Mar 18, 2011: From Summer To Winter

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


As a storm in Canada pulled in a much warmer air mass with a southwest wind, the area got to see a preview of summer today as temperatures surged into the 70s across most of the area, ending up slightly warmer than expected. Most of the immediate NYC area saw mid 70s, and Newark even reached 80 degrees!

A cold front moving through tonight will bring the area back to spring-like weather, with temperatures expected to stay in the mid 40s to mid 50s this weekend with mainly sunny skies. The drop in temperatures will continue through next week, as after a brief warm up on Monday night following a light rain event, the area will return to winter-like conditions, with a cold spell expected by the late week and into the weekend, and a storm on Wednesday and Thursday might even bring snow to parts of the area.

Weekend Outlook:

After today’s mild temperatures, tomorrow will be nowhere near as warm. High temperatures will return to more seasonable levels, peaking in the upper 40s to lower 50s across most of the area, with a few mid 50s near NYC and further southwest. Partly to mostly cloudy skies are expected early in the morning, however cloud cover will quickly clear up, with mostly sunny skies by the evening. A NNW wind is expected.

Saturday night is expected to bring much colder temperatures as a high pressure moves near the area. Clear skies are expected, with low temperatures dropping into the 20s for the entire area except for New York City, which should see lows in the lower 30s. The interior parts of the area may even reach the upper 10s. Sunday will be slightly cooler, with high temperatures generally expected to peak in the upper 40s to lower 50s with mainly sunny skies.

Monday – Tuesday: Light Rain, Briefly Warming Up
A storm is expected to move towards Maine on Monday night, which will push the cold air mass out of the region. Increasing cloud cover is expected on Sunday night, with occasional light rain on Monday. Precipitation will begin early on Monday morning, and it is possible that with cold temperatures initially in place, the storm may start out with snow and/or sleet in the western parts of the area. Temperatures will steadily rise throughout the day, eventually peaking in the early overnight hours in the mid 40s to lower 50s across the area. A brief break in the cloudy conditions is expected early on Tuesday along with high temperatures in the upper 40s to mid 50s across the area, with increasing cloud cover overnight.
By Wednesday, however, things become more uncertain. Today’s models took a low pressure just south of Chicago on Tuesday ESE as it is blocked from moving due east, with the low pressure ending up east of the North Carolina/Virginia border by Thursday morning. Most of the models today, including the GFS, GGEM and ECMWF have shown snow for at least parts of the area, however as this is expected to be a weak storm, precipitation from this storm should generally be light. The GFS has adjusted north from last night’s runs, however it may still be a little too far south, and I would not be surprised if it adjusts itself slightly further north with future runs.
Looking at the overall set up for the storm, it appears that the storm would likely move in an ESE direction, not due east, and it is unlikely to track north of the area, putting the area in the cold part of the storm. The exact details are still uncertain, which give a range of either no precipitation, a plain cold rain, rain switching over to light snow, or mostly light snow falling, with the storm reaching the coast either near the Virginia/North Carolina border or near southern Delaware, as the ensemble means of the GFS, GGEM and ECMWF show, however there is the potential for at least some light snow to fall out of this storm, with the best potential towards the interior parts of the area and during Wednesday night as the storm starts to end. As this is a weak storm and surface temperatures will not be much below freezing, if below freezing at all, if this storm brings snow to the area, any accumulations will be light.
It is not certain that it will snow, it is still possible that this will be plain rain or that the storm will miss the area to the south, however there is the potential for snow to fall in parts of the area. At this time, in the 5-Day Forecast, I went with mostly rain but mentioned the potential for snow to mix with the rain on Wednesday in the western parts of the area, however this is still a low confidence forecast and is subject to change. Stay tuned for more information on this storm and how it may affect the area.
Longer Range: After this storm moves out of the region, a colder air mass will move in. High temperatures will struggle to reach the 40 degree mark, and in the interior parts of the area may fail to reach 40 degrees, and overnight lows will be in the 20s, potentially upper 10s inland. The cold will begin to moderate by Sunday, however at this time it does not appear that any major warm up is expected any time soon.

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