall operational experiences. 

Stats are helpful...they temper enthusiasm but sample size can also have new contributions that are not in the more plentiful solutions.  

NBM has been steady through all the recent dailies.

 Even 18z EC has only 33F NYC Sat night... good VV and timing with the midnight ob might yield an inch Manhattan.  Think its going to be interesting NYC and northern LI.  Nothing off the table yet...in my mind.  I want to see if the 00z/5 12KM can settle on something more reasonable than its 18z predecessor. I'll  be sleeping when it comes in. 

[RU848789]

58 minutes ago, Dark Star said:

Elevation?

 

No, look at the NWS office maps side by side.  One can't have a discontinuity of <1" on the NWS-Philly side of the Morris/Somerset borders next to 3-4" on the NWS-NYC side of that same border.  Same thing with Middlesex adjacent to Union/SI (0" next to 1-2" in SI and <1" next to 2-3" in Union).  There was no collaboration, clearly.  

[mikeysed]

4 minutes ago, RU848789 said:

No, look at the NWS office maps side by side.  One can't have a discontinuity of <1" on the NWS-Philly side of the Morris/Somerset borders next to 3-4" on the NWS-NYC side of that same border.  Same thing with Middlesex adjacent to Union/SI (0" next to 1-2" in SI and <1" next to 2-3" in Union).  There was no collaboration, clearly.  

1-2 inches in Parsippany is comical. 4 to 6 minimum. If trends continue tonight, 6 to 8 would be more realistic.

[HVSnowLover]

41 minutes ago, qg_omega said:

I wish but much too cold for WP, maybe an inch or two before the rain.  Nothing for city or island

 

It probably won't be that extreme of a difference as that map shows but I would not be surprised at all if NYC is 35-36 flipping between rain and a mix all night while  White Plains is 33 and wet snow most of the storm. I also would think Newark would be closer to White Plains in this type of setup.

[WestBabylonWeather]

10 minutes ago, wdrag said:

Watch CMC trends... it tends to run warmer than NAM. HRRR ag 48 hours tends to run warm and then as we trend close toT0 it should cool.  Those two models are my overall operational experiences. 

Stats are helpful...they temper enthusiasm but sample size can also have new contributions that are not in the more plentiful solutions.  

NBM has been steady through all the recent dailies.

 Even 18z EC has only 33F NYC Sat night... good VV and timing with the midnight ob might yield an inch Manhattan.  Think its going to be interesting NYC and northern LI.  Nothing off the table yet...in my mind.  I want to see if the 00z/5 12KM can settle on something more reasonable than its 18z predecessor. I'll  be sleeping when it comes in. 

After this post odds have increased I’m going to the north shore Saturday night 

[uofmiami]

4 minutes ago, WestBabylonWeather said:

After this post odds have increased I’m going to the north shore Saturday night 

If I get more than a couple of inches, I'll be surprised.

[HVSnowLover]

17 minutes ago, wdrag said:

Watch CMC trends... it tends to run warmer than NAM. HRRR ag 48 hours tends to run warm and then as we trend close toT0 it should cool.  Those two models are my overall operational experiences. 

Stats are helpful...they temper enthusiasm but sample size can also have new contributions that are not in the more plentiful solutions.  

NBM has been steady through all the recent dailies.

 Even 18z EC has only 33F NYC Sat night... good VV and timing with the midnight ob might yield an inch Manhattan.  Think its going to be interesting NYC and northern LI.  Nothing off the table yet...in my mind.  I want to see if the 00z/5 12KM can settle on something more reasonable than its 18z predecessor. I'll  be sleeping when it comes in. 

This is likely an oversimplification but last year the RGEM never got in board with basically anything. Every winter is different but the fact it doesn't look that horrible I think might be a good sign.

[wdrag]

Lets look at the 00z-06z/5 NAM thermal profiles for NYC.  My guess is there will be steady snow much of Sunday NYC-northern Li but melt on pavement and have difficulty accumulating on grass during midday bit its all sub the about temps 32-34 and precip rate.  For now I think odds are under 3" CP-northern LI and mostly likely 1/2-2" but I've been wrong before.

I dont know if anyone has noticed the cyclic steadiness of EC and GGEM. 

Now I'm switching down to the HRRR, NAM RGEM.

[wdrag]

2 minutes ago, HVSnowLover said:

This is likely an oversimplification but last year the RGEM never got in board with basically anything. Every winter is different but the fact it doesn't look that horrible I think might be a good sign.

That in my opinion is correct.  Canadian has to be on board for synoptic scale snow. 

[donsutherland1]

Latest EPS and NBE information:

Be wary of snow maps e.g., the 18z NAM's depictions below:

A significant share of the precipitation is rain or mixed precipitation, not snow. For example, at 75 hours when the NAM is piling on the digital snow, the sounding shows the above freezing layer extending almost to 975 mb with above-freezing surface temperatures. Over New York City's urban heat island, that's not accumulating snow. The precipitation ends as snow, but accumulations will likely be limited. Outlier models for heavy snowfall that lack support should be disregarded given the marginal air mass and historic experience with snowfall at above freezing temperatures in New York City.

 

 

 

 

 

 

 

[wilsonvoid1]

my thinking
central park 5 inches jfk 4 white plains 8 poughkeepsie 12 boston 8 hartford 9 sussex county 12 mahopac 14


.

[wdrag]

I'll be keeping this thread active through about 12z Tuesday, with obs for whatever happens this first storm embedded. 

