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wdrag

Light snow possible between 1/19 Tue night-1/22 Noon Friday.

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Topic started to follow whether or not NYC can muster it's first measurable snow since December 17.  Other parts of the forum had some general snow on the 3rd. 

Lots of debate on what will happen, or not, so we might as well have some fun tracking it and keep the 25-26th and beyond out of this topic.  

First measurable snowfall (near climo) POSSIBLE between Tue night and Thursday night.  Two opportunities and both could be suppressed/dried out in northerly flow.  Also could be too warm to stick in NYC if snow were to occur, and especially if it occurs during the daylight hours.

These are probably minimal impact events, if any. 

Guidance probabilities are possibly conservative for short periods of light snow in a 12 hour period, especially with currently expected melted qpf under 0.10. Opportunities are associated with an esewd moving shortwave from the Great Lakes to new England early Wednesday and another esewd moving short wave from the Great Lakes late Thursday.

Climo snowfall for this during the 'climatologically' coldest winter average temps in NYC:  CP  0.2-0.3; POU 0.4.-0.5".  

Short events. As of this 1/15 412PM start,  probably under 8 hours total, possibly less than 1 hour in parts of the area?

I would hope we can muster half an inch between these two short wave passages in part of our NYC forum, be it se NYS, CT, e LI or maybe we get lucky for much of our forum?

I'll be glad to adjust this topic with any interesting information that is added from our group and of course if the models  somehow improve our chances which right now, per 12z/15 (Friday) NWS MOS and WPC extended, are less than 50%. 

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35 minutes ago, wdrag said:

 

 

Topic started to follow whether or not NYC can muster it's first measurable snow since December 17.  Other parts of the forum had some general snow on the 3rd. 

Lots of debate on what will happen, or not, so we might as well have some fun tracking it and keep the 25-26th and beyond out of this topic.  

First measurable snowfall (near climo) POSSIBLE between Tue night and Thursday night.  Two opportunities and both could be suppressed/dried out in northerly flow.  Also could be too warm to stick in NYC if snow were to occur, and especially if it occurs during the daylight hours.

These are probably minimal impact events, if any. 

Guidance probabilities are possibly conservative for short periods of light snow in a 12 hour period, especially with currently expected melted qpf under 0.10. Opportunities are associated with an esewd moving shortwave from the Great Lakes to new England early Wednesday and another esewd moving short wave from the Great Lakes late Thursday.

Climo snowfall for this during the 'climatologically' coldest winter average temps in NYC:  CP  0.2-0.3; POU 0.4.-0.5".  

Short events. As of this 1/15 412PM start,  probably under 8 hours total, possibly less than 1 hour in parts of the area?

I would hope we can muster half an inch between these two short wave passages in part of our NYC forum, be it se NYS, CT, e LI or maybe we get lucky for much of our forum?

I'll be glad to adjust this topic with any interesting information that is added from our group and of course if the models  somehow improve our chances which right now, per 12z/15 (Friday) NWS MOS and WPC extended, are less than 50%. 

If frozen fate smiles and I catch a snowflake landing on the postage stamp you’ll be the first to know. I’m hoping one of the later events can give my little UHI piece of paradise something measurable. I’m tired of that, finally gone to its fauna heaven, tomato plant whispering one and done.  I know I should pull it up and recycle but I can be an obstinate piece of ####, also. As always ....

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Basically no change to this topic since reviewing the 00z/16 OP's and ensembles.  EC is our best model bet right now.  I could have added a chance that the events for Li might be rain for Thursday, but I don't think so. Yet that is a possibility. What I do think is that there will be at least an hour or two of snow showers for parts of the forum, especially this coming Thursday.  

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As of 7AM Sunday 1/17 I have no changes to anything written since inception of this thread. No increases, no decreases. It's minor if it occurs.

I sort of like Wednesday morning when I think we could see pretty decent lapse rates and a decent short wave passage.  The possible snow or flurry event for late Thursday-early Friday is more WAA related, after what should turn out to be a pretty cold Wednesday. Hdre's the 06z/GEFS membership and mean as well as the anomaly modeled for 18z Wednesday.

