Nov 10, 2011: Cold, Windy Friday Expected

Note: I was unable to update the 5-Day Forecast and the Long Range Outlooks pages today. An updated 5-Day Forecast will be posted during Friday morning, and the discussion for the late November outlook will be posted with tomorrow evening’s update.

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As a cold front moved through the area today, pushing out the ridge that has been stuck over the region for the last few days, mild temperatures were observed prior to the frontal passage. The forecast from yesterday was too cold for the western half of the area, as unexpected sunny skies during the afternoon allowed temperatures to surge into the upper 60s from NYC and further west, while expected cloud cover and rain in Long Island and southern Connecticut resulted in high temperatures peaking in the lower to mid 60s, verifying yesterday’s forecast for that part of the area. Rainfall amounts ended up between 1/4 and 1/2 inch in the eastern parts of Long Island and SE Connecticut, and light to moderate rain currently moving into the immediate NYC area will bring up to 1/4 inch tonight.

Behind this cold front, a strong trough will briefly drop into the region, bringing high temperatures into the 40s and 50s again across the area along with windy conditions. Although this cold spell will not last long under the current pattern, with another ridge building by Sunday and Monday, gradual changes in the pattern will result in weaker warm spells across the area by the second half of the month.

Tomorrow’s Outlook:

With the strong trough over the area along with a tight pressure gradient and 850 mb temperatures near -5 degrees celsius, cold and windy conditions are expected across the area tomorrow. A strong NW/WNW wind is expected gusting up to 30-40 mph across most of the area, although it is not out of the question that a few parts of the area exceed 40 mph wind gusts. High temperatures will be much colder than those of today, peaking in the mid to upper 40s inland, upper 40s to lower 50s in the immediate NYC area with a few mid 50s possible south of NYC, and in the lower to mid 50s in Long Island and southern CT.

Weekend Outlook: Warming Up

Tropical Storm Sean, currently to the west of Bermuda, will be absorbed by this trough, and a strong non-tropical low pressure currently developing east of New England will quickly intensify while moving to the north. This intensifying storm will pull the trough along with it at the same time that another trough drops into the western US, resulting in yet another strong ridge building into the eastern US. This ridge will not be as warm as the current ridge, although it will bring above average temperatures once again to the area. With a high pressure moving into the region at the same time, mostly sunny skies are expected this weekend, along with high temperatures peaking in the mid 50s across most of the area on Saturday, slightly higher in parts of the immediate NYC area, and in the upper 50s to lower 60s on Sunday.

Next Week’s Outlook: Rain Returns, Then Increasing Uncertainty

The latest model guidance has trended towards a weaker ridge in the western Atlantic, failing to hold strong as modeled yesterday and instead remaining mainly south. Most of the latest models then push the cold front through the area on Monday and Tuesday, bringing rain followed by colder temperatures. The models appear to have issues with handling the pattern next week, as each model shows a different scenario; the GFS quickly brings in a strong trough by the second half of next week, the CMC keeps ridging in place, while the ECMWF has several storms moving through the central US, keeping the cold stuck to the northwest of the region while bringing more rain chances.

There is a high probability for rain to fall around the Monday-Tuesday time frame, although the intensity of the rain and whether it affects only parts of the area or the entire area is still uncertain. At this time, I am expecting ridging to remain in place through at least Tuesday, with light to possibly moderate rain possible between Monday afternoon through Tuesday. The potential may be there for another low pressure to affect the region around Thursday, although this potential is still uncertain and depends on Tuesday’s cold front and what comes behind it. Colder air will likely return by Wednesday, although it appears at this time that the better chance for stronger cold may be towards the end of the week. Stay tuned for more information on next week’s outlook as details become clearer.

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