Sunday, February 27, 2011

FEB. 27, 2011 - WHERE IS THE NORTH ATLANTIC OSCILLATION HEADED?


"NEW ENGLAND & THE NORTH ATLANTIC OSCILLATION" WEEKLY INDICE REVIEW

Ensemble Mean NAO Outlook
  The North Atlantic Oscillation (NAO) GFS (MRF) - Ensemble Indice Forecast from NOAA's Climate Prediction Center (CPC) is currently neutral. The GFS Ensemble Indice Forecast indicates that the NAO will become very weakly Negative around March 2-5.  The GFS Ensemble Indice Forecast then brings the NAO neutral to increasingly Positive during the second week of March.
  The NAO - Operational GFS Indice Forecast from (CPC) is also currently neutral. The Operational GFS Indice Forecast also indicates that the NAO will become very weakly Negative around March 2-5. This indice forecast then indicates that the NAO will be neutral to very weakly Positive during the second week of March.
DISCLAIMER: Adjustment was made to the "Current" Indice observation, due to upcoming changes and Forecaster's understanding of the current Longwave pattern.  

Ensemble Mean AO Outlook
  The Arctic Oscillation (AO) GFS (MRF) - Ensemble Indice Forecast from (CPC) like the NAO, is currently neutral. The GFS Ensemble Indice Forecast indicates that the AO will become very weakly Negative around March 2-5. This indice forecast then brings the AO neutral to increasingly Positive during the second week of March.
  The AO - Operational GFS Indice Forecast from (CPC) is currently neutral. The Operational GFS Indice Forecast indicates that the AO will also become very weakly Negative around March 2-5. This indice forecast also brings the AO neutral to increasingly Positive during the second week of March. DISCLAIMER: Adjustment was made to the "Current" Indice observation, due to upcoming changes and Forecaster's understanding of the current Longwave pattern. 

 Ensemble Mean PNA Outlook
  The Pacific-North American Oscillation (PNA) GFS (MRF) - Ensemble Indice Forecast from (CPC) is currently very weakly Negative. The GFS Ensemble Indice Forecast indicates that the PNA will weaken in a Negative state and become neutral around March 2-5. This indice forecast then appears to bring the PNA increasingly Negative during the second week of March.
   The PNA - Operational GFS Indice Forecast from (CPC) is also currently very weakly Negative. The Operational GFS indicates that the PNA will become very weakly Negative to neutral around March 2-5. This indice forecast appears to bring the PNA weakly Negative around the second week of March. DISCLAIMER: Adjustment was made to the "Current" Indice observation, due to upcoming changes and Forecaster's understanding of the current Longwave pattern.  
   
  The Eastern Pacific Oscillation (EPO) GFS (MRF) - Ensemble Indice Forecast from NOAA's Earth System Research Laboratory (Physical Sciences Division) and NCEP, is currently very weakly Negative. The GFS (MRF) Ensemble Indice Forecast indicates that the EPO will be weakly Negative around the first week of March. However, this indice forecast indicates that the EPO will become neutral to weakly Positive during the second week of March.
   The Western Pacific Oscillation (WPO) GFS (MRF) - Ensemble Indice Forecast from NOAA's ESRL (PSD) and NCEP, is currently moderately Negative. The GFS (MRF) Ensemble Indice Forecast indicates that the WPO will weaken, but still be weakly Negative around the first week of March. This indice forecast later indicates that the WPO will become neutral to very weakly Positive during the second week of March.

Ensemble Mean AAO Outlook
  The Antarctic Oscillation (AAO) GFS (MRF) - Ensemble Indice Forecast from (CPC) is currently neutral. The GFS Ensemble Indice Forecast indicates that the AAO will become neutral to very weakly Negative around March 2-5. This indice forecast then appears to bring the AAO increasingly Positive during the second week of March.
DISCLAIMER: Adjustment was made to the "Current" Indice observation, due to upcoming changes and Forecaster's understanding of the current Longwave pattern.  



EXTENDED OUTLOOK:  I am focusing on the AO & NAO for the Extended Outlook, due to brief important changes that will take place with these indices. The AO & NAO will become increasingly Negative during March 2-5, this will allow for a brief period of below normal temperatures as well as an increased threat for East coast cyclogenesis. There is a possible significant East coast storm threat around March 6-7, how this system affects New England is uncertain but key elements will be present. During this time-frame the AO & NAO will be weakening in a Negative state, and the PNA will trend neutral to very weakly Positive. The longwave pattern across the Northern Hemisphere will be in a state of change, which will aid-in fostering coastal development. After this System Exits - the available dynamics and energy within the Five hundered-millibar Height Pattern will be exhausted, with the remaining trough & Polar Vortex (PV) lifting Northeast. It is at this point when we can say "Goodbye" to the Winter Season 2010/11...
   
LONG RANGE THOUGHTS: Even though La Nina continues to weaken and the Madden Julian Oscillation (MJO) is non-active, the overall Longwave pattern across the Northern Hemisphere will de-amplify and become Zonal. On Friday, I discussed the possibility of the Western Pacific Oscillation (WPO) remaining in a Negative Phase. However, current Indice Forecasts from NOAA's ESRL (PSD) support the WPO to weaken toward neutral around March 6-7. As a result, it's clear that an intense Pacific jet-stream associated with strong Westerlies will drive across the northern United States with temperatures seasonal then above normal during March 8-13. Beyond this point, there is a strong potential for much Above normal temperatures in New England March 13-18, as the westerlies in concert with the Pacific jet-stream strengthens in reaction to a complete de-amplification of the Longwave pattern across the Northern Hemisphere.  In-return, the WPO & EPO will become increasingly Positive.    

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