March Madness! Spring Snowstorm Observations

There is still great uncertainty with the exact track of the surface low pressure that will develop off the coast. At this point we're within 24 hours of the event and models are still in disagreement. Take a look at the GFS vs. NAM at the 500mb level for a second.

GFS



NAM



The trough is neutral and heights are closer to the coast on the GFS compared to the NAM. This is why the low on the NAM deepens but ends up tracking more east than northeast. This SLIGHT variance is the difference between 12"+ of snow or 6"+ of snow for many areas. The 00z NAM last night was a solid hit for the area (looked like other models) but reverted back to this more east solution early this morning at its 06z run. At this point, the NAM is not just inconsistent but also on its own. The EURO, RGEM, SREFS and others are more in line with the GFS and the GEFS (GEFS more bullish than the GFS OP which also says something).

The EURO OP and the GFS OP are actually fairly close. I actually think after today's 12z runs we will see agreement between these 2 models in terms of track of the SLP, then we can use meso-scale models to determine where the CCB sets up and where the best snowfall rates will be. I think an area-wide Mothrazilla is a lock with a Godzilla being VERY close to happening. We will see at 12z today which way models lean. Do they stay near the coast and deliver a Godzilla, or do they get pulled slightly east to give everyone a Mothrazilla while also removing sleet and rain from the equation for coastal areas. We'll find out very soon.

I will have a final call snow map later today.

Rain getting into SNJ. Let's see how far north this gets today. A layer of snow or sleet before the main event moves in on Wednesday would help with accumulations. But I have a feeling most of what falls today will be rain. But we will see...

Trough is positively tilted now but once it crosses the Mississippi fully it will begin its turn to negative. Look at all the convection near the Gulf

Going to be interesting just how far north this precip gets with the 1st wave and how heavy it gets. Temperatures only around 32 in CNJ and with dew points in the teens, could be quite the sleet/freezing rain event this afternoon

If the tick east is real - and I have a feeling it might be because of the "push" of the confluence to the north - then there will be a sharp cut-off for areas like NEPA, NW NJ, and N of NYC.

This is insane, all due respect. No reliable guidance supports these agressive numbers. NWS struggling this season for sure. Not sure what's up. We'll see if their 4pm has drastic cuts if this east trend continues (as they usually change snow maps minute to minute lol)

Frank_Wx wrote:If the tick east is real - and I have a feeling it might be because of the "push" of the confluence to the north - then there will be a sharp cut-off for areas like NEPA, NW NJ, and N of NYC.

That seems to be pretty consistent on most models since last night. Once the storm gets to about the Maryland PA border latitude it hits a wall and goes mostly due east, then ENE. The TZ bridge seems to be the N/S border from there to 30 miles north where there will be a sharp cutoff somewhere in that 30 mile range.

SoulSingMG wrote:This is insane, all due respect. No reliable guidance supports these agressive numbers. NWS struggling this season for sure. Not sure what's up. We'll see if their 4pm has drastic cuts if this east trend continues (as they usually change snow maps minute to minute lol)

Totally agree Soul. I think 8-12” area wide from eastern NJ east. 4-8 NYC on West and North

SoulSingMG wrote:This is insane, all due respect. No reliable guidance supports these agressive numbers. NWS struggling this season for sure. Not sure what's up. We'll see if their 4pm has drastic cuts if this east trend continues (as they usually change snow maps minute to minute lol)

They are forecasting an area-wide Godzilla.

That is still on the table but I am thinking area-wide Mothrazilla with isolated towns receiving 12"+ depending where the CCB or heavier snow rates form. Big 12z runs today. If models tuck the low into the coast like EURO showed yesterday then that will result in Godzilla snowfall amounts. We need H5 to close off fast which allows heights to amplify along the east coast.

EXTREME?? Bullish, imo. (Thx @weatherwilly for map)

06z NAVGEM is a huge storm. Wow. Right to the BM

SoulSingMG wrote:EXTREME?? Bullish, imo. (Thx @weatherwilly for map)

wow

I wanna see the short range HRRR like models now inside of 24 hours. They do better in close like this.

ARW's looks fantastic

Frank_Wx wrote:If the tick east is real - and I have a feeling it might be because of the "push" of the confluence to the north - then there will be a sharp cut-off for areas like NEPA, NW NJ, and N of NYC.

wow 24 for me! What model is that?

jmanley32 wrote:

Frank_Wx wrote:If the tick east is real - and I have a feeling it might be because of the "push" of the confluence to the north - then there will be a sharp cut-off for areas like NEPA, NW NJ, and N of NYC.

wow 24 for me! What model is that?

DEEP THUNDER

31 degrees, feels like 23. Winds NE at 8mph. Dewpoint 12.

I'm not sure I get all the talk of eastward trends? From what I've seen, ONE model (the NAM) jumped east last night. That happens to be the model that was waaaay WEST at 0z yesterday evening. Not sure I would trust the model that had 20" of snow in NW NJ last at 0Z and then suddenly flurries at 6z run, when other models are staying more consistent. All the other models are status quo more or less. As for cutoffs, if we're talking about PA and far NW NJ, there's always been a good chance of a sharp cutoff there (look at my snow map yesterday, which was done before any east shift in the NAM).

jmanley32 wrote:

Frank_Wx wrote:If the tick east is real - and I have a feeling it might be because of the "push" of the confluence to the north - then there will be a sharp cut-off for areas like NEPA, NW NJ, and N of NYC.

wow 24 for me! What model is that?

This is the GEM LAM which is in MM for qpf
24 MM = .98 inches of Liquid (QPF)

The top image is Deep Thunder and the bottom one is GEM-LAM

NWS snow map


WPC much more conservative


ARW which have not wavered with this storm



From a couple for pro mets - 6Z NAM was a burp adn needs to be tossed for it SLP depiction. That should ease some of the panic in here