NAM Model showing weak high pressure keeping the weather fair on Tuesday.

A ridge of high pressure in the mid levels of the atmosphere is building in this morning, and will continue to do so throughout the day on Tuesday. The result will be pleasant weather, with clear skies and high temperatures in the low 60's. Winds will be out of the northwest behind a weak cold front that passed the area late Monday Night into Tuesday morning. The winds could be a bit breezy and gusty, mostly during the afternoon. It's a result of what is technically called "cold air advection" or "CAA". Behind a cold front, northwest or west winds usher in a new and cooler airmass, and the advection of this air behind a temperature boundary can often bring some moderate wind gusts. Tuesday will be no different. Low temperatures overnight Tuesday Night into early Wednesday Morning will likely dip into the middle 40's once again, as clear skies and light winds will allow for favorable radiational cooling conditions. However, by early Wednesday morning (possibly even the pre-dawn hours) clouds will begin to increase, owing to a system developing to the west of our area. This system looks to provide a very complicated scenario during the second half of the week. Keep reading for all of the details.

THE FORECAST...
Today (Tuesday): Mostly sunny, with a high near 64. Northwest winds 10 to 15 mph.
Tonight: Partly cloudy, with increasing clouds late. Low near 48. Northwest winds 5 to 10 mph.

LATE WEEK EVENT COULD PROVE TROUBLESOME (AND CHILLY):

NAM Model showing potential for some frozen precip in the interior Thursday evening. Notice the surface temps in the 30's(left) and moderate precip (right) Also notice warmer temps near the coast & city.

 The pleasant weather of the beginning of the week will become somewhat of a distant memory as we approach Wednesday, and continue through Thursday. A strong gradient in the mid levels of the atmosphere will develop across the Northeast by the end of the week, and the gradient will eventually extend down towards the surface in the form of a well defined frontal boundary, which will settle near the area by Thursday morning. This frontal boundary will serve as a "highway" for low pressure and moderate to heavy precipitation to develop at the surface, as a strong disturbance moves over the boundary in the mid and upper levels of the atmosphere. Such a development would most certainly bring a threat of moderate to heavy precipitation to the forecast area, beginning on Thursday and continuing through Thursday evening. 


Making the situation more complicated is the intrusion of significant cold air which is expected behind the cold front. This will bring colder temperatures into the system on Thursday, and the potential would exist for some frozen precipitation (yes, we're serious) in the higher elevations and the distant interior. Such an event would be isolated and likely confined to the higher elevations, but it's definitely worth mentioning. To be clear, we aren't expecting anything frozen in the city or immediate suburbs, but if you live in Northwest NJ or the higher elevations of Connecticut or Southeast New York, you may want to keep a very close eye on this system for the potential for snow as the system winds down Thursday Night. 


Either way, behind the front, we're expecting some of the coldest air so far this fall. This weekend looks to provide more dramatics, as the boundary settles offshore. Forecast models are beginning to hint at the potential for a nor'easter developing along the front on Saturday. We'll keep you updated during the week as we get a better idea of what's going to transpire.


Article written by JH. Published October 25th, 2011 at 12:04am. Looking for a forecast? See New York Metro Weather's Long Range Forecast for the upcoming work week, or view our Technical Forecast Discussion for the more serious weather enthusiasts. Also, check out our new Forecast Overview tab. For up to the minute details on forecasts, watches, warnings, and alerts, follow us on Twitter and Facebook.  

Summer 2011 average temperature (through August 31st)

We love summer, there's no denying it. So it's with heavy hearts that we had to compile the recap of this past summer, as we begin the transition in to fall. Don't worry, we actually love all seasons, but it's definitely harder to let go of the beautiful weather which summer often has to offer. This summer was no different.  As we take a look back, we'll begin to see that it was essentially a summer of two tales, and the last month of the summer became quite anomalous. In fact, much of the summers precipitation was recorded in August and September. The last week of June (when summer begins) into roughly the middle to end of July was not exactly a drought, but definitely featured most of the summers hot days and a general lack of heavy precipitation. Our area observed multiple 100 degree days in July, including one record breaking day on July 22, which saw Newark, NJ set it's all time record high temperature at 108 scorching degrees. Before we continue, we most note that these numbers are not final and do not include the 19 days of September, which technically will factor into the final summer departures and averages. 

