OT: Winter Storm Likely to Impact Our Area 1/16-17

[RU848789]

As we've been discussing in the pattern thread, the first threat of the ongoing cold and potentially snowy pattern likely through the end of January, is now about 5 days away. Specifically, a major winter storm is now very likely for the NE US and parts of the SE US and Mid-Atlantic, too. For our area, if the track is inland or just on the coast, there would be some snow to start for the 95 corridor, but mostly rain, with heavy snows 30-50 miles inland of 95. If the track is a bit offshore, everyone gets a major snowstorm (major to me is 8" or more and >12" is on the table) and if the track is well offshore it could be several inches of snow for 95 towards the coast with less inland. Way, way, way too early for any specific forecast, as per the wide range of potential outcomes - the take home message here is simply that a potentially impactful winter storm is looking likely for our area late Sunday into Monday.

Right now 2 of the 4 global models have track a bit inland (GFS/CMC) with a bit of snow to start and then mostly rain for 95 and some heavy snow and then mix well inland, while one (Euro) has a coastal hugger with snow to rain for the 95 corridor and heavy snows just NW of 95, while one (UK) has a major snowstorm for our entire area, so a wetter solution for the 95 corridor looks just a bit more likely. Still 5 days out and track errors at this point are still at least 200 miles, so everything except a complete rainstorm for everyone and a complete miss for everyone are very much in play (and even a rainstorm and a miss are not totally out of the question, but are far less likely). Also, right now most of the models have heavy snows down into GA/SC/NC/VA/MD (away from the coast) on Sunday, which is typical for a "Miller A" type winter storm that gets its start near/in the Gulf of Mexico and then usually moves to just off the coast of NC and then moves up the coast (or inland) as a nor'easter in our area.

With regard to model accuracy at this point, the NHC forecast track error for fully formed tropical systems is within a circle of radius of 200 miles at 5 days and we're at about 5 days before the event here and the forecast error for a poorly sampled system currently in the Pacific right now, which will morph and possibly phase in various unpredictable ways over the next 5 days, is a bit higher than that. And all we'd need for the GFS/CMC runs is a shift of about 100-150 miles for heavy snow along 95 and we'd need a shift of maybe 50 miles for that for the Euro. Also, note that the ensemble forecasts for at least the GFS and Euro (where the models are run dozens of times with variation of the initial conditions to gauge sensitivity of the models to those) indicate that the ensemble mean track is offshore and much snowier for the 95 corridor/coast and ensembles are often used by more pros at this point than any individual operational model run.

One last point: no matter what, we're going to have an astronomical high tide on Monday, so if we do get a strong coastal storm, coastal erosion and flooding could become an issue. Too early for model maps and stuff yet, IMO, but these are readily available in the storm threads on the weather boards linked below (or from Pivotal or Tropical Tidbits sites). This afternoon's NWS-NYC discussion was pretty good, below.

https://www.33andrain.com/topic/2076-116-17-high-impact-winter-weather-event/page/9/

https://www.americanwx.com/bb/topic...-jan-15-into-early-monday-jan-17-2022/page/8/

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

Area Forecast Discussion
National Weather Service New York NY
352 PM EST Tue Jan 11 2022

LONG TERM /THURSDAY THROUGH TUESDAY/...

Meanwhile, another shortwave moves onshore along the Pacific
Northwest on Thursday before digging south across the Central
US this weekend. In collaboration with neighbors, nudged PoPs
up a bit over NBM Sunday night and Monday as 12z guidance has
come into better agreement this cycle that a surface low
develops over the Southeast this weekend before moving north and
east. Global ensemble means track the low near the 40/70
benchmark early Monday, which would help keep the region cold
enough for all snow. However, with uncertainty as to the exact
strength and position of the low, the finer details will still
need to be resolved. Given a bit better consistency/convergence
with models and their respective ensembles systems, the
potential exists for a storm system to impact the region late
this weekend into early next week.

 

[RUPete]

Time to start monitoring the weenie boards now.

 

[e5fdny]

Keep me in the loop.

This one could affect me personally and more nerve-wracking, professionally.

 

[RU848789]

Interesting discussions from the NWS in Philly and NYC, with the Philly office more pessimistic on snow than the NY office, but both noting the high degree of uncertainty and wide range of possible solutions this far out; the NYC discussion also notes the difference between the more inland operational models and their more coastal ensemble means, which add to the uncertainty. Since the energy which will become our storm won't be on shore and highly sampled until Thursday morning, the model runs until then need to be taken with a grain of salt.

