Mar 11, 2012: Long Lasting Warm Spell Begins

Forecast Highlights:


- Tuesday will be warmest day of week; 75 degrees likely near NYC
- Slightly cooler yet still mild ending to week
- Warmer weekend, scattered showers are possible
- Biggest warmth possible next week; potential for up to 75-80 degrees


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With the high pressure still in place over the region, the cold air mass over the region yesterday left the region with a warmer air mass returning. Mostly sunny skies were observed today with high temperatures reaching the.

With no incoming trough behind the departing cold air mass, just about all signs of winter-like conditions have been erased from the US, except for cold and stormy conditions in the northwestern US. Factors such as a cold front on Wednesday and scattered showers over the weekend will prevent temperatures from reaching their maximum potential, but with today's warmth, a 2-week period of unusual warmth for March will begin for the eastern half of the US, with temperatures frequently much warmer than average allowing for this month to likely end up as one of the warmest Marches on record.


Monday's Outlook:


The warmth will continue to build into the region tomorrow (Monday) with southwest winds and partly sunny skies persisting. High temperatures are expected to be the warmest over northern NJ, SE NY and NYC, where highs will reach the mid to upper 60s, with parts of the immediate NYC area especially near northeastern NJ likely reaching and/or exceeding 70 degrees. Due to the SW winds, colder temperatures are expected further east, with lower to mid 60s in most of Long Island and southern CT, warmer closer to NYC and colder near the immediate coast, where highs will likely stay in the mid to upper 50s.


Tuesday - Thursday: Very Warm, Then Colder But Still Warm


As the cutoff low pressure currently near the central US slowly drifts towards the region, Tuesday will be the warmest day of the week. Occasional showers on Monday night will clear the area by the late morning hours on Tuesday, with partly sunny skies and SW winds expected for the afternoon. With these conditions, along with a warmer air mass, temperatures will quickly surge into the upper 60s to lower 70s across northern NJ, SE NY and NYC, with parts of the immediate NYC area, especially near NE NJ, likely to reach the mid 70s. Colder temperatures are expected further east, with lower to upper 60s across most of Long Island and southern CT, with upper 50s to lower 60s near the immediate coast. The cold front moving through is expected to be mainly dry, but especially with some instability, the potential is there for isolated thunderstorms on Tuesday evening, focusing over southern CT but possible for the rest of the area as well.

With the cutoff low pressure moving through the region, the cold front will move through the area, with clearing skies and colder temperatures for Tuesday night. Wednesday will bring mostly sunny skies with a west/WNW wind, which despite the cooler air mass will allow for temperatures to warm up into the lower to mid 60s across most of the area, even in Long Island and southern CT away from the immediate coast. Colder temperatures are expected overnight with lows dropping into the upper 30s to mid 40s across the area, although Thursday will be colder than Wednesday, with highs likely reaching the lower to mid 60s in northern NJ, SE NY, and NYC away from the coast, with highs in the mid to upper 50s in coastal parts of NYC, most of Long Island and southern CT, with the immediate coast possibly failing to reach 55 degrees. Although these temperatures are relatively colder than areas further south/west as well as the early week temperatures, this is still noticeably warmer than average.


Friday - Next Week: Back To Very Warm Temperatures


With the cutoff low out of the region on Friday, all of the models agree that a strong and very large ridge will set up over the eastern half of the US throughout next weekend and most of next week as well. There is increasing uncertainty, however, regarding the smaller parts of the set up that will determine how much rain, if any, the area gets, and how warm temperatures end up next week.

Considering the 18z NAM/DGEX combo as an outlier solution by bringing another cold front through on Thursday, a solution which no other model shows, it appears that scattered showers are likely to cover parts of the region during Friday and the weekend, although the location and timing is still uncertain; it is possible that locally heavy rain falls on any of these days, or that no precipitation falls for most of the area. The GFS is currently the most bullish with precipitation during the weekend, showing a localized heavy rain event on Saturday, which later forms into a low pressure offshore. The ECM and CMC show less rain, allowing for warmer temperatures. For now, I sided with the drier ECM/CMC solutions, expecting temperatures on Friday and Saturday to likely end up in the upper 60s to lower 70s away from the coastal areas along with partly sunny skies and a risk of isolated showers, although the temperature outlook is still subject to change; if there is more sunshine than expected, highs may reach the mid 70s in northern NJ, although should any scattered heavy rain shower move through during the day, high temperatures will be colder than those previously mentioned.

Once going beyond the weekend, the main area of uncertainty is with the location of the ridge; the ECM is so strong with the ridge that it shows it to the northwest of the area, keeping NYC with relatively colder temperatures while places much further west see the biggest warmth. The GFS, meanwhile, has the ridge further south, bringing at the very least 1-2 days of 80 degree weather for parts of the area, and the DGEX, with its 6z run staying warm and the 18z run trending back towards the rest of the models by the end of its run, also showed 80 degrees in parts of the area with today's runs. Considering the time range that this is in, there is still time for changes with the set up, and it is possible that the biggest warmth misses the area to the west, although given the intensity of the ridge and the warm air mass, should the ridge end up in a favorable position, there is a potential for temperatures to reach the 80 degree range for parts of the area next week. As previously mentioned though, it's still a potential at this time, and could still change. Stay tuned for more information on the warm spell and the potential temperatures for next week with tomorrow's update.