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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Continuing my earlier comment about those in Florida wishing for snow, here in NC we have some newcomers that we refer to as "halfbacks". Halfbacks are people from up north who move down to Florida and then decide that they miss having just a little bit of winter, so they move halfway back. Hence the name "halfback".
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It dropped from 57 to 44 in 3 hours, and now has risen to 46.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
Dey Plume o Doom...

Member Since: July 3, 2005 Posts: 421 Comments: 127691
Quoting jipmg:


Yes, Wilma was just amazing, but I was more impressed with Katrina, It was actually my birthday when the "eye" moved through my area.

My first experience with a Hurricane. I am sad for the damage it caused, but I am greatful for the experience it gave me, and how it made me love weather in such a way that only music can compare.


The eye went through my area as well. No one not even the mets expected it. I had shut off my tv at one point and then all of a sudden it became calm and I was like "NO!!!!! we can't be in the eye!!!."
Member Since: September 6, 2009 Posts: 2 Comments: 3710
From TBO.COM

#13 got me this morning. Never occured to me that my windshield wiper fluid would be different in FL.

#15 - YUCK!
15 things Floridians should heed in the cold
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If we hit 34 F before midnight ,we will have seen a 30 degrees Temp fall today.

We had a Noon High of 64F

Current Conditions

Uptown, New Orleans, Louisiana (PWS)
Updated: 1 min 40 sec ago
Overcast
37.6 F
Overcast

That would be close to a 12 Hour fall record.
Member Since: July 3, 2005 Posts: 421 Comments: 127691
Quoting Patrap:
Cue the Jaw's theme Music,



Not shark attack 3?
Member Since: September 6, 2009 Posts: 2 Comments: 3710
772. jipmg
Quoting ElConando:


Wilma was a sight to experience also, unless you fully shuttered in?


Yes, Wilma was just amazing, but I was more impressed with Katrina, It was actually my birthday when the "eye" moved through my area.

My first experience with a Hurricane. I am sad for the damage it caused, but I am greatful for the experience it gave me, and how it made me love weather in such a way that only music can compare.
Member Since: July 11, 2006 Posts: 14 Comments: 11198
I understand. I hope you get your snow. Growing up in Wilmington, NC, snow was a rare treat for me. I know how exciting it is to wish and hope for some snow!! I hope you get it!
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Quoting jipmg:


sorry, I was being a bit ignorant lol

Actually im only 17, I really can't just leave. It would be nice to see history with my own eyes, and me being a weather enthusiast, it just adds to the equation. Weather is my love, and seeing hail a yeaer or two ago was one of the greatest things I have ever witnessed.


Wilma was a sight to experience also, unless you fully shuttered in?
Member Since: September 6, 2009 Posts: 2 Comments: 3710
Area forecast discussion...updated
National Weather Service Mobile Alabama
803 PM CST Thursday Jan 7 2010


Mesoscale update...cold air advection has commenced over much of
the forecast area this evening with surface temperatures near freezing already
encroaching upon the far northwest zones. While low level thicknesses are
quickly beginning to lower from northwest to southeast...moisture and
lift is running out just ahead of critical thicknesses needed for
frozen precipitation. However...as strong cold air advection continues...
cannot rule out some sleet mixing in on the very back edge of the
precipitation. Given the brief nature of any sleet...do not expect any
accumulations and all winter weather advisories have been cancelled.
Also removed snow flurries from the forecast as model soundings
indicate there is not sufficient moisture in the dendritic growth
zone to support any snow. All precipitation should be clear of the
far eastern zones a few hours after midnight.

What is of more importance is the very cold air that will filter into
the area through the night. The first concern is for the potential
for icy spots on area roadways...especially on bridges and
overpasses...as temperatures quickly drop below freezing.
Secondly...winds will become blusterly...gusting to 20 to 25 miles per hour at
times overnight. This will result in wind chills dropping into the 5
to 15 degree range by morning. Have issued a Special Weather
Statement to detail these concerns.