Area Forecast Discussion
National Weather Service Mount Holly NJ
643 AM EST Wed Jan 12 2022
LONG TERM /SATURDAY THROUGH TUESDAY/...

The trends in the operational models with regard to the system
for Sunday into Monday are now favoring a low tracking up the
East Coast.

A robust mid level low is forecast to move onto the Pacific
Northwest Coast on Thursday. It should combine with additional
mid level energy dropping down from western Canada on Friday
over the northern Plains. The system is expected to reach the
lower Mississippi River Valley on Sunday morning. The sharpening
of the mid level trough is anticipated to cause the
strengthening surface low to track up the East Coast rather than
moving out to sea. As a result, we are anticipating
precipitation for Sunday afternoon into Monday morning. The core
of the cold air to our north and northeast is expected to move
quickly out to sea. Based on the forecast scenario, much of our
region would transition from frozen to liquid precipitation.
With the event being four days away, there is a good deal of
room for uncertainty so we will continue to monitor trends and
adjust the forecast accordingly.

Area Forecast Discussion
National Weather Service New York NY
726 AM EST Wed Jan 12 2022
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...

Models agree that a strong shortwave will track from the central
Plains Friday night, closing off as it works south and east into the
Lower Mississippi Valley, then heading northeast across the
Tennessee Valley on Sunday. The 00Z guidance continues to show a
westward shift in the surface low track in both the deterministic
and ensemble runs. However, the deterministic models continue to be
farther west than their ensembles. So while the deterministic
guidance points to a snow to rain event with an inland low track, it
would be prudent to be gradual with this westward shift as the
upstream Pac energy is still well offshore. In addition, there are
other factors to consider, how quickly the mid level confluent
zone departs from eastern Canada and a northern branch kicker
that trails the system. So it`s likely this is not the final
solution. Thus, right now still staying with a mainly snow
forecast with some mixing in of rain along the coast. Should the
westward trend continue, the transition to rain would become
increasingly likely, especially for coastal areas. At this time,
precipitation looks to begin late Sunday afternoon/early
evening, then ending Monday afternoon.

 

[RUPete]

NYC office is going to consider areas north and west of NYC, correct? Everyone knows Philly is on White Bus's heat island and they never get snow.

 

[mikemarc1]

Think it’s safe to say the area will avoid the huge snows..especially if these models are correct and starting to converge on an inland track. But certainly a thump of snow is possible

 

[RU848789]

NYC office is going to consider areas north and west of NYC, correct? Everyone knows Philly is on White Bus's heat island and they never get snow.

Philly covers the Poconos, Sussex, Warren and Morris and points south to DE/SNJ, while NYC covers Passaic/Bergen down to Union, as well as the Hudson Valley up to Orange/Putnam - see the map...

 

[RU848789]

Think it’s safe to say the area will avoid the huge snows..especially if these models are correct and starting to converge on an inland track. But certainly a thump of snow is possible

Disagree. Even the furthest inland solution, the GFS is still showing a few inches for the 95 corridor to start, followed by rain, but has 6" or more not far inland (like N/W of 80/287), so it wouldn't take a huge shift to get substantial snow into the 95 corridor, like the UK shows. Until the main shortwave is ashore and well sampled tomorrow morning, I wouldn't make any definitive forecast for this storm.

 

[mikemarc1]

Disagree. Even the furthest inland solution, the GFS is still showing a few inches for the 95 corridor to start, followed by rain, but has 6" or more not far inland (like N/W of 80/287), so it wouldn't take a huge shift to get substantial snow into the 95 corridor, like the UK shows. Until the main shortwave is ashore and well sampled tomorrow morning, I wouldn't make any definitive forecast for this storm.

we shall see. My post is certainly not a “definitive forecast” but with these trends, the heaviest snows in our area is looking less and less likely.

 

[bac2therac]

in these type of setups where the low is running inland the thump doesnt always occur and the transition to rain comes in quicker, the snow maps at this time out 4 days are not really accurate at all. The key to watch is the setup of the where the low pressure is going.

 

[mikemarc1]

in these type of setups where the low is running inland the thump doesnt always occur and the transition to rain comes in quicker, the snow maps at this time out 4 days are not really accurate at all. The key to watch is the setup of the where the low pressure is going.

dry slotting also becomes an issue.

 

[RU848789]

we shall see. My post is certainly not a “definitive forecast” but with these trends, the heaviest snows in our area is looking less and less likely.

