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wdrag

OBS and nowcast Thursday morning 2/18 - 11PM Friday 2/19/21

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515A/19: Intermittent event continues and precip intensification gradually changes freezing rain/freezing drizzle sleet near I95 eastward to snow. Ending time still the same, this afternoon sometime ne PA/nw NJ/se NYS and the remainder sometime this evening-early tonight.  Between 7AM-ending time, I expect a general base 1/2" new throughout the forum after 7am with possibly as much as 3" , the heaviest seeming to be near NYC into CT per a decent band developing this morning-midday, and possibly a nice hour of closing snow this evening.  Easy melting process on pavement expected during the midday-afternoon hours where temps above 25F and when snow lessens it's intensity.  Manageable but fun for us. 

 

450AM/18: overall no change in expectations. Might get started an hour or so slower but already flurries or steady light snow have occurred se NYS, ne PA, CT, far nw NJ.  See latest NWS products and your own judgement.  548AM added the 4AM NWS regional snowfall expectation that went into their early morning products. 

 

An overall manageable  24-36 hour wintry precipitation episode will probably see snow change to a mixed bag in NJ/LI, with even a bit of rain possible for a time eastern LI and the NJ coast.  

Snow should begin in seNYS/NJ/NYC between 2AM and 7AM Thursday and by 9AM elsewhere. It should snow moderately for a time sometime between 9AM and 4PM Thursday before probably transitioning to mixed precipitation or even quitting for a time in NJ/LI toward Thursday evening. Precipitation may intensify again as it probably changes back to snow everywhere on Friday and then gradually ends from west to east during the afternoon, or early Friday night. 

Graphics are the 21z/17 NWS ensemble 48 hour prob for 8"+ of snow, 4"+, the 12z/17 SPC HREF snowfall ending 00z/19 = 7PM Thursday, the 5PM/17 actual NWS regional deterministic (approximate) snowfall forecast and the 21z/17 WPC ensemble prob of .01" freezing rain. Thursday afternoon into Friday morning. 

Please contribute as needed. 

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Screen Shot 2021-02-18 at 5.42.48 AM.png

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Just now, LibertyBell said:

Walt, locals are going for a negligible change at the very end to a mix, with 6" or more for most of the area outside of southern NJ

Saying that the storm is trending SEward

Nothing more I can add. I've shown the NWS forecast snowfall. You can see there is hesitancy in the NWS decision regarding the watch, which to me indicates, is it warnable because doubts either of mixed precip not quite reaching warnable criteria, or is the duration too long to meet an 8" snowfall criteria over 24 hours.  Minimum snowfall of 3" looks good for the entire forum with a max over the entire event of 8 or 9".  So, if it's all snow NYC, we pop to at least top 5 February snowfall at CP (presuming the NWS 7" forecast is within an inch or so). I just see potential for mixed precip to LI and most of NJ,  and what about melting as it falls during the increasingly high sun angle midday Friday.  Those answers I do not have but attempt to provide some wiggle room on outcomes.  I hope it snows to the satisfaction of all members. For me here in Wantage NJ, I look for 5-9" but maybe this range will be too high?  This may be the last I comment till tomorrow morning.  Have at it. 

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4 minutes ago, wdrag said:

Nothing more I can add. I've shown the NWS forecast snowfall. You can see there is hesitancy in the NWS decision regarding the watch, which to me indicates, is it warnable because doubts either of mixed precip not quite reaching warnable criteria, or is the duration too long to meet an 8" snowfall criteria over 24 hours.  Minimum snowfall of 3" looks good for the entire forum with a max over the entire event of 8 or 9".  So, if it's all snow NYC, we pop to at least top 5 February snowfall at CP (presuming the NWS 7" forecast is within an inch or so). I just see potential for mixed precip to LI and most of NJ,  and what about melting as it falls during the increasingly high sun angle midday Friday.  Those answers I do not have but attempt to provide some wiggle room on outcomes.  I hope it snows to the satisfaction of all members. For me here in Wantage NJ, I look for 5-9" but maybe this range will be too high?  This may be the last I comment till tomorrow morning.  Have at it. 

well probably not all snow, but about 80% snow with mixing when the precip is light like you said.  The lack of WSW seems to be because of duration, except it's entirely possible we get to 6 inches by 4 PM. 5-9 sounds good for the majority of the area, which is what locals are going with

 

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Quick temp drop off here, down to 23. A few inches or so of absolute cement on the ground here in most places from before and mountains of dirt ice in the parking lots. 

Should be a fairly straightforward 5-8” total for most of us. 3-5” for the twin forks, lower NJ shore and north of I-84. 

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1 hour ago, wdrag said:

I did miss that (color coded) that OKX moved to an advisory only.  That might be right despite their 7" forecast for NYC. 

I like the call even though it's probably unpopular. Strictly by their guidance the forecast totals fall below warning criteria. And I think it's good to reserve warnings for the biggest events so the public doesn't get numb to them.

