The U.S. and European cold blast: blame the NAO

By: Dr. Jeff Masters , 4:00 PM GMT on January 07, 2010

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The Deep South shivered through another frigid morning today, with low temperature records crumbling again over much of Florida. Lakeland hit 27°F, smashing the old record of 34°F; Melbourne hit 28°F, eclipsing the old record of 32°F; and West Palm Beach bottomed out at 37°F, besting the old record of 38°F. The cold wave is being driven by an unusual sharp and persistent kink in the jet stream that is being blocked from moving by a strong ridge of high pressure over Greenland. As a result, an exceptionally strong surface high pressure of 1055 mb over the North Central U.S. is pushing large amounts of cold, Arctic air southwards from Canada. No coldest January temperature records have been set yet from the cold blast, but the 500 largest U.S. cities have been averaging about 11 new daily low temperature records per day the first five days of January, according to the National Climatic Data Center. The cold will ease Friday in the Deep South, but return with a vengeance Saturday night though Monday morning, as another push of cold air descending from Canada promises to bring a cold wave that will approach the December 1989 and January 1977 cold waves in intensity, and may being some new all-time January low temperature records to the South.

Colder in Florida than Alaska and Greenland
The sharp kink in the jet stream has brought record warm temperatures to a few stations in Alaska and the Pacific Northwest this week, making much of coastal Alaska warmer than Florida. Cold Bay, Alaska, set a record high yesterday of 47°F, after recording a low temperature of 30°F. This made Cold Bay warmer than Pensacola, Florida, which had a high of 47°F and a low of 24°F. In fact, most of Florida--including Jacksonville, Tampa, Melbourne, and Tallahassee--recorded lows at or below the 27°F low recorded in Anchorage, Alaska yesterday. The jet stream kink has also brought temperatures more than 30°F above average to Greenland. The temperature in Narsarsuaq, Greenland at 10am EST today was 46°F, far warmer than most of Florida.


Figure 1. Departure of the surface temperature from average for the first three day of 2010 shows much colder than average conditions were present over the Southeast U.S., much of Europe, and Central Asia. Much warmer than average temperatures were present over the Northwest U.S., Greenland, the Arctic, and Southern Asia. A sharp kink in the jet stream was responsible for the temperature anomaly pattern. Image credit: NOAA/ESRL.

Snow in Florida?
It doesn't snow very often in Florida, and the Wikipedia list of snow events in Florida lists only seven such events over the decade of the 2000s. This weekend's cold wave may be able to generate some snow over isolated regions of Central Florida, though it appears that the odds of this happening are less than 30%. The most widespread snowfall in Florida history occurred on January 19, 1977, when snow fell over much of the state, with flurries as far south as Homestead. Snow flurries also fell on Miami Beach for the only time in recorded history.


Figure 2. North Atlantic Oscillation (NAO) index for September 9, 2009 - January 6, 2010 (black line) and forecast from the GFS model (red lines). The NAO index was strongly negative, near -2.0, for much of December and January. Image credit: NOAA/CPC.

The winter cold blast: blame the North Atlantic Oscillation (NAO)
Why has the winter been so cold over Eastern North America and northern Europe? Well, don't blame El Niño. El Niño winters are rarely this cold. Instead, blame the the North Atlantic Oscillation (NAO). The NAO is a climate pattern in the North Atlantic Ocean of fluctuations in the difference of sea-level pressure between the Icelandic Low and the Azores High. It is one of oldest known climate oscillations--seafaring Scandinavians described the pattern several centuries ago. Through east-west oscillation motions of the Icelandic Low and the Azores High,the NAO controls the strength and direction of westerly winds and storm tracks across the North Atlantic. A large difference in the pressure between Iceland and the Azores (positive NAO) leads to increased westerly winds and mild and wet winters in Europe. Positive NAO conditions also cause the Icelandic Low to draw a stronger south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward. In contrast, if the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), westerly winds are suppressed, allowing Arctic air to spill southwards into eastern North America more readily. Negative NAO winters tend to bring cold winters to Europe, and the prevailing storm track moves south towards the Mediterranean Sea. This brings increased storm activity and rainfall to southern Europe and North Africa.

