2/1 - 2/4 Storm potential

[Mitchel Volk]

The trend is towards a more northerly track. The question is will this continue or will it reverse. The full data will be advailable once the short wave gets into a more data rich area, then we can make a better forecast.

[jdt]

Looks like snow to ice storm NW NJ, NE PA interior SE NY. But until we see sounding data can't say for sure snow vs sleet vs rain. Just one run of many to go. Ice storm for the NW burbs is a concern for sure especially with it bringing in cold behind it.

[tombo82685]

But the primary seems to want to keep going further north with less redevelopment....which was what the EURO had right?

It is not the EURO, but it is trending closer.

if u compare the 18z gfs to the 0z gfs, the 0z gfs is quicker with the redevelopment

[Analog96]

Well yeah, but the NAM's timing has been way to slow for awhile now with nearly every event.

Isn't that a very common bias of the NAM?

[jasonli18t]

I just hope we don't have another ridiculous coastal front torch up into the 40s like we had last week. That'll wipe out a ton of snow and create huge flooding problems at the same time. If it rains at 35 degrees, it's okay by me. I still think also that we get a lot on the front end before we get rain (if we get rain, there's still plenty of time for this to trend back less amplified).

I would think that with a dominant primary low and not much redevelopment off the coast we would be safe from those nasty coastal fronts. I think the warming would just come from the light to moderate southerly/sw'ly winds which would likely provide us with the 35 and rain you mentioned.

That said, the euro wanted to get us into the 40s, so who knows.

[ag3]

All storms in this range have been overamplified.

People should take these models of the idea of a storm.

We nail down timing and tracks no earlier then Monday 12z.

[NEG NAO]

Well if that's true then we're going to have to discuss flooding because we would def get a lot of flooding with a warm solution.

Please describe how you get alot of flooding with temps in the low - mid 30's at the tail end of the storm for less then 12 hours after 5 or more inches of snow has fallen

[NEG NAO]

Well if that's true then we're going to have to discuss flooding because we would def get a lot of flooding with a warm solution.

Please describe how you get alot of flooding with temps in the low - mid 30's at the tail end of the storm for less then 12 hours after 5 or more inches of snow has fallen

[Grothar]

LV is snow to sleet to maybe some FRZA, but a mess with nearly 1.25" QPF.

No its all snow- no freezing rain maybe some sleet in the heaviest bands. I see thundersnow and at least 13 inches of snow with ratios 12:1 or more. Why do I see this? Because it is our turn to see this

[MGorse]

Isn't that a very common bias of the NAM?

I believe so, but it seems like it has gotten a bit worse. I believe it has something to do with the spin-up time which ends up making the model to slow with the precipitation advancement.

[IsentropicLift]

To be honest, if some of these models are correct, we are going to start snowing in the NYC-PHI area at 84hrs or so and not stop the precip until hr 132 or so. That's a heck of a storm and honestly widespread 1"+ QPF on most models. What a nightmare setup, but I love it just the same

[ptb127]

It's important to note that it's still 5 days away. For the last storm, the euro run gave all of E PA 2.5" of QPF. Most of it only got approx. .25". So there is a lot of time to trend. People make me laugh that are getting all worked up about trends 5 days out.

[SnowGoose69]

GFS has 4"-7" of front end for NYC. Then a slop to rain.

Thats a very generous call...I'd go more 1-3...the JFK sounding is around -1 to -2 from 700-850 at 111 hours...given the SW flow of 80 knots I'd imagine we're getting sleet by 108-110 hours.

[hudsonvalley21]

Well if that's true then we're going to have to discuss flooding because we would def get a lot of flooding with a warm solution.

Ice jams along some rivers too.

[jm1220]

I would think that with a dominant primary low and not much redevelopment off the coast we would be safe from those nasty coastal fronts. I think the warming would just come from the light to moderate southerly/sw'ly winds which would likely provide us with the 35 and rain you mentioned.

That said, the euro wanted to get us into the 40s, so who knows.

The Euro is almost always too warm, so I'm not that scared of it right now. I'd really like though to see models cool off a bit literally and figuratively on this amplification. There's a ton of energy diving into this trough, which is never good for us when there's no blocking up over NE Canada. However, the highs and cold in place will provide a lot of cold air that the low will have to eat through first. It will be a mess either way. Again, still plenty of time for this to trend in the other direction. We just saw that with this last storm, with a high well offshore and no real -NAO.

[nzucker]

Looks like snow to ice storm NW NJ, NE PA interior SE NY. But until we see sounding data can't say for sure snow vs sleet vs rain. Just one run of many to go. Ice storm for the NW burbs is a concern for sure especially with it bringing in cold behind it.

