FEB 17th-18th Snow? Sleet? Rain?

That's right CP, the negative trajectory.next week's torch burns another week.

NWS still holding out with a Watch for southern nyc (Staten Island, Brooklyn, Southern Queens) and southern Nassau & Suffolk. I squeezed into warning criteria.

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Made a map. Using a blend here and hunch with the setup. Obv. tossing the GFS though it is still stubborn, my guess is it goes down with the ship it's on.

aiannone wrote:

NjWeatherGuy wrote:I think the GFS is out to lunch here. Fairly strong confidence in a stripe of 4-8" about 10-20mi NW of 95, possibly reaching down to 95 and surrounding areas itself but less confidence to the SE. In that bullseye area to the NW we have the combo of likely a heavy period of precip and cold enough temps down to the surface to support snow tomorrow evening, likely to remain an all snow event for CNJ into E-PA and possibly the northern and western part of LI. However, there I am less confident due to potential mixing issues, but I'd say more likely than not to be a moderate snowfall there, probably 3-6". In short, I'm pretty much in line with where the NWS has it's WSW likely to turn to warnings early tomorrow morning.

While I could be wrong, I challenge whether they will be warnings or advisories. I am leaning more towards the advisory. I know for Upton criteria, Warning is 6” or more in a 12 hour period. While this will be a short duration event and the 12 hour threshold will be used over the 24 hour threshold, I believe 6” is the max accumulation they will predict so confidence in meeting 6” area wide will be low. Advisory criteria is 3” or more in a 12hr period. Much more likely. So my opinion: Area wide advisory for 3-5” with isolated amounts to 6”

Yes you're right they dropped the WSW. Technically the right call bc the criteria is 6-7" in the area if I'm not mistaken. While I believe some areas will get there I don't suppose the chances are high enough/ a large enough area for the NWS to bite. I always dislike when they drop a WSW to a WAA for a very close event to warning criteria, as they've done a couple times this winter. The reason being 6" is far more disruptive than 2-3" which are typical advisory snows. A warning makes people take the event seriously and if it were me I would have it up in the northern areas they had the watch where 6-8" are completely in the realm of possibility and even likelihood.

Edit: Upton posted Warnings, Mt. Holly/Binghamton/St. College going with Advisories only.

NjWeatherGuy wrote:Made a map. Using a blend here and hunch with the setup. Obv. tossing the GFS though it is still stubborn, my guess is it goes down with the ship it's on.

Being in Upper Bucks County I like and agree with your map.  BL temps though are a concern to me.  How far up does the warm tongue push?

NjWeatherGuy wrote:

aiannone wrote:

NjWeatherGuy wrote:I think the GFS is out to lunch here. Fairly strong confidence in a stripe of 4-8" about 10-20mi NW of 95, possibly reaching down to 95 and surrounding areas itself but less confidence to the SE. In that bullseye area to the NW we have the combo of likely a heavy period of precip and cold enough temps down to the surface to support snow tomorrow evening, likely to remain an all snow event for CNJ into E-PA and possibly the northern and western part of LI. However, there I am less confident due to potential mixing issues, but I'd say more likely than not to be a moderate snowfall there, probably 3-6". In short, I'm pretty much in line with where the NWS has it's WSW likely to turn to warnings early tomorrow morning.

While I could be wrong, I challenge whether they will be warnings or advisories. I am leaning more towards the advisory. I know for Upton criteria, Warning is 6” or more in a 12 hour period. While this will be a short duration event and the 12 hour threshold will be used over the 24 hour threshold, I believe 6” is the max accumulation they will predict so confidence in meeting 6” area wide will be low. Advisory criteria is 3” or more in a 12hr period. Much more likely. So my opinion: Area wide advisory for 3-5” with isolated amounts to 6”

Yes you're right they dropped the WSW. Technically the right call bc the criteria is 6-7" in the area if I'm not mistaken. While I believe some areas will get there I don't suppose the chances are high enough/ a large enough area for the NWS to bite. I always dislike when they drop a WSW to a WAA for a very close event to warning criteria, as they've done a couple times this winter. The reason being 6" is far more disruptive than 2-3" which are typical advisory snows. A warning makes people take the event seriously and if it were me I would have it up in the northern areas they had the watch where 6-8" are completely in the realm of possibility and even likelihood.

