OT: Winter storm for 2/12 - Big Mess of Snow/Sleet/Rain (after minor snowfall on 2/11)

[bac2therac]

Mt Holly disco for Monday night and Tuesday

ow pressure is expected to move from the southern Great Plains
to the Great Lakes on Monday and Tuesday with a secondary low
developing in Virginia on Tuesday. The precipitation type
forecast remains quite complex. Arctic high pressure should
located in Quebec at that time and we are forecast to be on the
southern fringe of that air mass. Meanwhile, relatively warm air
will be draw over the low level cold air resulting in a
transition from snow to ice to rain. Unfortunately, surface
temperatures may not warm enough in parts of eastern
Pennsylvania and northern New Jersey to allow for the full
change to liquid precipitation and there is the potential for a
significant ice accumulation in our area north of the Interstate
78 Corridor.

Snow totals of several inches are possible in our northern
counties, with little snow expected in southern Delaware and far
southern New Jersey before the change-over.

By Tuesday evening, the main surface low is forecast to be
located in Michigan with a secondary low in our vicinity. Both
should lift to the northeast with the precipitation coming to an
end on Tuesday night.

 

[T2Kplus10]

wow you just basically say one thing and then cover yourself with another comment

What? Shocked that he would do something like this!
:)

 

[DJ Spanky]

The Bicker Brothers are in full voice!

 

[RU848789]

wow you just basically say one thing and then cover yourself with another comment

I think these snow maps cannot be trusted...you were even admonished on 33andrain about posting them.

this remains a complex setup and the models are far from coming to a consensus

Not sure what you mean and I was criticized by someone who didn't know what he was talking about. It doesn't only happen here.

 

[bac2therac]

Not sure what you mean and I was criticized by someone who didn't know what he was talking about. It doesn't only happen here.

33andrain the poster doesnt know what he is talking about????

 

[RU848789]

33andrain the poster doesnt know what he is talking about????

He knows his shit about a ton of things related to meteorology, especially synoptics and teleconnections, but he's not an expert on mixed precip events and calculations of snow vs. sleet nor the methods and algorithms used (he's also not a met). I was the first person on the site to research and find out what, exactly, the Kuchera method was and shared it with the site in a (surprise) long, detailed analysis. If you didn't notice, Analog, one of the best mets on that site, agreed with my perspective on that exchange. I'm on pretty firm ground on this one.

 

[RU848789]

The little appetizer system late Sunday into early Monday is looking a little more robust with 1" or so now possible for most of CNJ/NNJ/NYC and 2-3" or so possible from 195/276 southward. This will potentially be impactful on the Monday am commute with temps below 32F. The main event then rolls in late Monday evening and will bring a very mixed bag of precip from then through late Tuesday night. Still waiting on NWS updates on discussions/snowmaps.

The 12Z models today almost all trended colder/snowier, due to the primary midwest to Great Lakes low being weaker and the secondary coastal low which forms late Monday being a little stronger (but not a powerful storm), keeping colder air locked in place longer. This is not a done deal yet, but with pretty good model consensus on at least a few inches of snow and some sleet before any changeover and i

For the Philly-NYC corridor, we're looking at maybe a few to several inches of initial snow by Tuesday around sunrise, depending on the model, followed by possibly several hours of sleet as a warm nose aloft (at 700-850 mbar or 5000-9000' feet above the surface) melts the falling snow, but the resulting rain then refreezes into sleet pellets in the bottom ~2500 feet (below 900 mbar) of the column, producing maybe 1-2" of sleet (equivalent to 3-6" of typical 10:1 snow).

Then, depending again on the model, the sleet would then eventually change to rain, probably in the mid afternoon and we'd likely get 1/2" to maybe 1" of plain rain with surface temps in the mid/upper 30s. A couple of models are showing more like 4-8" of snow before any changeover to sleet and some models are showing 0.1-0.25" of freezing rain during that transition, especially NW of 95, which would be quite dangerous.

Still lots of uncertainty for the Tuesday system, in particular, as it's about 60 hours from starting (vs. the 7 am EST model data inputs for the 12Z model runs), but the uncertainty is decreasing with modest model consensus on at least an early thump of snow/sleet for the area. It also should go without saying that in a storm transitioning from snow to rain eventually, there will be more snow/sleet as one travels NW of 95 towards NE PA/NW NJ and N of 287 in the Hudson Valley, as well as less snow/sleet as one travels towards the coast. With the exception of the Monday snow likely being more S of 195/276.

I still don't think we'll have a great handle on this until Sunday and even after that there could be surprises, since a 2-hour delay in a changeover to rain could mean 2-3" more snow or vice-versa, since it's going to be a potent system with ~2" of total precip (liquid equivalent) in about 24 hours.The model outputs are below.

12Z GFS, still the least wintry model, but it was a bit snowier/sleetier than earlier runs; this is showing both snow and sleet (at 10:1 ratio).

12Z GFS-FV3, where about 2-3" of this is snow and the rest of the frozen is sleet, as modeled.

18Z NAM, which just came out and is a sleetfest for most (90% of that "snow" is sleet, as modeled)

12Z CMC (note that one should add 2" of sleet for most of CNJ/NNJ/NYC to this map, which only shows snow.

12Z UK (has been the snowiest model, consistently; it supposedly only shows snow - trying to confirm that)

12Z Euro, which also trended colder (also just snow and trying to confirm that)

And here's the NWS NYC snowmap. Not much snow for the early Monday system north of 78, so this is basically all for system 2. They've said there could be some sleet and freezing rain in addition to this, especially inland of NYC.