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NYC CP: While I expect scattered dustings to ~1/2 snow shower accumulations this week in parts of the I84 corridor down to just north and and west of NYC,  the chance of CP seeing 0.1" snowfall in time for an observation is rather low.  It's a matter of timing any snow shower with temps cool enough to allow accumulation and the observer to record it. The only reason for any attention to such a minor occurrence, is that it hasn't measured snowfall here in CP since the storm of the 16th-17th December.   

Instability and changes in instability with a trough passage both surface and aloft will be notable Wednesday (th instability already is). A NAM TSection check is showing the cold pool aloft and the RH spike but only a smattering of measurable around the NYC forum so odds favor no occurrence of 0.1" snowfall in CP.  

Already, late today, the snow showers sliding out NYS and PA from the west northwest may turn to sprinkles as they approach the near NYC environs but it will be colder Wednesday for a much more likely sustaining of flurries or even a snow shower into NYC or LI. 

Haven't studied Thursday-Friday, as it's a minor chance as it stands now-still possible but not a probable measure for NYC CP. 

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8 minutes ago, JoshSnow said:

Why is there a topic for non events like this?

First, it’s weather. Second, there is educational value e.g., Walt Drag, explained, “A NAM TSection check is showing the cold pool aloft and the RH spike but only a smattering of measurable around the NYC forum so odds favor no occurrence of 0.1" snowfall in CP.” If one goes to Bufkit, among other places, one can better see what a top meteorologist sees and learn to evaluate potential events in a fashion that can only increase one’s own skill. Third, it’s fun and interesting to read such discussions, if one enjoys meteorology.

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Thank you Don,  I don't have BUFKIT because of my MAC and so get by with Tsecs, R#, and various gust algorithms.

On dustings coming soon to nearby yards in our forum.  Not sure if anyone noticed the dew point isn't dropping.  That's a very good sign that we'll have enough low lvl RH to support snow showers making it to the surface. A few graphics follow that focus here near NYC 6A-2PM Wednesday. My dewpoint has been sitting around 30 since late yesterday.

Where they measure 1/4-1/2"... within10 Mi of CP??  Here's the 12z/18 FOUS. Note T1-T5 lapse rates over 15C and ...  strong stability change (drying out late Wednesday afternoon +15C change from 18z/20-00z/21). That and the wind shift-cold pool aloft should result in a chance of measurable SPS snow showers down to LI.   Used the NAM12K. 3K not quite as impressive but still notable. ICON, RGEM and recent EC have it in or within 15M of NYC.  I don't expect the GFS to be as clear cut.   The HRRR per NWS friend telcon is supposed to shine in convection. Not summer, but this is convective signal. Here's the12z/18  HRRR model for 12z Wednesday...bearing down from the nw.  Let's see if this risk diminishes or materlializes. I'm thinking this will happen but whether CP gets more than flurry??  But it could drop briefly to 3/4mi?  We'll see what gives.  IF the dew point can hold near 25F through 12z Wednesday... I like the odds.   I also added for those unfamiliar: credit to the online met and his support group... the FOUS interp guide.  Most people probably don't use the FOUS to their advantage.  It's a good tool to have for  a quick idea. Back at 4PM for a new thread to take into account NEG NAO impressions and  others, plus my own reevaluation for a new thread (25-26 and or possibly 27).

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5 minutes ago, JoshSnow said:

This is a non event and there shouldn’t be a section about this in my opinion.

We disagree. If you don’t wish to read a thread, you are not compelled to do so. I, for one, enjoy reading well-reasoned messages. Walt Drag’s posts are outstanding (as were his AFDs for those who recall his tenure at the National Weather Service). One can see both his expertise and passion for the weather.

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45 minutes ago, JoshSnow said:

This is a non event and there shouldn’t be a section about this in my opinion.

I am not understanding how your suggestion would make the world a better place, or for that matter how it would not detract from the value of this forum.  Perhaps if I understood what it is you are trying to accomplish I would feel differently.

