Klaus M. Weickmann

NOAA/ESRL/PSD

Edward K. Berry

NOAA/NWS

A synoptic-dynamic model with application to subseasonal monitoring and forecasting

eddies

convectionbase state

mountains

Snellman Forecast Funnel

Global Mean

THERE IS NOCOOK

BOOK!!!

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 timeteleconnections - ~6-10 day decay time20-30 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 averagestime-latitude/longitude/height plotszonal and global AAM budget

Indices used for lag regressions

Madden-JulianOscillation: EOF1 of 20-100 day filtered OLR

Teleconnections or“M-F index cycle”:global friction torquewith MJO removed

Baroclinic waves and wave packets:Global AAM timetendency filtered at< 30 days

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Application of GSDM

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

Evaluating real time signals in tropical convection, atmospheric angular momentum, baroclinic wave packets,

SST anomalies, persistent regimes,etc.

Case 2June 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

MJO#2

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Questions???

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

Madden-Julian Oscillation Activity

EH Consolidation

~30 days

~40 days

~20-30 days

~20 days

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Relative Atmospheric Angular Momentum (AAM)

Global AAM

Nov Dec Jan Feb Mar

12/03/05 to 01/02/06

12/03/05 to 01/01/06

03/03/06 to 04/02/06

03/03/06 to 04/01/06

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