I consider the entire NWS-Philly/NYC areas to be "our area" and a decent part of that area will still likely get heavy snows, even if 95/coast do not. If you're talking about just the 95 corridor, I agree that mostly rain is more likely than mostly snow, but mostly snow is still definitely possible.

 

[RU848789]

12Z GFS came a little east, showing a few inches for 95 then rain, but 6"+ well inland, while the 12Z UK went from full snowstorm for all at 0Z last night to a run like the Euro with the low 100 miles west of where it was, meaning almost all rain for 95, but 6" or more 25+ miles NW of 95. Certainly not good for snow lovers, but likely great for the ski resorts. Still too early to discount snow for 95, IMO, given how far out we are and the main energy still being offshore of the PacNW.

 

[mikemarc1]

I consider the entire NWS-Philly/NYC areas to be "our area" and a decent part of that area will still likely get heavy snows, even if 95/coast do not. If you're talking about just the 95 corridor, I agree that mostly rain is more likely than mostly snow, but mostly snow is still definitely possible.

just yesterday morning, models were showing a historic snowstorm, perfectly placed i95 special. That’s pretty much out the window. That’s all I meant by my first post.

there will all but certainly be snow from this storm, agreed

 

[RU848789]

just yesterday morning, models were showing a historic snowstorm, perfectly placed i95 special. That’s pretty much out the window. That’s all I meant by my first post.

there will all but certainly be snow from this storm, agreed

No, they weren't at 12Z yesterday - GFS was inland, although less than now, Euro was about the same as it is now (mostly rain for 95 and snow inland), the CMC was also a bit inland like the Euro and UK was out of range until last night. And a 95 snowstorm is not out the window at all. Shifts of 50-100 miles have occurred countless times at 4.5 days out - sure, a 95 snowstorm is less likely than a 95 rainstorm, but it's nowhere near off the table.

 

[RU#1fan]

Sam Champion said just now the system is currently 4000 miles away. Too soon for any predictions

 

[DJ Spanky]

Is it traveling first class or coach?

 

[Bleem Phuppert]

If it's too early for the NAM, the guidance will change.

 

[RU848789]

If it's too early for the NAM, the guidance will change.

Did you see the exchange on that on 33? One of the mods said, "If the NAM isn't in range, guidance will likely change," which I had heard before, but I then actually wondered if they picked the NAMs range to be 84 hours because that's often the time when Pacific storms come ashore and are sampled well, such that the models become a bit more accurate. 84 hours before this storm starts (Sun eve) is about Thursday morning, which is when the energy comes ashore...

 

[Bleem Phuppert]

Did you see the exchange on that on 33? One of the mods said, "If the NAM isn't in range, guidance will likely change," which I had heard before, but I then actually wondered if they picked the NAMs range to be 84 hours because that's often the time when Pacific storms come ashore and are sampled well, such that the models become a bit more accurate. 84 hours before this storm starts (Sun eve) is about Thursday morning, which is when the energy comes ashore...

I did see that. Pretty funny. I've just always favored the NAM for winter storms. Probably the shorter range has something to do with its apparent accuracy, but it's knocked it out of the park more than a few times.

 

[RU848789]

12Z GFS came a little east, showing a few inches for 95 then rain, but 6"+ well inland, while the 12Z UK went from full snowstorm for all at 0Z last night to a run like the Euro with the low 100 miles west of where it was, meaning almost all rain for 95, but 6" or more 25+ miles NW of 95. Certainly not good for snow lovers, but likely great for the ski resorts. Still too early to discount snow for 95, IMO, given how far out we are and the main energy still being offshore of the PacNW.

And the 12Z CMC had little change (maybe an inch for 95 and several inches inland before a changeover to sleet, then rain, but the Euro moved east a bit (25 miles), brining several inches on the front end to the 95 corridor and 6+" just 10-20 miles NW, i.e., Somerville with 8" vs. Sayreville with 2" and nada from Old Bridge and SE - even shows 8" for the Bronx and 1" for JFK. So, certainly rain is still favored over snow for 95, but we're still 4.5 days out and much bigger changes have occurred that far out - hell, the 1/3 system had zero snow for DC to AC 48 hours in advance and we know how that ended.

 

[29PAS]

Any idea about the origin of the OKX designation for the New York Weather Forcasting office? A play on yOrK maybe? Most of the others are pretty obvious. Just curious.

 

[bac2therac]

throwing amounts around is pretty laughable at this point 100 plus hours out, the general overview of what the models want to do with this storm is much more appropriate

 

[RedTeam1994]

I need a precise prediction of inches STAT

 

[RU#1fan]

I need a precise prediction of inches STAT

More than an inch and less than 2 feet

 

[RUScrew85]

I need a precise prediction of inches STAT

That's what she said!

