Oct 18, 2010 : Cool Conditions To End This Weekend

Note: I apologize for not being able to fully update the blog lately, including the 5-Day Graphics and the Long Island/S CT forecasts, as I have been busy lately. Once I have enough time, I will update these parts of the website, including adding more graphics to the daily discussion.


Today was a partly to mostly cloudy and dry day, with high temperatures ranging from the upper 50s inland to the lower 60s in the immediate NYC area. A few showers are expected for tonight into tomorrow morning, as well as Thursday, but anything more than light rain will wait until next week, when a warmer pattern is expected to dominate most of the United States.

Tomorrow’s Outlook:

Tomorrow will be mainly cloudy due to a weak low pressure riding along a stalled frontal boundary to the south of the area, but most of the rain will stay to the south. High temperatures will be in the upper 50s to lower 60s across the area.

Wednesday’s Outlook:

As another wave of low pressure stays to the south of the area, mostly cloudy skies are expected, with slightly warmer highs, in the lower 60s inland and lower to mid 60s in the immediate NYC area.

Thursday – Friday: Scaled Down Cold Spell?

A low pressure near the Great Lakes on Wednesday will move east and drop a strong trough into the region on Thursday afternoon. Thursday night will bring colder temperatures with low temperatures ranging from the mid 30s inland, to upper 30s-lower 40s in the N/W suburbs of NYC, to the upper 40s in NYC.

Afterwards, however, a slight change took place in the forecast. The whole pattern is now modeled to go faster than previously expected, with the trough moving in on Thursday night, not Friday. Looking at the pattern in the West Coast, a low pressure in southern Canada is modeled to be further south than previously expected, which prevents the trough in the East from digging as far south as it could have been. With the low pressure in Canada also moving faster than expected, it is expected to quickly push out the trough in the region, with the 0c line already moving out by Saturday morning when it was supposed to be at its southernmost extent.

While I think that the models could be a little too fast, this reduces the probability of seeing frost in the immediate NYC area and freeze inland. If the faster solutions do verify, no freeze will be observed inland, and the first freeze of the fall may end up coming later than the average. For now, I am going for a solution close to the NAM/GFS but a little slower, expecting Saturday’s highs in the mid 50s to lower 60s across the area, which is slightly below average, and lows in the mid-upper 30s inland and upper 30s to mid 40s in the immediate NYC area, which is close to the average lows. Note that these forecast temperatures are still subject to change over the next 2 days.

Saturday And Longer Range: Warmer, Rain Returns

What is likely is that on Saturday, warmer temperatures return to the area. The low pressure in southern Canada that I previously mentioned will be near the Great Lakes, which will bring another trough behind it. While there is uncertainty on how far south it drops, at this time I think that it will mainly stay in the Northeast, with the southern end potentially clipping the area. It is possible that the trough could be a little further south, but at this time it’s only a possibility. An area of rain is likely to set up near the southern end of this trough, which would bring several waves of weak low pressures to those areas producing light to moderate rain for Sunday and Monday. At this time, this is shown to be over the area, but could end up being slightly further north or south. Stay tuned for more details.

Afterwards, the pattern of a positive PNA and negative NAO is expected to collapse, with the trough and high pressure in the NE exiting and a storm potentially active in the north central US. This would bring a ridge into the area with warmer temperatures, with a rain storm possible for the 26-28th of October as the storm moves further east. This potential is still in the longer range, but it will be kept an eye on.

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