This looks like a very dangerous storm here in the NW burbs....having 6" of snow, then heavy icing, and finally -20C 850mb temperatures behind the system spells trouble. I'd like to see this storm trend further south so it's just a snow event since I know we'll get endless amounts of ZR in Westchester if the low cuts too much, given the brutally cold air present with the PV sitting to our north. That would be an extremely hazardous situation and would cause more interruptions for schools and businesses, basically the story of this winter multiplied by ten.

We haven't seen this type of a storm track in a while with the PNA going more negative and the PV centered over Hudson Bay/Baffin Island, but it's very reminiscent of 93-94 and may be indicative of what's to come this winter as the La Niña shifts the trough into the West for February, but with cold air remaining over the east due to high-latitude blocking centered over NW Canada/Alaska and Siberia. Could be an interesting pattern change from the sequence of coastal lows we've seen.

[ptb127]

To be honest, if some of these models are correct, we are going to start snowing in the NYC-PHI area at 84hrs or so and not stop the precip until hr 132 or so. That's a heck of a storm and honestly widespread 1"+ QPF on most models. What a nightmare setup, but I love it just the same

I strongly agree and a lot of it will be snow. This storm kinda reminds me of the V-Day storm a few years back. Highly memorable here for me as I got about 13" followed by pouring frz rain (with temps 22-25), then another 8" on top. Total QPF for that storm was over 3". Roads were closed for days as they needed graters to clear them I am sure many of you remember that storm.

[lisnow66]

In order of likelihood at this time and with low confidence: 1) Tuesday light snow then Wednesday snow, freezing rain and sleet heavy at times, 2) Tuesday light snow then Wednesday snow heavy at times, 3) Tuesday light snow then Wednesday mixed precip changing to rain heavy at times with lots of flooding. I'd like to let the 00Z GFS run finish and see a little more of the late night guidance before commenting further.

WX/PT

Thanks PT. I guess until that system enters the US the models might not get a handle on it. Hopefully as last storm the warmer/rain trending to colder/snowier solution can verify. Was the Euro 5 days prior to this week's storm also showing rainy solution or had it already turned colder?

[dbc]

Thanks PT. I guess until that system enters the US the models might not get a handle on it. Hopefully as last storm the warmer/rain trending to colder/snowier solution can verify. Was the Euro 5 days prior to this week's storm also showing rainy solution or had it already turned colder?

It was definitely a rainy solution at this stage with the last storm.

[Tiburon]

GFS has 4"-7" of front end for NYC. Then a slop to rain.

I've got about 0.35" of QPF with a snow sounding, then the ice kicks in. A lot of ice.

850's go from -1.8C @ h114 to +2.9C @ h120 with the surface temps in the mid 20s, but verbatim more than 0.5" QPF falls as ZR. That's NOT good at all.

Please describe how you get alot of flooding with temps in the low - mid 30's at the tail end of the storm for less then 12 hours after 5 or more inches of snow has fallen

Very easily. You've got high moisture content snow already on the ground, with more falling on top, after which you have ZR, and a lot, falling on top--as soon as surface temps get over 32F, you have melt off and melt through, which creates a hydrologic problem. I think the surface stays cold enough to avoid a major problem, but you've got a shot at having > 3" of liquid equivalent sitting in that snow/slop/****pack.

[SnowGoose69]

Thanks PT. I guess until that system enters the US the models might not get a handle on it. Hopefully as last storm the warmer/rain trending to colder/snowier solution can verify. Was the Euro 5 days prior to this week's storm also showing rainy solution or had it already turned colder?

The Euro is remarkably good with SW flow events...and you'll notice if you look at the 12Z run it was not suffering as severely or even at all from its bias of hanging anything back in thw SW all that long....I do like that the euro has at least been weak with the low...this shuold prevent a disaster rain event for the area, but we could have a historic sleet or ice storm if these solutions ultimately occur...I'm not sure I've ever seen the models at this range keep JFK below 0 at the surface with a system tracking this far to the west...it shows you how strong that cold dome is.

[nzucker]

Unreal how persistently cold this winter has been; at 144 hrs, the 0z GFS shows -20C 850s approaching NYC metro, again. There's just no reprieve from the barrage of snow, ice, and arctic air.

[NortheastPAWx]

I strongly agree and a lot of it will be snow. This storm kinda reminds me of the V-Day storm a few years back. Highly memorable here for me as I got about 13" followed by pouring frz rain (with temps 22-25), then another 8" on top. Total QPF for that storm was over 3". Roads were closed for days as they needed graters to clear them I am sure many of you remember that storm.