Reasonably good consensus on 1” or so N of 195/276 and 1-2” S of 195/276 late Sunday/early Monday, which could be impactful to the morning rush, given temps below 32F and people generally not being aware of this threat. This will be followed by the main event from late Monday through late Tuesday by a system which has trended a bit colder/whiter the past day or so. Still a fair amount of uncertainty as we’re 2 days out, but storm 2 is looking like a real mixed bag with a few inches of snow to start for most in the area, changing to sleet for several hours, putting down 1-2” of sleet (which is equivalent to 3-6” of “typical” 10:1, snow:liquid snowfall, as sleet has a 3:1 ratio of sleet to liquid equivalent), and then changing to rain for most by early/mid-afternoon, with another 0.5-1.0” of rain falling with temps in the mid-upper 30s by then.

This could be quite impactful as 2” of snow + 2” of sleet, for example, has the mass of almost 9” of snow (0.9” of liquid equivalent) and snow mass is what drives impact, at least with regard to shoveling, plowing and driving (if not visibility). Like most storms that transition to sleet, freezing rain and then rain due to warm air intrusion aloft, there will be more snow/sleet as one travels NW of 95 towards NE PA/NW NJ and N of 287 in the Hudson Valley; freezing rain is also most likely in these locations. And there should be less snow/sleet as one travels towards the coast and S of 195/276. Also, this could still change to wetter or whiter, but we have decent model consensus right now, so hopefully the general ideas outlined above will prove to be reasonably accurate (no guarantees this year though!). The NWS seems fairly aligned with this, but NWS-Philly hasn't issued maps yet, while the NWS-NYC map is above and shows 3-4" of snow and sleet for NYC/NE NJ, which is probably ~2" or snow and 1-2" of sleet (equivalent to 5-9" of 10:1 snow).

Models below, with the following comments vs. this afternoon's runs: the GFS got a bit colder/whiter, the CMC got a bit warmer/wetter, the GFS-FV3 held serve, the UK got a little whiter, and the NAM held serve, as did the Euro. The GFS, FV3, NAM, and I believe the Euro/UK (still trying to confirm) maps all show snow + sleet all at 10:1 ratios, with most of the frozen precip, by mass, being sleet for all of them, as far as I can tell. In general, all of the models are showing about 0.5-1.0" of liquid equivalent as frozen (snow + sleet) for Philly-NYC, which is a substantial amount of frozen precip, that would likely absorb much of the rain that follows it with temps in the 35-40F range after the change to rain. The CMC shows just snow, not sleet.

Edit - just saw this map from the NWS, which is presumably this is snow + sleet, even though it doesn't say it explicitly, since the NWS NYC in their discussion was talking about 3-4" of snow and sleet. So ifor example, if it were 2" snow, then 2" sleet (6.6" of snow equiv), that would be like 8-9" worth of regular 10:1 snow, by mass, but would only be about 4" in depth.

 

[bac2therac]

Models still not totally in agreement for Sunday night into Monday event but they are consistent with the greatest chances of accumulating snow south of Trenton.

Mt Holly for Sunday night/Monday

A one-two wintry punch is expected for our area through the
period.

The first will begin tonight, as a weak perturbation moves
through the northern Mid-Atlantic. The system will be weak and
fairly moisture-starved, but the antecedent cold air in the low
levels and quite decent lift will be sufficient for a period of
light snow overnight into Monday morning. Models are,
unfortunately, still all over the place regarding
magnitude/placement of QPF/snow amounts and low-level thermal
profiles. The GFS continues to look the weakest, with mostly
rain central/southern Delmarva and meager-looking snow to the
north. It is beginning to look more like an outlier now (with
only modest support from the ICON, though the 06z HRRR certainly
gives me some pause), and its warm bias looks to be in full
force. The 00z NAM, meanwhile, provides a veritable winter storm
along/south of the I-76 corridor, which is rather unlikely
given the overall character/speed of the associated perturbation
and attendant lift. (Notably, the 06z NAM is a little tamer.)
The NAM Nest, RGEM, FV3, CMC, and ECMWF provide a reasonable
consensus cluster, with a fairly broad region of 1-2 inch snows
expected from (roughly) the I-78 corridor southward to central
Delmarva, tapering off to the south as low- level temperatures
approach/exceed freezing for much or most of the event. Locally
higher snow totals are possible in nearly-impossible-to-
forecast steadier/narrow bands within the main precipitation
shield. There are hints of such an axis occurring near a
Wilmington to Ocean City line, but that is of quite low
confidence at this point. Should such trends continue in
subsequent model runs, some increase in totals may occur within
the advisory area.

Adding to the complicated forecast is the potential for some
mixing, especially in Delmarva and far southern New Jersey. As
warm advection will be playing a primary role in generating the
lift for the precipitation, some semblance of a warm nose will
develop and progress northward atop the colder air. Models are
in disagreement as to its resultant impacts on precipitation
type, with the NAM and NAM Nest indicating some potential for
freezing rain in Delmarva and adjacent far southern New Jersey.
The RGEM produces little of this, and other models nothing at
all. Such mixed precipitation could occur as far south as our
southern CWA border, so expansion of the advisory southward may
be required in subsequent forecasts.

