Hurricane Sandy Update 10/28/12

Sandy is starting to morph from a hurricane into the Über-Hybrid Nor’easter known as Frankenstorm. In addition to the massive cloud complex that has enveloped the eastern seaboard, you can see drier air wrapping into the eastern sector of the storm (shown by the brown):

Hurricane Sandy Water Vapor Picture

Hurricane Sandy Water Vapor Picture

Some of this dry punch will wrap itself into the northeastern quadrant of Sandy as she makes landfall. This will spare us the tremendous flooding like we had with 2011 Irene.

NAM is showing Sandy making landfall somewhere in central New Jersey by 8PM Monday. The massive upper level low digging into the Carolinas will shove Sandy westward into Pennsylvania after landfall: What a monster!

Sandy Landfall

Sandy at Monday 8PM

What to expect from Sandy:

The calm before the storm will last into early Monday. Northeasterly winds will strengthen dramatically in the afternoon, then eventually veer to easterly into the night. Peak wind gusts late Monday afternoon into Monday night should reach 40-60mph in most places. Higher terrain exposed to northeast or easterly winds will have gusts well over 60mph. Winds will further veer to the southeast early Tuesday and begin to weaken.

(Remember: In meteorology, wind direction ALWAYS refers to the direction in which the wind is blowing FROM.)

Rain will end up being the most over-hyped impact from Sandy over the North Country. The dirty secret is that the lion’s share of Sandy’s rainfall will be orographically driven by strong winds blowing across mountains and valleys:

Sandy Precipitation

Meso NAM forecast rainfall through Tuesday 8PM

You can see the severe “rain shadowing” from compressional drying in the Hudson, Champlain and St. Lawrence Valleys, with those areas only picking up 0.50 inch or less of rain through Tuesday evening. The high mountain ranges of the Adirondacks will do much better with 1.5-3 inches of rain, with the some of the High Peaks over 3 inches. In most of the Adirondack hamlets, rainfall may only be in the 0.5-1.5 inch range by Tuesday evening. Of course, there will be additional rains on Wednesday as the remnants of Sandy pinwheel from Pennsylvania into New York State. But the bottom line is that flooding will not be a major problem in the Adirondacks, aside from localized flooding near the high mountains and in leaf-clogged drains and culverts.

Sandy’s winds will be a far bigger story than her rain in the Adirondacks. Be prepared for fallen trees and loss of power. Snowmobile clubs and town crews will be busy with blowdown clean-up before winter.

How about snow?

Not this time! But you may wish to book a road trip to West Virginia where the high mountains will end up measuring snow by the feet!

Sandy snowfall over West Virginia

Snow (inches) through 8AM Tuesday

This is probably my final update before Sandy hits. I’ll try to hit with an update Monday evening with the storm underway, IF we still have power. At least you have been warned well in advance. :)

Comments welcomed!

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