Tuesday, January 6, 2009

More ice

The 18z GFS continues to be much much wetter than the NAM, and is a bit wetter than it's previous runs. With the 15z SREF coming in wetter as well, I think the NAM can be discounted to some extent. So still looks like at least .8" water equivalent - maybe more.

However, there are some changes to discuss as the title suggests. The models, leading with the 12z Euro, are more robust with mid level warmth again. This has been swinging back and forth for a couple days, and now 6 hours before the snow starts falling, it looks like we will be talking about more sleet and freezing rain. This should cut down on snowfall amounts a little. So at this point I'm thinking closer to 3" to 5" (cutting back by an inch) through Wednesday evening, plus another 1 to 2 Wednesday Night - Thursday morning (for a 4" to 7" total).

Now we are looking at ice accretion getting closer to .25" to .4" with up to an inch of sleet possibly. Not very fun stuff.

Regardless of some of these changes, cancellation potential is unchanged (if not better).

Nowcasting time is starting up now, with radar echoes near the NH/MA border. A lot of this is virga with low level dry air, however some snow showers will be breaking out north of the pike soon. A few scattered snow showers are possible in Keene after 10pm, but accumulation should be minimal through 1am.

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