A strong cold front will approach the region on Friday, bringing the first widespread rain event in nearly a month, yet still less significant than a typical fall rain event with at least 1/2 inch. The main highlight, however, is the wind, with gusts up to 40-50 mph expected, along with temperatures surging well into the 60s. Following a brief cool down over the weekend with cold temperatures returning, the pattern will trend warmer again going into next week.
Tonight – Friday: Warming Up Ahead Of Frontal Passage; Rain, Wind Expected
Forecast Analysis: As of this evening, a strong cold air mass was present over the northeast US, with temperatures aloft at 850 millibars near -4 to -8C. With a zonal flow aloft, however, this air mass failed to spread further south into the area, where 850mb temperatures were generally near 0C. As the trough exits the region, ridging will begin to amplify ahead of a strong upper level low exiting the western US, which will gradually bring warmer temperatures into the region. Meanwhile, a low pressure will organize in the central US on Wednesday and Thursday, producing widespread rain and severe weather, before rapidly tracking northeast through the Great Lakes on Friday while phasing with a strong Canadian trough and quickly intensifying in the process. This will bring a strong cold front through on Friday with warmer than average temperatures, widespread rain, and strong winds as a result of an intensifying low level jet with 925mb winds near 60-70 knots.
General Forecast: The high pressure that provided the region with mostly sunny skies today will exit to the east, with a frontal boundary spreading east bringing more widespread cloud cover for Wednesday and Thursday, with highs reaching the mid to upper 50s on Wednesday and the upper 50s to low 60s on Thursday, approaching the mid 60s near NYC. Winds will begin to increase on Thursday, with isolated showers possible north/west of NYC but with otherwise dry conditions for Halloween. As the cold front moves through, rain is expected to develop generally after 2-5 AM, continuing through 12-2 PM west of NYC and 2-4 PM east of NYC. Rain totals of at least 1/4 to 1/2 inch are expected, locally up to 3/4 to perhaps 1 inch towards interior areas. Strong wind gusts are expected as well, primarily late Thursday night into Friday morning and early afternoon, with sustained winds of 20-30 mph and gusts near/over 40 mph, locally up to 50 mph in Long Island and CT. Drier conditions are expected later in the day with highs in the mid to upper 60s.
One year ago at this time, the region was just past the peak of hurricane Sandy, one of the worst hurricanes to affect the US on record. This year’s pattern in this time frame is much quieter, however, with the main highlight the approaching cold front with moderate rainfall and relatively strong wind gusts. October 2013 continues the overall inactivity trend that has been present this fall, a rarity for recent Octobers which have often featured high impact events in the eastern half of the US. Should most of the rain hold off until after midnight on Thursday night as currently forecast, Central Park will be on track for a top 5 driest October and top 10 driest month on record.
Weekend – Next Week: Cold, Then Warming Up
A transient trough will slowly enter the region behind the departing cold front, which will nearly stall offshore for a brief period on Saturday as a coastal low pressure forms, but with no rain expected over the area as the moisture remains offshore. Another warmer than average day is expected on Saturday with partly sunny skies and highs in the low-mid 60s for most of the area, approaching the upper 60s in NE NJ and NYC. A more significant cool down is expected for Sunday into Monday, with a breezy NW wind on Sunday gusting up to 30 mph with mostly sunny skies and highs in the upper 40s-low 50s inland and mid 50s for the rest of the area. Cold temperatures are especially expected overnight, falling into the low-mid 20s inland, mid-upper 20s in radiational cooling spots in interior Long Island, upper 20s-low 30s in the north/west suburbs of NYC and the rest of Long Island, and the mid to upper 30s in NYC and the coast. Mostly sunny skies are then expected for Monday with a strong high pressure overhead and high temperatures struggling to reach 50 degrees, generally peaking in the upper 40s to low 50s for most.
This cool down will be brief, however; as the strong high pressure slides east with ridging rebuilding into the eastern US, continuing the pattern that has generally been present over the last month with a tendency for ridging in the southeastern US, temperatures will warm up again into the middle of next week, with low to possibly mid 60s not out of the question. The next trough and frontal system are expected to approach the region late in the week, towards Thursday and Friday, but with uncertainty regarding the setup; the latest model runs depict a significant storm affecting the region with heavy rainfall over 1 inch, which if verifies would be the most significant rain event since September 12 and would offer moderate relief from the current drought conditions. While rain is expected in this time frame, how much rain falls is still uncertain, especially if recent trends continue and the rainfall is ultimately less significant than initially signaled.
Beyond the late week, a cool down is expected again towards next weekend. Given the overall pattern, however, with a persistent signal for ridging in the east, a strong +NAO and +AO pattern with lower than average heights over Greenland and the North Pole, and persistent troughing in the western US associated with a -PNA, temperatures for the first half of November are overall likely to end up warmer than average, with precipitation slightly below average, as the main storm track remains north and west of the area.
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Monday, October 28 Observations:
A much stronger cold air mass entered the northern US, resulting in a brief warm up ahead of the colder temperatures. A southwesterly flow continued with high temperatures returning to near-slightly above average levels, peaking in the low to mid 60s across the area. The highest temperature was 64 degrees in Newark, NJ, and the coolest high temperature was 57 degrees in Port Jervis, NY.