Feb 17: Final Call For Weekend Snow

Jonathan Carr
By February 17, 2018 12:09

Feb 17: Final Call For Weekend Snow

snowmap2-17-2018

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Discussion: We’ve made a few tweaks based on live observations and the latest guidance data. Temperatures dropped below freezing statewide early this morning as expected. Warm air advection however has already spread into much of NJ. We can thank the departing high pressure for driving marine temperature influence onshore for this. Once the weak low approaches closer from the W/SW, the S flow will be even further re-enforced with more WAA from the S. Not only will the surface be unfavorable for stickage along and SE of I-95 but the warmer low-mid levels will likely feature warmer marine-influenced layers that should further prevent a high-impact wintry outcome. We also believe that this might force a tighter thermal gradient and enhance snowfall potential for the jackpot areas. Just keep in mind that this is a short-duration event with a marginal temperature profile.

For these reasons we believe that areas SE of I-95 (Zones F and G) will verify even warmer than we originally thought. There could still be snowfall either initially or mixed in throughout the event but zones F and G should not expect snow accumulations, especially on roads ways. The low-mid levels are expected to be simply too warm. I suppose natural surfaces could whiten up a bit but meh.

Zone E is right along the I-95 corridor. This region could see up to a few inches fall and possibly accumulate on natural surfaces. Treated roadways will likely just be wet with maybe a slushy coating on untreated roadways.

Areas along and NW of I-95 (C and D) are still favored for the snowier outcome from this event, especially parts of NJ to the N of I-78. In our first two calls, we were 2-4″ on this jackpot zone with the potential for 6″ of snow accumulation. The tweak we made here was to simply convert to a 4-6″ expectation. We feel that a minimum of 4 inches is more reasonable than 2 inches. The top bound of 6″ is still the same for the jackpot area which we’ve shifted a tad further to the SE.

Timing still looks like early evening today (Saturday) through early AM hours tomorrow (Sunday) morning. Precipitation arrives from the W and departs to the E. Therefore W parts of NJ could see precipitation begin as early as late-afternoon today and E parts of NJ will be the last to wrap up tomorrow morning.

In English: A light-to-significant snowfall is expected along and NW of I-95. A cold rain with snow possibly mixing in is possible to the SE of I-95. Extreme SENJ has the best chance to see all cold rain. Precipitation should break-out between late-afternoon and early-evening and wrap up by sunrise tomorrow morning. The above impact map represents our final call heading into live observations. Everyone have a great day and please be safe! JC

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Jonathan Carr
By February 17, 2018 12:09