IN-DEPTH: Arctic Ice Builds, Polar Vortex Strengthens With +AO/NAO… Looking Back To See What’s Ahead!

Written by on September 22, 2014 in Rest of Europe, United States of America with 0 Comments

The AO and NAO are both going positive as we head for October. While some may worry. This is GOOD because we will see the arctic sea ice grow with cold focusing over the arctic ocean forcing ice to grow and expand. This will build the polar vortex. The building blocks to the winter ahead!

Ultimately we don’t want to see a cold autumn down here as that means cold is spread out and is weaker in the source region. Obviously you need the pattern to deliver the cold into the mid-latitudes oncve winter and that didn’t happen last year on our side of the pond hits but without a decent positive AO phase in autumn, when this is the natural time for arctic air mass building, you don’t want to reach winter as the stock pile of cold isn’t there.

ao_sprd2

nao_sprd2

[s2If current_user_can(access_s2member_level1)]

Models show cooling at 10mb over the arctic which is evidence of the polar vortex building in response to the +AO.

gfs_t10_nh_f00

96 hrs

gfs_t10_nh_f96

168 hrs

gfs_t10_nh_f168

240 hrs

gfs_t10_nh_f240

Notice that the AO in 2009 bounced between slight positive and negative summer and autumn before tanking late autumn into winter.