Even if amounts do not meet advisory criteria (two inches), the
timing is quite concerning. With overnight snow, the Monday
morning rush could be quite problematic within the advisory
area. This was the main impetus for advisory issuance, with
forecast snow/ice totals a secondary factor.

As the perturbation moves offshore Monday morning,
precipitation should become lighter but may not completely stop,
especially south of the Philly metro. However, given the slight
warming expected during the day and downward trend in
precipitation, felt an end time of noon for the advisory was
warranted. Critically, the second round of wintry weather begins
by Monday evening, so there will be little "down time" between
the events.

 

[knightfan7]

Sleet makes you fall on your ass with two pizzas in your arm after leaving Star, that end up on the sidewalk.
Or in your case two Jimmy Buff Dogs all the way.

That'd be me lol.

Growing up my dad was more a Toast of the Town in Orange fan. I'd sit on the porch Friday evening waiting for him to pick me up after work because he'd buy me a coke while he'd have a beer waiting for the pie.

 

[bac2therac]

Dan Zarrow blog....this is very concise and detailed without a lot of words to bog people down in stuff they don't need to read or snowmaps that are useless for this storm

http://nj1015.com/snow-ice-rain-returns-to-nj-sunday-night-to-wednesday-morning-7-things-to-know/

Timeline

—9 p.m. Sunday... First flakes push over the Delaware River into southwestern New Jersey.
—Around Midnight... Snow begins for most for most of the state.
—Overnight... Light snow will continue falling, with bands of moderate snow in the southern half of New Jersey.
—Monday Morning... Snow and slush may cause significant slowdowns and school delays.
—10 a.m. Monday... Snow tapers off for most.
—Monday Daytime... Most of NJ enters a lull, although wintry mix and/or rain may continue to clip Cape May County throughout the day.
—3 p.m. Monday... Precipitation surges northward again. As temperatures drop, this would cause snow to once again spread through the state.
—Monday Evening... Evening commute hampered by slushy, icy roads and reduced visibility.
—Monday Night... Snow bands continue edging northward, leading to additional accumulations across the state.
—Early Tuesday Morning... Rising temperatures force a transition from snow to icy mix to rain. For the southern half of the state, this changeover should be complete (or at least underway) by the Tuesday morning rush hour.
—Late Tuesday Morning... North Jersey changing from snow to ice to rain. A period of sleet and/or freezing rain could make conditions extremely slippery in the northern half of the state.
—Tuesday Afternoon... Most of New Jersey rain now. Some wintry mix may linger in far North Jersey (north of I-78).
—By 5 p.m. Tuesday... Transition complete. All rain.
—5 a.m. Wednesday... Storm exits New Jersey and rain comes to an end.



Sunday night event

—South of I-195, by Monday morning... I'm still thinking an inch or two is likely from the first burst of snow. Small-scale bands of heavier snow seem to be a good bet, but pinpointing exactly where they set up is impossible. Would I be surprised to see a few 3+ inch totals? Nope. But such totals will be isolated — the exception, not the rule.

—North of I-195, by Monday morning... Not really your storm, North Jersey. (Not yet, at least.) Although roads could still get slushy and slippery with up to an inch of snowfall by Monday morning's commute. Don't be surprised if you don't see much through early Monday — the heaviest snow bands stay south.


Tuesday storm

—Southeast of Route 1, by Tuesday morning... The first to see the reintroduction of snow, but also the first to transition to all rain. The big questions: How fast will that burst of snow fall and accumulate? How fast will snow turn to rain? I've crafted a larger-than usual range of snow totals to account for these yet-unknown answers. Expect anywhere rom a coating to 2" of snow — the bulk of which will fall pre-Tuesday morning commute. The switch from snow to rain should flip quickly in the southern half of the state, so there is only a slight chance for icy mix here.

—Northwest of Route 1, by Tuesday afternoon... It will take a little while for wintry weather to return, but once it does there will be a period of 12+ hours of increasingly messy snow, ice, slush, and bleach. The big questions: When exactly will steady snow return? When will it transition? Will there be a stretch of perilous freezing rain and icing? Again, I've left my forecast some wiggle room here. "Advisory" level snow, on the order of 2 to 5 inches is expected, with the potential for up to a quarter-inch of ice. (I don't think anyone can really visualize numbers when it comes to ice accretion, so I'm just calling it a "glaze".)

 

[RUScrew85]

Reminds me of when we had a house up at Mt. Snow: we'd sit in the jacuzzi soaking up beer until we were overheating,then go run outside and roll in the falling snow. In our swimsuits.

I'm betting ya'll were naked.

 

[bac2therac]

Use today as your prep day. All the lunatics will be out tomorrow doing whatever they do before a storm

Tuesday morning commute will be atrocious. Most schools likely closed and I would say alot businesses as well. Murphy will be declaring a state of emergency and this time it makes sense. because no one should be on the roads Tuesday morning.

 

[knightfan7]

Use today as your prep day. All the lunatics will be out tomorrow doing whatever they do before a storm

Tuesday morning commute will be atrocious. Most schools likely closed and I would say alot businesses as well. Murphy will be declaring a state of emergency and this time it makes sense. because no one should be on the roads Tuesday morning.

Milk! Bread! Eggs!