The winter of 2009 - 2010 has seen a very strong negative NAO, causing much of our cold weather over Eastern North America and Europe. The NAO index for the month of December 2009 was -1.93, which is the third lowest NAO index since 1950 for a winter month (December, January, or February). The only winter months with a lower NAO index were February 1978 (-2.20) and January 1963 (-2.12). January 1963 was one of the coldest months on record in the UK and the Eastern U.S.. February 1978 was the coldest February on record for five U.S. states, and featured the historic blizzards in both the U.S. and UK. The NAO so far for January 2010 has continued to stay strongly negative, ranging between -1.5 and -2.1. However, the blocking ridge over Greenland is forecast to weaken next week, allowing the sharp kink in the jet stream to straighten out. This will increase the NAO index to more typical values, allowing a return of more ordinary winter weather to the U.S. and Europe.

Jeff Masters

From The Porch 1 (suzi46)
from our porch view of sunrise this morning..totally different from the 'splendiferous' shots 1-8 taken from the top of our field overlooking the mountains
From The Porch 1
First snow (Rowdyblue)
of winter in South Mississippi.
First snow
Wind blown snow (bikesnapper)
Like sand dunes or Antelope Canyon
Wind blown snow

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2729. Patrap

Costanza/The Times-Picayune

Men representing Lafitte's pirates warm up by a fire Friday during events marking the 195th anniversary of the Battle of New Orleans in the War of 1812 at Chalmette Battlefield.


It was cold in the winter of 1815, when U.S. troops fended off the British in the Battle of New Orleans. So this weekend's weather only added to the accuracy of the re-enactment commemorating the battle on its 195th anniversary.
Member Since: July 3, 2005 Posts: 427 Comments: 129439
Quoting ElConando:


It will still be bad imo but not as widespread.


So far SPC rightly is not sure how much of a severe threat it really is with so much dry, stable air in place and slow moderation expected. Lots of area under strong inversions right now...

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0348 AM CST SUN JAN 10 2010

VALID 131200Z - 181200Z

...POTENTIAL TOO LOW TO DELINEATE A SVR THREAT AREA...

MODELS CONTINUE TO INDICATE AMPLIFICATION WITHIN A STRONG BELT OF WESTERLIES ACROSS THE SUBTROPICAL PACIFIC BY THE MIDDLE OF THE COMING WORK WEEK. EMERGING SHORT WAVE IMPULSES ARE THEN PROGGED TO TRANSLATE EASTWARD INTO THE SOUTHERN BRANCH OF DOWNSTREAM SPLIT UPPER FLOW...ACROSS THE EXTREME SOUTHERN TIER OF THE U.S...THE MEXICAN PLATEAU AND THE GULF OF MEXICO THROUGH THE REMAINDER OF THE PERIOD. CONSIDERABLE SPREAD LINGERS CONCERNING THE EVOLUTION OF THESE FEATURES...INCLUDING A POTENTIALLY STRONG LEAD IMPULSE THAT COULD IMPACT PORTIONS OF THE WESTERN GULF OF MEXICO AS EARLY AS THURSDAY. BOUNDARY LAYER MOISTENING AND DESTABILIZATION OVER THE GULF OF MEXICO IN THE WAKE OF THE RECENT SIGNIFICANT COLD INTRUSIONS IS MORE UNCLEAR...AND SEEMS TO BE THE PRIMARY UNCERTAINTY CONCERNING ANY SEVERE THUNDERSTORM POTENTIAL. WITH SUBSTANTIVE MODIFICATION NOT LIKELY TO COMMENCE UNTIL MID TO LATE WEEK...THIS POTENTIAL STILL SEEMS LOW...OR LIKELY TO BE RATHER LOCALIZED AT BEST. BUT...SEVERE PROBABILITIES MAY NOT BE COMPLETELY NEGLIGIBLE...PARTICULARLY IN THE VICINITY OF MID/LOWER TEXAS COASTAL AREAS LATE THURSDAY/THURSDAY NIGHT...PERHAPS CENTRAL FLORIDA PENINSULA GULF COASTAL AREAS FRIDAY NIGHT INTO EARLY SATURDAY.


