WINTER STORM WARNING Tuesday Midnight - Thursday morning 3/20 - 3/22

While there is generally a strong signal in the forecast for some form of precipitation towards the middle of next week, the track and nature of the system is still very unclear.  Possible outcomes range from mostly rain to all snow, and from showers to another 4-6".    Much depends also on timing, with a daytime event tending towards rain and at night towards snow.

We will know more in the next 24 hours as a key componant of the system, which is still offshore in the Pacific, begins to cross the continent and the NWS can start to get detailed readings.  Until then, prediction will not get any more accurate, so I will update Saturday.


Important Question:  Has The Weather Channel named this storm yet?


The models are still bouncing around with both placement and intensity of next week's system.  This morning's runs are promising, with many members well to our south and then well offshore, but this is just one run.  What I am not seeing is any trend in the models to come into an agreement on a serious storm, but we are still 100+ hours out so much can still change.  So I guess I am back to last week's "cautiously optimistic" forecast stance.  Will update tomorrow.

The map below is the same model and time frame as the one above.  It shows where the model (this is the GEFS, a sister to the GFS) is placing the center of the storm as an average and where all the different componants of the model (the little red numbers) place it before averaging.   This morning the average is further offshore, away from us, and to the south.  The elements are more closely packed with less clustering towards the coast.  Clustering towards the coast can indicate a future shift in that direction though, as we see today, not always.  I this particular run of this particular ,odel were to become reality, this sstorm would miss us completely.  But to keep things cautious, I am also including the previous run of the Euro, which does show us getting something from the storm.



Hasn't the Euro model been better at predictions? 



mfpark said:

Hasn't the Euro model been better at predictions? 

Not as much this year, but only because no model has really been good with these storms.  And remember, the Euro above is 24 hours older than the GEFS right above it.


While the overall sense of the forecast models is that this event (or events -- some of the models show the system in two seperate parts) will not be a snowstorm here, there is still considerable disagreement from model to model, from run to run, and even within the various models.  So we will have to sit tight for another day or so until we get a better sense of this thing.   It does seem that, should we get precipitation, it would most likely be snow and would have a hard time accumulating on paved surfaces, meaning a slushy event, especially if it falls during the day.

It looks breezy and gusty for the time frame, though, that has been a fairly consistent signal for a while.


This complex system is coming into better focus, but there are still some major differences in the models.

What is becoming more likely is that we should have a long period event with at least some snow, most likely during the day Wednesday, with a much lighter snowfall Tuesday.  This Tuesday first shot could be nothing or it could be 1-2" that mostly sticks to the grass.

Wednesday is showing a stronger signal.  One of the things the models do not yet clearly show is whether the two major parts of the system that arrive here in that window combine to form one storm, or pass through seperately.  A combined storm could drop up to 6" Wednesday, a weaker system 1-3"

In addition, I should note there are two more systems behind these two on the long-range forecast.  Friday looks to miss us but Saturday could hold some more snow or rain.

Current NWS snow map.  This could change:


well, my dog has been freaking out since about 10 this morning, so SOMETHING is on the way. He has PTSD from the last two, as his doggie ears sense all the branches falling, thunder snow, and then the snow coming off the roofs in a thunderous rush.


Wow, I agree, the models are all over the place.  Channel 4 is calling for snow mainly Wednesday into Wednesday night, 3-6 south and east of NYC, 1-3 in NYC, and nothing for Maplewood or Morristown.

Mt Holly says it is far to early to call it either way, but that there is a better than even probability that Maplewood and Morristown will see some snow (and close to 90% that the Jersey shore will see snow).  Could be a lot of snow if the high pressure in Ontario moves to the southeast, could be a little snow if it stays to the northwest.

Upton seems to be hedging more towards a low-snow event mainly impacting south and east of NYC.  But they are also leaving plenty of room for up to 6" depending on how far north the low is when it passes through the area and how much snow banding this creates.

I am trying to figure out if and how much snow removal crew to leave on duty Tuesday night and again on Wednesday night for my properties in NYC and I really have no idea at this time.  Tuesday night could be a wash out in terms of snowfall, Wednesday during the day could be heavy, and there is a chance the heavy stuff holds off until Wednesday night or even does not show up at all.  Ugh.

The one good piece of news for me is it does not look like a tree-breaking line-snapping snow for Morristown.  At least not at this time.


Dark Sky has backed way off its predictions 


Ruh Roh.  Upton's "expected snowfall map" has 11" over Newark!  Mt Holly shows 10" over Morristown!!

Max, save us!!  (Yes, I realize that the range is from about 2" up to 11"--but the expected snowfall is close to the high end of the range).

https://www.weather.gov/okx/winter

https://www.weather.gov/phi/winter



doulamomma said:

Dark Sky has backed way off its predictions 

Dark sky about to look stupid.