Good luck Bac $$$$

 

[borochop]

ug flight to KC Tues around 8:30am. getting to EWR from H-boro will be an adventure yes?

many thanks for the updated 411, its the best

 

[bac2therac]

sorry for the bad news.....the snow will begin monday probably before midnight so yes any changeover probably will not happen til early afternoon Tuesday at the earliest

 

[borochop]

sorry for the bad news.....the snow will begin monday probably before midnight so yes any changeover probably will not happen til early afternoon Tuesday at the earliest

roger that, joys of winter travel! thx

 

[bac2therac]

I think its becoming clearer that we are headed to our biggest impact weather event of the winter season. Expect any watches and advisories to be issued with the late afternoon Mt Holly disco.

 

[DJ Spanky]

NWS NYC has this out for the Tuesday event, Philly is focusing on tonight's event so doesn't have a map out yet:

Use today as your prep day. All the lunatics will be out tomorrow doing whatever they do before a storm

Tuesday morning commute will be atrocious. Most schools likely closed and I would say alot businesses as well. Murphy will be declaring a state of emergency and this time it makes sense. because no one should be on the roads Tuesday morning.

Damn right, the potential for an unholy mess is all there. Doesn't mean it will happen, but better not to take changes.

 

[bac2therac]

i think Mt Holly will go with 2-4 or 3-6 when they put the totals up with 1-3 to the coast

this will include snow and sleet and I know Numbers will come here with long explanation snow mass...yes sleet is dense and harder to remove and one inch of sleet might be equivalent up to 2-3 inches of snow when melted but officially they will be lumping sleet in with the snow

 

[RU848789]

Reasonably good consensus on 1” or so N of 195/276 and 1-2” S of 195/276 late Sunday/early Monday, which could be impactful to the morning rush, given temps below 32F and people generally not being aware of this threat. This will be followed by the main event from late Monday through late Tuesday by a system which has trended a bit colder/whiter the past day or so. Still a fair amount of uncertainty as we’re 2 days out, but storm 2 is looking like a real mixed bag with a few inches of snow to start for most in the area, changing to sleet for several hours, putting down 1-2” of sleet (which is equivalent to 3-6” of “typical” 10:1, snow:liquid snowfall, as sleet has a 3:1 ratio of sleet to liquid equivalent), and then changing to rain for most by early/mid-afternoon, with another 0.5-1.0” of rain falling with temps in the mid-upper 30s by then.

This could be quite impactful as 2” of snow + 2” of sleet, for example, has the mass of almost 9” of snow (0.9” of liquid equivalent) and snow mass is what drives impact, at least with regard to shoveling, plowing and driving (if not visibility). Like most storms that transition to sleet, freezing rain and then rain due to warm air intrusion aloft, there will be more snow/sleet as one travels NW of 95 towards NE PA/NW NJ and N of 287 in the Hudson Valley; freezing rain is also most likely in these locations. And there should be less snow/sleet as one travels towards the coast and S of 195/276. Also, this could still change to wetter or whiter, but we have decent model consensus right now, so hopefully the general ideas outlined above will prove to be reasonably accurate (no guarantees this year though!). The NWS seems fairly aligned with this, but NWS-Philly hasn't issued maps yet, while the NWS-NYC map is above and shows 3-4" of snow and sleet for NYC/NE NJ, which is probably ~2" or snow and 1-2" of sleet (equivalent to 5-9" of 10:1 snow).

Models below, with the following comments vs. this afternoon's runs: the GFS got a bit colder/whiter, the CMC got a bit warmer/wetter, the GFS-FV3 held serve, the UK got a little whiter, and the NAM held serve, as did the Euro. The GFS, FV3, NAM, and I believe the Euro/UK (still trying to confirm) maps all show snow + sleet all at 10:1 ratios, with most of the frozen precip, by mass, being sleet for all of them, as far as I can tell. In general, all of the models are showing about 0.5-1.0" of liquid equivalent as frozen (snow + sleet) for Philly-NYC, which is a substantial amount of frozen precip, that would likely absorb much of the rain that follows it with temps in the 35-40F range after the change to rain. The CMC shows just snow, not sleet.

Edit - just saw this map from the NWS, which is presumably this is snow + sleet, even though it doesn't say it explicitly, since the NWS NYC in their discussion was talking about 3-4" of snow and sleet. So ifor example, if it were 2" snow, then 2" sleet (6.6" of snow equiv), that would be like 8-9" worth of regular 10:1 snow, by mass, but would only be about 4" in depth.

Just got in from Sunday morning soccer and lunch and models are trending even colder/whiter with today's 12Z runs. It's definitely looking like an inch or so of snow late tonight early tomorrow, N of 195/276 and up to 2" S of that line and then an absolute mess starting late Monday evening and lasting through Tuesday night. Near/along the 95 corridor from Philly NYC we can expect a few to several inches of snow (depending on when the change over to sleet occurs, which is likely around rush hour in Philly, maybe mid-morning in NB and noon in NYC, followed by probably 6+ hours of sleet, producing probably 2" of sleet (from 0.6" or so of liquid equivalent falling as sleet at 3:1 ratios of sleet to liquid) on top of the snow.

While 1-3/2-4" of snow doesn't sound like a big deal, it's a pretty big deal if 2" of sleet is added on top of that, as the total would be in the range of 0.6-1.0" of liquid falling as frozen precip (equiv in mass to 6-10" of snow). That much mass of frozen precip will be very impactful on shoveling. plowing and driving. NWS in NYC upped their snow/sleet forecasts (the maps include both) this morning, as per the map below.

