Where's spring? 2nd most extreme March jet stream pattern on record extends winter

By: Dr. Jeff Masters , 3:15 PM GMT on March 20, 2013

Share this Blog
41
+

Punxatawney Phil got it way wrong. Pennsylvania's famous prognosticating rodent predicted just three more weeks of winter back on February 2. It's the first day of spring, but winter remains firmly entrenched over the eastern half of the U.S., where temperatures of 5 - 25°F below average have been the rule all week. The culprit is the jet stream, which has taken on an unusually contorted shape that is allowing cold air to spill down over the Eastern U.S. and Western Europe, but bringing near-record warmth to portions of Greenland. One measure of how contorted the jet stream has become is by measuring the difference in pressure between the Icelandic Low and the Azores High. There are two indices used to do this--one called the Arctic Oscillation (AO), which treats the flow over the entire Northern Hemisphere, and another called the North Atlantic Oscillation (NAO), which is more focused on the North Atlantic. The two are closely related about 90% of the time. When these indices are strongly negative, the pressure difference between the Icelandic Low and the Azores High is low. This results in a weaker jet stream, allowing it to take large, meandering loops, letting cold air to spill far to the south from the Arctic into the mid-latitudes. The AO index hit -5.2 today (March 20). This is the second most extreme March value of the index since record keeping began in 1948; only an AO value of -6.3 in March 1970 was more extreme. We've had some wildly variable jet stream patterns in recent years in the Northern Hemisphere. Just last year, we had the opposite extreme in March, when our ridiculous "Summer in March" heat wave brought a week of temperatures in the 80s to the Midwest U.S. The first day of spring today in Chicago, IL is expected to have a high temperature of just 25°F--a 60 degree difference from last year's high of 85°F on March 20!


Figure 1. The jet stream is taking a large dip to the south over the Eastern U.S., allowing cold air to spill southwards and bring winter-like conditions.

Unusual winter jet stream patterns tied to Arctic sea ice loss
Unusual jet stream contortions in winter have become increasingly common in recent years, according to a March 2013 paper by Tang et al., "Cold winter extremes in northern continents linked to Arctic sea ice loss". They found a mathematical relationship between wintertime Arctic sea ice loss and the increase in unusual jet stream patterns capable of bringing cold, snowy weather to the Eastern U.S., Western Europe, and East Asia, typical of what one sees during a strongly negative Arctic Oscillation. They theorized that sea ice loss in the Arctic promotes more evaporation, resulting in earlier snowfall in Siberia and other Arctic lands. The earlier snow insulates the soil, allowing the land to cool more rapidly. This results in a southwards shift of the jet stream and builds higher atmospheric pressures farther to the south, which increases the odds of cold spells and blocking high pressure systems that can cause extended periods of unusually cold and snowy weather in the mid-latitudes.

Related posts
From Heat Wave to Snowstorms, March Goes to Extremes by Andrew Freedman of Climate Central
Extreme jet stream causing record warmth in the east, record cold in the west (January 2013)
Arctic sea ice loss tied to unusual jet stream patterns (April 2012)
Our extreme weather: Arctic changes to blame? (December 2011)
Florida shivers; Hot Arctic-Cold Continents pattern is back (December 2010)
Jet stream moved northwards 270 miles in 22 years; climate change to blame? (June 2008)

I'll have a new post on Thursday.

Jeff Masters

()
Gusty Winds (novembergale)
High winds create huge waves behind ice dunes on Lake Erie this last day of winter.
Gusty Winds
After the blizzard (springsun)
Extreme severe winterconditions in the northeast of Germany, Kap Arkona. Source: wetterzentrale
After the blizzard

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 18 - 1

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 — Blog Index

From the previous blog:

Quoting AGWcreationists:
Tell me exactly how carbon emissions can be curtailed without a dramatic change to American lifestyles.

That is the true issue here. And the reason why it will be so difficult to reduce carbon emissions.

