Nov 24, 2012: Weak Storm For Tuesday

Forecast Highlights:

Following last night's cold front, a much colder air mass resulted in colder temperatures and windy conditions across the area, with isolated snow showers observed in some areas especially north and west of NYC. This colder pattern will last through the end of the month; while no significant storms are expected for at least the next 2 weeks, the main highlight will be a fast moving low pressure producing a light rain/snow event for Tuesday.

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Sunday - Monday: Chilly, Dry

Winds will decrease for Sunday and Monday, although generally chilly temperatures will continue with no precipitation expected. High temperatures will reach the upper 30s to low 40s inland and the low to mid 40s for the rest of the area on Sunday, with warmer temperatures for Monday reaching the mid 40s inland and the mid to upper 40s for the rest of the area, reaching 50 degrees near NYC.


Tuesday - Wednesday: Light Rain/Snow Expected

As with yesterday, model differences continued for the mid week storm with uncertainty regarding the handling of several shortwaves approaching the region. The most extreme of today's runs were the 0z and 6z GFS which showed more phasing, with a stronger low pressure bringing rain for most of the area and a significant snowstorm for most of the interior Northeast. Since then, however, the trend has been for less phasing with a further south storm, with some of this evening and night's models keeping the majority of precipitation to the south of the area, with no more than light rain/snow showers. Although the overall trend today has been south, there is still inconsistency with the model guidance, as the 12z CMC and the latest 0z UKMET had a further north and stronger storm. The models are still having some difficulty handling the shortwaves involved, and additional changes in the models are still expected over the next day or two. The current forecast is not final, although confidence in widespread light-moderate accumulations has somewhat decreased compared to yesterday.

For tonight's forecast, I am siding with a track slightly south of yesterday's forecast, with light rain expected across the area with snow especially west and north of NYC. Precipitation is expected to remain generally light, with any snow accumulations likely to remain light as well. Considering that the storm is weak, not very moist, and fast moving with a progressive flow in place, no significant snow accumulations are expected out of this storm, and at this time the main light snow potential focuses in the northern Mid Atlantic (southern Pennsylvania and New Jersey), possibly extending into southeastern New York and southern New England, more likely closer to the southern coast. As previously mentioned, this is still not a final forecast, and some changes are still possible over the next day or two; should the latest trends end up correct, the forecast may be adjusted drier with the next update. Stay tuned for more information on this storm.


Beyond the storm: Cold, then warmer

Despite differences with the storm for the middle of the week, a stronger cold air mass is still expected for the late week with another round of cold temperatures expected to be colder than those of this weekend, with more widespread highs in the 30s as well as lows in the 20s, with sub-20 degree lows likely for interior parts of the area. This second round of cold won't last for long, however, as the pattern becomes warmer for the first week of December; there's still uncertainty with exactly how warm temperatures get although highs are likely to return into the 50s. No significant storm is expected through the first few days of December.