Jan 3, 2011: Cold And Stormy Pattern Developing



***This post is from 2011. Please visit the MAIN PAGE to see the latest forecasts for January 2012.

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Notes:

– The 5-Day Forecast was updated for the interior and the immediate NYC area tonight.
– The poll for the most extreme weather event of 2010 remains open until Wednesday. Please vote in the poll if you have not done so yet.
– Another poll has been opened for the potential impacts of the Friday-Sunday storm. Please vote your thoughts in the poll, which will close on Thursday.

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With the passage of the cold front last night, a cold air mass returned to the area today, giving the area a sneak peek of what is to come later this month. High temperatures were generally in the mid 30s across the area, with some upper 30s in the immediate NYC area. Dry conditions will continue until Friday, when a storm is expected to bring the potential of a snowstorm to the area, however this will start what will likely be an active middle of January.

Tomorrow’s Outlook:

Tomorrow will be a mostly cloudy day across the area, with a southwest wind expected. High temperatures will be warmer than today, in the upper 30s inland with a few lower 40s possible, and in the upper 30s to lower 40s across the rest of the area, perhaps leaning closer to the mid 40s in the warmer parts of the immediate NYC area.

These warmer temperatures will be due to a weak low pressure near the Great Lakes, which may lead to an isolated flurry in the northern parts of the area but keep the better chance of snow showers well to the north and northeast of the area.

Wednesday – Thursday: Dry, Slightly Colder Than Average

On Wednesday, as the weak low pressure exits the region, a colder air mass will return once again with 850 mb temperatures slightly below -10c, however the surface temperatures may not be as cold, with high temperatures in the lower to upper 30s across the area. Thursday will bring similar temperatures, but with increasing cloud cover as a low pressure from the Great Lakes approaches that for the several days afterwards will bring widespread light snow to the region and the potential for a heavy snow event in New England.

Friday – Saturday: Watching Snowstorm Potential

Today’s models continued the uncertainty from yesterday about this storm and how it develops, however there were some models showing a significant storm today, including the UKMET, the 00z ECMWF run which brought a huge snowstorm to the area even though it is likely an outlier in terms of how it handled the storm, and the GFS which showed a significant snowstorm for New England with smaller amounts for eastern Long Island/SE CT and barely any snow in NYC.

At this time, it appears that we will likely see a primary low pressure in the Great Lakes with the storm redeveloping off the coast and intensifying, potentially retrograding northwest towards the coast. Where the storm redevelops, intensifies, and where it moves from there are the main questions at this time, and could put the range of possibilities from a widespread heavy snow event from the NYC area further northeast into New England, to a storm which mainly affects New England with light snow for NYC, to a storm that stays mainly offshore with some moderate snow closer to the coast. At this time, however, the best chance for a significant storm still appears to be in New England.

At this time, I went with a 50% chance of light snow in the 5-day forecast, with potential mixing with rain near the coast due to above freezing surface temperatures in the beginning of the storm, but it may not be until Wednesday or Thursday when we see the models start to agree on a solution, so at this time the forecast has a slightly lower confidence level, and is subject to change. Stay tuned for more information on this storm and how it may affect the area.

Longer Range: Cold, Then Another Storm?

Once the storm exits, cold conditions will stay in the area, with high temperatures still in the 20s for parts of the area, moderating by the start of next week. However, it appears that there may be another storm threat for the January 12-14 time frame. The ECMWF has been showing a significant snowstorm for 2 consecutive runs for the area with the 18z GFS also showing a large storm, and while it is too early to look at the smaller details such as the exact storm track and precipitation types, there is the potential for a storm to affect the area during this time frame. More information will be posted on this over the next few days.

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