TEMPERATURES...

Departure from average temperature (through Aug 31)

To cut straight to the good stuff, Summer 2011 was another above average summer, marking the second in a row since the absolute scorcher that was the Summer of 2010. Average temperatures through August 31st were over 76 degrees in the New York City Metro area. The summer of 2010, for comparison purposes, offered very similar average temperatures, but these high averages were more spread out across the entire Northeast. This summer, there was a sharp gradient over the interior and areas to the North and West. In fact, to our north over New England, average temperatures were nearly 10 degrees cooler.

Temperature departures this summer were generally 2 to 3 degrees above normal throughout the entire area. There were several factors that lead to this--but essentially, the warm start of the summer had our area at nearly 5 degrees above normal as we entered August. However, the relatively average and somewhat cooler month of August knocked down the above average departures to more mediocre levels. In fact, areas of Northwest New Jersey and Southeast New York saw temperature departures of 1 to 2 degrees below average during the month of August, after experiencing a scorching hot July with the rest of us.

Overall, this summer featured temperatures moderately above average, but nearly 2 degrees "cooler above average" than the summer of 2010. On the opposite end of the spectrum, the summer of 2009 ended with temperatures 1 to 3 degrees below average. It has been a tale of three completely different summers over the last three years in our area for sure.

PRECIPITATION...


With the ridge of high pressure built in, providing the historic levels of heat (we mentioned the 105+ degree numbers earlier) and above average temperature departures early in the summer, also came a drier than normal month of July throughout the area. It almost comes with the territory, when you're talking about multiple 100 degree days. As our area began to head into August, precipitation departures were nearly 3 to 5 inches below normal across much of the forecast area. Essentially, the persistent ridge of hot weather and high pressure which was built in over the Central Plains (we are sure you have heard of the historic heat this summer brought them) was flexing it's muscles during the first half of the summer across our area, leaving us generally drier and warmer than normal. Most of our precipitation through August 1st came in the form of scattered showers and thunderstorms, and the occasional extended period of rain along a warm front.

None of us, however, could have seen August coming. In what would become the wettest month in recorded history at New York City, we not only erased the negative precipitation departures, but posted major gains. Our area received over 300 percent of our normal precipitation in the month of August, and we ended the summer with a departure of +10 inches from normal precipitation. Areas near Northwest New Jersey received nearly 15 inches of normal precipitation over the summer. The pattern change from the first half to the second half of the summer in regards to precipitation was truly amazing (and historic) to watch unfold.

WHAT CAN 100 DEGREE DAYS TELL US ABOUT WINTER?

NYC snowfall after multiple 100 degree days in previous summer Credit: Yehuda Hyman

Meteorology is not only about learning from the past events, but also looking to the future. So, you may be asking yourself: what can we learn from summer, that may help us get an idea as to what the winter has to offer? The answer, really, is that the summer can more often than not be a toss up when it comes to being of direct relation to winter forecasting. Much more answers lie in the autumn season, as the pattern begins to change, and we begin to get an idea of the atmospheric transitions which are occurring (see our sea ice level post from this evening). Still, with this being the second summer of multiple 100+ degree days in New York City, we pulled out the statistics for snowfalls after such events in the summer. Having multliple 100 degree days is a rare enough event in New York City itself that we haven't seen it in back to back years since 1953. The last time we saw it, prior to last summer, was 1999, and that winter offered less than 20 inches of snowfall.

However, if the winter of 2010 has anything to say about what's to come, we may be in for another long winter. Additionally, the average snowfall after the previous summer featured multiple 100+ degree says is over 30 inches, higher than the normal average snowfall. So, there may be some argument over time that summer which feature these heating days may be foreshadowing an above average winter. The truth is, we don't truly know what to expect at this point. The spread is too large among the data we've compiled. We'll just have to watch carefully over the next several weeks as we head into autumn, as father time begins to transition us into another one of the four seasons we have the privilege of experiencing in our area.


Article written by John Homenuk, with contributions from Yehuda Hyman. Published September 19th, 2011 at 11:37pm. Looking for a forecast? See New York Metro Weather's Long Range Forecast for current work week, or view our Technical Forecast Discussion for the more serious weather enthusiasts. Also, check out our new Forecast Overview tab. For up to the minute details on forecasts, watches, warnings, and alerts, follow us on Twitter and Facebook.