bluewave Posted October 18, 2014 Share Posted October 18, 2014 ........ Link to comment Share on other sites More sharing options...
Sundog Posted October 18, 2014 Share Posted October 18, 2014 That record last January fell on the warmest record low of the month. It was a fluke that the previous record was so warm for January standards. Link to comment Share on other sites More sharing options...
HailMan06 Posted October 19, 2014 Share Posted October 19, 2014 Possibly increased periods of blocking for the month. Link to comment Share on other sites More sharing options...
uncle W Posted October 19, 2014 Share Posted October 19, 2014 since the 1900's January hasn't warmed much...the 1930's and 1990's were the warmest decades...not counting the 1800's the 1920's and 1970's were the coldest...the 1931-60 January normal was 33.2...the 1970's brought that average down a lot...the 1961-90 normal was near 31.5... January decade average... 1870's...30.3 1880's...28.7 1890's...31.7 1900's...32.1 1910's...32.4 1920's...30.5 1930's...34.7 1940's...31.0 1950's...33.7 1960's...31.8 1970's...30.6 1980's...31.3 1990's...34.8 2000's...33.1 2010's...32.6 Link to comment Share on other sites More sharing options...
uncle W Posted October 19, 2014 Share Posted October 19, 2014 the 1990's is the warmest December decade...I think the ever growing heat island is moderating early cold but I'm guessing... December decade averages... 1870's...32.7 1880's...33.6 1890's...35.9 1900's...34.8 1910's...34.1 1920's...35.5 1930's...35.9 1940's...35.4 1950's...36.8 1960's...34.8 1970's...37.4 1980's...36.6 1990's...39.5 2000's...37.7 2010's...39.2 Link to comment Share on other sites More sharing options...
JBG Posted October 19, 2014 Share Posted October 19, 2014 Perhaps the fact that the "cold phase" we're in is relatively new. Cold phases favor cold Decembers. Februaries don't have the same pat explanation but some of the February records, such as -15 in 1934 are probably not going to be beaten. Ditto many of the records in that exceptional cold wave that ended 1917 and started 1918. Perhaps the extreme depths of some of those fluke events explain the overall difficulty in piercing records. Link to comment Share on other sites More sharing options...
uncle W Posted October 19, 2014 Share Posted October 19, 2014 February's warmest decade is 1990 also... 1870's...30.6 1880's...30.5 1890's...31.9 1900's...29.4 1910's...30.4 1920's...32.1 1930's...32.5 1940's...32.6 1950's...35.1 1960's...32.6 1970's...32.6 1980's...35.4 1990's...36.3 2000's...35.2 2010's...35.1 Link to comment Share on other sites More sharing options...
NEG NAO Posted October 19, 2014 Share Posted October 19, 2014 Plain and simple folks - January is the coldest month of the year in most areas of the Northern Hemisphere because the sun angle is at its lowest during the month as a whole. In addition, there is no sun at all above the Arctic Circle and does not allow for any warmth from the sun at all. Hence, it gets colder and colder there. Now, these airmasses regularly come down into our regions of the U.S. and bring with them colder and colder temperatures. Link to comment Share on other sites More sharing options...
GaWx Posted October 19, 2014 Share Posted October 19, 2014 I'm assuming that a good portion of this warming (say, ~35-40%) has been due to the increased heat island effect from a much larger city as opposed to global warming, which has warmed the planet only ~2 F since the late 1800's. DJF have warmed ~3.2 F/century in NYC. Opinions? Link to comment Share on other sites More sharing options...
GaWx Posted October 19, 2014 Share Posted October 19, 2014 For comparison, ATL has had a similar pattern. If I compare 1981-2010 to 1879-1940, Feb. is a whopping 1.6 F warmer while Dec. is only 0.7 warmer and Jan. is unchanged! Link to comment Share on other sites More sharing options...
Absolute Humidity Posted October 19, 2014 Share Posted October 19, 2014 I'm assuming that a good portion of this warming (say, ~35-40%) has been due to the increased heat island effect from a much larger city as opposed to global warming, which has warmed the planet only ~2 F since the late 1800's. DJF have warmed ~3.2 F/century in NYC. Opinions? Definitely heat island, there's so much more concrete and asphalt sprawl over the area since the 1800's. Also, I wouldn't be surprised to see if NYC's snowfall is relatively unchanged since then either due to UHI having little effect during storms. Generally NYC's temps remain the same outside the UHI when it's snowing, although during marginal temp events and spring time April events snow typically falls as white rain, even in the park where grassy accumulations may occur but usually less than areas outside of the UHI. I'm sure Uncle has these stats readily available. Hope he can comment soon. Link to comment Share on other sites More sharing options...
Sundog Posted October 19, 2014 Share Posted October 19, 2014 The problem with the UHI argument is rural stations that have remained largely unchanged also have this pattern of warming. The Adirondacks are a famous example. Link to comment Share on other sites More sharing options...
