Thursday, January 10, 2013

Jan 9, 2013: Mild Weekend, Then Rain


Note: Tonight's post includes a brief overview of the longer range pattern beyond mid next week. Tomorrow's pattern outlook will discuss the longer range, specifically the upcoming pattern for the end of January, in more details.

Forecast Highlights:

Due to unexpected scattered showers and more cloud cover than expected, temperatures today were not as warm as expected but still warmer than average, in the low to mid 40s inland, mid 40s in southern CT, and upper 40s-low 50s for the rest of the area. Temperatures will slightly cool down on Thurs and Fri with a light rain event on Friday, but warm up again for the weekend with temperatures as much as 15-25 degrees warmer than average before a cold front ends the warmth early next week.





Tonight - Friday: Slightly Cooler, Some Rain

A weak cold front is moving through the region tonight, with mostly sunny skies expected for Thursday. Temperatures will fail to cool by much behind the cold front, however, with highs in the low to mid 40s inland and the mid to upper 40s for the rest of the area. A weak low pressure will move through the region on Friday with occasional showers expected throughout the day into the early overnight hours, with totals generally under 1/4 inch. Interior parts of the area north and west may see some freezing rain to start, although no significant icing is expected. Highs will be in the upper 30s to low 40s in NW NJ, SE NY and southern CT, and low to mid 40s in the immediate NYC area and Long Island.


Weekend - Monday: Significantly Warmer Temperatures

The weak low pressure will move out of the area on Friday night, but temperatures will fail to cool down behind it; instead, with a strong ridge over the eastern US, a significant warmth surge will affect the region with temperatures 15 to 25 degrees warmer than average across the majority of the region. The Mid Atlantic south of the Maryland/Pennsylvania border will be the warmest, with widespread temperatures near or above 70 degrees expected this weekend, while New England will be cooler with highs in the 40s. The NYC area will be in between, with highs generally likely to reach the low to mid 50s for the eastern half of the area, and mid to upper 50s, approaching 60 degrees, in the immediate NYC area and further west. Saturday and Sunday will have similar temperatures, with Saturday the cooler of the two, with highs in the upper 40s possible further north and east.

Overnight temperatures will be mild as well, with temperatures on Saturday night only falling into the upper 30s to low 40s inland and low to mid 40s for the rest of the area, slightly warmer in NYC; this is several degrees warmer than the average high temperatures. A cold front will then approach the region on Monday; originally, this looked to move through on Tuesday night or Wednesday, but now looks to move through faster than originally expected, likely on Monday. As a result, some showers are expected on Sunday night into Monday, with temperatures struggling to drop below 45-50 degrees overnight. High temperatures on Monday are still uncertain and depend on the timing of the frontal passage; for now I am siding slightly slower than the GFS with highs still reaching the 50s before dropping overnight. The temperature forecast for this time frame is still slightly uncertain and is subject to minor revisions.


Next Week: Colder, Stormier And Eventually Snowier Pattern Develops

With the unseasonably mild week and weekend for the region, there have been comparisons made to last year, when winter never arrived in the region. This year, it will not be the case. Significant pattern changes are already expected to develop in the medium range, with the pattern gradually trending colder for the region. With this trend, however, comes the question of the magnitude and duration of the colder pattern. Forecasts have ranged from a transient cold surge on the 17-20th followed by a mild pattern, to a significant cold pattern persisting over the region straight into February.

Tomorrow's pattern outlook will discuss these changes in more details; while a sustained much colder than average pattern is not expected to develop for the East at this time, the pattern will gradually trend colder, with occasional periods of cold likely from January 17-20th into parts of February. With the cold comes the eventual potential for snow; a weak low pressure will likely affect the region around Wednesday next week with light to moderate precipitation, and may produce snow in parts of the Northeast, but likely still north of the area. Beyond this storm, however, snow may be more likely for the area starting around January 20, perhaps a bit earlier or later. Stay tuned for more information with tomorrow's pattern outlook covering the rest of January.

2 comments:

  1. What's your take on the rain event hitting the south as we speak, any chance we get that storm? And if so, how much rain could we be talking about?

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    Replies
    1. The rain event in the southern US will affect us tomorrow, although it won't be anything significant. The rain is associated with a strong shortwave currently in Texas, which will reach the Ohio Valley on Friday and NYC overnight, although it will weaken as it reaches the area. Occasional showers are expected especially on Friday afternoon and evening, possibly with some freezing rain inland initially, with rain amounts generally between 0.1 and 0.3 inch.

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