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2 hours ago, donsutherland1 said:

First, it’s weather. Second, there is educational value e.g., Walt Drag, explained, “A NAM TSection check is showing the cold pool aloft and the RH spike but only a smattering of measurable around the NYC forum so odds favor no occurrence of 0.1" snowfall in CP.” If one goes to Bufkit, among other places, one can better see what a top meteorologist sees and learn to evaluate potential events in a fashion that can only increase one’s own skill. Third, it’s fun and interesting to read such discussions, if one enjoys meteorology.

Don for some of us the adage “ a little knowledge is a dangerous thing”. Applies quite well. Now I’m wondering what a lot of knowledge might do. As always ...

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This may be getting a little more interesting for ne PA/se NYS/n NJ/ LI/s CT Wednesday morning, Probably worth monitoring for a small accumulation within 4 hours of sunrise Wednesday.  Some of the modeling is trying to combine the cold frontal trough instability snow showers with an area of weak low pressure moving off s NJ. No consensus on that occurrence. Otherwise the cold frontal surge of instability changes, spikes in RH etc as discussed yesterday prevails. If it doesn't snow by Noon Wednesday, then the afternoon snow showers will be gradually drying out to virga in the gusty northwest flow of drier colder air.  Right now I expect fairly widespread coverage of dustings to 3/4" ne PA/n NJ/se NYS/s CT - LI including NYC.  Whether it's more than a trace NYC or observed officially before melting (NYC mostly 8A-11A), that i don't know.

 

If the 12z and beyond cycles of the RGEM/HRDPS drop it, then I've hit this too hard. 

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Parts of the region usually see heavier snow squalls when the mid level lapse rates are this steep. Could be the type of morning when the visibility briefly falls to 1/4 of a mile in a few spots. Winds may also beat expectations since the low level lapse rates become so steep by the afternoon.

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53 minutes ago, bluewave said:

Parts of the region usually see heavier snow squalls when the mid level lapse rates are this steep. Could be the type of morning when the visibility briefly falls to 1/4 of a mile in a few spots. Winds may also beat expectations since the low level lapse rates become so steep by the afternoon.


 

Agreed... nice lapse rate post to demo the potential.  I do not think we can say no problem.  IF this occurs as anticipated. roads will not be treated during the heavier of whatever Inauguration morning commute, but I'm pretty sure slippery spots will develop, un beknownst to some of our faster drivers from PA to NYC. Definitely a potential SPS event. 

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Tomorrow morning  should be a bit of fun around here... am hoping NYC can measure by 7A. If it's after 7A,  then the 1P may not catch the possible 0.1" dusting of snow.

Unsure how this turns out but should  be bit active with dustings of snow up to 3/4" in our forum (even in some of the boroughs and LI) between 3AM and Noon with a couple straggler snow showers in the afternoon.

This after two successive days of afternoon flurries in the forum per mPing.  

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11 hours ago, wdrag said:

Tomorrow morning  should be a bit of fun around here... am hoping NYC can measure by 7A. If it's after 7A,  then the 1P may not catch the possible 0.1" dusting of snow.

Unsure how this turns out but should  be bit active with dustings of snow up to 3/4" in our forum (even in some of the boroughs and LI) between 3AM and Noon with a couple straggler snow showers in the afternoon.

This after two successive days of afternoon flurries in the forum per mPing.  

Lee Goldberg had a prediction of 0.6" for NYC and Long Island (based on the HRRR I think?) said snow squalls are possible between 7 AM and 11 AM.

 

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No change for me on this mornings event.. now in progress. S-/S--  in Wantage..tinge of white on the ground since sometime just before 5A. mPING has flurries to just outside NYC at 545A. IF NYC is to measure, my guess is primary time as listed above in previous post... could melt on the CP snowboard, esp if no check between 7A-1P.  NAM3K centers NYC max chance on the front end around 8A.  That's the general snow band.  Snow showers possible til 2PM NYC but chances are NYC won't measure on the snow showers, while the suburbs do. Enjoy whatever you get. Trace here in this part of Wantage NJ 545A. 

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