Mt. Holly is still only showing the map from yesterday for the minor part 1, which I think is a mistake, I imagine most schools will be closed on Tuesday and some businesses - I know I'll be working from home and I'm sure bac will finally make some extra $$, so maybe he won't be so cranky, lol. I expect watches to go up for most of the area with the 4 pm packages, even if the depth won't reach 6" in many places (the mass will and there's still a risk of freezing rain, especially NW of 95). Will share some models later.

TWC is going pretty bullish on snowfall for the area - surprising, as they're usually pretty conservative with snow.

Just for posterity, for me, here are the 12Z model outputs - mostly held serve or were a bit colder/whiter than 0Z last night.

12Z GFS (snow + sleet counted as 10:1 snow)

12Z GFS-FV3 (snow + sleet counted as 10:1 snow)

12Z CMC, which is snow only; the model shows ~2" of sleet for the 95 corridor, but it's not shown on map - that would make the 1-2" of snow into the snow equivalent of 7-9" (1-2" of sleet is equiv to 3.3-6.6" of snow).

12Z NAM (snow + sleet counted as 10:1 snow)

12Z UK (snow + sleet)

12Z Euro (just snow; like the CMC, shows 1-2" sleet, but not on map)

 

[RU848789]

i think Mt Holly will go with 2-4 or 3-6 when they put the totals up with 1-3 to the coast

this will include snow and sleet and I know Numbers will come here with long explanation snow mass...yes sleet is dense and harder to remove and one inch of sleet might be equivalent up to 2-3 inches of snow when melted but officially they will be lumping sleet in with the snow

Good call - that's my thinking, roughly, for part 2: 1-2" of snow/sleet S of 195, with the lower amounts towards the coast, 2-4" of snow/sleet for the 95 corridor from Philly to NYC (which will likely be 2" of snow and 1-2" of sleet, which is 5-8" of "snow equivalent"), and 3-6" of snow/sleet NW of a line from about Doylestown to Mahwah, roughly along 202/287, and then extending N of 287 in NY - and probably 6-10" for the Poconos, Sussex and anywhere north of about 84 (and probably much of Orange/Putnam south of 84).

And yes the NWS does lump snow and sleet together and yes, I'll probably make more posts about frozen mass vs. depth, but I think the NWS might issue watches, which are usually reserved for 6" of pure snow, for the 95 corridor, since the frozen equivalent will likely be 6" of "snow equivalent" or more. The risk of 0.1" or more of freezing rain might also tip the scales towards watches (and eventually warnings tomorrow morning if the models don't change much). We'll see soon.

Edit: Was wrong on the guesses about the NWS - they only issued watches for the Poconos/Sussex and Orange/W. Passaic (in blue with a grey tint). Advisories (blue with a purple tint) are up S of 195/276 for Monday morning's snow, which could put down 2" or so. Tan is just a weather statement.

Edtt#2 - good discussion from the NWS-Philly office...

National Weather Service Mount Holly NJ
356 PM EST Sun Feb 10 2019

NEAR TERM /THROUGH MONDAY/...
High pressure located off the Middle Atlantic coast this afternoon
will continue to drift southeastward tonight and Monday. Weak warm
advection on the back side of the high is expected to affect our
region tonight. Arctic high pressure sliding from Ontario to Quebec
should begin to nose down into our area on Monday.

Light precipitation approaching from the Ohio River Valley is
expected to overspread our region late this evening. We are
anticipating light snow in eastern Pennsylvania, and in northern
and central New Jersey. Snow, sleet and freezing rain are expected
for northeastern Maryland, Delaware and southern New Jersey. The
mixed precipitation should change to all rain in the Maryland
counties of Talbot and Caroline, the southern half of Delaware and
Cape May County in New Jersey toward morning.

The precipitation is forecast to end on Monday morning across most
of eastern Pennsylvania, and northern and central New Jersey. The
light wintry mix should linger during the morning in parts of
northeastern Maryland, Delaware and southern New Jersey.

As broad low pressure begins to approach from the west, the
precipitation will begin to spread back to the north on Monday
afternoon, with light snow returning to eastern Pennsylvania, and to
northern and central New Jersey. A light wintry mix, favoring rain,
should continue in our southern counties.

The expected snow totals in the northern half of our forecast area
for tonight do not warrant an advisory. We will keep the Winter
Weather Advisory in place for the southern half of our region from
1000 PM this evening until noon on Monday. We have expanded the
advisory to include the Maryland counties of Talbot and Caroline,
and Sussex County, Delaware (except for the beaches) due to the
expectation of a light glaze of ice in parts of those counties.

Low temperatures for tonight should favor the 20s and lower 30s with
a light and variable wind. A northeast wind around 5 to 10 MPH is
forecast to develop on Monday. High temperatures will likely be in
the 30s.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
This portion of the discussion will focus on the 2nd of the one-two
punch.

Synoptically...The period starts with a warm front well to our south
and high pressure centered well to our north. The front will be
attached to a low west of the Mississippi. This low will track
northeast and be positioned near the Great Lakes 24 hours later, on
Tuesday evening. At this time, a secondary low will develop near the
coast of NJ and track northeast Tuesday night.

Impacts...This event will cross the Tuesday morning commute as well
as the Tuesday evening commute. For the I95 corridor, the morning
commute will experience the most impacts. Further north and west,
the morning commute will be a snowy one and the evening one could be
a mixed bag of snow, ice and freezing rain.

Headlines...Winter Storm Watch posted for the southern Poconos and
NW NJ to account for both the snow and ice.