 

[RedTeam1994]

More than an inch and less than 2 feet

I'll work off that. thanks!!

 

[RedTeam1994]

That's what she said!

I work in centimeters when it comes to that.helps my self esteem

 

[Scarlet_Monster]

Down here in Charlotte they are predicting 5-8 inches this Sunday.

I moved down here to get away from the snow dammit.

 

[RU848789]

Down here in Charlotte they are predicting 5-8 inches this Sunday.

I moved down here to get away from the snow dammit.

You're likely to get everything and need to really watch out for an ice storm, which is possible. I have family there and gave them the heads up today. Probably worth thinking about what you might do without power for a few days, just in case.

 

[RU848789]

throwing amounts around is pretty laughable at this point 100 plus hours out, the general overview of what the models want to do with this storm is much more appropriate

You'll never understand will you? I gave a general overview and only shared the specific amounts to illustrate the kind of gradient we're likely to have from mostly rain to mostly snow over short distances, but we simply don't know where that will be yet, plus it does illustrate that it's possible that transition is over or or close to the 95 corridor. And I've said multiple times that making any specific forecast before the storm comes ashore in the PacNW tomorrow morning is unwise, given the very high uncertainty.

 

[RedTeam1994]

You'll never understand will you? I gave a general overview and only shared the specific amounts to illustrate the kind of gradient we're likely to have from mostly rain to mostly snow over short distances, but we simply don't know where that will be yet, plus it does illustrate that it's possible that transition is over or or close to the 95 corridor. And I've said multiple times that making any specific forecast before the storm comes ashore in the PacNW tomorrow morning is unwise, given the very high uncertainty.

Such nuances are lost on him I’m afraid

 

[bac2therac]

You'll never understand will you? I gave a general overview and only shared the specific amounts to illustrate the kind of gradient we're likely to have from mostly rain to mostly snow over short distances, but we simply don't know where that will be yet, plus it does illustrate that it's possible that transition is over or or close to the 95 corridor. And I've said multiple times that making any specific forecast before the storm comes ashore in the PacNW tomorrow morning is unwise, given the very high uncertainty.

Your giving amounts what models are showing 100 hours out. Its meaningless that the model shows 2 inches in sayreville and 8 inches in somerville as if that has ever happened...and given the volatility of the situation model snow maps are worthless right now

Nothing nuanced about it.

 

[RocktheRac]

Is it traveling first class or coach?

Hope it wear a mask.

 

[Scarlet_Monster]

You're likely to get everything and need to really watch out for an ice storm, which is possible. I have family there and gave them the heads up today. Probably worth thinking about what you might do without power for a few days, just in case.

Going to the food store tomorrow to stock up on essentials. I went to school down here and everything shut down for a dusting. They don't have the infrastructure for this.

 

[RocktheRac]

That's why posting at 2am Tuesday morning for a possible storm Sunday night with inches is totally absurd.

 

[RU848789]

Any idea about the origin of the OKX designation for the New York Weather Forcasting office? A play on yOrK maybe? Most of the others are pretty obvious. Just curious.

Got the answer from a met on 33andrain as I had no idea - I was told the OK comes from Brookhaven Labs and they add X to a lot of office names, hence OKX...

 

[Tango Two]

NWS:

Good Evening Everyone! You may have heard about a system affecting our region late this weekend. Here is the latest (as of Wednesday evening). A system is expected to cross over our region from late Sunday into Monday. The latest trend with the models has been for this to take a more inland track (instead of staying just off the coast). If this trend continues, that would mean more rain for the I- 95 corridor and coastal plains, while more wintry mix for areas north and west of the I-95 corridor. With this track, very little of our region would see a mostly snow event.

This is still 5 days out, so there remains quite a bit of uncertainty. We won't have a snow forecast for this until Friday night or Saturday morning (due to inherent uncertainty with snow forecasting, snow amount forecasts are issued for up to 3 days in advance). In the mean time, you can view the extended winter weather outlook (from NOAA NWS Weather Prediction Center) here: https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php and read our forecaster discussion on this system here: https://www.wrh.noaa.gov/total_forecast/getprod.php?new&prod=XXXAFDPHI&wfo=phi

 

[Phi_1055]

Thanks for the heads-up, Numbers.

fwiw, I understand the distinction between a forecast and a guarantee or promise, and that it’s a developing situation.

 

[Tango Two]

Is it traveling first class or coach?

Lol