And note how the potential that is mentioned pinpoints 2 places. The timing of the location of the L with peak daytime heating is important to maximize CAPE and well overcome capping due to inversions aloft.

Given the timing of a yet-to-be-seen L 5 - 7 days out, I am surprised they mention 2 specific areas this far out...might be getting a little ahead of themselves.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
2727. KEEPEROFTHEGATE (Mod)
sorry no respite only more winter
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Right now my weather shows a chance for showers and isolated thunderstorms Friday and Saturday.
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2725. unf97
I am watching very closely if more arctic air may be pulled in behind this intense GOM Low being projected by the models tis weekend. After this proloned cold spell these first ten days of 2010, man do we need a respite from Old Man Winter.
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2724. unf97
I am watching very closely if more arctic air may be pulled in behind this intense GOM Low being projected by the models tis weekend. After this proloned cold spell these first ten days of 2010, man do we need a respite from Old Man Winter.
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High cloud cover has keep it a little cooler than forecast if it stays around maybe it will be a little warmer tonight. I didnt realize until someone posted last night its a little harder for snow and I would guess frost to form in high humidity. I think that is what's saving the crops.I remember we get lots of frost in the low thirties, didn't see any last night.
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Quoting KEEPEROFTHEGATE:
maybe not a superstorm but still a storm and a poss strong one with brief warm rtn follow by a cooling again


It will still be bad imo but not as widespread i.e. a southeastern severe event.
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Didn't think it was going to make it to the 50's today - 2:30 and the outside temp is 46.

I don't ever remember a cold stretch that has gone on for this long. Not that I'm advocating for 90's, but about 10 degrees warmer would be nice!
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Must be close to record low for a high temp. in Miami 2 o'clock and 44. I am afraid for the crops tonight.
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Quoting KEEPEROFTHEGATE:



at the moment this is what iam seeing



Tweety is watching the deep L developing in the model forecast and he doesn't look happy!!

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Havana is less than 100 miles north of us and their temp now is at 57.
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Quoting 954FtLCane:

What was your low? that is odd.. wow
So far, that is the low but predictions say low 60's tonight but I think at this rate maybe upper 50's. One year it went down in the 40's here.
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Quoting BahaHurican:
Wow! In Cayman!!! This is really an unusually cold frontal passage....
I agree. Temps are starting to drop so I think it will reach the low 60's tonight.
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Quoting stormwatcherCI:
East End,
Grand Cayman current temp is 67 and very windy.

What was your low? that is odd.. wow
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2714. KEEPEROFTHEGATE (Mod)
Quoting BahaHurican:
KOTG, is that supposed 2 b wind chill map?

Edit: NVM
thats 1000mb precip surface pressures with temp GFS-MRF 240 HRS OUT model

system appears to start dev at the 120 hr mark so appears there is to be dev what remains to be seen
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Quoting stormwatcherCI:
East End,
Grand Cayman current temp is 67 and very windy.
Wow! In Cayman!!! This is really an unusually cold frontal passage....
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2712. IKE
12Z ECMWF
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting BahaHurican:
Ditto for the 68 they have forecasted here.... Pretty windy from time to time here.
East End,
Grand Cayman current temp is 67 and very windy.
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Quoting KEEPEROFTHEGATE:
maybe not a superstorm but still a storm and a poss strong one with brief warm rtn follow by a cooling again


I agree, we just need to HOPE that big L that develops in the GOM does NOT tap any of that Arctic air!

I used to live about 120 miles S of Toronto, Canada, in Buffalo, NY. I have lived in the Dallas-Ft Worth, TX area approaching 30 yrs. I can deal with the cold, it feels like "home"! The Southern Plains, the Deep South and Florida have truly had enough! It is amazing the citrus and strawberry crops have basically escaped serious damage.

My utility bill literally doubled. Many homes in the Southern US are not well insulated. I just hope and pray the CONUS gets at least a 2 week reprieve from the Arctic air!!
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KOTG, is that supposed 2 b wind chill map?

