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January Forecast Discussion


REDMK6GLI

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I will tell you what, if by the 15th of the month we haven't seen or don't start seeing a pattern more conducive for sustained cold and wintry weather on the models I think it will be time to punt winter. I am hoping there will be a turnaround for the second half of the month and going into February. February has been known to bring us some of our biggest snowstorms/blizzards so hopefully we can make up for some lost time.

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The Arctic shots since January 94 just haven't been as cold. That was the last time NYC dropped below 0.

I think the very potent +AMO pattern which developed in 1995 helped to limit the cold potential around our area.

 

Probably, if you look back at many of the outbreaks during the 80s you see -35C 850s....we really have not seen that in awhile.

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Guest Pamela

Probably, if you look back at many of the outbreaks during the 80s you see -35C 850s....we really have not seen that in awhile.

 

NYC would not actually see -35 C at 5000 feet / 850 mb or so above them...probably no worse than -25 C...the -35 C would be at the heart of the anticyclone over the N. American interior...though I realize you know this / just clarifying in case some one else might be unclear. 

Ultimately, it is rare to have the temperature at 850 mb drop to -40 C anywhere and anyplace in N. America...one probably sees such readings with greater frequency at the surface than aloft at  850 mb during the winter because really cold air is heavy and shallow.

Obviously, it does get really cold in the upper reaches of the troposphere / just below the stratosphere. 

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Probably, if you look back at many of the outbreaks during the 80s you see -35C 850s....we really have not seen that in awhile.

1982:

011112.png

011715.png

1985:

012112.png

1994:

011912.png

all had 850 temps below -25C... jan 2004 had an outbreak with temps below -25c at 850 but we had a strong gradient

011606.png

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Guest Pamela

Tuesday's wave (January 6, 2015) has some potential to produce snow around here.  The GFS always does reasonably well with progging wintertime clippers inside 120 hours. 

With 850 mb temps in the -10 C range...precip type should not be a factor...though I would watch for them to edge upwards ever so slightly in subsequent runs...as they invariably do as the actual onset of precipitation nears. 

One thing to watch for is how well the clipper handles its trip over the mountains (a fair percentage dry out)...and the precise track of the surface feature...if it stays south of NYC's latitude...expect NE winds and possibly a plowable snow event...if a surface feature intensifies and passes to our north...just expect some snow shower activity.  The latter seems likely south of central New Jersey at this point in time...especially when one considers climatological normals and mean storm tracks at this time of the year.   

The global model also hints at a follow up event towards Day 10 / Hour 240...which would be next Sunday. 

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NYC would not actually see -35 C at 5000 feet / 850 mb or so above them...probably no worse than -25 C...the -35 C would be at the heart of the anticyclone over the N. American interior...though I realize you know this / just clarifying in case some one else might be unclear. 

Ultimately, it is rare to have the temperature at 850 mb drop to -40 C anywhere and anyplace in N. America...one probably sees such readings with greater frequency at the surface than aloft at  850 mb during the winter because really cold air is heavy and shallow.

Obviously, it does get really cold in the upper reaches of the troposphere / just below the stratosphere. 

 

From what I've seen, -30 850 should be cold enough to get NYC between -5 and -10 if other factors line up right.  Don't ask me for the math to prove it, but I think -30 would be in the zone at 850.  IIRC, 850s at NYC in Jan 2004 got to about -27, with -30 passing just (just!) to the north and BOS got to -7.

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Guest Pamela

From what I've seen, -30 850 should be cold enough to get NYC between -5 and -10 if other factors line up right.  Don't ask me for the math to prove it, but I think -30 would be in the zone at 850.  IIRC, 850s at NYC in Jan 2004 got to about -27, with -30 passing just (just!) to the north and BOS got to -7.

 

-27 C is what I think is needed nowadays to drop NYC below zero...the comparison to Logan is a fair one...though on the water and subject to all types of warming from the *west* as well (being on the eastern edge of town with a prevailing westerly flow)...I'd still contend that Logan radiates a fraction better than sad LGA or KNYC...probably more in tune with JFK. 

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Guest Pamela

For those not terribly well acquainted with the NYC urban heat island effect, here is a copy 'n paste of something I wrote some time ago...
 
