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smike
01-12-2010, 07:07 PM
<span style="font-size: 11pt"><span style="font-weight: bold">January Thaw?

<span style="text-decoration: underline">Highlights</span> </span> </span>

Warm up over the next 2-3 days, then a short cold shot followed by longer term warm up next week.

Warm up will be dry for the most part, The lack of winds coming from the south west will have a hard time displacing the low level cold air. (Forecast temps will general bust on the low side)

South facing aspects will get hammered through. (Sun angle is a little higher, and lack of cloud cover over the next day or so)

Shaded and fat climbs should do alright through the weekend.

<span style="font-size: 11pt"><span style="font-weight: bold"><span style="text-decoration: underline">Details</span> </span> </span>
Finally the Negative NAO and AO have started to let go. As mentioned before when these two both go negative they get locked in and stick around causing a continual dump of cold in the NE (as evident by the last 40 days)

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.fcst.gif

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.fcst.gif

It’s a slow break down, one that doesn’t scream rush of warm air and way above average temps. A quick shot of cold this weekend (with the possibility of a decent snow event) and then the more longer term warm up unfolds next week. Most indications point to this lasting about 7-10 days with temps normal in extreme northern sections of the NE with above average in the Mid Atlantic. After that we should got back into the pattern we have been enjoying for the last 40 days but it may not be as strong of a cold push. Areas up north I don’t think will get wiped off the map and will get back into top shape quickly around end of Jan / early Feb. For areas in the mid Atlantic, this could shut things down and the chances of coming back to current levels in Feb might be a long shot.

Overall to think that's it, winter's over is nonsense. The second half should begin toward the end of the of the month. Plus the chances for big snows always increase in Feb into early March (Synoptically and historically speaking )

smike
01-15-2010, 05:37 AM
<span style="font-size: 11pt"> <span style="text-decoration: underline">Thaw 101</span> </span>

Not all thaws are alike. Being out last night made we realize that just looking at the outside temperature may not give you very accurate depiction of what is going with the state of ice.

Case in point, see the weather reading from the weather.gov

http://neice.com/photopost/data/500/untitled.JPG

Notice the temperature is 43 (That should clearly mean a decent amount of melting is going on, or at least wet sloppy ice)

Now take a look at the 2 circled readings the first is the winds, (almost none). Lack of wind means that there is very little mixing of the air, so that the warm air has a hard time getting to the lowest levels of the atmosphere (Ground level to 10’)

The second is the dew point temperature. (This is the key) It was well below the actual temperature and below freezing. This severely hinters the transport of the heat energy from the air to any object. (Sort of the same effect as a “Dry heat” but for different reasons)

So what I found as a result after a full day of this was near perfect dry plastic ice. (about as nice as you could order up). So when you see the above conditions expect the melting process to be very slow regarding shaded ice.


<span style="font-size: 11pt"><span style="text-decoration: underline"> January Update for this weekend: </span></span>

The warm up has been limited and very dry and thus should have not much impact on conditions for the most part anywhere in the NE this weekend. (Especially in the northern sections) I’d still be suspect of south facing stuff. As for Sunday, looks like rain for the Mid Atlantic, but it should stay out of the New England States, so no worries up north. Next week still looks as if temps throughout the NE will get into the mid 40s for a couple of days, but things are trending to a shorter lasting warm up. Again it will not be a huge surge of warm air and rain so most stuff may end up getting a nice new patina to fill in all the holes.

More info later on the indications of the pattern we have had over the last 40 days re-emerging and locking back in over late Jan all the way into March.