Tatamy

I am seeing that also.

This is a radar view of what I was referring to. It is right near the Delaware River. Your shot also shows it.

The coastal has exited stage right if you will. It was never expected to be a big player in providing snow to this area. The trough and IVT are the features that going forward will provide the snow with this event.

Take a look at high resolution radar. I use the site weather.cod.edu. If you look closely at the elements you can plainly see echos coming west from the Jersey Shore while other echos come east from central PA. They are meeting along the Delaware River. This is where the IVT is currently set up. Where these echoes meet the accompanying moisture is lifted higher into the atmosphere and then precipitates back down mainly in the form of snow in this instance. This matches where the models are calling for the higher snow accumulations. Later tonight as the trough moves in the feature will weaken and push out to the east.

“Heaviest” snows will be north and west of NYC. The coastal was expected to move out quickly from our area this afternoon making room for the trough and IVT to approach from the west.

Steady light snow with a coating on most surfaces. 31/29

Snowing very hard now in the Harrisburg area as the IVT begins to set up.

New 12z HREF with 1-2” for most and 2-4” for elevated locations N&W. Only exceptions would be the Jersey Shore and the South Shore and East End of LI

Steady light snow with a light coating on some colder surfaces. 31/29

The precip along the Jersey coast is rain. Temps there are in the upper 30s and low 40s. Temps out on LI are in the mid to upper 30s. Anecdotally the R/S line looks to be roughly along I95

Currently heavily overcast where I am. 31/25. There are a few lonely snow flakes around as well.

We don’t live in Massachusetts. (Unless you’re visiting from the New England board.). Just because there are echoes on radar doesn’t mean it’s snow. You are correct about the precip from the coastal being west however the precip field from that feature will move out to the east this afternoon. If anything accumulates that would most likely be this evening and tonight.

The precip coming up from off the Delmarva coast and right along would be in the form of rain. There are no current reports of precip reaching the ground there. Temps there are in the mid 40s. Temps along the NJ coast and LI are in the mid 30s and that would support mainly rain during the daytime hours with snow possibly mixing in during any heavier bursts on LI. In any case no snow accumulations are expected during the daytime hours except for higher elevations well north and west. This is the theme of what the NWS is going with for the area. The best chance for snow accumulations for most of us is dependent on additional energy coming in tonight with the trough. We still have the possibility of the formation of the IVT as well for tonight.

FWIW whatever snow that falls during the day tomorrow before 4pm will be melting on contact unless you have at least 500-700’ in elevation or are in a place that gets good rates.

I remember that the HRRR had it but was not sure of the others. Thanks.

Which ones?

Looks like it missed the I78 deathband.

The concern from Mt. Holly about mixing primarily relates to their southern NJ, SE PA, and Delaware zones. For the remainder of their CWA the snowfall amounts will be related to the evolution of the IVT. As shown on numerous model runs it looks like the primary impacts from the IVT look to be from NYC on west. As for the coastal depending on your model of choice most of its impacts will be east of the city and perhaps well east at that. FWIW some of the models that show the coastal closer to the coast also have rain for a time in the coastal areas. Many moving parts here.

This is this morning's AFD from Mt. Holly for the Friday through Saturday night period: .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... A deepening upper trough will be approaching the area to close the week, which will be accompanied with several shortwaves embedded in the flow. At the surface, low pressure originating over the High Plains will traverse across the southern Great Lakes region and approach our region by Friday afternoon. Forecast guidance has trended a little deeper with the primary shortwave, so as the low approaches, some precipitation is expected to develop and overspread the area through the day Friday. At the same time, a secondary low will be developing a couple hundred miles off the Mid-Atlantic coast and deepen rapidly as it lifts northeast; enhanced by speed max rounding base of the upper trough. With the low offshore remaining in `close enough` proximity to the area, it is likely that there will be some areas of mainly light rain and snow across the area on Friday into Friday night as the initial low transitions its energy to the offshore low. In addition, some forecast guidance indicates the development of an inverted / Norlun trough set-up on the northwest side of the offshore low. This would enhance precipitation across portions of the area, however, it is still uncertain where or if this feature is to even develop at this time. For now, the best chance of observing accumulating snow will be across the Lehigh Valley, northern New Jersey and in the Poconos where temperatures will be cooler through the duration of the event. Current forecast snow totals in these areas are for between 1-2", locally up to 3". Light accumulations of a dusting up to 1" are possible across the remainder of New Jersey, Pennsylvania and northern Delaware as rain transitions to snow on Friday night as temperatures cool below/near freezing. It should be noted though that these type of inverted trough setups are notoriously difficult to forecast as they can sometimes have localized heavier precipitation amounts. If this occurs, some areas could "over perform" and see snowfall amounts as high as 4 or 5 inches. Best chances for this would be central into NW NJ, NE PA. Precipitation will taper off from west to east by early Saturday morning as the low exits toward Nova Scotia. The remainder of the day Saturday will be blustery and cold with highs ranging from the 20s to low 30s north with mid to high 30s for highs near and south/east of the I-95 corridor. Temperatures are expected to the fall into the teens Saturday night an Arctic airmass begins to take hold across the region.

It was mainly alone on the 0z run however now with the 06z run it is getting some support from the 3k NAM. It’s kind of a long shot but let’s see what the rest of the models do as we go through the day.

You do realize that the NAM is literally an ocean apart from all the other guidance. Good luck with the remaining runs from the 0z suite.

Thank you for finding and posting this. Very unique system in terms of how it evolved. The gradient on that was something straight out of a lake effect band.

It’s been there for a few days.

Wise move on your part. I don’t think people on this board want to go down the same path as what is going on in the New England forum with the potential system for the end of the week.

We had the same type of gradient out here with that event. There was some type of convergence zone with this system. The band of heavy snow with this was only about 15-25 miles wide. It was visible on radar out in Ohio the day before. Interesting synoptic setup with that one.