2009  7 21 -0.231
2009  7 22  0.209
2009  7 23  0.304
2009  7 24 -0.304
2009  7 25 -1.302
2009  7 26 -1.621
2009  7 27 -1.899
2009  7 28 -2.003
2009  7 29 -1.793
2009  7 30 -1.435
2009  7 31 -0.941
2009  8  1 -0.870
2009  8  2 -0.726
2009  8  3 -1.005
2009  8  4 -1.467
2009  8  5 -1.601
2009  8  6 -0.906
2009  8  7 -0.227
2009  8  8  0.053
2009  8  9  0.395
2009  8 10  0.827
2009  8 11  0.199
2009  8 12 -0.914
2009  8 13 -1.566
2009  8 14 -2.030
2009  8 15 -2.161
2009  8 16 -1.931
2009  8 17 -1.888
2009  8 18 -1.320
2009  8 19  0.386
2009  8 20  0.705
2009  8 21 -0.089
2009  8 22 -0.467
2009  8 23 -0.360
2009  8 24 -0.077
2009  8 25 -0.038
2009  8 26 -0.464
2009  8 27 -0.358
2009  8 28  0.038
2009  8 29 -0.149
2009  8 30 -0.824
2009  8 31 -1.732
2009  9  1 -2.081
2009  9  2 -1.907
2009  9  3 -1.294
2009  9  4 -0.279
2009  9  5  0.035
2009  9  6  0.096
2009  9  7  0.656
2009  9  8  1.266
2009  9  9  1.468
2009  9 10  1.578
2009  9 11  1.488
2009  9 12  0.954
2009  9 13  0.763
2009  9 14  0.457
2009  9 15 -0.096
2009  9 16 -0.493
2009  9 17 -0.610
2009  9 18 -0.465
2009  9 19 -0.480
2009  9 20 -0.681
2009  9 21 -1.079
2009  9 22 -1.735
2009  9 23 -2.414
2009  9 24 -2.401
2009  9 25 -1.405
2009  9 26 -0.057
2009  9 27  1.382
2009  9 28  2.738
2009  9 29  2.539
2009  9 30  1.507
2009 10  1  0.554
2009 10  2  0.137
2009 10  3 -0.012
2009 10  4  0.646
2009 10  5  1.226
2009 10  6  1.791
2009 10  7  1.774
2009 10  8  1.146
2009 10  9  0.985
2009 10 10  0.347
2009 10 11 -0.791
2009 10 12 -1.756
2009 10 13 -1.030
2009 10 14 -0.016
2009 10 15  0.528
2009 10 16  0.389
2009 10 17  0.027
2009 10 18 -0.104
2009 10 19 -0.300
2009 10 20 -0.661
2009 10 21 -0.589
2009 10 22 -0.446
2009 10 23 -0.874
2009 10 24 -1.140
2009 10 25 -0.449
2009 10 26  0.755
2009 10 27  0.822
2009 10 28 -0.450
2009 10 29 -0.942
2009 10 30 -0.070
2009 10 31  0.961
2009 11  1  0.829
2009 11  2 -0.233
2009 11  3 -1.023
2009 11  4 -1.023
2009 11  5 -1.316
2009 11  6 -2.112
2009 11  7 -3.138
2009 11  8 -3.888
2009 11  9 -3.769
2009 11 10 -3.624
2009 11 11 -3.630
2009 11 12 -3.848
2009 11 13 -3.759
2009 11 14 -3.887
2009 11 15 -3.509
2009 11 16 -3.250
2009 11 17 -3.409
2009 11 18 -3.502
2009 11 19 -2.366
2009 11 20 -0.927
2009 11 21 -0.389
2009 11 22 -0.072
2009 11 23  0.437
2009 11 24  0.541
