Jan 7, 2012: Rain Returns On Thursday

Although a cold front moved through the region today, southwest winds continued across the region along with a very warm air mass, with 850mb temperatures dropping from their peak of 10 degrees Celsius. These conditions resulted in the warmest January day in the area since 2008. With mostly sunny skies, temperatures surged into the upper 50s inland, lower to mid 60s in the immediate NYC area, and the mid 50s to lower 60s in Long Island and southern CT. The average high temperatures for this time of the year are in the mid to upper 30s across most of the area; as a result, today ended up with well above average temperatures, with Central Park’s afternoon temperature a remarkable 24 degrees above average.

Although the very warm temperatures are already ending tonight, above to well above average temperatures will continue through this week, with highs still generally in the mid to upper 40s, about 5-10 degrees warmer than average. A storm will approach the region on Wednesday night, bringing moderate to heavy rain, potentially near or above 1 inch, along with temperatures returning back into the 50s for Thursday and breezy winds. Colder temperatures will return again for next weekend, although there is still no notable snow potential showing up in the forecast.

Tomorrow’s Outlook:

A colder air mass will return tomorrow (Sunday), bringing much colder yet still above average temperatures. Mostly to partly sunny skies are expected with high temperatures reaching the lower to mid 40s inland and the mid 40s across the rest of the area, passing 45 degrees in parts of the immediate NYC area and Long Island. NW winds are expected for tomorrow as well.

Monday – Wednesday: Mild, Dry

A weak low pressure will form in the southern Mid Atlantic before moving east on Monday evening. As a result, partly cloudy skies are expected on Monday, with partly to possibly mostly cloudy skies on Monday night. Temperatures will peak in the lower 40s inland and the lower to mid 40s across the rest of the area. The latest model runs have trended stronger and further north with this wave of low pressure, and while no significant impact is expected from this storm anywhere in the region, an isolated shower or flurry could be possible in parts of the area on Monday night. Warmer temperatures will return on Tuesday with highs reaching the mid 40s to lower 50s across the area, once again nearly 10 degrees warmer than average, along with partly sunny skies, with these temperatures lasting through Wednesday along with increasing cloud cover and a few showers late.

Wednesday Night – Thursday: Rain, Mild, Windy

The next storm to affect the area will be on Thursday. With the set up in this case, not only will this not be a snowstorm for the area, but for most of the Northeast as well. The shortwave responsible for this storm is a cutoff low which will be near Texas tomorrow into Monday. With the cutoff to the south, a ridge in the northern and western US, and a west flow, the warmth will be able to spread east to the north of the cutoff low, still stuck over the southern US, with a warmer air mass moving back in by Tuesday as previously mentioned. This will place a mild air mass ahead of the storm and prevent the storm from starting out as snow.

With the mild air mass in place, the storm will move towards the region, with the low pressure likely to track near or east of I-95. Despite this track, the mild air mass ahead of the storm will still result in mild temperatures, with temperatures steady in the 40s on Wednesday night, possibly rising a bit towards Thursday morning as the low pressure gets closer. Widespread moderate to locally heavy rain is expected across the area out of this storm, with the rain starting around Wednesday evening and ending by Thursday morning. Rain totals are likely to end up near or slightly above 1 inch across a large part of the area. With the mild air mass in place due to the storm, mild temperatures are likely to return on Thursday, which could once again reach the mid 50s across the area, along with breezy winds, likely gusting near or above 30 mph, especially towards the afternoon and evening. Stay tuned for more information on the Wednesday-Thursday outlook.

Longer Range: Cold, Dry Conditions Return

The Wednesday night storm does not change the pattern in place. An approaching trough to the west will bring colder temperatures back for the weekend, although it also won’t exactly change the pattern in place. There are increasing differences with the models for the longer range, with the GFS showing a weak rain/snow event for the Mid Atlantic, the CMC has a weak coastal low offshore, and the ECMWF has light rain/snow for the area on Friday which develops into a snowstorm for New England. The CMC right now is an outlier with how it handles the set up, although the other reasonable models, the GFS and ECM, are still different with their set-ups. There is uncertainty if a storm does affect the region, but if there is a storm, which is a possibility, it could be focused between Friday and Saturday, and unlike the previous events, may actually bring snow to parts of the area if the track if favorable. Regardless of these differences, however, colder temperatures are likely to return for next weekend, with temperatures dropping back to near average, possibly into the mid 30s to lower 40s range. Stay tuned for more information on the longer range outlook.

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