Mar 1, 2011: Heavy Rain Potential Sunday Night

With yesterday’s storm out of the region, temperatures dropped last night into the upper 20s inland, and returned to more seasonable levels for today’s highs, peaking in the lower to mid 40s across the area with upper 40s in Newark. As a weak storm in Canada will bring a cold front through tomorrow, temperatures will warm up well into the 40s, with lower to mid 50s for parts of the immediate NYC area, especially southwest of NYC, with Thursday bringing a noticeable difference in temperatures as high temperatures struggle to reach the 30-35 degree mark across the area.

These dry conditions will not last long, as starting on Friday, mostly cloudy to cloudy skies will develop with mainly cloudy conditions lasting through at least Monday night or Tuesday. Even though the mainly cloudy conditions will last for a few days, the main storm will take place on Sunday night through Monday afternoon/evening, and while the smaller details are uncertain, this storm has the potential to produce widespread flooding in parts of the region.

Tomorrow’s Outlook:

Tomorrow will be a partly sunny day across the area with a southwest wind becoming west by the late afternoon ahead of a cold front, which will move through the area around the afternoon hours. High temperatures will warm up into the lower to mid 40s for the eastern parts of the area, mid to upper 40s for the interior parts of the area, and the upper 40s to lower 50s for the immediate NYC area. Even though not expected at this time, a few mid 50s cannot be ruled out southwest of NYC.

Thursday: Much Colder

Behind the cold front, a much colder air mass will move into the region with a strong high pressure resulting in clear skies. As a result, temperatures will quickly drop into the 10s for the entire area except for NYC and parts of Long Island, which should see lows in the lower 20s. Low temperatures in the interior parts of the area, especially towards northwestern Sussex and Orange counites, may even reach the mid to upper single digits.

Sunny skies will continue through Thursday with unseasonably cold temperatures for this time of the year, peaking only in the upper 20s to lower 30s in the northern parts of the area and in the lower to mid 30s for Long Island and the immediate NYC area. A few upper 30s are possible southwest of NYC. Overnight lows will not be as cold, dropping into the mid 10s to lower 20s for the interior parts of the area as cloud cover increases.

Friday – Monday: Stormy Conditions Expected

Once mostly cloudy skies cover the area by Friday morning, they will remain generally mostly cloudy to cloudy through at least Monday night or Tuesday. On Friday evening into the overnight hours, light precipitation is expected to affect the area, and with temperatures in all layers cold enough, snow may fall in the interior parts of the area. The GFS runs earlier today showed a widespread light snow for most of the area, however it is likely too far south and too cold, and I went with the further north and warmer solutions for this round.

On Saturday, mostly cloudy skies are expected again as most of the rain stays to the west of the area, with a few showers potentially reaching the area. High temperatures will be warmer, rising into the mid 40s to lower 50s across the area. The storm will slowly move to the east, with a line of heavy rain and potentially thunderstorms moving into Pennsylvania by Sunday. A heavier rain will begin to affect the area on Sunday afternoon or evening, but what happens from there is a question.

Each model handles the storm’s development from there differently, with the GFS developing a low pressure along the front that moves up the coast, but differs with each run, showing 2 to 5 inches of rain in the area with its 06z and 18z runs, and showing the storm ending with moderate frozen precipitation for parts of the area on its 12z run. While a snowstorm is unlikely from this storm, the potential for some snow at the end especially for the interior parts of the area will be watched.

While the smaller details are uncertain, there is the potential for heavy precipitation amounts out of this storm, which may result in flooding. Stay tuned for more information on this storm as details become clearer.

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