Mar 16, 2014: More Sustained Warmup This Week

Forecast Overview:

nerad25The latest regional radar to the left, from the Pennsylvania State University e-Wall, depicts a broad area of moderate snow to the south of the area. As noted with previous updates, the presence of a strong cold air mass and upper level low near the northeast US ahead of the system helped to keep enough cold air in place to support snow near the northern end of the precipitation shield while also preventing significant height rises downstream and thus more amplification of the storm. Additionally, the setup of a positively tilted trough axis and elongated vorticity lobe extending from the Ohio Valley into Texas further prevented additional amplification, ultimately resulting in a relatively weak, elongated and suppressed system with the snow remaining south of the area. Mainly cloudy skies will continue tonight as snow stays to the south, with lows falling into the 10s inland and low-mid 20s near NYC and the coast, with clearing skies later on Monday with high temperatures generally in the low to mid 30s.

A more sustained warm up is expected later in the week as a strong trough enters the northwest and later north central US, aiding in more significant height rises downstream with a mid-upper level southwesterly flow removing the cold air mass from the region. The elongated trough over the southern US will ultimately consolidate as it tracks northeast off the coast with stronger forcing supporting the deepening of a surface low pressure on Tuesday; this will remain well off the coast and will not directly affect the region. In the meantime, the ongoing warm air advection will allow for a warmup over the region on Tuesday and Wednesday, but with a persisting easterly flow near the surface keeping Long Island and southern CT cooler than western parts of the area for both days. Mostly sunny skies are expected on Tuesday with highs in the low 40s further west and upper 30s further east, with mostly cloudy skies on Wednesday and highs in the mid 40s further west and low 40s further east.

The strong trough over the northern US will gain more of a negative tilt as it lifts northeast, with a relatively strong surface low pressure accordingly tracking northeast into Canada, bringing a cold front east towards the region. The frontal boundary is expected to move through on Wednesday night, with occasional showers amounting to less than 1/4 inch. Behind the front, a cooler air mass will move in for Thursday, but with clearing skies and a downsloping westerly wind, warmer temperatures are expected again, and at this time I am siding with warmer temperatures than the model guidance, peaking in the mid to upper 50s across the area. Temperatures are likely to end up a few degrees cooler on Friday and Saturday, with another risk of scattered showers on Saturday. Another cool down is anticipated behind the Saturday low pressure, with highs likely to return into the mid 30s-low 40s range by next Sunday and Monday.

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