Thursday, October 20, 2011

Oct 20, 2011: Chilly Weekend Ahead

After the update last night was posted, additional showers affected the area, increasing the rain amounts across the area to a total of about 1/2 to 1 inch across most of the area, though amounts reached the 1-2 inch range in parts of Long Island and southern CT. After the spike in temperatures last night, when temperatures surged into the 65-70 degree range across the area, temperatures slightly dropped this morning, but went up again this afternoon, reaching a secondary peak in the mid to upper 60s across the area. Windy conditions were observed as well, with gusts in the 20-35 mph range across the area and a peak gust of 41 mph in Islip, NY.

Behind the storm, a colder air mass is moving into the region, which will bring slightly below average temperatures across the area for this weekend. The pattern we are currently in suggests that the cold will not be long lasting, and this will be the case once again as the cold weakens by early next week, with temperatures returning into the upper 60s and/or the 70s towards the middle of next week, which is warmer than normal for this time of the year. Even though the first part of the week will be dry, the wet pattern hasn't given up just yet, as yet another rainstorm will affect the area by the end of next week.


Tomorrow's Outlook

Tomorrow will bring colder high temperatures across the area as the colder air mass moves in, with 850 mb temperatures between 2 and 4 degrees celsius. With a WSW wind expected along with partly sunny skies, high temperatures will reach the upper 50s inland, upper 50s to mid 60s in the immediate NYC area, and the lower to mid 60s in Long Island and southern Connecticut.


Saturday - Tuesday: Chilly, Some Rain

With a high pressure moving over the region, mostly sunny skies are expected for this weekend along with near to slightly below average temperatures. Both days will bring high temperatures similar to but slightly warmer than those of tomorrow, with Saturday bringing high temperatures into the upper 50s to lower 60s inland and the lower to mid 60s across the rest of the area. Sunday will be slightly warmer than Saturday.

The coldest temperatures are expected for Saturday night across the area, when mostly clear skies are expected along with a high pressure providing light winds. With 850 mb temperatures still in the 2-5 degrees celsius range, low temperatures are likely to drop into the lower to mid 30s inland, mid 30s to lower 40s in the immediate north/west suburbs of NYC including Rockland/western Bergen counties, upper 30s to lower 40s in Long Island/S CT, and the mid 40s in NYC. These conditions will likely bring the potential for frost in the interior parts of the area.

A weak low pressure will approach the region from the northwest of Monday, bringing increasing clouds cover for Sunday night into Monday morning. Mainly cloudy skies are expected by the afternoon with scattered showers likely for the afternoon and evening hours, bringing less than 1/4 inch of rain in places that do see rain fall. High temperatures will be slightly warmer, reaching the mid 60s across most of the area, but with the low pressure keeping the cold air briefly in place on Tuesday, temperatures will cool back down into the lower to mid 60s with partly sunny skies.


Wednesday - Saturday: Rain Returns Again


The wet pattern the region has seen since the middle of this summer is not showing any signs of giving up, as yet another rain storm will affect the region by the second half of next week. There is uncertainty with the specific details given the time range, but the overall idea is there for a low pressure to move through the central/northern US, probably somewhere near the Ohio Valley or the Great Lakes and towards the Northeast US, with a surge of cold air entering the northern US behind this storm. Some models show tropical interaction or a secondary low pressure forming further south, but it is still too far out to determine whether we will see these scenarios taking place. When looking at the overall picture, however, the idea is there that warmer temperatures may return around Wednesday, with high temperatures potentially reaching the lower 70s again in the warmer case scenario, otherwise staying in the mid to upper 60s, with rain expected to affect the region, including the area, on Wednesday and Thursday. Stay tuned for more information on this storm.

Behind the storm, the latest models continue to show cold air reaching the region, but the models have backed away from the intensity of the cold surge shown over the last few days. As I mentioned over the last few days, the current pattern is not supportive of sustained below average temperatures across the region, with the coldest departures focusing to the west of the area, and at this time, it appears that the potential cold for the end of October may be no exception to the pattern, with the potential for warmer temperatures to return towards the start of November. Stay tuned for more information on the longer range.

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