Hopefully for us snow lovers it proves to be the wrong decision.

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3 hours ago, eduggs said:

I like the call even though it's probably unpopular. Strictly by their guidance the forecast totals fall below warning criteria. And I think it's good to reserve warnings for the biggest events so the public doesn't get numb to them.

Hopefully for us snow lovers it proves to be the wrong decision.

I don't like the decision, since much of the snow will be falling during the day, perhaps at a pretty good clip, making travel difficult as all snow will accumulate on any untreated surfaces with temps well below 32F for everyone.  If it's a 50-50 call, I'd always err on the side of being conservative, probably from spending much of my career being involved in sitewide emergency management for a 5000 person site in Rahway NJ (Merck), as a side job, but an important one.  Many people may dismiss this and if it overperforms even a little bit the afternoon rush could be a problem, especially.  

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4 hours ago, eduggs said:

I like the call even though it's probably unpopular. Strictly by their guidance the forecast totals fall below warning criteria. And I think it's good to reserve warnings for the biggest events so the public doesn't get numb to them.

Hopefully for us snow lovers it proves to be the wrong decision.

Right well personally I'd move Warning criteria over to 10" snowfalls and higher, especially since we no longer have Heavy Snow Warnings.  We dont really consider an 8 incher  a big snowstorm.

 

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58 minutes ago, RU848789 said:

I don't like the decision, since much of the snow will be falling during the day, perhaps at a pretty good clip, making travel difficult as all snow will accumulate on any untreated surfaces with temps well below 32F for everyone.  If it's a 50-50 call, I'd always err on the side of being conservative, probably from spending much of my career being involved in sitewide emergency management for a 5000 person site in Rahway NJ (Merck), as a side job, but an important one.  Many people may dismiss this and if it overperforms even a little bit the afternoon rush could be a problem, especially.  

This is an important consideration especially with past history when traffic on NYC gets shut down with even 4 inch snowfall that falls during one of the rush hour periods

 

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330AM: Wantage NJ, at the nw tip of NJ We too flurries began here around 323A. 22.6/7.2  Notice from mPing snowing into s CT part of the forum  as well. Notice NAM about 40% heavier on qpf NYC on its 06z cycle. Just getting up so no feel on what may have changed and is reliable via 00z-06z cycles but snow is at hand. Good news.

450AM:  flurries continue. no acc. 21/15. Dewpoint increased 8F since 330A. 

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Slept 2 hours and woke up, lol. Mt. Holly cut back a little (maybe 1") in some places, but not all on both the map and in the warnings ("4-6 inches with locally higher amounts" now for most). On the flip side, Channel 7 increased their general snowfall for the entire area from 4-8" to 5-9". Sleet is still a significant risk to these snowfall amounts, especially south of 276/195 and SE of the NJ TPK from 195 up to about the Raritan.  And of course the 6Z NAM looks great (6-10" for most over both parts), while the RGEM looks anemic (3-5") and the GFS ok (4-7").  In addition, radar is juicier than previously modeled and it looks like accumulating snow will arrive by 6-7 am for most of CNJ, which is an hour or two earlier than expected. Nap time for now.

qwPAnkI.png

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...28.8* here on the east end..overcast w/ heavy virga.

actually radar looks good to the south and west..

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1 hour ago, RU848789 said:

Slept 2 hours and woke up, lol. Mt. Holly cut back a little (maybe 1") in some places, but not all on both the map and in the warnings ("4-6 inches with locally higher amounts" now for most). On the flip side, Channel 7 increased their general snowfall for the entire area from 4-8" to 5-9". Sleet is still a significant risk to these snowfall amounts, especially south of 276/195 and SE of the NJ TPK from 195 up to about the Raritan.  And of course the 6Z NAM looks great (6-10" for most over both parts), while the RGEM looks anemic (3-5") and the GFS ok (4-7").  In addition, radar is juicier than previously modeled and it looks like accumulating snow will arrive by 6-7 am for most of CNJ, which is an hour or two earlier than expected. Nap time for now.

qwPAnkI.png

And to dovetail, the regional look adds OKX etc. 

Screen Shot 2021-02-18 at 5.42.48 AM.png

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5 minutes ago, wdrag said:

And to dovetail, the regional look at adds OKX etc. 

Screen Shot 2021-02-18 at 5.42.48 AM.png

I would probably include nyc in the 6-8 range as well..seems like some of the banding is kinda setting up over nyc as we speak and points south.

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1 minute ago, Northof78 said:

New nam back to an inch of total QPF for most of the region with both waves, and a nice hit from 

The radar is popping right over n.y.c..we might get some of the best banding for the next few hours..its gonna snow and fast pretty soon around here.

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25 minutes ago, EpicHECS said:

I had snow apparently, because the roads are all white but it doesn't appear to be doing anything now and the NWS has lowered totals in my area to 4-7". 

Where are you located ?

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