March 1, 2012: Cold Start, Warm Ending Next Week

Long Range Update:


The March 2012 Outlook has been posted in the Long Range Forecasts page, along with an overview of February.


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Forecast Highlights:


- Stormy Friday Night/Saturday Morning, Drier Afternoon
- Colder temperatures return for Sunday through Tuesday
- Warmer ending to next week likely; 60 degrees possible


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The storm that has affected the region over the last two days, starting out yesterday with rain in NYC, a rain/snow mix in the north/west suburbs, and snow to rain with light accumulations towards SE NY and interior southern Connecticut, is finally moving out, with precipitation ending across Maine as the latest radar to the left shows. Cloudy skies with occasional showers were observed today, with highs reaching the upper 30s inland (NW NJ, Orange County in NY), and the lower 40s across the rest of the area.

The next storm will affect the area on Friday night into Saturday, with more rain, temperatures reaching 50 degrees, and perhaps a rumble of thunder. Although a colder air mass will return behind the storm with lows dropping below 20 degrees for parts of the area on Monday Night, the cold will not be long lasting, as a warmer air mass will return into the region, bringing the first potential since last week for temperatures to return to the 60 degree range, but this time without the clouds and rain associated with the previous warm spells.


Friday - Saturday: Rain Returns, Briefly Warmer


During the day tomorrow, a developing low pressure well to the west of the area will produce a large severe weather outbreak from the southeastern US into the Ohio Valley. The storms will stay to the west of the area during the day, with partly cloudy skies and highs reaching the lower to mid 40s across the area.

By the evening into the early overnight hours, some of the thunderstorms will reach the region, and while they will be non-severe and mostly falling just as plain rain, a rumble of thunder cannot be ruled out with some of the storms, along with locally moderate-heavy rain. The rain is expected to develop around Friday evening, towards 7-10 PM, lasting through the first half of the overnight hours, approximately by 2 AM, before weakening as the warm front gets closer to the area. Temperatures overnight will be steady in the upper 30s in SE NY and southern CT and the lower to mid 40s in northern NJ, NYC and Long Island, before rising across the entire area by the morning hours.

There is some uncertainty with the warm front, although at this time the area is expected to be in the warm sector for only a very brief period of time. Some models continue to show thunderstorms and up to 60 degrees for the area; as I have mentioned with my updates a couple of days ago, the models were showing the storm too strong and too far west, some of them bringing 60-65 degrees and widespread thunderstorms for Saturday earlier this week, and most of the models since then have adjusted towards not as warm and weaker storm solutions, and most of the thunderstorms that will develop in the Southeast tomorrow night with the cold front as a result are expected to stay mostly to the east of the area, keeping the area out of the 60 degree and stronger thunderstorm potential. Regardless of these storms, a brief period of temperatures surging up to near 55 degrees is possible early on Saturday with some showers and perhaps a thunderstorm depending on how far north the warm front gets, with temperatures otherwise staying in the upper 40s to mid 50s across the area throughout the day. Breezy conditions are also expected to develop, but with no strong winds expected.


Sunday - Tuesday: Colder, Dry


Behind the Saturday storm and the cold front, a colder and drier air mass will return into the region. Little, if any precipitation is expected with this trough, although temperatures will become seasonable again instead of above average, possibly even ending slightly colder than average for two consecutive days, a scenario almost unheard of this winter.

On Saturday afternoon, a wave of low pressure will develop along the cold front offshore and quickly intensify while moving towards Newfoundland. The latest NAM runs attempt to develop this into a larger storm, with snow even falling in North Carolina and the western part of the storm barely east of NYC. Given the NAM's history, this is likely a typical scenario where the NAM exaggerates a storm development in its hour 60-84 range, and with the rest of the model guidance consistently further offshore, I am considering the NAM as an outlier model. Although the storm may end up a little stronger and further west than the GFS, which barely develops it at all, it's still not expected to affect the area with more than partly cloudy skies, perhaps mostly cloudy in Long Island. Even with the storm staying east, some scattered rain/snow showers are possible on Sunday evening/night, mostly to the west of NYC.

Temperatures will end up cooler on Sunday with partly cloudy skies and highs reaching the mid to upper 40s. Monday and Tuesday will be the coldest days, with highs in the upper 30s to lower 40s across the area. Monday night is expected to be the coldest night, with lows dropping into the mid 20s in NYC, lower 20s in the north/west suburbs, and possibly reaching the 10s for parts of, if not most of interior areas away from NYC. Tuesday night will still be chilly but not as cold.


Longer Range: Warming Up Again


The high pressure that will bring the dry and mostly sunny conditions for Monday and Tuesday will move off the East Coast, but at the same time, a large ridge will build over the eastern US, along with the high pressure settling offshore in a position that produces a SW/SSW wind across most of the region, bringing a warmer air mass into the entire region. This is a set up for a typical early spring warm spell for the region, although the high pressure is not at an ideal location to provide SW winds that would bring the maximum potential temperatures for the area. Despite this, temperatures are still expected to surge into the 50s between late next week into next weekend and beyond, with 60 degrees possible at least once, if not more. Unlike the previous warmth surges where temperatures reached 60 degrees, this will not be a cloudy, wet and windy warm spell, as the previous surges of warmth the area had were mostly associated with the area ending up in the warm sector of a storm, while in this cases the warmth is from a longer lasting ridge in the region. Stay tuned for more information on the longer range, including the warmth.