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OT: Moderate to Significant Snow (and some rain SE of 95) for Sunday, 1/19.
- By RU848789
- Rutgers Football
- 488 Replies
Summary: A 2-4" snowfall for the region (Philly-NJ-NYC) is starting to look likely on Sunday given improving model consensus on that outcome. 4-6" amounts have been seen on some models and no models are showing significant areas <2" (other than the CMC which is an outlier; see below), so it's looking like 4-6" is still on the table as is 1-2", but likely not less than that or more than 6". Precip starts in the 1-3 pm timeframe for most (1 pm towards Philly/SNJ, 3 pm for CNJ and towards NYC) with temps around 32F to start, but dropping quickly into the 20s for most of the storm, which will likely be over by 2-4 am on Monday. Accumulations are likely on all untreated surfaces, so road conditions will go downhill quickly and could still be difficult on Monday morning and with temps in the deep freeze after that for several days, it'll look like deep winter here.
And huge win for RU tonight!
Details: The 18Z models had no surprises/major changes vs. 12Z (just minor differences), so let's get right to the 0Z runs tonight and there were mostly minor changes for the models, except that the Euro went from a 1-2" snowfall to a 2-4" snowfall for most. So we now have every 0Z model showing 2-4" or 3-6" amounts for just about everyone (Philly-NJ-NYC), except for the CMC which still shows 6"+ just NW of 95 and a lot less towards the coast, but it's clearly an outlier. Outliers have been right before, although not that often. Details below in model order they come out.
Based on us now having 3 straight model suites showing at least decent consensus and better consensus now at 0Z than it was at 12Z earlier today, confidence is certainly higher in most of our area getting a 2-4" snowfall, with a 3-6" event also very possible. More than 6" for anyone is pretty unlikely, just like <1" is now very unlikely for anyone, unless the CMC scores a huge outlier coup. However, that's not how mets put together forecasts, so we should expect the NWS to probably come out with maps showing 2-4" for most with maybe some 3-5" spots and possibly 2" or less at the coast. This wouldn't be too far off what Lee Goldberg is still predicting, i.e., 2-4" for everyone, with 4-6" for points NE of NYC. We're now within ~60 hours of the start of the event, so changes are still possible, but significant changes are becoming less likely.
- The ICON showed a bit less precip/snow than 12Z, with a general 3-4" for everyone.
- The GFS was a bit snowier than 12Z, showing 4-7" for just about everyone (highest amounts towards the coast)
- The CMC again showed 6"+ starting on a SW to NE line about 5-10 miles NW of the TPK with 2-4" along the TPK and <1" just 10-15 miles SE of the TPK and nada SE of there to the coast. Very steep gradient.
- However, the CMC ensemble mean is much further SE than the Op with 3-5" NW of 95, but 1-3" SE of 95 to the coast, implying the Op might be a bit of NW outlier relative to its own ensemble mean, which happens sometimes.
- The UK is similar to 12Z with a general 3-5" event for most, except 2-3" near the coast, due to less precip falling (not rain)
- And finally, the Euro is a bit snowier than 12Z, showing a 2-4" event for most, except 1-2" near the coast, due to less precip (not rain), which is similar to the UK.
- Note that all but the CMC (the only one showing rain/mix) are still generally <32F for the duration with falling temps into the 20s during the snowfall, which could lead to elevated snow/liquid ratios (maybe 12-15:1 - same mass, more depth) if those temp verify - and if the snow crystal growth aloft is good, although it's too early to make that assumption, so all of the snowfalls I quoted above are at 10:1 ratios.
- The Euro AIFS (their new AI model, which has been pretty accurate) shows a 4-6" snowfall for everyone.
- The NAM showed basically no snow, but it's past the end of its useful range (usually best inside 48 hrs and the snow starts around 66 hrs), so the pros are discarding it. Similar thing for the RGEM, which looks almost identical to the CMC (both Canadian models share code). These models will be taken more seriously starting around tomorrow night.