The Central Park Observatory, LaGuardia Airport, and Kennedy Airport are the three first-order weather stations in New York City. They are also probably the three best examples of the urban heat island effect in the United States. Reagan Airport in Washington D.C. is an extreme example of this phenomenon, but even that station takes a back seat to these three weather observatories when this topic is considered.  
The average low temperature during November at Central Park is 40.8 degrees...which is the exact same average low at Atlanta, Georgia during that time of year, despite Atlanta being at a latitude more than 480 miles to the south of NYC.  True, the Georgia capitol is almost 1000 feet higher in elevation than New York, but that shouldn't be worth more than about 3 degrees.
As for the two other stations, Kennedy Airport tends to mirror Central Park with regard to nightime minimums, while LaGuardia, believe it or not, often averages 2 degrees higher than Central Park. There have been occasions at LaGuardia Airport where, after a very hot day (upper 90's), the temperature was still in the low to mid 90's at 11:00 PM at night.  
To say that these thermal conditions are laughably unrepresentative of temperatures outside of the city is an extreme understatement.  Average monthly minimums in eastern Nassau County (on Long Island) run 4 to 6 degrees lower than in the city, and if the month is particularly anticyclonic, can range up to 7 degrees.  Average monthly minimums deviate by up to 10 degrees in interior northern New Jersey, especially in sparsely populated Sussex County.  Remember, these are average monthly minimums, not extreme minimums.  Extreme minimums for a month, particularly for a winter month when the dew point is very low, are often 20 degrees colder in northern New Jersey and 10 -12 degrees lower in eastern Nassau County.    
Perhaps the best example of the utterly extraordinary heat island that is New York City can be found in the fact that the Central Park thermometer drops to 32 degrees or below an average of only 81 days a years.  The Charlotteburg Reservoir, in a rural setting in northern New Jersey, (Passaic County) drops to or below 32 degrees an average of 149 days per year.  The Charlotteburg Reservoir is only 30 miles northwest of Central Park, although it is 628 feet higher.  
One somewhat bizzare characteristic of the weather in this region is the "north to northwest wind at Kennedy Airport during anticyclonic conditions in the afternoon phenomenon".  Kennedy Airport is a little less than 30 miles south of Westchester County Airport, Kennedy being a negligible few miles to the west of due south.  It is not unusual for the temperature to be 24 degrees at Westchester County Airport and 30 degrees at Kennedy Airport during a winter afternoon with clear skies, strong north to northwest winds at both locations, and similar snow cover.  While the wind at Westchester is coming off essentially rural terrain, the north wind at Kennedy is coming off a huge industrial area and a "concrete jungle", heating up considerably and taking into account the increase in friction, as Kennedy Airport is in the southeastern section of New York City.  Yes, Westchester Airport is about 450 feet higher than Kennedy, but that should only cause about a 1.5 degree deviation.  
LaGuardia Airport and Central Park usually check in with numbers about halfway between those two extremes during these conditions.  But Kennedy's average daytime maximums are not significantly higher than Central Park's or LaGuardia's because Kennedy is extremely close to the Atlantic Ocean, putting it well within the reach of the sea breeze, while the other two stations are somewhat removed from it.  This tends to cause a balancing out during an average year.

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-27 C is what I think is needed nowadays to drop NYC below zero...the comparison to Logan is a fair one...though on the water and subject to all types of warming from the *west* as well (being on the eastern edge of town with a prevailing westerly flow)...I'd still contend that Logan radiates a fraction better than sad LGA or KNYC...probably more in tune with JFK. 

 

Agreed, but the -7 day at BOS in 2004 was all CAA if I am not mistaken.

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Tuesday's wave (January 6, 2015) has some potential to produce snow around here.  The GFS always does reasonably well with progging wintertime clippers inside 120 hours. 

With 850 mb temps in the -10 C range...precip type should not be a factor...though I would watch for them to edge upwards ever so slightly in subsequent runs...as they invariably do as the actual onset of precipitation nears. 

One thing to watch for is how well the clipper handles its trip over the mountains (a fair percentage dry out)...and the precise track of the surface feature...if it stays south of NYC's latitude...expect NE winds and possibly a plowable snow event...if a surface feature intensifies and passes to our north...just expect some snow shower activity.  The latter seems likely south of central New Jersey at this point in time...especially when one considers climatological normals and mean storm tracks at this time of the year.   

The global model also hints at a follow up event towards Day 10 / Hour 240...which would be next Sunday. 

 

 

I think everyone right now will be happy with 1-3....I still think it may track too far north, the trof is not sharp in the East and nothing occurs our west or over ERN Canada to sharpen it so this thing being able to dig much south of SNJ is basically out of the question, hence I think a redeveloping SECS is not happening but a decent dry snow could.

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Guest Pamela

Agreed, but the -7 day at BOS in 2004 was all CAA if I am not mistaken.

 

I'd really have to consult observation records to recall many of these near zero mornings in & around the city concerning sky condition, wind speed & direction at the surface...and even snow cover.  Just too long ago with too many obscure days when I likely had other stuff on my mind...precluding them from being indelibly etched.

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Tuesday's wave (January 6, 2015) has some potential to produce snow around here.  The GFS always does reasonably well with progging wintertime clippers inside 120 hours. 

With 850 mb temps in the -10 C range...precip type should not be a factor...though I would watch for them to edge upwards ever so slightly in subsequent runs...as they invariably do as the actual onset of precipitation nears. 

One thing to watch for is how well the clipper handles its trip over the mountains (a fair percentage dry out)...and the precise track of the surface feature...if it stays south of NYC's latitude...expect NE winds and possibly a plowable snow event...if a surface feature intensifies and passes to our north...just expect some snow shower activity.  The latter seems likely south of central New Jersey at this point in time...especially when one considers climatological normals and mean storm tracks at this time of the year.   