Edit: Upton posted Warnings, Mt. Holly/Binghamton/St. College going with Advisories only.

Upton WSW criteria is 6 inches, in Mt. Holly area it's 5 inches, in Binghamton and Albany it's 7 inches.

NjWeatherGuy wrote:Made a map. Using a blend here and hunch with the setup. Obv. tossing the GFS though it is still stubborn, my guess is it goes down with the ship it's on.

I actually like your map. You take the topography of the north shore of LI into consideration. It’s one of the only maps I’ve seen people do this with.  Nice job. And you put me in the highest category while only giving Scott less than an inch. Double nice

What the heck is going on! Even the tv Mets don’t know .one I just saw said rain for LI , yet showed another model that has me in 2-5 inches .

One thing to consider maybe. It was supposed to get down into the mid 20s last night but I fell 4 degrees short in my back yard. It’s currently 31 and sunny. Let’s hope temps don’t get too high because we are skating a very fine line here. If temps bust 3-4 degrees high with this storm like they are now we rain.

NJ TOM great map there.
Thanks for posting and adding to the convoy here.
GFS us abysmal with these marginal thermal profile set ups.
Kudos to Upton staying the course since yesterday overall.
We see what happens but I shall this again this is a nine esque type storm that reminds me of the 70's and 80's to a degree where N&W of NYC saw the heaviest snows while S &E did not.

syosnow94 wrote:One thing to consider maybe.  It was supposed to get down into the mid 20s last night but I fell 4 degrees short in my back yard.  It’s currently 31 and sunny.  Let’s hope temps don’t get too high because we are skating a very fine line here.  If temps bust 3-4 degrees high with this storm like they are now we rain.

Thanks for the map compliment btw, much obliged. But overall similar here, forecast mid 20s but my therm says we only got to 28-29, I'm not overly concerned. I think it will be a tight gradient in some areas however (what else is new...) with areas getting mostly rain the whole storm and areas just miles to the NW all snow with several inches more. I'm still liking 95 as this general area and the LIE in the western half of LI as the general battle line. I'm not seeing this as a storm in which the line shifts a lot, where it sets up early on will make or break the forecast.

CPcantmeasuresnow wrote:

NjWeatherGuy wrote:

aiannone wrote:

NjWeatherGuy wrote:I think the GFS is out to lunch here. Fairly strong confidence in a stripe of 4-8" about 10-20mi NW of 95, possibly reaching down to 95 and surrounding areas itself but less confidence to the SE. In that bullseye area to the NW we have the combo of likely a heavy period of precip and cold enough temps down to the surface to support snow tomorrow evening, likely to remain an all snow event for CNJ into E-PA and possibly the northern and western part of LI. However, there I am less confident due to potential mixing issues, but I'd say more likely than not to be a moderate snowfall there, probably 3-6". In short, I'm pretty much in line with where the NWS has it's WSW likely to turn to warnings early tomorrow morning.

While I could be wrong, I challenge whether they will be warnings or advisories. I am leaning more towards the advisory. I know for Upton criteria, Warning is 6” or more in a 12 hour period. While this will be a short duration event and the 12 hour threshold will be used over the 24 hour threshold, I believe 6” is the max accumulation they will predict so confidence in meeting 6” area wide will be low. Advisory criteria is 3” or more in a 12hr period. Much more likely. So my opinion: Area wide advisory for 3-5” with isolated amounts to 6”

Yes you're right they dropped the WSW. Technically the right call bc the criteria is 6-7" in the area if I'm not mistaken. While I believe some areas will get there I don't suppose the chances are high enough/ a large enough area for the NWS to bite. I always dislike when they drop a WSW to a WAA for a very close event to warning criteria, as they've done a couple times this winter. The reason being 6" is far more disruptive than 2-3" which are typical advisory snows. A warning makes people take the event seriously and if it were me I would have it up in the northern areas they had the watch where 6-8" are completely in the realm of possibility and even likelihood.