It goes beyond the realm of science into the personal and political.




The personal and political aspects of AGW/CC are only attempts to escape the reality of what the science tells us. Unfortunately, you are correct that personal and political ideologies have trumped what should be the logical approach to the problems that we ourselves have created for ourselves and to all that we hold to be moral truths.

I brought this conversation froward to only bring the AGW/CC "debate" into proper perspective. You can either embrace your personal/political ideologies or you can heed the warnings of the evidence presented before you and perform accordingly.
Member Since: Posts: Comments:
Quoting RitaEvac:


How much you get?


Not a whole bunch as its mostly dried up already but will take whatever. Dont have a gauge so I really dont know how much or how little

Did you get any?
Member Since: Posts: Comments:
1) Punxsutawney Phil has lost all credibility; the rodent is hereby fired. (Though to be fair, he's probably only the second-worst forecaster in Pennsylvania.)

2) The change from last year's extreme-in-the-other-direction March is truly astounding. March 2012 saw a whopping 15,272 record daily highs and high minimum temperatures, and just 888 record daily lows or low maximums. By comparison, this March to-date has seen just 1365 of the former, and 532 of the latter.

3) We can antiicpate many more wild extremes in years to come as the Arctic ice melts away into nothingness. Note the astounding loss of Arctic sea ice volume in the following graph:

ice
Member Since: Posts: Comments:
looks to be an active week

Dr. Greg Forbes Torcon Index

Thursday, March 21

A small area of severe thunderstorms ahead of a surface low along and just northeast of a
warm front where just enough moisture returns. Dry antecedent conditions limit severe storm
coverage to northwest TX near Childress, Abilene and Wichita Falls, southwest, central and
northeast OK. TOR:CON - 3 southwest OK and near Wichita Falls TX. Primarily a hail threat
in central and northeast OK, spreading overnight across extreme north-central and northeast TX east-central and southeast OK, west-central and southwest AR. TOR:CON - 2 or less.

TOR:CON details:
AR west-central, southwest night - 2 or less
OK southwest - 3
OK northeast, central; east-central and southeast night - 2 or less
TX northwest near Wichita Falls - 3
TX north-central, northeast night - 2 or less
other areas - 1 or less
Friday, March 22

Computer models have come into agreement on a slow moving surface low rolling east-southeast along a slowly advancing warm front. Severe thunderstorms in northeast TX, southeast OK, central and south AR, central and south MS, southwest AL, north, central, and southeast LA. TOR:CON - 4 northeast TX, northwest LA; 2 or less rest of severe threat area above (mainly a hail threat).

TOR:CON details:
AR southwest - 2 to 3
AR central, southeast - 2 or less
LA northwest - 4
LA northeast, central, southeast - 2 to 3
LA northeast - 2 or less
MS central, south - 2 or less
OK southeast - 2 to 3
TX northeast - 4
Saturday, March 23

Scattered severe thunderstorms along a stationary front in extreme southwest KS, east OK
panhandle, northeast TX panhandle, south OK, south AR, central and south MS, south AL, south GA, LA, FL panhandle, northeast FL. TOR:CON - 4 extreme southwest KS, east OK panhandle, extreme northeast TX panhandle; 4 - east-central MS, southwest AL.

TOR:CON details:
AL southwest - 4
AL southeast - 3
AR south - 3 or less
FL panhandle, northeast - 3
GA south - 3
KS extreme southeast - 4
LA - 3 or less
MS south, east-central - 4
MS central - 3
OK east panhandle - 4
OK south - 3 or less
TX northeast, north-central, east-central - 3
Sunday, March 24

Severe thunderstorms in southeast IL, south IN, west and central KY, west and middle TN,
northeast MS, north AL. TOR:CON - 4 in these areas.

