NYC/Tri-State Area OBS and Disco

[NorthShoreWx]

NYC's lows dont count

44 here at 6am

They sure do count. Average NYC low is 39. Thats 13 above normal for this morning's low. Its not like there are lots of radiational cooling lows in that 39 average.

61 in the park at 3PM is also 10 degrees above the average daily high.

Today's NYC departure is > 10 degrees on both ends.

[Analog96]

They sure do count. Average NYC low is 39. Thats 13 above normal for this morning's low. Its not like there are lots of radiational cooling lows in that 39 average.

61 in the park at 3PM is also 10 degrees above the average daily high.

Today's departure is > 10 degrees on both ends.

Yeah but you can't really compare lows, because they vary too much. For example, the high temperature at MMU is probably a degree or two different for highs and like 10 degrees colder for lows. And besides, your argument will get totally destroyed tonight, because NYC will be lower than 52 before midnignt anyway.

[NorthShoreWx]

Let's leave low temperatures out of the equation, because they are too variable. My low was 47 and I live in an urban location. If you want to play the low game, NYC probably gets below 52 before midnight tonight anyway.

Disagree. During most nights with a wide range between city and surburbs, the central park temperature is within a couple of degrees of the temperature just over the suburban surface inversion (say ~300 feet as on the tower at OKX). I think the NYC low is the best way to compare lows to average because they vary so little.

[Analog96]

Disagree. During most nights with a wide range between city and surburbs, the central park temperature is within a couple of degrees of the temperature just over the suburban surface inversion (say ~300 feet as on the tower at OKX). I think the NYC low is the best way to compare lows to average because they vary so little.

Did you really just write this and realize what you wrote? I live in Elizabeth, NJ. We have 130,000 people and are 2 mi from EWR. On good radiative nights, I can be 10F colder than Central Park.

[NorthShoreWx]

Did you really just write this and realize what you wrote? I live in Elizabeth, NJ. We have 130,000 people and are 2 mi from EWR. On good radiative nights, I can be 10F colder than Central Park.

So you're saying today is an average day with respect to normal?

[green tube]

anyone care to make a prediction for thursday night's jets game at the meadowlands?

i'm talking about a weather prediction.... not a final score.

models have been trending drier.

[NYCSuburbs]

Please correct me if I'm wrong, but I think what we're seeing for Thursday looks a little like a CAD set up, right? A storm moving into the region with a small area of cool 850 mb temperatures moving from PA into N NJ/NYC along with the front end of the storm and dew points potentially over 10 degrees colder than the actual temperatures could lead to evaporative cooling, and if the precipitation is heavy enough, a wintry mix is possible west of NYC in the late morning to the early afternoon hours on Thursday before a changeover to rain. Looking at the models, it looks like a lack of precipitation could be a problem, but the models also showed barely 0.1" of precip with the November 8 storm and the NYC area still saw a light wintry mix.

[CooL]

Please correct me if I'm wrong, but I think what we're seeing for Thursday looks a little like a CAD set up, right? A storm moving into the region with a small area of cool 850 mb temperatures moving from PA into N NJ/NYC along with the front end of the storm and dew points potentially over 10 degrees colder than the actual temperatures could lead to evaporative cooling, and if the precipitation is heavy enough, a wintry mix is possible west of NYC in the late morning to the early afternoon hours on Thursday before a changeover to rain. Looking at the models, it looks like a lack of precipitation could be a problem, but the models also showed barely 0.1" of precip with the November 8 storm and the NYC area still saw a light wintry mix.

Yup, you are right. Its definately a potential sleet setup for areas to the west of NYC, as earthlight has noted yesterday. Will be interesting if we see some wintry precip again before November turns the corner.

[MJO812]

Point and click forecast has drizzle and flurries for Thursday morning.

[Alpha5]

Disagree. During most nights with a wide range between city and surburbs, the central park temperature is within a couple of degrees of the temperature just over the suburban surface inversion (say ~300 feet as on the tower at OKX). I think the NYC low is the best way to compare lows to average because they vary so little.