Edit: Upton posted Warnings, Mt. Holly/Binghamton/St. College going with Advisories only.

Upton WSW criteria is 6 inches, in Mt. Holly area it's 5 inches, in Binghamton and Albany it's 7 inches.

In that case I would have definitely kept the WSW. I thought it was more for some reason, those numbers are easily achievable and likely to be surpassed in many areas IMO north of 78.

12z NAM looking good!

What a tough forecast here specifically for LI. Have many people relying on my forecast for plowing purposes and I having to use the LIE as a dividing line always scares me. LI is so small that if the r/s line is 5mi more north this will be more of a rain event and they won’t have anything to plow lol. I trust the NWS and they usually go warmer for LI so their warning is concerning. My forecast for the island is 2-4” island wide with isolated 5” amounts on the north shore of the western part of the island. The twin forks 1-2” isolated 3” on the north fork.

And as I write that the 12z NAM Is mostly rain for LI lmao. Who knows. Going to be a nowcast. Much easier for y’all NW

HRRR likes the NWS. Mirror image lol

One of my concerns on this that I mentioned yesterday in terms of trying to nail down accumulation amounts remains ground temps. This may not be an issue further nort and west of me, but in my area it is 33* and sunny going up to 40*. Hourly forecasts never show the temp getting below 32* during the snow (or just barely) and this follows several days of 50-plus highs. So I do think it could snow for awhile at the outset with no stickage. Now if I do fall in the all snow zone that might not be as big a deal because it only costs me an inch or two, but if I combine that with any mixing of rain it will have a bigger impact on final total. At least most of this is after dark so solar heating of the ground won’t be a factor.

I'm wondering if we are going to see 10:1 ratios with such marginal temps... figuring we might just see 8:1 so those snow map totals will be lower by a smidge. 5" for me, I'll take it

latest HRRR upped amounts a bit... It's gonna THUMP later!

SoulSingMG wrote:latest HRRR upped amounts a bit... It's gonna THUMP later!

Wow that would make the whole board happy

The 3k NAM falls pretty well in line with my thinking. Tough forecast for LI and the Jersey Shore, very tight gradient. 3-6" NW LI and 1-3" decreasing south and east. As the storm nears in the coming hours I will look at the HRRR more, right now its kind of still in the waffling range.

aiannone wrote:

SoulSingMG wrote:latest HRRR upped amounts a bit... It's gonna THUMP later!

Wow that would make the whole board happy

This is the first positive sign out yet of the short range models for the Jersey Shore...I'm still expecting closer to 0" than 1-2", but we'll see!

The high res RGEM has a brutal cutoff in western Suffolk and the NJ shore. 4" NW and 0 about 5-10mi east. That reminds me of the Boxing Day Bust (Yes I'm still salty about that if anyone is wondering lol)

Highway signs up and running on LI

aiannone wrote:Highway signs up and running on LI

Good call by Upton here. I still think Mt. Holly ought to raise warnings for the northern half of the state to be on the safe side, if they don't by this afternoon they probably will just stick with the advisory.

Currently 33 degrees with a dew point of 16 very low-level dry air which should help with wet-bulb temperatures. Got down to 26 last night however my ground is not Frozen. We may lose initially to melting but a solid 3 to 6 in look likely from the city north and west obviously Long Island and Jersey Shore still up in the air

Dynamic cooling will be the key. Recall the last “surprise snowstorm on LI”. Temps were in the 40s all day, 37 on the onset and not much was accumulating. It occurred at night as well. As precip picked up temps dropped to 32 and snow began to stick. No high to the north either. Than as the precip became even heavier temps dropped all the way down to 26 degrees. Immediately after the precip ended temps rebounded to 38. Don’t underestimate dynamic cooling when upper levels are cold