Snow/sleet amounts...Ranging from 5 to 8 across the Southern Poconos
and NW NJ, 3 to 5 across Berks and the Lehigh Valley, then 2 to 4
down to I95. 1 to 2 when you cross the river into NJ and also for
northern Delmarva. An inch or less south and east of there.

Freezing rain...Tricky here at this point and depends on the
strength of the low-level warm nose. For now, have .2/tenths of
ice across the Southern Poconos and NW NJ, .1 to .2/tenths
across Berks, the Lehigh Valley and Morris County in NJ, a trace
to a .1/tenth down to the urban I95 corridor, and then a trace
south of there. Cape May county and Sussex county may not see
much snow or ice at all.

For the Poconos and NW NJ, it`s not out of the realm of
possibility of receiving more ice. Some of the forecast
soundings over the last two runs have up to .4/tenths.

Rain...Not sure the Poconos will ever go over to all rain. The
Lehigh Valley and Berks are forecast to change over late Tuesday,
and the urban corridor around midday Tuesday.

QPF...This is not a weak/dry system. Total QPF, when all said
and done will be between 1.00 and 2.00 inches. Where the ptype
is mainly liquid, expect minor flooding in the most prone areas.
Even across locals that get accumulating snow, moderate to
heavy rain is possible after the changeover.

Transitions...As stated, the frozen/freezing may never change over
across the far north. For the Lehigh Valley, going with all snow
Monday night into Tuesday morning and transitioning to all rain
Tuesday afternoon. Across the urban and I95 region, going with snow
Monday night to a mix by daybreak Tuesday, followed by all rain in
the afternoon. The Tuesday morning commute looks nasty for this
area. Across the coastal plain and our southern Delmarva zones,
going with snow to rain on Monday night. Looks like all rain here
Tuesday and Tuesday night.

 

[bac2therac]

Cant argue with this. Winter lovers rejoice...this is finally your week in a winter that is slipping away

 

[R1766U]

Any school predictions for Middlesex County. Tomorrow and Tuesday?Thanks.

Btw do school districts hire weather consultants typically or just have someone watch the news and make the xall? Always wondered that.

 

[e5fdny]

Use today as your prep day. All the lunatics will be out tomorrow doing whatever they do before a storm..

I did my part.

Had three HUGE pieces of french toast at a place right outside of Hershey, PA before my Son’s college hockey team played in their championship game. They won. But I really should have gone with the two pieces instead. They were that big.

 

[RU848789]

Any school predictions for Middlesex County. Tomorrow and Weds? Thanks.

Btw do school districts hire weather consultants typically or just have someone watch the news and make the xall? Always wondered that.

Tomorrow should be fine (unless you're south of Philly to LBI where more than 2" could fall), Wednesday ought to be fine, unless it doesn't change to rain for the 2nd half of the storm (1 in 10 shot maybe), but Tuesday would be massive closings if the models and forecasts are correct, at least for anyone along or NE of the NJ TPK. Still a 1 in 10 shot that the storm underperforms significantly, due to much faster warm air intrusion and a much faster changeover to rain - if it changes over to rain in Philly before about 8 am, then it's likely going to be underperforming and could change to rain in the CNJ area by 9-10 am.

For 15+ years, I've been the semi-official weather consultant for Metuchen schools, as one of my best friends was a Principal and an Asst Superintendent for a long time and liked my weather emails and we would usually chat the night before or even at 5-6 am. Some schools hire consultants, but anyone with a half-decent understanding of the weather ought to be able to make an informed decision, plus there's a fair amount of "group-think" that goes on, where neighboring districts often collaborate on the decision.

 

[Knight Shift]

Good call - that's my thinking, roughly, for part 2: 1-2" of snow/sleet S of 195, with the lower amounts towards the coast, 2-4" of snow/sleet for the 95 corridor from Philly to NYC (which will likely be 2" of snow and 1-2" of sleet, which is 5-8" of "snow equivalent"), and 3-6" of snow/sleet NW of a line from about Doylestown to Mahwah, roughly along 202/287, and then extending N of 287 in NY - and probably 6-10" for the Poconos, Sussex and anywhere north of about 84 (and probably much of Orange/Putnam south of 84).

And yes the NWS does lump snow and sleet together and yes, I'll probably make more posts about frozen mass vs. depth, but I think the NWS might issue watches, which are usually reserved for 6" of pure snow, for the 95 corridor, since the frozen equivalent will likely be 6" of "snow equivalent" or more. The risk of 0.1" or more of freezing rain might also tip the scales towards watches (and eventually warnings tomorrow morning if the models don't change much). We'll see soon.

Edit: Was wrong on the guesses about the NWS - they only issued watches for the Poconos/Sussex and Orange/W. Passaic (in blue with a grey tint). Advisories (blue with a purple tint) are up S of 195/276 for Monday morning's snow, which could put down 2" or so. Tan is just a weather statement.

Edtt#2 - good discussion from the NWS-Philly office...

National Weather Service Mount Holly NJ
356 PM EST Sun Feb 10 2019

NEAR TERM /THROUGH MONDAY/...
High pressure located off the Middle Atlantic coast this afternoon
will continue to drift southeastward tonight and Monday. Weak warm
advection on the back side of the high is expected to affect our
region tonight. Arctic high pressure sliding from Ontario to Quebec
should begin to nose down into our area on Monday.

