12/29 Potential Snowstorm Update #1

36° and dropping, NAM soundings for tomorrow morning suggest freezing rain to start here in NNJ, going to be a rough morning until it changes over....

Dunnzoo wrote:36° and dropping, NAM soundings for tomorrow morning suggest freezing rain to start here in NNJ, going to be a rough morning until it changes over....

I'm no expert here but I thought there were no problems at the mid levels with this setup, I thought it was surface temps that were going to be the problem and cause rain for most.

If it's 28 degrees and raining here tomorrow morning I may actually do something drastic, a man can only endure so much.

CPcantmeasuresnow wrote:

Dunnzoo wrote:36° and dropping, NAM soundings for tomorrow morning suggest freezing rain to start here in NNJ, going to be a rough morning until it changes over....

I'm no expert here but I thought there were no problems at the mid levels with this setup, I thought it was surface temps that were going to be the problem and cause rain for most.

If it's 28 degrees and raining here tomorrow morning I may actually do something drastic, a man can only endure so much.

I'm worried about the surface, I'm already down to 33° and even if it starts as rain and I get no snow, it will freeze on contact...

34* here, and likely to drop into the upper 20s before leveling off. I suspect though the temperature may start to creep up again before the rain commences tomorrow morning helping to avoid any ice concerns here. That may not be the case where Janet is though where temps may take longer to rebound.

You can disregard my 1st call snow map. I think a couple of inches could fall in NEPA and areas N&W of NYC, but other then that, this will be a fast moving system with too much warm air advection keeping precip in the form of rain.

HRRR suggests snow beings breaking out in eastern PA and western NJ between 6:30-7:30am.



By 9am, moderate to heavy snow could be falling in NW NJ, NEPA, and SW NY.



By 11am, likely sooner, almost everyone is rain except for high elevations of PA.



4KM NAM is similar. Here is 8am.



Then 1pm



Precip should shut off between 3-4pm.

CPcantmeasuresnow wrote:

Dunnzoo wrote:36° and dropping, NAM soundings for tomorrow morning suggest freezing rain to start here in NNJ, going to be a rough morning until it changes over....

I'm no expert here but I thought there were no problems at the mid levels with this setup, I thought it was surface temps that were going to be the problem and cause rain for most.

If it's 28 degrees and raining here tomorrow morning I may actually do something drastic, a man can only endure so much.

CP you should be absolutely fine.  I checked soundings for your location.  Janet however, and areas in NE NJ ish, the soundings show below freezing in the mid layers, but a warm nose sticking out just above 1000mb before it goes back to below freezing again at the surface at the onset of the precip moving in.  Above that warm nose precip is falling as snow, but then as it falls through the layer above freezing it melts, conts as rain; then freezes on contact on a below freezing surface.  Its very short lived(couple of hrs at most), and soundings not that far away dont show it, but any freezing rain if your unlucky enough to be driving while it happens could suck.  I labeled an image of 18z NAM soundings at hr18 that shows the warm nose.  Hopefully it doesnt happen Janet.

I actually think CP and DOc will turn to rain. NAM, HRRR support that and GFS at 1pm has 925mb above freezing for them.

Well it seems the next major point of interest may be the Jan. 8 set-up.

Frank_Wx wrote:I actually think CP and DOc will turn to rain. NAM, HRRR support that and GFS at 1pm has 925mb above freezing for them.

I'm talking more about freezing rain. They should at least start as snow before changing.

Currently 29* here.

Interestingly already 26* and clear. Already colder at 9 pm than the projected low temperature. Not that it makes much difference I guess other than the aforementioned ice concerns.

Since the map thread is locked already, I'll post my final call here:

Start:5-9am
End: 3pm (west)-12am Friday (northeast)



Still think the northern and western areas end up getting snow-holed with this one because of a couple of reasons, which is why I stuck with the general idea of my first call. We'll see how it turns out!!