2009 11 25  0.380
2009 11 26 -0.296
2009 11 27 -1.259
2009 11 28 -1.369
2009 11 29 -1.102
2009 11 30 -0.955
2009 12  1 -0.782
2009 12  2 -0.076
2009 12  3  0.440
2009 12  4  0.548
2009 12  5  0.265
2009 12  6 -0.228
2009 12  7  0.028
2009 12  8  0.058
2009 12  9  0.487
2009 12 10  0.861
2009 12 11  0.884
2009 12 12  0.746
2009 12 13  0.723
2009 12 14  0.758
2009 12 15  0.632
2009 12 16  1.051
2009 12 17  1.792
2009 12 18  2.176
2009 12 19  2.161
2009 12 20  1.663
2009 12 21  1.026
2009 12 22  0.711
2009 12 23  0.784
2009 12 24  0.551
2009 12 25  0.672
2009 12 26  0.814
2009 12 27  0.568
2009 12 28  0.320
2009 12 29  0.038
2009 12 30 -0.550
2009 12 31 -1.063
2010  1  1 -1.391
2010  1  2 -1.646
2010  1  3 -1.722
2010  1  4 -1.791
2010  1  5 -1.711
2010  1  6 -1.585
2010  1  7 -1.621
2010  1  8 -1.495
2010  1  9 -1.646
2010  1 10 -1.529
2010  1 11 -0.918
2010  1 12 -0.684
2010  1 13 -0.345
2010  1 14  0.104
2010  1 15  0.347
2010  1 16  0.455
2010  1 17  0.582
2010  1 18  0.543
2010  1 19  0.238
2010  1 20 -0.042
2010  1 21 -0.432
2010  1 22 -0.813
2010  1 23 -0.731
2010  1 24 -0.634
2010  1 25 -0.511
2010  1 26 -0.273
2010  1 27 -0.393
2010  1 28 -0.677
2010  1 29 -0.708
2010  1 30 -0.746
2010  1 31 -0.928
2010  2  1 -1.116
2010  2  2 -1.105
2010  2  3 -0.506
2010  2  4 -1.110
2010  2  5 -1.758
2010  2  6 -1.709
2010  2  7 -1.205
2010  2  8 -0.958
2010  2  9 -1.402
2010  2 10 -1.929
2010  2 11 -2.074
2010  2 12 -1.843
2010  2 13 -1.862
2010  2 14 -1.863
2010  2 15 -1.704
2010  2 16 -1.550
2010  2 17 -1.198
2010  2 18 -0.808
2010  2 19 -0.770
2010  2 20 -0.393
2010  2 21  0.139
2010  2 22  0.413
2010  2 23  0.529
2010  2 24  0.411
2010  2 25  0.584
2010  2 26  1.247
2010  2 27  1.402
2010  2 28  1.140
2010  3  1  0.565
2010  3  2 -0.210
2010  3  3 -0.759
2010  3  4 -0.345
2010  3  5  1.140
2010  3  6  2.648
2010  3  7  3.336
2010  3  8  3.156
2010  3  9  2.158
2010  3 10  0.778
2010  3 11 -0.226
2010  3 12 -0.993
2010  3 13 -2.030
2010  3 14 -2.356
2010  3 15 -2.270
2010  3 16 -2.031
2010  3 17 -1.511
2010  3 18 -1.247
2010  3 19 -0.877
2010  3 20 -0.015
2010  3 21  0.754
2010  3 22  0.692
2010  3 23  0.402
2010  3 24 -0.030
2010  3 25 -0.180
2010  3 26 -0.109
2010  3 27  0.134
2010  3 28  0.033
2010  3 29  0.369
2010  3 30  0.971
2010  3 31  1.147

