The clipper going through tonight, I expect a Coating to 1″ for most areas and amounts up to 2″ are not out of the question for areas in North-Central NJ, Orange County in NY, as the low heads right over them and with best lift there. And also over Eastern LI and Eastern Conn, as the storm begins to intensify offshore later tonight.

As for storm on Thurs. night and Fri AM, you’ve seen me discuss it on tri-state, so now you want to know snowfall amounts. I’m actually suprised by the amount of forecasts, already out there even though it is premlinary, give large amount variables there are and changes that can still occur. Anyway, it appears that models have come to an agreement on a track further offshore than earlier this morning. Normally that would bring more snow to the coastal areas, but being that there will be no ridge to the our north to keep cold air and the wind direction coming from the warmer than normal ocean waters, a change to snow to rain is likely along coastal areas.

For now I will put a “Snowfall Potential” map, that will be more of an outlook on how much snow I feel we may get around the tri-state right now. This is NOT a preliminary forecast map and I probably will not put one until sometime tomorrow:

http://img401.imageshack.us/img401/8499/snowfallpotentialzf6.png

To explain in short, I think that 3″ or more is possible over many inland areas away from the coast, where they should not see so much of marine influence and remain mainly snow. Closer to the coast, accumulations are most likely to be under 3″ due to the likely changeover. However, a few questions for me:

1. How much moisture will get back to the west? Will the east trends on the models continue?

2. How fast will the storm move out? Will the most of the precip be over before the changeover along the coast?

3. What about the warming layer that the GFS Bufkit keeps showing at 900mb to 925mb level across the area? There could be a period of freezing rain from some coastal areas, before a complete changeover to rain. Also some inland areas not far the coast may see a mix or changeover to freezing rain as well, cutting down snowfall amounts.

Back to tristateweather:

http://www.tristateweatherboard.com

When these things become clearer to me I’ll put a forecast map.

Forecast Amounts for tonight here:

http://img95.imageshack.us/img95/3822/sundaypmyf7.png

The latest runs of the GFS, NAM, SUNY MM5, have shifted the inverted surface trof axis down to Southern NJ for tonight event. The heaviest amount of snow should occur along and north of that trof axis. For those that don’t understand that, you see how I’ve illstruated here from the latest 6z NAM at 24hrs and 30hrs:

http://img258.imageshack.us/img258/5015/namp06024luq0.gif

http://img227.imageshack.us/img227/2130/namp06030lev5.gif

Although the NAM and MM5 is shows more than a .25″ liquid in Central and Southern NJ, I suspect this may be overdone and the GFS shows far about .10 or less here. So I’ve comprised expecting about .10″ to .20″ across Southern NJ and .05″ to .15″ across SE PA and Central NJ. With snowfall ratios tonight going down from 15:1 to 20:1, I’m expecting to 1″ to 3″ in general places. It is possible that a few spots get up to 4″.The rest of the area will see lighter snowfall amounts as they will be farther away from the surface trof. The models do not show any precip for NYC, LI and areas to the North and East tonight. But decent 700mb Omega on the NAM suggest precip, perhaps unmeasurable, can still could occur. Some very light snow or flurries is possible with little or no accumulation.If the models shift the trof axis back north today, than heavier snowfall amounts, will likely shift back north as well. I don’t really expect this to happen, but this will still be watched.

Back to tristateweather:

http://www.tristateweatherboard.com/

The models are showing an area of low pressure developing along the Mid-Atlantic or SE Coast tomorrow and take it well offshore. Depending how this area low pressure evolves, tracks, with a strong upper-level shortwave trough approaching from the Ohio Valley tilting negative, will decide how much snow we around here. At this time, it appears that main storm will stay out in the Atlantic. However, a inverted surface trough, is likely to form somewhere along the Northern Mid-Atlantic coast and Southern New England, with another weaker low developing a little closer to the coast on Sunday night. There will also be a strong 500mb vort max, coming around the base of this upper-level trof. Where this surface trough sets up and the vort max goes, 1″ to 3″ and perhaps little more of snow appears likely on Sunday night and early Monday morning. 6z runs of the NAM and GFS appear set this trof south of LI and across Central NJ and but the GFS moves the 500mb vort max further south than the NAM, causing more upward vertical motion on the south side of the trof. This results in heavier precip across Central and Southern NJ rather than on LI, as shown on the NAM.

Another storm is possible late next week coming up from the southern states, but the models will be all over the place with their solutions and I will focus on that storm after the storm on Sunday night.

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http://www.tristateweatherboard.com/