GaWx Posted October 19, 2014 Share Posted October 19, 2014 The problem with the UHI argument is rural stations that have remained largely unchanged also have this pattern of warming. The Adirondacks are a famous example. I think going with it being a combo of GW and UHI makes the most sense. I think that the fact that NYC's and ATL's DJF warming have had similar patterns is a sign of GW. However, the fact that NYC's DJF warming overall has been about quadruple the ATL warming is a sign that there is a sig. UHI effect involved, too. Also, ATL having moved to the airport along with the huge growth at the airport tells me that the UHI type of effect is a sig. portion of ATL's warming. I see it every radiational cooling type of night. It cools horribly on those nights. I could see the majority of warming there possibly being UHI related. What's fascinating is the net zero change at ATL in Jan. Actually, Jan had cooled about 1F between the 1879-1940 and 1961-90 periods before warming back up to where it was. Link to comment Share on other sites More sharing options...
PB GFI Posted October 19, 2014 Share Posted October 19, 2014 That's correct. The Blue Hill Observatory in the more rural Milton ,MA has the exact same pattern. ............Dec.....Jan......Feb.....temperature change per century NYC....+3.3.....+0.9....+5.5 MQE....+3.7.....+1.3....+5.2 Screen shot 2014-10-19 at 8.08.37 AM.png Screen shot 2014-10-19 at 8.08.58 AM.png Screen shot 2014-10-19 at 8.09.18 AM.png GreatBlueHill_aerial.jpg Since Feb is Historically our snowiest month I would assume snow cover would mute day time temps , so the difference could be found there. Link to comment Share on other sites More sharing options...
Stormlover74 Posted October 19, 2014 Share Posted October 19, 2014 Since Feb is Historically our snowiest month I would assume snow cover would mute day time temps , so the difference could be found there. So why is Feb warming so much more than January? Link to comment Share on other sites More sharing options...
Isotherm Posted October 19, 2014 Share Posted October 19, 2014 Since January is the coldest month climatologically speaking, and the Canadian airmasses tend to reach their coldest magnitude at this time of year -- this is what's required to push the urbanized locales well below normal (on average). Airmasses in December and February generally haven't been bitter enough to really balance out the averages for NYC. Their heat island necessitates colder airmasses (airmasses that 60+ years ago would've produced lower temperatues). January is the month one would expect to produce the coldest airmasses relative to normal. Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 19, 2014 Share Posted October 19, 2014 Autumn has had an anomalously extended nature to it for years; this has lingered well into December as the initial cold Canadian surges are always slow to reach the East Coast...having to contend with the warm, open Great Lakes & the Appalachians. I would figure that any tempering of the severity of winter would first be felt on the margins, i.e. December, February, & March...January, the veritable heart of the cold season...sees the least change. Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 19, 2014 Share Posted October 19, 2014 Since January is the coldest month climatologically speaking, and the Canadian airmasses tend to reach their coldest magnitude at this time of year -- this is what's required to push the urbanized locales well below normal (on average). Airmasses in December and February generally haven't been bitter enough to really balance out the averages for NYC. Their heat island necessitates colder airmasses (airmasses that 60+ years ago would've produced lower temperatues). January is the month one would expect to produce the coldest airmasses relative to normal. Bear in mind, there was a time when February was a slightly colder month than January in NYC...this has changed over the passage of time. Link to comment Share on other sites More sharing options...
Isotherm Posted October 19, 2014 Share Posted October 19, 2014 Now, there is a warming component that's certainly been occurring on a more globally averaged level (skewed toward the north pole in particular), but this long term warming trend has generally not significantly impacted USA temperatures as of yet, as one would anticipate for mid latitude locations. Overall, there has been a very slight warming in the US since 1973 when we adjust for population density. Link to comment Share on other sites More sharing options...
Isotherm Posted October 19, 2014 Share Posted October 19, 2014 Bear in mind, there was a time when February was a slightly colder month than January in NYC...this has changed over the passage of time. That time must have been hundreds of years ago. Comparing NYC to Bar Harbor's current climate -- located adjacent to the ocean, their Jan average temp is 23F while Feb's average temp is 26F. If our climate 200 years ago was similar to the climate of coastal Maine (for example), you'd think we'd see that reflected in present day Maine numbers. http://www.weather.com/weather/wxclimatology/monthly/USME0018 Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 19, 2014 Share Posted October 19, 2014 That time must have been hundreds of years ago. Comparing NYC to Bar Harbor's current climate -- located adjacent to the ocean, their Jan average temp is 23F while Feb's average temp is 26F. If our climate 200 years ago was similar to the climate of coastal Maine (for example), you'd think we'd see that reflected in present day Maine numbers. http://www.weather.com/weather/wxclimatology/monthly/USME0018 Bear in mind, there was a time when February was a slightly colder month than January in NYC...this has changed over the passage of time. January decade average / NYC 1870's...30.3 1880's...28.7 1890's...31.7 1900's...32.1 1910's...32.4 1920's...30.5 1930's...34.7 January Mean 1870-1939: 31.49 February decade average / NYC 1870's...30.6 1880's...30.5 1890's...31.9 1900's...29.4 1910's...30.4 1920's...32.1 1930's...32.5 February Mean 1870-1939: 31.06 Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 19, 2014 Share Posted October 19, 2014 That time must have been hundreds of years ago. Comparing NYC to Bar Harbor's current climate -- located adjacent to the ocean, their Jan average temp is 23F while Feb's average temp is 26F. If our climate 200 years ago was similar to the climate of coastal Maine (for example), you'd think we'd see that reflected in present day Maine numbers. http://www.weather.com/weather/wxclimatology/monthly/USME0018 Even at the height of the LIA...I doubt NYC weather was really (I mean for a prolonged (10 years +) period) similar to coastal Maine...NYC probably had a climate similar to modern day Logan Airport in Boston...maybe like Portsmouth, NH...at its absolute worst. Link to comment Share on other sites More sharing options...