The global model also hints at a follow up event towards Day 10 / Hour 240...which would be next Sunday. 

Pamela, potential is your key word and realistically we are 5 days out so things will change.  Remember MIT, meteorologist Edward Lorenz, whose chaos theory says small differences now can lead towards large differences in the future.  The GFS is just one model ..  The mets say they want run to run continuity with other models support.   Finally, ensemble forecasting (spaghetti plots) increase confidence in the forecast while taking into account some of the atmosphere's chaos.   Time will tell, but it would be good to finally see more than an inch of snow.  Good luck, you all..

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I will tell you what, if by the 15th of the month we haven't seen or don't start seeing a pattern more conducive for sustained cold and wintry weather on the models I think it will be time to punt winter. I am hoping there will be a turnaround for the second half of the month and going into February. February has been known to bring us some of our biggest snowstorms/blizzards so hopefully we can make up for some lost time.

http://www.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/

 

 

http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/images/summaryCFSv2.NaT2mProb.201501.gif

 

take your pick

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From what I've seen, -30 850 should be cold enough to get NYC between -5 and -10 if other factors line up right.  Don't ask me for the math to prove it, but I think -30 would be in the zone at 850.  IIRC, 850s at NYC in Jan 2004 got to about -27, with -30 passing just (just!) to the north and BOS got to -7.

 

We got totally screwed that day by the sun coming out which was not forecast...we had the snow in the morning and it was expected to be fairly cloudy most of the day, but it cleared and we reached 18 or 19, that was too much to overcome, had it stayed 13-14 as was expected we probably would have had a low of -2 to -3.

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Those look like the euro weeklies as week 3 and 4 look warm. Week 3 is probably warmer than 4 . Notice the higher heights in Alaska. That argues for a some trough near the lakes.

The jan 1 thru 10 period colder than normal departures looks like they could be 5 to 7 F below normal.

But there looks to b a 10 day break , again . There's some good model agreement on that.

I think the next question is where do we go after the 20th.

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January 1-7 is already starting a little milder than expected last week for NYC with the

weekly departure set to finish at around +2.3. We could see the coldest readings of the month

on the 8th and 9th followed by moderating temperatures after. The main culprit this week

was the models missing the strength of the SE Ridge amplification. The latest Euro weeklies

are mild for most of the month after the 8th and 9th as the SE Ridge/WAR keeps rebuilding over

the very warm SST's off the coast reinforcing the +AO pattern.

 

Link to Euro weeklies updated Jan 1,2015.

 

https://fox12weather.wordpress.com/2015/01/01/ecmwf-weekly-maps-18/

 

1-1-15.......0

1-2-15......+5

1-3-15.....+2

1-4-15.....+16

1-5-16.....+2

1-6-15.....-4

1-7-15.....-5

When I saw that week 4 last night and I saw that Neg EPO

I said man if this was last winter that trough would be deeper in the east.

That pattern worked great last year and whenever it popped up on the JMA weeklies we just knew it would push the pattern around.

Now I look at it and the fact that this model at week 4 blows and how bad we have been this winter I just assume the SE ridge would find a way to push this pattern around.

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I hope things end up mild as things continue to look bleak. Why shiver when the pattern is awful I look forward to spring like conditions and if the weeklies are correct it'll feel that way soon.

Now the question will be if we can set some record low snowfall records around here this winter.

 

Won't happen....I think we're mostly -EPO and eventually +PNA the rest of the way, and the AO is bound to go negative eventually...even if the MJO does not reach 7 and 8 which it may not my initial thoughts that we'd go cold after the 20th through March may end up correct for the wrong reason...I think we just need to avoid another high amplitude MJO wave through 4-6.  If it does into the COD here we should be fine, not as good as if it went into 7-8-1 but still good...I'm not sure why DT is so negative on things if it fails to go into 7-8-1 because COD at this point will work.

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Below normal December snowfall like we just had following a 50 inch or greater NYC seasonal  snowfall since 1990

favors a below normal snowfall season in NYC. 

 

93-94.......53.4

Dec 94...T.........94-95 season......11.8

 

95-96......75.6

Dec 96....T.......96-97  season......10.0

 

10-11.....61.9

Dec 11....0........11-12 season.......7.4

 

13-14......57.4

Dec 14....1.......14-15 season........?

 

 

Honorable mention to 2004.  Not saying this is what I am thinking at this point, I actually always liked the 94/95 analog but think we will double that season's total but 04/05 certainly a heck of a turn around from Jan 15 - March.

 

2003/2004 : 42/6

Dec 04 - trace     04/05 season : 41.0

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I think normal is going to be difficult given the SST pattern with near record warmth off the East Coast and

the cold pool NE favoring a mostly +AO pattern. This regime favors a strong SE Ridge/WAR with amplified

storms cutting right through the end of January. Trying to get back to normal with below normal December

and January snowfall is a tough task.

How do we know January will finish below normal though? Its January 2nd, its impossible to tell how this entire month shakes out.

A really crappy month with a snowstorm on the 29th can put the month above average.

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