Feb 4, 2013: Snow Again Tonight, Tomorrow

Parts of the forecast have been changed for Friday; an afternoon update will be posted today (2/5/13).

Forecast Highlights:

Cold temperatures continued across the region today, with highs peaking in the upper 20s to low 30s across the area. An active pattern of weak, fast moving light snow events continues with 1/2 to 1 inch of snow possible tonight, followed by another light snow event with up to 1/2 inch on Tuesday night. A warmer pattern will return by the late week into the medium range after a rain/snow storm expected for Friday, although despite the temporarily warmer pattern, winter is not over yet this year.

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Tonight - Thursday: More Light Snow Expected

As the radar to the left shows, scattered light snow is currently located over Pennsylvania, with light snow spreading east towards the area with a relatively narrow swath of accumulations expected. This has some similarities to the 1/24 and 2/1 clippers in the central Mid Atlantic, which overperformed in terms of snow totals compared to expectations, although unlike these clippers, this one will not be quickly intensifying once reaching the coast, and similar totals compared to the 2/1 event when coastal locations in southern NJ received a surprise 4-8" are not expected out of this for the area tonight. Despite this, at least some intensification of the precipitation is expected as it reaches the coast, with totals generally less than 1 inch of snow across the area tonight. The potential is there for a narrow swath of 1-2 inch totals, perhaps locally higher, to focus towards central NJ and possibly into Long Island.

Behind tonight's event, another shortwave will quickly race towards the region, with another minor snow event affecting the region on Wednesday. Conditions will briefly dry up for Tuesday, however, with partly cloudy skies and highs in the upper 20s to mid 30s across the area. The focus of the Tuesday night snow event will be further north, generally from the NYC area into New England, with totals mainly under 1 inch expected again. A brief update will be posted on Tuesday morning reviewing tonight's light snow event with an update on tomorrow night's forecast.

Warmer temperatures will return for Wednesday and Thursday, getting back closer to average; the latest model guidance has trended warmer with temperatures, with some suggesting highs in the low 40s across the area on Wednesday. At this time, the forecast high temperatures have been raised into the mid to upper 30s inland and upper 30s to low 40s for the rest of the area, with slightly cooler temperatures on Thursday in the low to mid 30s inland and mid to upper 30s for the rest of the area.


Friday - Beyond: Rain/Snow, Then Temporarily Warmer

*Tuesday, 2/5 Update: While the initial ECM solution of a low pressure over or very close to NYC is unlikely to verify, the probability of a significant event is increasing for the region. More information will be posted with an early discussion later today.*

By Friday, the next storm will affect the region. There is still uncertainty regarding the exact scenario, with the GFS and CMC still showing a minor event with precipitation focused mostly north and south of the area. The ECM model as with yesterday continues to show a coastal low pressure developing and quickly intensifying, but has trended slightly weaker and southeast of yesterday's runs, with the latest 12z run keeping the heaviest precipitation offshore with a light to moderate rain event for the area, considering that boundary layer temperatures are too warm to support snow for most of the area with the ECM considering there is a primary low initially in place further north, resulting in above freezing temperatures ahead of the coastal low. While the ECM's earlier runs with a strong low pressure close to or over NYC were likely too strong and too far northwest, it may be onto something regarding the development of a coastal low directly affecting the region, and at this time I am siding with a solution weaker than the ECM but stronger than the GFS, with a moderate rain and potentially snow event affecting the area, although the forecast is still subject to some revisions regarding the exact development of the storm, with the potential for a somewhat more significant event to affect the region. More information will be posted as details become clearer.

Towards the medium range, thinking has not changed in that a temporary warm up in the pattern will take place as a trough focuses over the western-central US, with temperatures likely rising back into the 40s for highs at some point in the weekend or early next week, ahead of another storm in the early week, currently more likely to produce rain than snow given ridging near the East US.