Details in a few minutes, need to look this over some more.


Well, pardon my anglo-saxon but this forecast is a real sh*tshow.

First the headline:

The NWS has issued a Winter Storm Watch for our area from Tuesday 6:00 pm until midnight Wednesday for rain, snow, and sleet.

But this system is, to quote the NWS Mt. Holly office, "a forecasting nightmare."

What we are fairly confident about:

A two-part winter storm will be affecting the area from Tuesday evening into the small hours Thursday.  The first part of the system, Tuesday evening, is most likely to pass well to our south and not be a serious concern, except for rising gusty winds being possible.

While I was writing the above, the NAM came through with a big hit for the first 12 hours.  I cannot type fast enough to keep up with how fast this is changing.

But somewhere early Wednesday morning, a second passage of the system, this time to our east, is loaded with water (between 0.5" and 1.5" on most models but more on the NAM and Canadian).  The question is where and in what form will that water fall from the sky, and depending on what you look at it could be rain, snow, sleet, or a combination of the three whizzing back and forth like the three stooges from hour to hour.  There is also a possibility of freezing rain overnight.

The commute Wednesday morning could be very difficult. 

As a result of this complexity, and the fact that it is the FIRST DAY OF SPRING TOMORROW the accumulation predictions on this one are a crap shoot, and really will be until we are looking out the window at it.

Here is my best shot at a forecast.  Expect it to change.

Tonight, clear and cold.  Low in the mid 20's.

Tomorrow, gathering clouds in the afternoon.  Could see some sleet or snow in the afternoon and early evening, changing to snow or a wintery mix after dark.

Wednesday, could start out as sleet, freezing rain, wintery mix, or snow, changing to all snow as the storm intensifies.

Total accumulation projected at this time (I kid you not) 2" - 14".  Snow is likely to be heavy and wet, with a layer of sleet.

Shown below are the NWS snow maps.  In the forecast discussion, Mt. Holly says, referring to the maps:  "

Snow and ice maps you see on our Monday afternoon web site posts
are an attempt at a ballpark figure for a set of model guidance
that still has variability. Its for the entire period...start to
finish of the storm. It will be adjusted on the following
shifts. I could see it too high I95 east and too low to the
northwest. Just dont know for sure. Ptype and amts will play a
role.

So take them at their word.

Winter Storm Watch

URGENT - WINTER WEATHER MESSAGE...CORRECTED
National Weather Service New York NY
431 PM EDT Mon Mar 19 2018
NJZ002-004-006-103>108-NYZ067>075-176-178-200400-
/O.COR.KOKX.WS.A.0008.180320T2200Z-180322T0400Z/
Western Passaic-Eastern Passaic-Hudson-Western Bergen-
Eastern Bergen-Western Essex-Eastern Essex-Western Union-
Eastern Union-Orange-Putnam-Rockland-Northern Westchester-
Southern Westchester-New York (Manhattan)-Bronx-
Richmond (Staten Island)-Kings (Brooklyn)-Northern Queens-
Southern Queens-
431 PM EDT Mon Mar 19 2018
...WINTER STORM WATCH IN EFFECT FROM TUESDAY EVENING THROUGH
WEDNESDAY EVENING...
* WHAT...Heavy wet snow possible. Total wet snow accumulations 
of  5 to 11 inches, with locally higher amounts possible.
* WHERE...New York City, the Lower Hudson Valley and northeast 
New  Jersey.
* WHEN...From Tuesday evening through Wednesday evening.
* ADDITIONAL DETAILS...Plan on difficult travel conditions,  
including during the evening commute on Wednesday. Significant  
reductions in visibility are possible. A combination of the  
heavy wet snow and wind gusts of 25 to 40 mph could bring down  
tree limbs and power lines, creating power outages.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Winter Storm Watch means there is potential for significant
snow, sleet or ice accumulations that may impact travel. Continue
to monitor the latest forecasts.



should have stayed in bed


can you explain “watch” vs “warning”? Is it simply a matter of timing or does it more indicate the level/degree of the storm?



conandrob240 said:

can you explain “watch” vs “warning”? Is it simply a matter of timing or does it more indicate the level/degree of the storm?

Timing and probability.

From the NWS:

Winter Storm Watch

A Winter Storm Watch is issued when there is the potential for significant and hazardous winter weather within 48 hours. It does not mean that significant and hazardous winter weather will occur...it only means it is possible.

Significant and hazardous winter weather is defined as a combination of: 1)  5 inches or more of snow/sleet within a 12-hour period or 7 inches or more of snow/sleet within a 24-hour period AND/OR 2)  Enough ice accumulation to cause damage to trees or powerlines. AND/OR 3)  a life threatening or damaging combination of snow and/or ice accumulation with wind.