Have already sent updates to the gridded and text products. Low temperature
forecast is on track...but slightly adjusted the hourly temperature curve
based on upstream observation. Also increase wind gusts through Friday given
the mixing expected with the strong cold air advection.


bummer...maybe next time..:(
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Cue the Jaw's theme Music,

Member Since: July 3, 2005 Posts: 421 Comments: 127691
That's the way snow is in NC. It snows once in a while, but doesn't stick around very long at all! It just seems so rediculous for people, especially in Orlando and Tampa, to be wishing for snow!! I know it's possible and I hope you get it, but REALLY!!
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Quoting natrwalkn:


I'm sorry you've never seen snow, but aside from being imprisoned, nobody is forced to live anywhere. Pack a bag, stand on the side of I95 with your thumb out, and SOMEONE will take you north!

Don't give em any ideas lol!!!
Member Since: September 6, 2009 Posts: 2 Comments: 3710
764. jipmg
Quoting natrwalkn:


I'm sorry you've never seen snow, but aside from being imprisoned, nobody is forced to live anywhere. Pack a bag, stand on the side of I95 with your thumb out, and SOMEONE will take you north!


sorry, I was being a bit ignorant lol

Actually im only 17, I really can't just leave. It would be nice to see history with my own eyes, and me being a weather enthusiast, it just adds to the equation. Weather is my love, and seeing hail a yeaer or two ago was one of the greatest things I have ever witnessed.
Quoting AllyBama:


ahhhh, I like your dream and wish for the snow..I think that we all wish for the beauty and peaceful feeling that it gives us..

Yes, unless you're homeless or a lizard.
Member Since: July 11, 2006 Posts: 14 Comments: 11198
Quoting jipmg:
I'm going to sleep, when I awaken I hope to see a LOW in the central/southern gulf bringing snow across the gulf coast states, and bring mix and snow into north central florida. Then I hope, METS in miami start concidering the possibility of atleast sleet in atleast portions of palm beach or northern SFL.


ahhhh, I like your dream and wish for the snow..I think that we all wish for the beauty and peaceful feeling that it gives us..
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Quoting jipmg:


I am forced to live in Florida, I would kill to see snow, I ve never seen it in my life


I'm sorry you've never seen snow, but aside from being imprisoned, nobody is forced to live anywhere. Pack a bag, stand on the side of I95 with your thumb out, and SOMEONE will take you north!
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Another record low set here today.

Record Report
Statement as of 4:35 PM EST on January 07, 2010

... Record low temperature set at Daytona Beach... a record low temperature of 29 degrees was set at Daytona Beach today. This ties the old record of 29 set in 2001.

I think that's two days in a row now.
Member Since: July 11, 2006 Posts: 14 Comments: 11198
Quoting natrwalkn:
Why are there so many people in Florida wishing for snow? FLORIDA!! If you like snow, then why the h*** do you live in FLORIDA?? At least live somewhere that can reasonably expect a little snow now and then. Not saying move to Buffalo, but for goodness sake!!
I think it is called novelty and a little payback. If we have to have a week of northern cold we want the pretty snow to play in a few hours go in drink Coco and it will be melted LOL.
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758. jipmg
I'm going to sleep, when I awaken I hope to see a LOW in the central/southern gulf bringing snow across the gulf coast states, and bring mix and snow into north central florida. Then I hope, METS in miami start concidering the possibility of atleast sleet in atleast portions of palm beach or northern SFL.
TWC puts Orlando at 38 for a high on Saturday with windchill's 15-25 with a chance of snow with ice pellets(40-50%)! Brrr...
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Quoting natrwalkn:
Why are there so many people in Florida wishing for snow? FLORIDA!! If you like snow, then why the h*** do you live in FLORIDA?? At least live somewhere that can reasonably expect a little snow now and then. Not saying move to Buffalo, but for goodness sake!!


Cause we could watch it and say "How Pretty!" and know that it's not going to last and we WON'T have to shovel it!
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Quoting Patrap:
To build a fire, one only needs a small flame.

This should be the spark,now..how can we generate cyclogenesis?


Folks in Fla stay tuned,this could be your Saturday inspiration beginning.