Wrong....lows cover a much larger spectrum on any given night than highs do. UHI is part of the problem, highs are much more reliable, UHI has a lesser effect on these values.

Did you really just write this and realize what you wrote? I live in Elizabeth, NJ. We have 130,000 people and are 2 mi from EWR. On good radiative nights, I can be 10F colder than Central Park.

Same here

[NYCSuburbs]

Same here

I live somewhere around 10-12 miles north of Central Park, and it also tends to get much colder here than in NYC in clear nights. As you said, UHI seems to have more of an effect on overnight lows than daytime highs.

[snowman21]

Wrong....lows cover a much larger spectrum on any given night than highs do. UHI is part of the problem, highs are much more reliable, UHI has a lesser effect on these values.

Same here

I agree that lows have a much larger spatial variation, but in this case we are talking about specific stations that haven't moved a whole lot in the past 50 years. For example, LGA, JFK, and EWR have all been where they are for quite some time.

STATION  NORMALS  NORMLOW
--------------------------------
KEWR  	1941-1970    36
KEWR  	1951-1980    37
KEWR  	1961-1990    37
KEWR  	1971-2000    37

KLGA  	1941-1970    39
KLGA  	1951-1980    39
KLGA  	1961-1990    39
KLGA  	1971-2000    39

KJFK  	1941-1970    37
KJFK  	1951-1980    37
KJFK  	1961-1990    38
KJFK  	1971-2000    38

KNYC  	1941-1970    38
KNYC  	1951-1980    38
KNYC  	1961-1990    39
KNYC  	1971-2000    39

Based on this normal lows haven't moved a whole lot. Now of course this could be explained by different measuring techniques, normals computation methods, etc., but when did UHI became a real huge impact on lows? Ten years ago? 25? I'd suspect when the new normals come out we'd see some sort of reflection as there is clearly an upward trend, albeit a slight one, in the published normals over the past half century.

[tmagan]

Point and click forecast has drizzle and flurries for Thursday morning.

I've mentioned on the other board that I hate the point and click forecasts.

Edit: Just looked at the text ZFP. It says the same thing amazingly.

[snowman21]

I've mentioned on the other board that I hate the point and click forecasts.

Edit: Just looked at the text ZFP. It says the same thing amazingly.

Well considering the ZFP is the same forecast as the point and click you shouldn't be surprised. They're just different formats of the same forecast.

[tmagan]

Well considering the ZFP is the same forecast as the point and click you shouldn't be surprised. They're just different formats of the same forecast.

They can sometimes be different. It seems hard to believe that we could have flurries on Thanksgiving morning in NYC.

[hudsonvalley21]

Point and click forecast has drizzle and flurries for Thursday morning.

Same thing up here to your north.

[NorthShoreWx]

Wrong....lows cover a much larger spectrum on any given night than highs do. UHI is part of the problem, highs are much more reliable, UHI has a lesser effect on these values.

Same here

I said that NYC lows are relevent to determining whether an air mass is warmer or cooler than normal...much more so than lows in the burbs and are as relevant as daytime highs (which can be affected by things like cloud cover, wind direction, etc.). UHI has given us the gift of having a sea level location to look at that is reflective of the temps higher in the column. If its 50 at night in Manhattan and 25 at FOK with a light SE wind, it is not going to snow at FOK in this airmass...50 is more representative of what you get when you mix out.

Check out the tower temps from OKX on a good radiational cooling night when the pine barrens is an icebox. I'll bet the 88 meter temp is within a couple degrees of central park:

http://wx1.bnl.gov/w...item=temp_tower

NYC low temps vary more directly with the temperature of the airmass overhead (as compared to your sliver of colder air on a clear calm night). Radiational cooling outside of the city is more a function of how dry the air is assuming calm winds. It never ceases to amaze me how so many on a "weather" board fail to recognize how thin and fragile that inversion is on calm nights.

