After over 20 days of near-above average temperatures, in what is one of the warmest Octobers on record, the pattern will gradually turn colder starting on Tuesday as a cold front moves through, with temperatures ending up slightly to moderately below average, in the 50s for highs and 30s for lows with frost possible away from the coast. The pattern stays dry, however, with no sign of any significant rain event until the end of the month or early November. (Image credit: PSU e-Wall)
Today – Tuesday: Still Warmer Than Average
Last night, a weak cold front moved through the region, with widely scattered showers but with rain totals remaining under 0.1 inch, except for far western areas where such totals were observed. Behind the front, a cooler air mass moved in for today with a breezy west wind at 8-15 mph, but temperatures will fail to drop below average, staying in the low to mid 60s for highs and the upper 30s to upper 40s for lows. This cooler air mass is only short lasting, however, as a warmer air mass returns for Monday and Tuesday ahead of the next cold front, with highs rising into the mid to upper 60s again with a southwest wind and mostly to partly sunny skies. Isolated showers may be possible for far interior areas on Tuesday, with otherwise dry conditions.
Wednesday – Saturday: Colder, Rain Stays East
Behind Tuesday’s cold front, which will produce little to no rainfall, a colder air mass will gradually shift east into the region, but will not fully enter until later on Wednesday when a shortwave trough swings through the region. Initially, there was some speculation regarding a coastal low which the ECM and GFS runs depicted yesterday, but as was the trend in many cases this fall, both models lost the significant storm signal, and now only depict a developing wave of low pressure producing isolated showers especially east of NYC before moving out. Given the progressive flow aloft, this appears to be a more likely scenario, and at this time I kept a low risk of isolated showers in the 7-day forecast, which may be removed with tomorrow’s update. High temperatures are expected to reach the mid 50s across the area.
The colder air mass will slowly enter the region on Thursday through Saturday, but the core of the cold will fail to enter the region, staying in the Great Lakes and western Northeast regions before lifting out by Saturday night into Canada, with 850mb temperatures likely to struggle falling below -4C over the area. For now, the forecast high temperatures have not been changed, but given recent trends it is not out of the question that temperatures currently modeled for the area may be a little too cold. High temperatures are likely to reach the low to mid 50s across the area, struggling to reach 50 degrees towards interior NW NJ and SE NY, with overnight lows in the upper 20s-low 30s inland, mid to upper 30s in the north/west suburbs, southern CT and interior Long Island, and upper 30s to low 40s in NYC and the coast. The first widespread frost of the season may be possible in this time frame.
Sunday – Next Week: Moderation In Temperatures
As yesterday’s pattern outlook noted, once the cold air mass enters the region, it will not remain settled in; as another trough enters the Midwest during the weekend, the trough over the region will lift out with weak ridging developing, and along with the surface high pressure staying south of the area, temperatures are expected to warm up to near to slightly above average, back into the upper 50s and low 60s, but with no significant warm up or cool down expected through the middle of next week. Yesterday’s update noted the potential for a stronger cool air mass reaching the region by the end of the month; should it occur, a cold front would move through around the middle of the week, possibly producing rain, followed by the colder temperatures. This is still a medium range potential, however, and it is possible the air mass may either struggle to enter the region or stay to the west, in which case temperatures would struggle to fall below average by much, if at all. More information will be posted on next week’s outlook over the next few days.
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Saturday, October 19 Observations:
Another weak cold front approached the region on Saturday, producing widespread cloud cover and scattered showers but again with little to no rain affecting the area, as a narrow line of moderate rain developed in eastern Pennsylvania but collapsed before reaching NYC. Temperatures were slightly cooler due to the cloud cover, peaking in the low to mid 60s for most. The highest temperature was 67 degrees in Islip, NY and Shirley, NY, and the coolest high temperature was 62 degrees in Danbury, CT and White Plains, NY.