Before the very cold first half of winter 2010-11 and coldest December in 100 years for the UK, the AO was dominated by positive and wasn’t extremely negative when it mattered.

2010  7 10  1.540
2010  7 11  1.743
2010  7 12  1.607
2010  7 13  0.855
2010  7 14  1.258
2010  7 15  2.345
2010  7 16  2.900
2010  7 17  3.117
2010  7 18  2.905
2010  7 19  3.276
2010  7 20  3.904
2010  7 21  4.037
2010  7 22  3.635
2010  7 23  3.985
2010  7 24  4.159
2010  7 25  3.295
2010  7 26  2.280
2010  7 27  1.640
2010  7 28  0.871
2010  7 29  0.674
2010  7 30  0.774
2010  7 31  0.613
2010  8  1  1.439
2010  8  2  2.518
2010  8  3  2.835
2010  8  4  2.582
2010  8  5  1.958
2010  8  6  1.214
2010  8  7  1.249
2010  8  8  1.878
2010  8  9  1.916
2010  8 10  2.308
2010  8 11  2.631
2010  8 12  2.936
2010  8 13  2.768
2010  8 14  2.239
2010  8 15  2.112
2010  8 16  1.757
2010  8 17  1.767
2010  8 18  2.060
2010  8 19  2.092
2010  8 20  1.713
2010  8 21  1.498
2010  8 22  0.787
2010  8 23  0.354
2010  8 24  0.147
2010  8 25 -0.603
2010  8 26 -1.083
2010  8 27 -1.011
2010  8 28 -0.347
2010  8 29  0.599
2010  8 30  1.023
2010  8 31  1.722
2010  9  1  2.086
2010  9  2  1.897
2010  9  3  0.733
2010  9  4  0.008
2010  9  5  0.428
2010  9  6  1.700
2010  9  7  1.521
2010  9  8  2.119
2010  9  9  2.289
2010  9 10  1.607
2010  9 11  1.449
2010  9 12  1.834
2010  9 13  1.295
2010  9 14  0.233
2010  9 15 -0.265
2010  9 16 -0.414
2010  9 17 -0.802
2010  9 18 -0.498
2010  9 19  0.400
2010  9 20 -0.133
2010  9 21 -1.078
2010  9 22 -1.624
2010  9 23 -1.578
2010  9 24 -1.198
2010  9 25 -0.674
2010  9 26 -0.817
2010  9 27 -1.025
2010  9 28 -0.362
2010  9 29  0.794
2010  9 30  1.622
2010 10  1  1.452
2010 10  2  1.524
2010 10  3  1.579
2010 10  4  1.277
2010 10  5  0.502
2010 10  6 -0.185
2010 10  7 -0.642
2010 10  8 -0.325
2010 10  9  0.491
2010 10 10  1.232
2010 10 11  2.122
2010 10 12  2.310
2010 10 13  1.628
2010 10 14  1.181
2010 10 15  1.241
2010 10 16  1.631
2010 10 17  1.491
2010 10 18  1.344
2010 10 19  1.149
2010 10 20  0.706
2010 10 21  0.890
2010 10 22  1.359
2010 10 23  1.831
2010 10 24  1.887
2010 10 25  1.874
2010 10 26  1.539
2010 10 27  1.219
2010 10 28  1.165
2010 10 29  1.591
2010 10 30  2.316
2010 10 31  2.447
2010 11  1  2.003
2010 11  2  1.238
2010 11  3  0.341
2010 11  4 -0.389
2010 11  5 -0.321
2010 11  6  0.002
2010 11  7 -0.544
2010 11  8 -0.533
2010 11  9  0.335
2010 11 10  0.978
2010 11 11  1.248
2010 11 12  1.595
2010 11 13  1.951
2010 11 14  2.143
2010 11 15  2.429
2010 11 16  2.287
2010 11 17  1.785
2010 11 18  1.616
2010 11 19  2.108
2010 11 20  2.124
2010 11 21  1.918
2010 11 22  1.989
2010 11 23  2.359
2010 11 24  2.292
2010 11 25  2.073
2010 11 26  2.028
2010 11 27  1.920
2010 11 28  2.160
2010 11 29  2.387
2010 11 30  2.262
2010 12  1  1.920
2010 12  2  1.609
2010 12  3  1.172
2010 12  4  1.014
2010 12  5  0.661
2010 12  6  0.008
2010 12  7 -1.023
2010 12  8 -1.707
2010 12  9 -1.494
2010 12 10 -1.196
2010 12 11 -0.681
2010 12 12 -0.482
2010 12 13 -0.591
2010 12 14 -0.682
2010 12 15 -0.875
2010 12 16 -0.451
2010 12 17  0.300
2010 12 18  1.086
2010 12 19  1.651
2010 12 20  1.747
2010 12 21  1.453
2010 12 22  0.957
2010 12 23  0.517
2010 12 24  0.121
2010 12 25 -0.414
2010 12 26 -0.391
2010 12 27 -0.138
2010 12 28 -0.033
2010 12 29  0.507
2010 12 30  0.790
2010 12 31  0.707
2011  1  1  0.428
2011  1  2  0.235
2011  1  3  0.480
2011  1  4  1.014
2011  1  5  1.422
2011  1  6  0.944
2011  1  7  0.376
2011  1  8  0.346

