After a relatively chilly pattern for the last 2 weeks, a warm up will take place this week with highs returning into the upper 70s to low 80s across most of the area, with continued mostly sunny skies and a lack of rain as a coastal low pressure stays well to the east. The 2-week rain drought will end next weekend, however, as a strong cold front produces widespread rain, followed by a cooler start to next week.
Today – Tuesday: Slowly Warming Up
yesterday, a developing wave of low pressure in the Midwest region moved north into Canada, dragging the cooler air mass behind it further north as well. As a result, the approaching cold front is collapsing, and will fail to reach the area. With a coastal low pressure staying well to the east, mostly sunny skies and dry conditions will continue through Tuesday. Temperatures will begin to slightly warm up, reaching the upper 60s to low 70s today, upper 60s-low 70s east of NYC and low-mid 70s from NYC And further west tomorrow, and the mid 70s on Tuesday, possibly upper 70s in northeast NJ.
Wednesday – Saturday: Warmer Weather Returns
As yesterday’s pattern outlook noted, a strong trough will quickly move east through southern Canada, setting up for a zonal flow aloft for the mid to late week. With the westerly winds, a strong warm air mass will be quickly pushed into the region on Wednesday without being interrupted by any sort of trough to the east, the first time this has happened since the September 10-12 heat surge, which will lead to warmer temperatures returning into the area. With sunny skies, west winds and dry conditions on Wednesday, highs are expected to reach the upper 70s to low 80s across the area, possibly approaching the mid 80s in northeast NJ; with average high temperatures in the upper 60s, these temperatures will be at least 10 degrees above normal on average. Similar temperatures, if not a degree or two cooler, will continue through Saturday as ridging holds over the region, amplifying by the weekend in response to a digging trough to the west. Cloud cover will remain mostly sunny for the late week, aside from Thursday night when a brief increase in cloud cover is possible, followed by partly cloudy skies towards Saturday. Overnight lows will gradually rise as well, with widespread lows in the upper 50s-low 60s expected by Friday night.
Weekend – Next Week: Rain Returns, Then Cooler
A strong trough will amplify in the central US towards Friday and Saturday, which then reaches the region to bring the first widespread rain event in 2 weeks. There is some uncertainty regarding the timing of the frontal passage, with possible scenarios ranging from Saturday to Monday; at this time, I am siding with a Sunday night frontal passage with rain on Sunday and Sunday night, although some changes are still possible. A strong cold front is expected to move through the region, with moisture from the Gulf of Mexico and Atlantic Ocean being pulled up the East Coast ahead of the front, which enhances probabilities of possibly heavy rainfall with the frontal passage. At this time, I introduced an 80% rain chance in the 7-day forecast for Sunday, with timing the main limiting factor in the percentage, as the highest probability of rain could shift between Saturday night and Monday.
Behind the cold front, a cooler air mass will return into the region for the early week, with temperatures back to near or slightly below average; as mentioned yesterday, however, the progressive pattern is unfavorable for a cold air mass to settle over the region, and temperatures may warm back to above average by the mid to possibly late week ahead of the next potential cool down. More information will be posted on the weekend cold front and next week’s outlook over the next few days.
Friday, September 27 Observations:
As with the rest of the week, a high pressure remained parked over the region, with a stale cool air mass slowly drifting southwest from Nova Scotia into the area. While the forecast expected mostly sunny skies to continue, widespread cloud cover persisted across the region, which kept temperatures cooler than forecast, peaking in the mid 60s to low 70s. The highest temperature was 71 degrees in Teterboro, NJ and Somerset, NJ and the coolest high temperature was 63 degrees in Danbury, CT.