Edit: NVM
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Quoting 954FtLCane:

Mara I live in Oakland park also and the temp at the school safety dept (off powerline & 38th) is 41.8.. I don't think we're gonna see the 53 they were calling for.
Ditto for the 68 they have forecasted here.... Pretty windy from time to time here.
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2707. KEEPEROFTHEGATE (Mod)



at the moment this is what iam seeing

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2706. eddye
will some people join me in weather chat
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2705. eddye
will some poeple join me in weather chat
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2704. Patrap
Almost NO Low pressure in the CONUS save for one Lil "L" near the border in N Dakota.

Rare indeed.


Member Since: July 3, 2005 Posts: 427 Comments: 129439
2703. KEEPEROFTHEGATE (Mod)
Quoting Bordonaro:
I believe Atmoaggie was right when he stated the GOM L that develops will be almost as strong as a STS. I believe GFS and ECMWF are under-estimating the Low's intensity.

However, I do not believe we are looking at a superstorm.
maybe not a superstorm but still a storm and a poss strong one with brief warm rtn follow by a cooling again
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That ridge of High pressure over Alaska just needs to STAY PUT!!!

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Quoting mara0921:
Right now currently 43.9 degrees at my place in Oakland Park, FL @ 1:31 PM. High level cloudiness keeping temps lower than central and north florida even. I see that the final push to clear things out will be here later this afternoon. Then the temps should plummet below 32 by 11 PM or so

Mara I live in Oakland park also and the temp at the school safety dept (off powerline & 38th) is 41.8.. I don't think we're gonna see the 53 they were calling for.
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Right now currently 43.9 degrees at my place in Oakland Park, FL @ 1:31 PM. High level cloudiness keeping temps lower than central and north florida even. I see that the final push to clear things out will be here later this afternoon. Then the temps should plummet below 32 by 11 PM or so
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2697. Patrap
Thats easy to answer.

My Post was is reference to the Naval World at sea. On US Ships,Marines are resposnible for "Interior Guard" of the Crew and Ship.

We dont stand watches,the Naval crews do.

As per the question you pose,

Hate is easy,..Love takes Courage.
Member Since: July 3, 2005 Posts: 427 Comments: 129439
Quoting Patrap:
Glad I was USMC,..we lost a Fantail Watch overboard in 84 on the USS Raleigh LPD-1 Just Leaving England in the N Atlantic,..he fell overboard and nobody knew for 3 hours till his replacement showed up,and he was gone.

The Fleet turned round but in the N. Atlantic in April,well,,,he didnt suffer long.
Was a Sad trip back stateside for us.


patrap,

sometimes i wonder if you have a heart of gold or a heart of stone. why is it that some are here to see so much? and that others are here to do so little?

sorry, didn't mean to get to heavy.
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I believe Atmoaggie was right when he stated the GOM L that develops will be almost as strong as a STS. I believe GFS and ECMWF are under-estimating the Low's intensity.

However, I do not believe we are looking at a superstorm.
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2693. Patrap
Glad I was USMC,..we lost a Fantail Watch overboard in 84 on the USS Raleigh LPD-1 Just Leaving England in the N Atlantic,..he fell overboard and nobody knew for 3 hours till his replacement showed up,and he was gone.

The Fleet turned round but in the N. Atlantic in April,well,,,he didnt suffer long.
Was a Sad trip back stateside for us.
Member Since: July 3, 2005 Posts: 427 Comments: 129439
Quoting Orcasystems:


I would say.. put on a jacket or sweater... but I doubt may people have them down there.

Hint from years of experience standing brow watches... in a pinch, socks make decent mittens :)

I know.. you wear sandals.. who wears socks..


What are brow watches?
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Quoting rainmound:
So this doesn't have anything to do with warming oceans altering the jet stream? Seems to me that warmer oceans have created a conveyor belt of warmer air splitting the arctic vortex in two.

On another note: has anyone noticed the heat and fire going on in Antarctica? This is a perfect example of a predictable result of climate change: the extra energy in the system created by the global warming process has resulted in more extreme weather which seems to change more quickly.