Blizzard Warning

A Blizzard Warning means that the following conditions are occurring or expected within the next 12 to 18 hours. 1) Snow and/or blowing snow reducing visibility to 1/4 mile or less for 3 hours or longer AND 2)  Sustained winds of 35 mph or greater or frequent gusts to 35 mph or greater. There is no temperature requirement that must be met to achieve blizzard conditions.

Winter Storm Warning

A Winter Storm Warning is issued when a significant combination of hazardous winter weather is occurring or imminent.

Significant and hazardous winter weather is defined as a combination of: 1)  5 inches or more of snow/sleet within a 12-hour period or 7 inches or more of snow/sleet within a 24-hour period AND/OR 2)  Enough ice accumulation to cause damage to trees or powerlines. AND/OR 3)  a life threatening or damaging combination of snow and/or ice accumulation with wind.

Ice Storm Warning

¼ inch or more of ice accumulation.

Winter Weather Advisory

A Winter Weather Advisory will be issued for any amount of freezing rain, or when 2 to 4 inches of snow (alone or in combination with sleet and freezing rain), is expected to cause a significant inconvenience, but not serious enough to warrant a warning.

More details here: https://www.weather.gov/okx/wwa_definitions




I've got a bad feeling about this.


WINTER STORM WARNING

A two-part nor'easter is expected to impact the area tonight through Wednesday night with possible rain, sleet, freezing rain and snow.  Significant accumulations are becoming more likely, especially Wednesday afternoon.

That said, the output of the computer models is still very inconsistant. A storm of this magnitude, this late in the year, is almost unprecedented.   While some runs have a signal justifying the snow totals the NWS are projecting, the latest runs are a bit more moderate.  It is possible the NWS is hedging their bets a little.  We can hope.

But, to be clear, we are talking about a major storm.  The uncertainty is about *how much*, not *if*.

Forecast:

Today, gathering clouds, cool, might see some drizzle or flurries.

Tonight starts out with light precipitation, rain or sleet, perhaps some light snow.

By Wednesday morning, expect more steady precipitation, sleet, snow, or wintery mix.  Precipitation becomes all snow as this very long winter event intensifies Wednesday afternoon and evening, with heavy snow likely for a while as bands of very intense precipitation set up and pass through.  The location of these bands will have a lot to do with where the heaviest snow falls. Thundersnow is a possibility.

Snow continues into Wednesday night, ending early Thursday morning.

Total snowfall for the next 48 hours, including any accumulated sleet, 8" - 15"

Snow will be heavy and wet, and with winds steady in the 20-25mph range, we may have more trees down and outages.

There is still some variability in this forecast.

Winter Storm Warning

URGENT - WINTER WEATHER MESSAGE
National Weather Service New York NY
344 AM EDT Tue Mar 20 2018

...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 8 AM
EDT THURSDAY...

* WHAT...Heavy mixed winter precipitation transitioning to heavy
  snow is expected. Total snow accumulations of 12 to 16 inches
  and light ice accumulations are expected.

* WHERE...Portions of northeast New Jersey and southeast New
  York.

* WHEN...From midnight tonight to 8 AM EDT Thursday.

* ADDITIONAL DETAILS...Travel will be very difficult to
  impossible, including during the evening commute on Wednesday.
  Expect significant reductions in visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning means significant amounts of snow, sleet
and ice will make travel very hazardous or impossible. Check
local Department of Transportation information services for the
latest road conditions.

&&




Ugh.  I am staying home tomorrow and plan to shovel early and often.  The last dump of 21 inches just about killed me to move.


Max,

On Feb 2 the all-knowing Punxsutawney Phil predicted only 6 more weeks of winter.  

Those 6 weeks were up on March 15th, so how can you possibly talk about snow for tomorrow?



mfpark said:

Ugh.  I am staying home tomorrow and plan to shovel early and often.  The last dump of 21 inches just about killed me to move.

I shoveled in the afternoon and at night, and the heavy snow still got me the next day... but maybe it was better than if I hadn't.



tomcat said:

Max,

On Feb 2 the all-knowing Punxsutawney Phil predicted only 6 more weeks of winter.  

Those 6 weeks were up on March 15th, so how can you possibly talk about snow for tomorrow?



ugh I’m in Miami and trying to get home. I’m supposed to land at 6pm this evening. :/



mammabear said:

ugh I’m in Miami and trying to get home. I’m supposed to land at 6pm this evening. :/

Tonight should be fine other than crowding due to people trying to change Wednesday flights, a good number of which will probably be cancelled.


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