As for the NAO which is crucial for us here in the West of Europe if you like it cold, in 2009 it was mainly negative during summer then shifted closer to neutral, sometimes positive through autumn.

What’s interesting is that November 2009 saw a firmly negative NAO but the UK was warm and very wet. December started mild then turn dramatically cold towards Christmas. The NAO only went slightly negative. Not deeply negative and it hovered that way through much of that winter despite it being more often than not, cold!.

2009  6 22 -0.391
2009  6 23 -1.078
2009  6 24 -1.805
2009  6 25 -2.340
2009  6 26 -2.455
2009  6 27 -2.774
2009  6 28 -3.235
2009  6 29 -3.011
2009  6 30 -2.594
2009  7  1 -2.541
2009  7  2 -2.489
2009  7  3 -2.089
2009  7  4 -1.514
2009  7  5 -1.708
2009  7  6 -2.380
2009  7  7 -2.572
2009  7  8 -2.346
2009  7  9 -2.093
2009  7 10 -1.436
2009  7 11 -1.806
2009  7 12 -1.868
2009  7 13 -1.222
2009  7 14 -0.762
2009  7 15 -0.462
2009  7 16 -0.191
2009  7 17  0.688
2009  7 18  0.861
2009  7 19  0.151
2009  7 20 -0.171
2009  7 21 -0.231
2009  7 22  0.209
2009  7 23  0.304
2009  7 24 -0.304
2009  7 25 -1.302
2009  7 26 -1.621
2009  7 27 -1.899
2009  7 28 -2.003
2009  7 29 -1.793
2009  7 30 -1.435
2009  7 31 -0.941
2009  8  1 -0.870
2009  8  2 -0.726
2009  8  3 -1.005
2009  8  4 -1.467
2009  8  5 -1.601
2009  8  6 -0.906
2009  8  7 -0.227
2009  8  8  0.053
2009  8  9  0.395
2009  8 10  0.827
2009  8 11  0.199
2009  8 12 -0.914
2009  8 13 -1.566
2009  8 14 -2.030
2009  8 15 -2.161
2009  8 16 -1.931
2009  8 17 -1.888
2009  8 18 -1.320
2009  8 19  0.386
2009  8 20  0.705
2009  8 21 -0.089
2009  8 22 -0.467
2009  8 23 -0.360
2009  8 24 -0.077
2009  8 25 -0.038
2009  8 26 -0.464
2009  8 27 -0.358
2009  8 28  0.038
2009  8 29 -0.149
2009  8 30 -0.824
2009  8 31 -1.732
2009  9  1 -2.081
2009  9  2 -1.907
2009  9  3 -1.294
2009  9  4 -0.279
2009  9  5  0.035
2009  9  6  0.096
2009  9  7  0.656
2009  9  8  1.266
2009  9  9  1.468
2009  9 10  1.578
2009  9 11  1.488
2009  9 12  0.954
2009  9 13  0.763
2009  9 14  0.457
2009  9 15 -0.096
2009  9 16 -0.493
2009  9 17 -0.610
2009  9 18 -0.465
2009  9 19 -0.480
2009  9 20 -0.681
2009  9 21 -1.079
2009  9 22 -1.735
2009  9 23 -2.414
2009  9 24 -2.401
2009  9 25 -1.405
2009  9 26 -0.057
2009  9 27  1.382
2009  9 28  2.738
2009  9 29  2.539
2009  9 30  1.507
2009 10  1  0.554
2009 10  2  0.137
2009 10  3 -0.012
2009 10  4  0.646
2009 10  5  1.226
2009 10  6  1.791
2009 10  7  1.774
2009 10  8  1.146
2009 10  9  0.985
2009 10 10  0.347
2009 10 11 -0.791
2009 10 12 -1.756
2009 10 13 -1.030
2009 10 14 -0.016
2009 10 15  0.528
2009 10 16  0.389
2009 10 17  0.027
2009 10 18 -0.104
2009 10 19 -0.300
2009 10 20 -0.661
2009 10 21 -0.589
2009 10 22 -0.446
2009 10 23 -0.874
2009 10 24 -1.140
2009 10 25 -0.449
2009 10 26  0.755
2009 10 27  0.822
2009 10 28 -0.450
2009 10 29 -0.942
2009 10 30 -0.070
2009 10 31  0.961
2009 11  1  0.829
2009 11  2 -0.233
2009 11  3 -1.023
2009 11  4 -1.023
2009 11  5 -1.316
2009 11  6 -2.112
2009 11  7 -3.138
2009 11  8 -3.888
2009 11  9 -3.769
2009 11 10 -3.624
2009 11 11 -3.630
2009 11 12 -3.848
2009 11 13 -3.759
2009 11 14 -3.887
2009 11 15 -3.509
2009 11 16 -3.250
2009 11 17 -3.409
2009 11 18 -3.502
2009 11 19 -2.366
2009 11 20 -0.927
2009 11 21 -0.389
2009 11 22 -0.072
2009 11 23  0.437
2009 11 24  0.541
2009 11 25  0.380
2009 11 26 -0.296
2009 11 27 -1.259
2009 11 28 -1.369
2009 11 29 -1.102
2009 11 30 -0.955
2009 12  1 -0.782
2009 12  2 -0.076
