Klaus M. Weickmann

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A synoptic-dynamic model with application to
subseasonal monitoring and forecasting
mountains
eddies
Klaus M. Weickmann
NOAA/ESRL/PSD Edward K. Berry
NOAA/NWS
convection
base state
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Snellman Forecast Funnel
Global Mean
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THERE IS NO COOK BOOK!!!
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Global Synoptic-Dynamic Model (GSDM)
Seek to extract repeatable behavior by the the
global circulation Includes four subseasonal
time scales MJO - 30-60 day quasi-oscillation,
baroclinic wave packets - 1-2 day decay
time teleconnections - 6-10 day decay
time 20-30 day quasi-oscillation Keyed to the
time tendency of global atmospheric angular
momentum (AAM) some averaging necessary
vertical, zonal, etc. mountain, friction
torques, momentum flux conv. GSDM combined with
rigorous daily monitoring and synoptic
analysis animations of daily, 7-day, 30-day, etc
averages time-latitude/longitude/height
plots zonal and global AAM budget
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Indices used for lag regressions
Madden-Julian Oscillation EOF1 of 20-100 day
filtered OLR
Teleconnections or ?M-?F index cycle global
friction torque with MJO removed
Baroclinic waves and wave packets Global AAM
time tendency filtered at lt 30 days
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Application of GSDM
Evaluating real time signals in tropical
convection, atmospheric angular momentum,
baroclinic wave packets, SST anomalies,
persistent regimes,etc.

• Case 1 May 4-10, 2003
• Several Severe Local Storms Outbreaks
• Strong MJO
• GSDM Stage 1

• Case 2 June 2006
• Excessive East Coast Rainfall Event
• Hot/Dry Regime Intensifies for Western and
  Central USA

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Case 2 June 2006

• Generally persistent tropical convection across
  western Pacific as part of a ENSO/global warming
  signal
• Poleward propagation of zonal mean anomalous
  easterly flow off the equator leads to strong
  North Atlantic trades
• 50-60 day oscillatory tropical convective
  variations across the western Pacific
• 30 day tropical convective variability with
  coherent eastward propagation
• Baroclinic wave packets/Rossby wave energy
  dispersion processes
• GSDM Stage 2

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Stage 3
Stage 1
wet
dry
wet
Stage 2
Stage 2
Stage 4
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6/16
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6/17
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6/18
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6/19
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6/20
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6/21
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6/22
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6/23
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6/24
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6/25
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6/26
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6/27
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6/28
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6/29
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6/30
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Questions???
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Case 1 November December 2005

• Strong North Pacific December Jet despite
  La-Nina and Indonesian tropical convective
  forcing
• Initiated during early November from Rossby Wave
  linked to west Pacific tropical forcing
• Recurrent Kamchatka blocks eventually overspread
  polar latitudes
• Postulated feedbacks include positive mountain
  torques, East Asia cold outbreaks and strong flux
  convergence of AAM 30N
• GSDM Stage 3 circulation with Stage 1 convection
• Break down during early January as Kelvin
  wave/MJO develops across Indian Ocean

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Madden-Julian Oscillation Activity
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EH Consolidation
A
1
30 days
WH
2
B
40 days
WH
3
C
20-30 days
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D
20 days
WH
E
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Relative Atmospheric Angular Momentum (AAM)
Global AAM
Stage 1 circ Stage 1-2 conv
Stage 3 circ Stage 1-2 conv
Stage 2 circ Stage 2 conv
Nov Dec Jan
Feb Mar

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12/03/05 to 01/02/06
12/03/05 to 01/01/06
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03/03/06 to 04/02/06
03/03/06 to 04/01/06
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--

12/03/05 to 01/02/06
12/03/05 to 01/02/06
--

--
03/03/06 to 04/02/06
03/03/06 to 04/02/06
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9 Nov
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15 Nov
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28 Nov
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4 Dec
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12 Dec
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21 Dec
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4 Jan
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12 Feb
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