Nov 8, 2011: Rain Returns On Thursday

With a strong ridge building into the region, mostly sunny skies were observed again across the area, and along with 850 mb temperatures near 10 degrees celsius, high temperatures ended up well above average across the area, and broke the daily records in parts of the area, such as in Islip, NY. High temperatures reached the upper 60s to lower 70s across most of the area except for southern Connecticut, where high temperatures were in the mid to upper 60s. The average high temperatures for this time of the year are only in the mid 50s.

With the ridge remaining in place through Thursday, warm temperatures will be observed again tomorrow across the area but with slightly more cloud cover. By Thursday, as Tropical Storm Sean interacts with a cold front approaching the coast, scattered showers will affect the area, which will be followed by a strong yet brief trough bringing near to slightly below average temperatures along with windy conditions. The pattern we are now in does not favor sustained cold, and this will prove to be the case once again, as this trough will be quickly replaced by another strong ridge, bringing temperatures back into the 60s next week but along with more rain chances.


Tomorrow's Outlook:

Tomorrow will bring mostly to partly sunny skies to the area along with a SSE/SE wind. Similar 850 mb temperatures are expected, but due to the onshore wind and slightly more cloud cover than today, temperatures will slightly cool down, reaching the mid 60s from NYC and further west with a few upper 60s possible in parts of NE NJ, and in the lower to mid 60s in Long Island and southern Connecticut.


Thursday - Friday: Rain, Then Colder And Windy

Last night, the subtropical disturbance mentioned in the discussion was designated as Subtropical Storm Sean, making this the 18th named storm of this year's hurricane season. With Sean added to the list of storms, this year is one of the most active years on record in terms of named storms, but in comparison to the number of storms observed so far, there have not been many hurricanes and major hurricanes. Sean is not expected to become a hurricane, likely intensifying a little more into a strong tropical storm with about 60 mph sustained winds as it moves NNW, to the west of Bermuda.

A strong trough will move towards the coast on Thursday, which will pull Sean northwards as Sean loses its tropical characteristics and becomes an extra-tropical cyclone. Due to the negative tilt of the trough, Sean will be pulled north then NNW, with the extratropical system moving east of eastern New England and into Canada. This track will keep the heavier rain in eastern New England and Nova Scotia, while bringing scattered showers into the area. Most of the showers will fall during Thursday night, although scattered showers are possible between Thursday afternoon and Friday morning.

With the extratropical storm moving into Canada, a strong trough will move into the area, with 850 mb temperatures dropping to near -5 degrees celsius. Combined with partly to mostly cloudy skies and a strong WNW/NW wind, with gusts in the 30-40 mph range across parts of the area, much colder high temperatures are expected, only peaking in the mid to upper 40s inland, upper 40s to mid 50s in the immediate NYC area, and the lower to mid 50s in Long Island and southern Connecticut.


Saturday - Tuesday: Warming Up Again

As with the pattern we are now in, this cold spell will not last for long. An unusually strong storm will move into Alaska tomorrow, one of the strongest on record for that region, and as a part of the storm will move towards the NW US, another trough will drop into the western US, resulting in a strong ridge rebuilding in the eastern US by Sunday. Temperatures will slowly warm up during the weekend as a result, reaching the mid to upper 50s across the area on Saturday and the upper 50s to lower 60s on Sunday. With a high pressure to the south of the region keeping the rain away from the area, mostly to partly sunny skies are expected.

The ridge will remain persistent through the first half of next week, although a cold front will try to approach the area on Monday and Tuesday, bringing increased cloud cover and a risk of light rain. With a SSW wind expected, temperatures will surge into the lower to mid 60s across the area again, and if there is less cloud cover than currently expected, upper 60s may be possible in parts of the area once again, although temperatures are unlikely to pass 70 degrees at this time.


Longer Range: By the middle of next week, another storm is likely to develop towards the central US. This will keep the ridge in place through at least Wednesday, and while there is more uncertainty due to the time range, the potential is there for a cold front to move through the region during the second half of next week, potentially bringing more widespread rain. Although colder temperatures will likely return behind this cold front, they are unlikely to be cold and sustained, at least not yet.