2009 12  3  0.440
2009 12  4  0.548
2009 12  5  0.265
2009 12  6 -0.228
2009 12  7  0.028
2009 12  8  0.058
2009 12  9  0.487
2009 12 10  0.861
2009 12 11  0.884
2009 12 12  0.746
2009 12 13  0.723
2009 12 14  0.758
2009 12 15  0.632
2009 12 16  1.051
2009 12 17  1.792
2009 12 18  2.176
2009 12 19  2.161
2009 12 20  1.663
2009 12 21  1.026
2009 12 22  0.711
2009 12 23  0.784
2009 12 24  0.551
2009 12 25  0.672
2009 12 26  0.814
2009 12 27  0.568
2009 12 28  0.320
2009 12 29  0.038
2009 12 30 -0.550
2009 12 31 -1.063
2010  1  1 -1.391
2010  1  2 -1.646
2010  1  3 -1.722
2010  1  4 -1.791
2010  1  5 -1.711
2010  1  6 -1.585
2010  1  7 -1.621
2010  1  8 -1.495
2010  1  9 -1.646
2010  1 10 -1.529
2010  1 11 -0.918
2010  1 12 -0.684
2010  1 13 -0.345
2010  1 14  0.104
2010  1 15  0.347
2010  1 16  0.455
2010  1 17  0.582
2010  1 18  0.543
2010  1 19  0.238
2010  1 20 -0.042
2010  1 21 -0.432
2010  1 22 -0.813
2010  1 23 -0.731
2010  1 24 -0.634
2010  1 25 -0.511
2010  1 26 -0.273
2010  1 27 -0.393
2010  1 28 -0.677
2010  1 29 -0.708
2010  1 30 -0.746
2010  1 31 -0.928
2010  2  1 -1.116
2010  2  2 -1.105
2010  2  3 -0.506
2010  2  4 -1.110
2010  2  5 -1.758
2010  2  6 -1.709
2010  2  7 -1.205
2010  2  8 -0.958
2010  2  9 -1.402
2010  2 10 -1.929
2010  2 11 -2.074
2010  2 12 -1.843
2010  2 13 -1.862
2010  2 14 -1.863
2010  2 15 -1.704
2010  2 16 -1.550
2010  2 17 -1.198
2010  2 18 -0.808
2010  2 19 -0.770
2010  2 20 -0.393
2010  2 21  0.139
2010  2 22  0.413
2010  2 23  0.529
2010  2 24  0.411
2010  2 25  0.584
2010  2 26  1.247
2010  2 27  1.402
2010  2 28  1.140
2010  3  1  0.565
2010  3  2 -0.210
2010  3  3 -0.759
2010  3  4 -0.345
2010  3  5  1.140
2010  3  6  2.648
2010  3  7  3.336
2010  3  8  3.156
2010  3  9  2.158
2010  3 10  0.778
2010  3 11 -0.226
2010  3 12 -0.993
2010  3 13 -2.030
2010  3 14 -2.356
2010  3 15 -2.270
2010  3 16 -2.031
2010  3 17 -1.511
2010  3 18 -1.247
2010  3 19 -0.877
2010  3 20 -0.015
2010  3 21  0.754
2010  3 22  0.692
2010  3 23  0.402
2010  3 24 -0.030
2010  3 25 -0.180
2010  3 26 -0.109
2010  3 27  0.134
2010  3 28  0.033
2010  3 29  0.369
2010  3 30  0.971

So, is there a clear cut trend? From this data the answer is no but for me. It’s important to see a positive NAO/AO in autumn which allows cold air to build, then if or when the pattern set’s up, well we have a descent discharge of arctic air south into the mid-latitudes.

Autumn 2009 was warm for the UK as you can see from the chart below.

Credit: Crown/Met Office

Credit: Crown/Met Office

Autumn 2010 was colder before winter hit early but notice September was warm/October was around average and then November turned cold.

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

In terms of precipitation, 2009 displaced a dry Sept and Oct before a very wet November and that’s what I’ve got for this year.

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Credit: Crown/Met Office

Moral is, most (recent) cold winter’s have been preceded by a warm autumn with dry start/wet finish.

As Joe Bastardi states, where the ridge sets up in late summer/autumn, that’s often where the winter trough goes.

In terms of getting the right upper air pattern and blocking for winter will be down to the atmosphere’s response from the sun, ocean and possible volcanic eruption. See earlier posts for more.

[/s2If][s2If current_user_cannot(access_s2member_level1)][magicactionbox id=”18716″][/s2If]

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