A strong cold front moved through the area early today, producing the most significant rain event in nearly a month with rain totals as high as 1/4 to locally 1/2 inch, along with strong wind gusts and wind damage reported in northern NJ. Other than a brief rain event on the 7th, the dry pattern is expected to continue into the first half of November, but with frequent temperature swings, ranging from highs in the 60s on Saturday, to the low-mid 40s on Monday, then back to near 70 degrees by Thursday.
Tonight – Monday: Much Colder, Breezy Sunday Expected
A rapidly intensifying low pressure tracked northeast through the Great Lakes and central Canada last night, which brought a strong low level jet through the region today along with a narrow line of heavy rain. The strongest wind gusts were generally confined to this narrow squall line, with scattered reports of wind damage across northern NJ. The strong low level jet advected a much warmer air mass from the south, with temperatures surging into the upper 60s and low 70s across the area today, which is over 10 degrees warmer than average. The front has stalled to the east of the area, however, as the initial shortwave trough associated with the strong low pressure quickly lifted north into Canada; a broad trough currently over the central US will gradually shift east into the region, which along with a surface high pressure building in from the northwest will result in a gradual cool down through Saturday and Sunday.
Partly sunny skies are expected on Saturday with a southwest wind and high temperatures remaining unseasonably warm, peaking in the low-mid 60s inland and mid-upper 60s elsewhere. A second, dry frontal passage is expected on Saturday night, with strong cold air advection for Sunday with mostly sunny skies, a breezy north wind at 10-20 mph, gusting up to 30 mph, and high temperatures struggling to warm by much, only reaching the low to mid 40s towards interior SE NY and CT, and the mid to upper 40s for the rest of the area. The coldest temperatures are expected overnight into Monday, as a strong high pressure will be positioned to the north with temperatures falling into the low to mid 20s inland (NW NJ, SE NY, interior CT), mid 20s to near 30 degrees in the north/west suburbs of NYC, southern CT and interior Long Island, and low to mid 30s in NYC and the coast. Frost is likely for locations that have not had it yet. With the cold air mass still in place on Monday, mostly sunny skies are expected with high temperatures struggling to warm beyond the low to mid 40s.
Tuesday – Thursday: Mild Again, Rain Briefly Returns
In a continuation of the current pattern with frequent troughing in the western US, another strong trough is expected to enter the northwest US by the early week with an organizing low pressure in the central US; as the weekend trough moves out of the region, a widespread southwesterly flow will return as a strong southeast US ridge re-establishes itself with higher than normal 500 millibar heights, up to 588-594 decameters. As a result, a quick warm up in temperatures is expected into the mid 50s on Tuesday, mid 60s on Wednesday, and the upper 60s to low 70s on Thursday, with partly sunny skies expected.
The next cold front will affect the area on Thursday evening and night, as the central US low pressure intensifies while tracking into the Midwest and Canada, bringing a strong cold front into the northeast US region. As with this week, the strongest forcing and thus the heaviest rain is likely to stay north of the area again. However, this event may have the potential to produce somewhat more rainfall than today’s cold front, which produced rain amounts generally less than 1/2 inch, with the front likely becoming negatively tilted as it moves through the region along with a sharp temperature gradient behind the front, unlike today when the best forcing quickly lifted north well into Canada, leaving the front stalled near the area with little change in air mass behind the front. While rain totals are still uncertain at this time, there is higher confidence for at least somewhat higher totals than observed today, with at least 1/2 inch of rain possible, potentially higher inland. Windy conditions are also possible with the frontal passage, but with the low level jet likely weaker than today’s system.
Behind the cold front, another transient cool down is expected for Friday and the weekend with highs back into the upper 40s-low 50s and lows in the 20s and 30s across the area. The next pattern outlook will be posted on Saturday, and will discuss in more details the upcoming pattern beyond next weekend along with some clues as to how winter might start.