Well put Pat.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
I do not want snow or sleet or freezing rain.
This is Daytona Beach, Florida:

Friday Night
Mostly cloudy. A chance of showers through early morning...possibly mixing with light snow or sleet toward sunrise. Lows in the lower 30s. Northwest winds 10 to 15 mph. Chance of precipitation 40 percent. Wind chill readings 22 to 25.
Saturday
Cloudy. A chance of morning showers...possibly mixing with light snow or sleet. Highs in the lower 40s. Northwest winds 10 to 15 mph. Chance of precipitation 30 percent

Good grief!
Member Since: July 11, 2006 Posts: 14 Comments: 11198
Quoting jipmg:
its colder in cuba.. than miami

52 vs 54

o-O
Quoting jipmg:
its colder in cuba.. than miami

52 vs 54

o-O


Cuba is at higher elevation so it is not uncommon for Cuba to have lower temps than Miami.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
To build a fire, one only needs a small flame.

This should be the spark,now..how can we generate cyclogenesis?


Folks in Fla stay tuned,this could be your Saturday inspiration beginning.

Note the Motion vector as well,,,






Member Since: July 3, 2005 Posts: 421 Comments: 127691
10pm forecasted low was originally 41 then was changed to 39 around noon reality is currently 37 and falling still...Daytona area
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749. jipmg
Quoting natrwalkn:
Why are there so many people in Florida wishing for snow? FLORIDA!! If you like snow, then why the h*** do you live in FLORIDA?? At least live somewhere that can reasonably expect a little snow now and then. Not saying move to Buffalo, but for goodness sake!!


I am forced to live in Florida, I would kill to see snow, I ve never seen it in my life
Why are there so many people in Florida wishing for snow? FLORIDA!! If you like snow, then why the h*** do you live in FLORIDA?? At least live somewhere that can reasonably expect a little snow now and then. Not saying move to Buffalo, but for goodness sake!!
Member Since: Posts: Comments:
Sometimes Levity,can be the breath of Wisdom.


But In my case,.."brevity" is a good thing usually.
LOL


Member Since: July 3, 2005 Posts: 421 Comments: 127691
746. jipmg
its colder in cuba.. than miami

52 vs 54

o-O
Quoting Patrap:


Low,"La Bomba" 2010,...


lol took me a second to understand what you were saying.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
Post 739 above amended to add,

"Wowza! record already broken, and it's not midnight yet!"
Member Since: October 25, 2005 Posts: 19 Comments: 21597
Quoting ElConando:
Pat: what are you thinking could occur in the gulf if it all came together at the right time?


Low,"La Bomba" 2010,...

With the Cold in Place,someone somewhere could see 4" plus,but Im being very "vary "Liberal..Wink,Wink..
Member Since: July 3, 2005 Posts: 421 Comments: 127691
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BTW, here is

Nassau Airport, Bahamas, The
Updated: 28 min 12 sec ago
56 °F / 13 °C
Scattered Clouds
Humidity: 91%
Dew Point: 54 °F / 12 °C
Wind: Calm

Boy, sure likes we are heading for a record low tonight.....
Member Since: October 25, 2005 Posts: 19 Comments: 21597
Pretty much staying at 44 degrees atm.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
Evening everyone. Hope everyone is staying warm and safe as the temps bottom out tonight.

Who was it yesterday saying Edzani would likely bomb out given the environment at the time? Not surprising, but also makes one wonder what February will have in store, when tracks are more likely to move towards the East African coast.....
Member Since: October 25, 2005 Posts: 19 Comments: 21597
Pat: what are you thinking could occur in the gulf if it all came together at the right time?
Member Since: September 6, 2009 Posts: 2 Comments: 3710
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Quoting Patrap:
Stay tuned to this Winter Weather Channel.


Note the Moisture "pooling" in N Mexico,Below Brownsville.
Keep ya focus there the next 24.



Sir yes sir!
Member Since: September 6, 2009 Posts: 2 Comments: 3710
If I had realized there was ice underneath the snow, especially that much I wouldn't have even tried leaving. I've driven on snow before, just nothing like this. The whole road 2 large dowhill slopes, was covered in ice, just underneath the snow. Guess I'll know to check for that next time before driving.
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SH072010 - Tropical Cyclone EDZANI

Enhanced Infrared (IR) Imagery (4 km Mercator)



Tropical Cyclone EDZANI, RAAMB Page
Member Since: July 3, 2005 Posts: 421 Comments: 127691
729. jipmg
No mention of any possibility of frozen precip from miami local mets..

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.