Light precipitation approaching from the Ohio River Valley is
expected to overspread our region late this evening. We are
anticipating light snow in eastern Pennsylvania, and in northern
and central New Jersey. Snow, sleet and freezing rain are expected
for northeastern Maryland, Delaware and southern New Jersey. The
mixed precipitation should change to all rain in the Maryland
counties of Talbot and Caroline, the southern half of Delaware and
Cape May County in New Jersey toward morning.

The precipitation is forecast to end on Monday morning across most
of eastern Pennsylvania, and northern and central New Jersey. The
light wintry mix should linger during the morning in parts of
northeastern Maryland, Delaware and southern New Jersey.

As broad low pressure begins to approach from the west, the
precipitation will begin to spread back to the north on Monday
afternoon, with light snow returning to eastern Pennsylvania, and to
northern and central New Jersey. A light wintry mix, favoring rain,
should continue in our southern counties.

The expected snow totals in the northern half of our forecast area
for tonight do not warrant an advisory. We will keep the Winter
Weather Advisory in place for the southern half of our region from
1000 PM this evening until noon on Monday. We have expanded the
advisory to include the Maryland counties of Talbot and Caroline,
and Sussex County, Delaware (except for the beaches) due to the
expectation of a light glaze of ice in parts of those counties.

Low temperatures for tonight should favor the 20s and lower 30s with
a light and variable wind. A northeast wind around 5 to 10 MPH is
forecast to develop on Monday. High temperatures will likely be in
the 30s.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
This portion of the discussion will focus on the 2nd of the one-two
punch.

Synoptically...The period starts with a warm front well to our south
and high pressure centered well to our north. The front will be
attached to a low west of the Mississippi. This low will track
northeast and be positioned near the Great Lakes 24 hours later, on
Tuesday evening. At this time, a secondary low will develop near the
coast of NJ and track northeast Tuesday night.

Impacts...This event will cross the Tuesday morning commute as well
as the Tuesday evening commute. For the I95 corridor, the morning
commute will experience the most impacts. Further north and west,
the morning commute will be a snowy one and the evening one could be
a mixed bag of snow, ice and freezing rain.

Headlines...Winter Storm Watch posted for the southern Poconos and
NW NJ to account for both the snow and ice.

Snow/sleet amounts...Ranging from 5 to 8 across the Southern Poconos
and NW NJ, 3 to 5 across Berks and the Lehigh Valley, then 2 to 4
down to I95. 1 to 2 when you cross the river into NJ and also for
northern Delmarva. An inch or less south and east of there.

Freezing rain...Tricky here at this point and depends on the
strength of the low-level warm nose. For now, have .2/tenths of
ice across the Southern Poconos and NW NJ, .1 to .2/tenths
across Berks, the Lehigh Valley and Morris County in NJ, a trace
to a .1/tenth down to the urban I95 corridor, and then a trace
south of there. Cape May county and Sussex county may not see
much snow or ice at all.

For the Poconos and NW NJ, it`s not out of the realm of
possibility of receiving more ice. Some of the forecast
soundings over the last two runs have up to .4/tenths.

Rain...Not sure the Poconos will ever go over to all rain. The
Lehigh Valley and Berks are forecast to change over late Tuesday,
and the urban corridor around midday Tuesday.

QPF...This is not a weak/dry system. Total QPF, when all said
and done will be between 1.00 and 2.00 inches. Where the ptype
is mainly liquid, expect minor flooding in the most prone areas.
Even across locals that get accumulating snow, moderate to
heavy rain is possible after the changeover.

Transitions...As stated, the frozen/freezing may never change over
across the far north. For the Lehigh Valley, going with all snow
Monday night into Tuesday morning and transitioning to all rain
Tuesday afternoon. Across the urban and I95 region, going with snow
Monday night to a mix by daybreak Tuesday, followed by all rain in
the afternoon. The Tuesday morning commute looks nasty for this
area. Across the coastal plain and our southern Delmarva zones,
going with snow to rain on Monday night. Looks like all rain here
Tuesday and Tuesday night.

In response to your and bac's posts, I inflated the flat tire on my snowblower, checked the gas, and started it up to be ready for the snow here in Wall. Getting the snowblower ready is usually the kiss of death for accumulating snow. :pray:

 

[Tango Two]

Any school predictions for Middlesex County. Tomorrow and Tuesday?Thanks.

Btw do school districts hire weather consultants typically or just have someone watch the news and make the xall? Always wondered that.

Most consult with the police to decide

 

[RU848789]

Some useful snow forecast maps. First one is from the Eastern Region NWS, second one is from the NWS-NYC and it is a bit snowier than the Eastern Region map for the NW half of NNJ. Both have a general 3-4/4-6" amounts along the 95 corridor from Philly to NYC, which is a bump up from earlier (3-4" near the TPK and 4-6" near Rt 1). Third map is from The Weather Channel, who also increased snowfall forecasts for

Just got in from Sunday morning soccer and lunch and models are trending even colder/whiter with today's 12Z runs. It's definitely looking like an inch or so of snow late tonight early tomorrow, N of 195/276 and up to 2" S of that line and then an absolute mess starting late Monday evening and lasting through Tuesday night. Near/along the 95 corridor from Philly NYC we can expect a few to several inches of snow (depending on when the change over to sleet occurs, which is likely around rush hour in Philly, maybe mid-morning in NB and noon in NYC, followed by probably 6+ hours of sleet, producing probably 2" of sleet (from 0.6" or so of liquid equivalent falling as sleet at 3:1 ratios of sleet to liquid) on top of the snow.