 

At about 12z Tuesday, I'll get the OBS thread specific to the 9th-10th started as it is going probably be many pages (flooding rain, damaging wind, maybe front end snow west of I950. This storm as you're probably aware has potential for 2-3" in 12 hours (rain) and melting whatever water equivalent in NJ (mainly I80 south) is going to result in very rapid rises of rivers on the 10th. Looks to me like considerable river flooding of varying magnitude, awaiting reality. 

Passaic Pine Brook, IF 3" occurs total from these two storms, it goes to MDT flood on the 10th. Some our BOM guidance has 3.5-4" for basins.  Not sure if it will be that much but if your sump pump dont work because of power outages... 

Worthy to monitor. Not Sandy etc but pretty significant.

 

[kingbaus]

Haven't been this nervous in awhile. Hopefully 0z runs can slam us on the backside.

[wdrag]

17 minutes ago, donsutherland1 said:

Latest EPS and NBE information:

Be wary of snow maps e.g., the 18z NAM's depictions below:

A significant share of the precipitation is rain or mixed precipitation, not snow. For example, at 75 hours when the NAM is piling on the digital snow, the sounding shows the above freezing layer extending almost to 975 mb with above-freezing surface temperatures. Over New York City's urban heat island, that's not accumulating snow. The precipitation ends as snow, but accumulations will likely be limited. Outlier models for heavy snowfall that lack support should be disregarded given the marginal air mass and historic experience with snowfall at above freezing temperatures in New York City.

 

 

 

 

 

 

 

the 18z NAM looked off... something not right about it. It's companion 3KM looked better.  Your stats seem to me to  indicate 1" categorical NYC (not 100%).  I have great respect for Cliff Mass (NBM) as I do for Lance.  In the case of of the NBM, its at 0.6" as I interpret.  That is splitting hairs. 1 hr dump at 33F and measuring at 05z could make it 1.5.  The idea though... NYC from your stats should at least see a r/s mix for a while at the start and I think the bulk of Sunday, if not all snow at the start and end. and some sort of whitening of the CP ground. 

Now that we're at 48 hours away... from 2"- 8PM in Wantage NJ... I'm thankful that so far, that which makes forecasters queazy because of a sudden warm wet, or goodbye out to sea "probably" won't be happening. 

[wdrag]

am done for the night... flushing it for now. 

[jdj5211]

00Z NAM running now....let's see what she's got

[psv88]

3 minutes ago, wdrag said:

am done for the night... flushing it for now. 

Thanks Walt. It’s very informative to read your analysis

[donsutherland1]

13 minutes ago, wdrag said:

the 18z NAM looked off... something not right about it. It's companion 3KM looked better.  Your stats seem to me to  indicate 1" categorical NYC (not 100%).  I have great respect for Cliff Mass (NBM) as I do for Lance.  In the case of of the NBM, its at 0.6" as I interpret.  That is splitting hairs. 1 hr dump at 33F and measuring at 05z could make it 1.5.  The idea though... NYC from your stats should at least see a r/s mix for a while at the start and I think the bulk of Sunday, if not all snow at the start and end. and some sort of whitening of the CP ground. 

Now that we're at 48 hours away... from 2"- 8PM in Wantage NJ... I'm thankful that so far, that which makes forecasters queazy because of a sudden warm wet, or goodbye out to sea "probably" won't be happening. 

The 2.0” figure I showed was for Central Park, not JFK. I commented on JFK, because soundings are available for JFK. Sorry about any confusion.

[RU848789]

21 minutes ago, wdrag said:

I'll be keeping this thread active through about 12z Tuesday, with obs for whatever happens this first storm embedded. 

 

At about 12z Tuesday, I'll get the OBS thread specific to the 9th-10th started as it is going probably be many pages (flooding rain, damaging wind, maybe front end snow west of I950. This storm as you're probably aware has potential for 2-3" in 12 hours (rain) and melting whatever water equivalent in NJ (mainly I80 south) is going to result in very rapid rises of rivers on the 10th. Looks to me like considerable river flooding of varying magnitude, awaiting reality. 

Passaic Pine Brook, IF 3" occurs total from these two storms, it goes to MDT flood on the 10th. Some our BOM guidance has 3.5-4" for basins.  Not sure if it will be that much but if your sump pump dont work because of power outages... 

Worthy to monitor. Not Sandy etc but pretty significant.

 

I assume you've seen the latest WPC graphic on QPF from now through Wednesday.  3-6" for most of the EPA-NJ-SENY region would likely put many streams and river basins into major flood stage.  

[kingbaus]

Looking juicy 

[HVSnowLover]

24 minutes ago, jdj5211 said:

00Z NAM running now....let's see what she's got

Whatever it shows likely won't be an actual solution but the NAM is good for entertainment.

[kingbaus]

confluence looking somewhat better as of now.

[BoulderWX]

9 minutes ago, kingbaus said:

Looking juicy 

Agree. Like it so far. Reno or profiles TBD but as you said it looks juicy so far 

[jdj5211]

storm begins around 4pm Saturday still.....low is about 100 miles to the NW compared to 18z run however

[tristateweatherFB]

No clue what ppl talking about but the low is further nw.   This should be warmer. And then have to see second piece of energy 

[kingbaus]

Just now, jdj5211 said:

storm begins around 4pm Saturday still.....low is about 100 miles to the NW compared to 18z run however

Seeing what happens during the 2nd wave with the CCB potentially 

[MJO812]

Just now, tristateweatherFB said:

No clue what ppl talking about but the low is further nw.   This should be warmer. And then have to see second piece of energy 

More confluence though

[BoulderWX]

48 looks very nice

[kingbaus]

Trailing s/w looking stronger 

[MJO812]

Nam is nice