Mar 21, 2013: Pattern Likely To Continue Into April

Forecast Highlights:

A coastal low developed well offshore today with scattered snow showers observed and temperatures generally peaking in the 30s across the area, continuing the colder than average in place since the 14th. With the current pattern expected to last through at least early April, temperatures will remain mostly colder than average for the rest of the month, and additional snow events are still likely to affect the region and possibly the area.

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Tonight - Weekend: Chilly, Dry

As a strong low pressure continues to intensity well east of the area, producing a major snowstorm in Atlantic Canada, a trough remains in place over the region through Friday and the weekend. The air mass in place will slightly weaken, with a slight warm up in temperatures expected for the weekend but still remaining colder than average. The current cold temperatures significantly contrast the pattern that was in place at this time last year; on March 22, 2012, temperatures soared into the mid to upper 70s across the area in what was just one of many record breaking warm days that month. In comparison, high temperatures today reached 39 degrees in Central Park, 12 degrees colder than average.

Partly sunny skies are expected on Friday with highs in the upper 30s to low 40s across the area. Mostly sunny skies are then expected for Saturday and Sunday with slightly warmer temperatures, peaking in the low to mid 40s across the area on Saturday and in the mid to upper 40s on Sunday, which if verifies would make Sunday the warmest day of this pattern so far. Overnight lows will remain in the 20s across the area.


Next Week: Monday Storm Potential

During the weekend, the next winter storm will develop over the central US, producing a widespread snowstorm across the Plains into the Ohio Valley before reaching the region on Monday. There remains uncertainty regarding how far north the storm tracks and how strong it ends up; The GFS and ECM are among the southern and drier scenarios, with scattered rain/snow showers as most snow accumulations focus towards Pennsylvania and West Virginia, while the CMC and NAM are among the northern and stronger models, with a significant wet snowstorm in Pennsylvania which extends into the NYC area. The ensembles offer mixed signals, with the GFS and ECM ensemble means north of the operational run, while the CMC ensemble mean is south of the operational run.

By this time frame, a stale air mass is expected to be in place, which results in marginal temperatures for snowfall accumulations. Several factors, including a stronger storm with heavier precipitation rates, would be required to overcome these issues for eastern regions, which at this time only the CMC and NAM support. According to most of the models, interior areas are likely to be favored for snow accumulations, although should the storm end up stronger and further north with heavier precipitation in the area, snow accumulations could spread through the rest of the area as well. The overall thinking at this time is for a moderate impact storm to affect the region on Monday with rain/snow likely, especially south of the area, with accumulating snow expected especially further inland and for parts of the area. The specifics of the storm are still likely to change over the next few days as the models narrow down the smaller details. More information will be posted on this storm over the next few days as details become clearer.

Beyond the early week storm, the current pattern continues with a broad trough covering the eastern half of the US, keeping temperatures in the 40s for highs, which likely continues through the end of the month. Should the latest models verify, it is a realistic possibility that every day of the second half of this month starting on 3/14 ends up colder than average. Looking into the longer range, a rapid decline of this pattern is still not showing up in sight, although the potential is there for the pattern to moderate after the beginning of April with temperatures possibly climbing back towards average.