Forecast Highlights: As a strong high pressure remains centered over the region, mostly sunny skies and temperatures in the low to mid 80s will continue today, with a slight cool down on Monday as cloud …
Forecast Highlights: A weak coastal low pressure produced areas of light to moderate rain yesterday, with rain totals generally between 1/4 to 1/2 inch, locally up to 1 inch east of NYC. Mostly sunny skies …
Forecast Highlights: A coastal low pressure currently off the coast of North Carolina will track NNE up the coast, producing widespread rain across the region on Thursday with temperatures struggling to rise above 60 degrees. …
A weak coastal low pressure produced areas of light to moderate rain yesterday, with rain totals generally between 1/4 to 1/2 inch, locally up to 1 inch east of NYC. Mostly sunny skies and warm temperatures will continue through Sunday, with highs in the upper 70s to low 80s, before a possible coastal low sets up off the coast for the midweek time frame followed by another late week or weekend rain potential.
A coastal low pressure currently off the coast of North Carolina will track NNE up the coast, producing widespread rain across the region on Thursday with temperatures struggling to rise above 60 degrees. A high pressure will build in for the weekend with temperatures climbing back into the upper 70s and low 80s before cooling back down into the 70s next week, along with a risk of light rain in the mid-late week.
The model guidance has trended west with a coastal low pressure on Thursday, introducing widespread cloud cover, chilly temperatures and at least some rain on Wednesday night into Thursday, especially south and east of NYC. As the system departs, a high pressure will build into the region, providing mostly sunny skies through early next week as temperatures climb into the upper 70s and low 80s.
Forecast Update: Rain Possible on Thursday
The previous forecast discussion posted two days ago, on Sunday, noted that a coastal low pressure was forecast to develop off the coast, but with a prolonged sunny and dry period likely barring any significant change with the model guidance. Trends over the last day have done just that, and introduce widespread cloud cover, chilly temperatures and possible rain on Thursday, interrupting the stretch of sunny and dry conditions which will resume again for Friday through next weekend.
6z GFS hour 54, valid at 12z Thursday (8am EDT), depicting a weak low pressure south of NYC with heavy rain extending into the area. This run is near the wetter end of the model guidance this morning, with the ECMWF drier but continuing to trend wetter for the area (image credit: PSU e-Wall).
As the previous update noted, the coastal low was forecast to develop well off the coast due to sufficient forcing ahead of a weak cutoff upper level low and the favorable positioning of an upper level jet streak off the East Coast. The intensity of the surface low has not changed, progged to remain relatively weak with minimum pressure near only 1016-1020 hPa but with sufficient lift and mid level warm air advection combined with a plume of tropical moisture from the Atlantic Ocean to produce heavy rainfall. What has changed, however, is the track of the low pressure, as in the short term, the model guidance trended stronger with low-mid tropospheric ridging near Bermuda, to the east of the low pressure, forcing it on a more northerly track closer to the coast. This system will likely at least produce widespread cloud cover and chilly high temperatures in the 60s on Thursday, along with a chance of rain between Wednesday night and Thursday afternoon. The northward extent of the heavy rainfall remains uncertain, as this system is capable of producing over 1 inch of rain, but with the NAM and ECMWF near the drier end of the model guidance with below 1/2 inch of rain, and the GFS and CMC on the wetter end of the guidance with 1 to 2 inches of rain.
Additional data is needed to complete a more detailed and thorough analysis, especially considering the volatility of significant trends in the model guidance; one such example is mid-October 2013, when the model guidance trended towards a significant coastal low pressure with heavy rain in the NYC area in the relatively short term, but with the rain ultimately remaining south of the area. Stay tuned for an afternoon update analyzing the expected scenario for Thursday in more detail.
A weakening cold front is currently moving through the region, its rainfall limited by a deepening coastal low east of the area. Following the passage of the cold front, which is likely to leave most of the area dry, a strong high pressure will set up over the region, providing at least a week-long stretch of mainly sunny skies and near to above average temperatures from Tuesday through the weekend and early next week.
The recent dry pattern is forecast to continue through the foreseeable future as the only rain-producing system in the forecast range, on Sunday night, will mostly dry up to the west with only isolated showers possible, bringing a quick end to a weekend warm-up with highs in the 70s and low 80s. A broad upper level ridge will settle overhead from Tuesday, with sunshine, near to above average temperatures and no rain in sight through the rest of the forecast range.
Temperatures will remain in the low to mid 70s through Thursday, when a cold front will usher in cooler temperatures with highs struggling into the upper 60s on Friday. Temperatures will quickly warm into the 70s and low 80s by the weekend, followed by the possibility of rain early next week and another round of chilly temperatures.
Following a high pressure which provided the area with cool temperatures last night, highs will generally remain in the mid 60s to low 70s range this week with some rain expected on Tuesday. The cool temperatures are forecast to peak on Friday, followed by a brief warming trend in the weekend and a risk of rain on Sunday or Monday, with temperatures otherwise remaining near to slightly below average.