While 1-3/2-4" of snow doesn't sound like a big deal, it's a pretty big deal if 2" of sleet is added on top of that, as the total would be in the range of 0.6-1.0" of liquid falling as frozen precip (equiv in mass to 6-10" of snow). That much mass of frozen precip will be very impactful on shoveling. plowing and driving. NWS in NYC upped their snow/sleet forecasts (the maps include both) this morning, as per the map below.

Mt. Holly is still only showing the map from yesterday for the minor part 1, which I think is a mistake, I imagine most schools will be closed on Tuesday and some businesses - I know I'll be working from home and I'm sure bac will finally make some extra $$, so maybe he won't be so cranky, lol. I expect watches to go up for most of the area with the 4 pm packages, even if the depth won't reach 6" in many places (the mass will and there's still a risk of freezing rain, especially NW of 95). Will share some models later.

TWC is going pretty bullish on snowfall for the area - surprising, as they're usually pretty conservative with snow.

Just for posterity, for me, here are the 12Z model outputs - mostly held serve or were a bit colder/whiter than 0Z last night.

12Z GFS (snow + sleet counted as 10:1 snow)

12Z GFS-FV3 (snow + sleet counted as 10:1 snow)

12Z CMC, which is snow only; the model shows ~2" of sleet for the 95 corridor, but it's not shown on map - that would make the 1-2" of snow into the snow equivalent of 7-9" (1-2" of sleet is equiv to 3.3-6.6" of snow).

12Z NAM (snow + sleet counted as 10:1 snow)

12Z UK (snow + sleet)

12Z Euro (just snow; like the CMC, shows 1-2" sleet, but not on map)

The 18Z runs of the GFS, GFS-FV3, NAM and Euro look reasonably close to what they were before - some fluctuations, but not all in any direction to detect any significant changes in what's coming, so I'm not posting them (twice a day is more than enough). However, here are some good maps from various sources.

The first one from the NWS Eastern Region is great for seeing the big picture from the NWS...although it seems to be a bit at odds with the 2nd map from NWS-NYC, especially for the NW half of NNJ (a bit more in the NYC graphic), below. These also appear to not include the snow from "storm" 1, as amounts S of 276/195 are low. I included that below, also, as well as the NWS-NYC map, which bumped up totals from this morning. Still haven't seen a map from NWS-Philly for storm 2, but the fact that these other maps are out there must mean they're in agreement. In addition, I included an updated map from TWC, which bumped totals up a bit again, but it's not that far off from the NWS maps (a little higher).

Will be interesting to see if these maps verify or not. With mixed precip events, featuring a significant warm layer aloft moving in over time and cold air damming trying to keep the cold air from the high in eastern Canada in place, bust potential on either side is pretty high. If that warm layer arrives a few hours later, a 3" of snow + 1" of sleet forecast could easily become a 6" of snow + 1" of sleet, whereas if the warm layer arrives a few hours early, that outcome could change to <1" of snow + 1" of sleet. Huge difference in outcomes over something that is quite difficult to predict accurately 1.5 days out or even 6 hours out.

 

[Jm0513]

Hard yes or no...will this interfere with my Valentine's day?(essex co) I can't read the whole thread...thx[thumb2]

 

[phs73rc77gsm83]

Hard yes or no...will this interfere with my Valentine's day?(essex co) I can't read the whole thread...thx[thumb2]

No offense but do you really think anyone—professional meteorologist of not—could give you a “hard yes or no”? It’s not an exact science and you’d be ill-advised to take any “hard yes or no” from anyone. You’re talking about weather...

 

[WhiteBus]

Hard yes or no...will this interfere with my Valentine's day?(essex co) I can't read the whole thread...thx[thumb2]

I'll send you flowers no matter what the weather is.

 

[Jm0513]

I'll send you flowers no matter what the weather is.

No red roses... please be creative! Puppies or kittens are acceptable as well[laughing]

 

[Jm0513]

No offense but do you really think anyone—professional meteorologist of not—could give you a “hard yes or no”? It’s not an exact science and you’d be ill-advised to take any “hard yes or no” from anyone. You’re talking about weather...

It was a JOKE! Lol

 

[WhiteBus]

No red roses... please be creative! Puppies or kittens are acceptable as well[laughing]

Puppies yes. Kittens...pass.

 

[bac2therac]

No red roses... please be creative! Puppies or kittens are acceptable as well[laughing]

how about some veal

 

[bac2therac]

Hard yes or no...will this interfere with my Valentine's day?(essex co) I can't read the whole thread...thx[thumb2]

the 14th will be fine weatherwise

 

[DJ Spanky]

Puppies yes. Kittens...pass.

Well you could send kittens with recipes!

 

[NickRU714]

Lets make simple.

What should be the shoveling schedule?
Once it starts to turn in the afternoon, move the snow off?
Then again Tuesday night?

 

[DJ Spanky]

What should be the shoveling schedule?
Once it starts to turn in the afternoon, move the snow off?
Then again Tuesday night?

Definitely get that snow off before the sleet/rain gets going, otherwise you will end up with several inches of cement to move.

 

[RU848789]

Definitely get that snow off before the sleet/rain gets going, otherwise you will end up with several inches of cement to move.

Definitely shovel before it turns to rain, as most of the rain will be absorbed into the slushpack and become extra weight to move. However, it shoiuldn't become frozen cement, because temps are very unlikely to go back below freezing before Wednesday night.