Holy hell what a mess.

4" of snow on the front end, to about 4" of sleet, followed by 9" of snow. Formed a glacier that lasted here until late March in piles.

Temps stuck in the teens/low 20s that whole storm -- KAVP had 12*F and sleet at one point.

Then you had temps plunging into the single digits afterwards.

[SnowGoose69]

Unreal how persistently cold this winter has been; at 144 hrs, the 0z GFS shows -20C 850s approaching NYC metro, again. There's just no reprieve from the barrage of snow, ice, and arctic air.

The one good thing about this thing tracking west is that its more likely we'll get an event from the storm at 160-180 hours...if the first storm ultimately goes more SE I think the 2nd event is a miss....so the choice might be 2 inches, then sleet/ZR and then another storm...or 5-8 inches mostly snow, then no 2nd event.

[NEG NAO]

I've got about 0.35" of QPF with a snow sounding, then the ice kicks in. A lot of ice.

850's go from -1.8C @ h114 to +2.9C @ h120 with the surface temps in the mid 20s, but verbatim more than 0.5" QPF falls as ZR. That's NOT good at all.

Very easily. You've got high moisture content snow already on the ground, with more falling on top, after which you have ZR, and a lot, falling on top--as soon as surface temps get over 32F, you have melt off and melt through, which creates a hydrologic problem. I think the surface stays cold enough to avoid a major problem, but you've got a shot at having > 3" of liquid equivalent sitting in that snow/slop/****pack.

NYC metro from Northern Middlesex County NJ north will more then likely avoid this situation - areas to the south and east would have a better chance of more flooding - seems like the guidance is keeping below 32 temps to the north of the raritan river in central NJ

[facciolo]

what if this storm were to slow down like the last one? That seemed to be what eventually changed the out come from rain to snow in the cities from our last storm as high pressure had more time to move in. Would the cold high pressure have more time to drop further in this situation as well? I'm new so this might be a stupid question and I know there is a lot more going on than simply the speed of the storm. On more than one occation this winter I recall the models being too fast with the low out of the south and slowing them down by as much as a day especially from about this far out.

[Grothar]

I strongly agree and a lot of it will be snow. This storm kinda reminds me of the V-Day storm a few years back. Highly memorable here for me as I got about 13" followed by pouring frz rain (with temps 22-25), then another 8" on top. Total QPF for that storm was over 3". Roads were closed for days as they needed graters to clear them I am sure many of you remember that storm.

Sleetfest 07 where 78 was a disaster. Realistically 8-12 inches of snow followed sleet would be a nightmare to shovel. Heart attack city and piling this stuff on the existing snowpiles or just plowing will cause a lot of mechanical breakdowns in snow removal equipment. I hope the Euro gets colder.

[jm1220]

The Euro is remarkably good with SW flow events...and you'll notice if you look at the 12Z run it was not suffering as severely or even at all from its bias of hanging anything back in thw SW all that long....I do like that the euro has at least been weak with the low...this shuold prevent a disaster rain event for the area, but we could have a historic sleet or ice storm if these solutions ultimately occur...I'm not sure I've ever seen the models at this range keep JFK below 0 at the surface with a system tracking this far to the west...it shows you how strong that cold dome is.

That's why I'm at least optimistic at this time that most of us stay a frozen (or freezing) precip type for most of the storm, since we have a LOT of cold air to eat away and tons of snow on the ground to try to lock cold air in before we see plain rain. But that energy needs to phase less and be more progressive, that kind of trough/ridge config and northern stream diving in over the Rockies would ordinarily lead to massive torch here.

The typical Nina pattern of lake cutters and SE ridge is slowly trying to reassert itself, but the pattern to our north is still behaving cooperatively for now, even without the NAO.

[_AR_]

The one good thing about this thing tracking west is that its more likely we'll get an event from the storm at 160-180 hours...if the first storm ultimately goes more SE I think the 2nd event is a miss....so the choice might be 2 inches, then sleet/ZR and then another storm...or 5-8 inches mostly snow, then no 2nd event.

Or 10" overrunning snows and another near miss to the east for inland folks?

[dbc]

NYC metro from Northern Middlesex County NJ north will more then likely avoid this situation - areas to the south and east would have a better chance of more flooding - seems like the guidance is keeping below 32 temps to the north of the raritan river in central NJ

Yes, if what is depicted verifies. I also doubt 3 inches of qpf anywhere in New Jersey verifies from this, not even half that is likely to verify.