If you missed it, here's a repost of the link I posted yesterday discussing the recent temporary diversion of the Gulf Stream west of Greenland: Link

Here's another link, the day before Christmas Eve when the warm Gulf Stream waters were observed to invade the Arctic Ocean north of Russia: Link

Global ocean currents seem to be fluctuating and partially slowing down due to storms, thereby allowing more cold Arctic air to descend into Northern Hemisphere continents, clashing with warm tropical oceanic air and producing more storms that further alter the ocean currents.
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2690. Patrap
Finally above 0 Celsius here,..,but I have 2 Broken Pipe repairs already under raised wood frame Homes on my Street,same Landlord.
Folks didnt prep or run a trickle of water..
Turned the Main valves OFF,and will do tomorrow.

Current Conditions

Uptown, New Orleans, Louisiana (PWS)
Updated: 1 min 13 sec ago
Clear

32.7 F

Clear
Windchill: 30 F
Member Since: July 3, 2005 Posts: 427 Comments: 129439
2689. IKE
Member Since: June 9, 2005 Posts: 23 Comments: 37860
2688. Patrap
Looks like they said in the discussion Ike,more agreement that its going to the N GOM.


WUnderful,..not.
Member Since: July 3, 2005 Posts: 427 Comments: 129439
Good Morning All,

i got this link from GrtLksQuest:

http://mashable.com

it has photos of the eureka, ca. i don't think the older homes that are not eq updated faired so well.
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Some cloud iridescence setting up over S. Ontario as we have cirrus, cirrostratus and especially cirrocumulus clouds moving over the area. Minimum temperature last night was -16.9C. East of the Amery Ice shelf in Antarctica, one embayment is currently 9C.
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2685. IKE
12Z CMC...


12Z UKMET...
Member Since: June 9, 2005 Posts: 23 Comments: 37860
2684. Patrap
from the NWS NOLA Discussion 11:41 am CDT

Friday through the weekend...the upper low will finally stop digging
Friday morning/midday as the middle/upper level jet starts to round the
base of the low. By Friday evening the upper low will begin to slowly
work east-northeast towards the Upper Texas coast pushing across the lower MS
valley through the day Sat and into the Ohio/Tennessee Valley sun. At the surface
cyclogenesis will begin across the western Gulf early Friday with the surface
low pushing towards the northwestern Gulf Friday afternoon. This will lead to srly
ll flow increasing across the region that in combination with SW
flow aloft will really help to bring in moisture. The surface low will
move over across the northern Gulf Friday night and early Sat. The increase
in moisture and lift will lead to widespread rain showers with heavy rain
possible across portions of the County Warning Area beginning Friday afternoon through Sat
morning but given the very slow progression of this system...rain
will be possible late Thursday night through Sat night. As for
thunderstorms and rain...right now given the track the models are indicating we would
likely remain on the cool side so thunderstorms and rain will likely be more isolated and
confined to the Gulf waters and coastal parishes/counties. One thing
to mention the models have continue the trend of keeping the surface low
mostly in the Gulf and with this the risk for strong/severe weather
remains low but we are in the right area for heavy rain and given
the recent cold conditions the ground will have a hard time soaking
up much rain possibly leading to some runoff problems. /Cab



Member Since: July 3, 2005 Posts: 427 Comments: 129439
Quoting Bordonaro:


I can see you Taz doing a Snoopy Happy Dance from here!!




lol
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Quoting Tazmanian:
i dont think FL can stan other cold night


the good news is in all of this is big storms are on the way for CA why thing heat up back E


I can see you Taz doing a Snoopy Happy Dance from here!!

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2681. ycd0108
Link to local news re: earthquake near Eureka, California:
http://www.times-standard.com/ci_14157864
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i dont think FL can stan other cold night


the good news is in all of this is big storms are on the way for CA why thing heat up back E
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Orca and KOG, and ALL your Canadian compadres, PLEASE shut off the fans and close the back door to the Arctic please :0). Open the side door on the left and right, feed the Arctic air to the Polar Bears in Alaska and Greenland.

What America needs is a week of temps about 10 to 20F ABOVE normal, alot of sun for a few days, and some rain for the Florida peninsula.
This has been a public service announcement on behalf of about 280 million very cold and peeved residents!!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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