TOR:CON details:
AL north - 4
IL south - 4
IN south - 4
KY west, central - 4
MS northeast - 4
TN west, middle - 4
Member Since: Posts: Comments:
Quoting txjac:
Really enjoyed the rain that we were blessed with this morning in Houston ... hopefully all the pollen and dust and whatever in the air has settled a bit ...my poor pooch is sufferning from alergies ...had to take her to the vet to get meds


How much you get?
Member Since: Posts: Comments:
Really enjoyed the rain that we were blessed with this morning in Houston ... hopefully all the pollen and dust and whatever in the air has settled a bit ...my poor pooch is sufferning from alergies ...had to take her to the vet to get meds
Member Since: Posts: Comments:
Quoting FunnelVortex:
Thanks Doc.

I just hope AGW fights don't start up here.
it's simple, folks need stop butting opinions against facts.. facts against facts; should go well.
Member Since: Posts: Comments:
well it was a good blog while it lasted..

Thanks Dr. Masters..
Member Since: Posts: Comments:
Heavy lake-effect snows today over the Wisconsin and western UP snowbelts today as cold air pours south from Canada and a trough sweeps around the backside of the departing low pressure system in the NE.US and E.Can.



The snows over the Penokee/Gogebic ranges (WI/MI border) are below the radar tilt and not showing up on KDLH's radar image.

Luckily I'm between the two heaviest bands today, but the winds are still blowing loose snow on the ground horizontally. This morning I had 15" of snow still on the ground and have received 68" total this winter, a few inches above average. On this date last year all the snow pack had melted already.



And just for fun, Wisconsin's average winter snowfall map. I wasn't able to readily find one for Michigan's UP:

Member Since: Posts: Comments:
Thanks Dr. Masters and good day to all. The poor groundhog! The people in PA should be ashamed of how they abuse that poor animal. They pluck him out of his "tree" burrow and hold him up for the world to see. I think I would get it wrong as well just to spite the people. Maybe they will leave him alone and let him get some sleep!LOL

Whatever weatherman had the imput for the forcast of winter was obviously wrong. I wonder if the groundhog's name will change next year.
Member Since: Posts: Comments:
Thank you Dr. Master.... Brrrr, Been in Florida for 30 years, those pictures make me shiver
Member Since: Posts: Comments:
I think the effects of human-caused global warming are "snowballing" a lot faster than expected.
Since we're very recent additions to the biosphere it's quite possible our 'reign on earth' will be relatively brief.

The basic timeline of a 4.6 billion year old Earth, with approximate dates:
3.6 billion years of simple cells (prokaryotes),
3.4 billion years of stromatolites demonstrating photosynthesis,
2 billion years of complex cells (eukaryotes),
1 billion years of multicellular life,
600 million years of simple animals,
570 million years of arthropods (ancestors of insects, arachnids and crustaceans),
550 million years of complex animals,
500 million years of fish and proto-amphibians,
475 million years of land plants,
400 million years of insects and seeds,
360 million years of amphibians,
300 million years of reptiles,
200 million years of mammals,
150 million years of birds,
130 million years of flowers,
65 million years since the dinosaurs died out,
2.5 million years since the appearance of the genus Homo,
200,000 years of anatomically modern humans,
25,000 years since the disappearance of Neanderthal traits from the fossil record.
13,000 years since the disappearance of Homo floresiensis from the fossil record.
Source: Link Timeline of evolutionary history of life
Member Since: Posts: Comments:
Thanks Dr. Masters.
Member Since: Posts: Comments:
Thanks Dr. Masters ....love the pictures ...I miss the snow
Member Since: Posts: Comments:
Wow! interesting...
Was wondering why spring refuses to arrive.
Member Since: Posts: Comments:
Thanks Doc !!
Member Since: Posts: Comments:
Thanks Doc.

I just hope AGW fights don't start up here.
Member Since: Posts: Comments:
Thanks Dr Masters
Member Since: Posts: Comments:

Viewing: 18 - 1

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 — Blog Index

Top of Page

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.