GaWx Posted October 19, 2014 Share Posted October 19, 2014 January decade average / NYC 1870's...30.3 1880's...28.7 1890's...31.7 1900's...32.1 1910's...32.4 1920's...30.5 1930's...34.7 January Mean 1870-1939: 31.49 February decade average / NYC 1870's...30.6 1880's...30.5 1890's...31.9 1900's...29.4 1910's...30.4 1920's...32.1 1930's...32.5 February Mean 1870-1939: 31.06 That's interesting that the 1900's and 1910's at NYC were both the warmest for Jan. and coldest for Feb. of the decades that span the 1870's-1920's. Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 19, 2014 Share Posted October 19, 2014 Places like Nantucket Island also show this effect, i.e. February not only being the snowiest month, but also the coldest...as the maritime influence and the cooling of the surrounding waters has a very pronounced impact on air temperatures. Link to comment Share on other sites More sharing options...
GaWx Posted October 19, 2014 Share Posted October 19, 2014 That's interesting that the 1900's and 1910's at NYC were both the warmest for Jan. and coldest for Feb. of the decades that span the 1870's-1920's. I found a very similar pattern at Atlanta vs. NYC for Jan vs. Feb. when comparing 1900-1919 to the 1879-1899/1920-29 periods. Interesting stuff! Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 19, 2014 Share Posted October 19, 2014 I found a very similar pattern at Atlanta vs. NYC for Jan vs. Feb. when comparing 1900-1919 to the 1879-1899/1920-29 periods. Interesting stuff! I'd blame it on Sherman... Link to comment Share on other sites More sharing options...
Isotherm Posted October 19, 2014 Share Posted October 19, 2014 January decade average / NYC 1870's...30.3 1880's...28.7 1890's...31.7 1900's...32.1 1910's...32.4 1920's...30.5 1930's...34.7 January Mean 1870-1939: 31.49 February decade average / NYC 1870's...30.6 1880's...30.5 1890's...31.9 1900's...29.4 1910's...30.4 1920's...32.1 1930's...32.5 February Mean 1870-1939: 31.06 Good stuff, didn't realize this. It's interesting that the decades in which NYC's Feb mean temp was colder than Jan occurred w/in the bounds of a relative solar minimum (very weak cycles from late 1800s-early 1900s, akin to cycle 24 right now). The current climate probably wouldn't produce a similar result, but I'm wondering if the decreased solar constant during the 1890-1910 period had a role in inducing colder Februaries. Link to comment Share on other sites More sharing options...
Isotherm Posted October 19, 2014 Share Posted October 19, 2014 I found a very similar pattern at Atlanta vs. NYC for Jan vs. Feb. when comparing 1900-1919 to the 1879-1899/1920-29 periods. Interesting stuff! Given that variation holds true for ATL, a location well inland, that raises my suspicion regarding the very weak solar cycles of 1890-1910 influencing winter time temperatures. Link to comment Share on other sites More sharing options...
Guest Pamela Posted October 19, 2014 Share Posted October 19, 2014 Good stuff, didn't realize this. It's interesting that the decades in which NYC's Feb mean temp was colder than Jan occurred w/in the bounds of a relative solar minimum (very weak cycles from late 1800s-early 1900s, akin to cycle 24 right now). The current climate probably wouldn't produce a similar result, but I'm wondering if the decreased solar constant during the 1890-1910 period had a role in inducing colder Februaries. One would have to analyze quite a bit of climatological data to reach any determinative conclusions on your theory...at multiple stations. Link to comment Share on other sites More sharing options...
uncle W Posted October 19, 2014 Share Posted October 19, 2014 from 1959-60 to 2013-14 the coldest month was... Dec Jan Feb Mar ...5...32...17...1..... 1869-70 to 1909-10... ...3...22...13...2... during the 1910's February was coldest seven times while January was three times... March was the coldest twice in the 40 years...December three times...The last 55 years December was the coldest five times and January 32...February had 17 while March just once...1960... Link to comment Share on other sites More sharing options...
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