Now what were we talking about...oh yeah, the NYC mean temp today was 11.5 degress above the norm for the date. Its beyond me how the fact that West Bumphart, New Jersey radiates better than Manhattan changes the fact that today was way above normal. But if you can convince me that it does, I'm all ears.

I'm going to hang in the SNE thread for a while. Heavy heavy meteorology there.

[Analog96]

So you're saying today is an average day with respect to normal?

I don't think you can read very well, I'm sorry.

[NorthShoreWx]

I don't think you can read very well, I'm sorry.

I read very well. Another posters contention, which you supported, was that NYCs low temperatures this morning were of no relevance to calling todays weather abnormally warm. My contention was that they were relevant and I gave my reasons. You have replied directly to me twice, both times with insults rather than discussion of the topic.

[nzucker]

I read very well. Another posters contention, which you supported, was that NYCs low temperatures this morning were of no relevance to calling todays weather abnormally warm. My contention was that they were relevant and I gave my reasons. You have replied directly to me twice, both times with insults rather than discussion of the topic.

NYC's lows matter just as much as the high. Urban heat island for the city hasn't changed much at all in the last 50 years...sure, the N and NW winds do flow over developed areas now as opposed to rural ones forty years ago, but the actual city space is the same. I'd guess lows in places like western LI have seen much bigger changes since 1960 than Central Park. Since we're comparing against a 1971-2000 average in which most of the urbanization had already taken place, the lows are important. I completely agree with you.

[Alpha5]

40.1 here and mostly cloudy with a brisk north wind

Upton says were going down to 25 tonight

[rgwp96]

You are correct.

only problem is nyc lows are so screwed up because of the heat island effect that it doesnt represent the surrounding areas.   What has their low been so far this season?  I know for a fact a few rural areas have been as low as 15 already.   

[NorthShoreWx]

only problem is nyc lows are so screwed up because of the heat island effect that it doesnt represent the surrounding areas. What has their low been so far this season? I know for a fact a few rural areas have been as low as 15 already.

Screwed up might not be the best way to describe NYC low temperatures (its the urban microclimate that is screwed up) but I agree that they are not representative of lows outside of the urban areas. Actually, that is probably a given in most cities.

[blazess556]

Beautiful day. Not a cloud in the sky. A little windy but temp is up to 49

[NYCSuburbs]

Today is very chilly in comparison to yesterday, only 49 here. Upton is now showing rain for all of their area for tomorrow, though I think they should add snow/sleet to at least places west of NYC in their next update, even the 12z NAM is showing frozen precipitation in NW NJ and as far east as NE NJ. Mt. Holly is already showing light accumulations in NW NJ up to 1/2 inch.

[blazess556]

Dewpoints are really low. Temps will plummet once the sun goes down if we can stay clear tonight.

[earthlight]

12z NAM probably starts as snow 21z Thursday in areas away from the city. Here's the 21z sounding for KMMU (Morristown, NJ)

[earthlight]

Associated precipitation at that time frame

http://www.meteo.psu.edu/~gadomski/ETAPA_12z/f33.gif

[earthlight]

On that note, the 18z NAM is a few degrees warmer throughout the entire column. So go figure, I guess...we will see.

[NYCSuburbs]

On that note, the 18z NAM is a few degrees warmer throughout the entire column. So go figure, I guess...we will see.

It seems to mainly depend on the timing on the NAM. The 12z run was faster, bringing the precipitation in by 18z-21z Thursday, which allowed for frozen precip to fall west of NYC, but the 18z run is slower once again, which leads to warmer temperatures further east, and it keeps the rain from falling until after 21z, which would be too late for snow/sleet to fall. I did notice though that the NAM is too slow with the timing even as of now, as it seems to keep most of the rain in Indiana at 21z today when the heaviest rain is already in Ohio, and the NAM tended to have a slow bias with previous storms. It will be interesting to see whether the faster or slower solution verifies.