First snowfall maps have been issued from NWS Philly and NYC and they're pretty close to what was discussed above and a bit higher than what Lee Goldberg had forecast last night with a general 3-5" forecast for everywhere in the Philly-NJ-NYC area (with their 4" line very close to 95 from Philly to NYC) except for near the NJ coast, where 1-3" are forecast (due to the likelihood of some rain holding down accumulations) SE of the 3" line which runs from about Manasquan to Alloway in Salem County. This would certainly be the biggest snowfall this season for everyone except for most of SENJ/DE, which got more on 1/6.,
The NWS-Philly discussion, below, details how this is a preliminary forecast and that significant changes are still possible, as we're still 54 hours from the start of the event and there is still model variability as discussed above, which is part of why they have held off on any watches/advisories as they'd like to see more consensus before issuing them (plus the current forecast has most locations just below warning criteria). Lots more models to come. It's also worth noting that the 6Z global models (Euro/GFS/ICON/UK) are fairly similar to what they were last night at 0Z, although the GFS and UK did bump amounts up a bit. although they both show more mixing towards the coast, so the risk of a more CMC-like solution (with heavier snows NW of 95 and mostly rain SE of 95) is still there.
One thing worth noting is that for anywhere that gets a mix of snow and rain, producing a slushy mess, temps will be tumbling through the 20s by Sunday night, so shoveling before then is an absolute must for those folks, as anything not shoveled by then will likely become a permanent frozen mass that will stick around all week given the brutal cold that is coming. Specifically, we'll have highs in the teens Tues/Weds (and 20s Mon, Thurs and Fri) and lows in the single digits to maybe below 0F for NW areas on Tues/Weds/Thurs mornings with even colder wind chills.
https://forecast.weather.gov/produc...&format=CI&version=1&glossary=1&highlight=off
Area Forecast Discussion
National Weather Service Mount Holly NJ
630 AM EST Fri Jan 17 2025
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
From here, forecast guidance still varies significantly,
considering it`s only 48-60 hours away. The track and strength
of the surface low will ultimately determine what type of
precipitation our area experiences Sunday into Sunday evening.
If the track of the low is close enough to the coast, a large
portion of the region is likely to observe accumulating snowfall
(similar to what the 00Z GFS and ECMWF depict). If the track of
the low, hugs the immediate coastline, or ends up inland over
the coastal plain, then the most significant snows will be
focused north and west of I-95 (depicted by the 00Z Canadian).
Such a solution would also mean rain for the immediate coast,
and perhaps as far inland as the I-95 corridor. The previous
suppressed solution appears to have fallen out of favor of the
deterministic and probabilistic guidance as of the 00Z suite. So
precipitation appears increasingly likely across much of our
area, but the exact detail still remain unclear based on the
track. Ultimately, the outcome probably lies somewhere between
the first two aforementioned solutions. PoPs have been increased
to 60-70% area wide. We have introduced more mention of rain
for the coast and coastal plain inland to I-95 with this
morning`s forecast update, and increased snowfall amounts a bit
farther inland from there.
So with all of this being said, the greatest potential for
significant accumulations remains for areas along the I-95
corridor and points north and west. Within this zone, forecast
amounts were increased about 1" across the board, and now stand
between 3-5", with locally higher amounts possible as usual.
Lesser amounts upwards of 1-2" remain in the forecast for the
coastal plain, and amounts for the immediate coast were lowered
slightly in light of the increasing potential for some rain to
mix in during the event. The far southern coastal areas such as
Cape May and southern Delaware likely end up with less than 1",
though potential exists for higher accumulations there.
Since warning level snowfall does not currently appear likely to
occur (though this certainly remains possible for some inland
areas), we have not issued any watches at this point. Our
current forecast support mainly a widespread advisory type of
event, but given the relatively low confidence and quickly
changing forecast, we`ll hold of on any advisories for now as
well. Obviously, a lot can change over the next 48 hours as
more hi- res/short range forecast guidance comes into the
picture. Note that the forecast is likely to change, so stay
tuned for the latest details to the forecast over the next
couple days!
