A Winter North Atlantic Oscillation Predictor in the North Pacific ONLY during El Nino Events.

Here is a bit of climate research from the summer of 2004. It ONLY works during El Nino years defined with the 1971-2000 base period Oceanic Nino Index. From here we look to the North Pacific Sea Level Pressure status throughout October to be deterministic of the December-March North Atlantic Oscillation (NAO). October SLP's below 1013-hPa indicate a higher likelihood of a -NAO, while SLP's above indicate a higher likelihood of a +NAO or Neutral NAO.

Now, the problem for the winter 2014-2015 is we don't know if we will have an official El Nino event as defined by the ONI (5 trimonthly periods of 0.5C or higher in Nino Region 3.4). Some models are predicting an El Nino, some are not. Right now, according to climatology I have used, the only type of +ENSO events that really can occur is a weak event, with a very outside chance of moderate.

The Experimental Winter DJF 2014-15 NAO Forecast using Zonal Wind indicators from May & September

This is a NAO forecast based on research done in 2011, whereby certain zonal wind anomalies in the Northern Hemisphere during May and September are used as predictors. It has worked decent during 2 of 3 forecasts from the winters of 2011-12 & 2012-2013, but busted rather harsh during the Winter of 2013-2014.

Figure 1. Tropical Northern Hemisphere 500mb Loading Pattern in +Mode (NOAA/CPC)

In my attempt to try to figure out why, I remembered the extreme North Pacific regime and Tropical Northern Hemisphere (TNH) (Figure 1) blocking in the Winter 2013-2014 was dominant to the point where I believe it may have affected some way the expected Atlantic DJF blocking outcome (NAO). I noticed the 2 times the model failed quite badly was during periods of extremely positive TNH values, as a matter of fact the winters of 2008-2009 and 2013-2014 had the highest DJF TNH values since 1948. This meant a very strong Hudson Bay Low anomaly over Canada and above normal 500-hPa heights from the Gulf of Alaska to just of the coast of California. Out of all the winters with a TNH of +1 S.D., 4 out of 6 had inaccuracies, which was the largest cluster of inaccuracy found in the data. The model's R^2 has dropped from 0.79 to 0.69 due to the 2013-14 forecast failure, but still describes 69% of the NAO.

NAO Forecast Graphic

The Winter of 2014-2015 could very much be driven by North Pacific dominate variables, although that is not a guarantee. If that is the case, this forecast could be offset by a +TNH dominant winter, so take it as an "Experimental" tool not a definite. The NAO is essentially being forecasted as neutral with a value of -0.13 but with error -0.13 +/- 0.2 or -0.33 to 0.07.

Summer U.S. Temperature 2014 - GWO Forecast (From May 2014) Verification

Here is what was forecasted using Global Wind Oscillation Data from May 2014, specifically key on the temperature distribution across the United States in the bottom-right area of the graphic below.

Now compare it to what actually happened, I believe this summer forecast went rather well.

6-Month North Pacific SST Pool Analogs For the Winter of 2014-2015.

Hello everyone, been awhile since I have blogged, been a busy last summer working at the Midwestern Regional Climate Center in Champaign, IL. As for me, I'm back to checking out what the coming winter could possibly be like. Here are the Top 10 Warmest NPAC analogs for the 30N-70N and 180W-130W bounded SST Pool from March to August in comparison to this last period (MAMJJA 2014) with respect to Winter (DJF) 500mb height anomalies.

These analogs are also broken down by ENSO category with respect to U.S. Temperatures during the November through March Period, notice areas of the Midwest, Great Lakes, and Eastern U.S. have a decent shot at seeing a cold winter based solely on past occurrences of ENSO/NPAC combinations. I wouldn't use this as an exact forecast for winter, but as guidance for the upcoming winter according to what the NPAC looks like now. Notice only one analog had a nation wide warm winter (2005-2006). The MEI is used as the metric to categorize ENSO status.

Summer GWO Radii Model, ENSO Status, Cool Summer on Tap for most of country, West Coast Above Normal Temps...

• The global wind oscillation is progressing along in a more neutral atmospheric ENSO phase where negative mountain and frictional torque rules instead of the "La Nina" like anomalies 15-45 days earlier. The GWO has yet to couple with the oceanic ENSO state. The oceanic ENSO state in the next 30-60 days should shift to Weak El Nino status, a much more tamed +ENSO event than many had already forecasted. The whole idea of a runaway El Nino like that of 97/98 or 82/83 did not make much sense looking at trends in NOI, SOI, and sub-surface temperature wise. This idea of a "Super El Nino" is nothing more than hype by some meteorological outlets and a few environmental pundits. That being said, the PDO being above 1.5 the 1st time since 2005 should help propel the oceanic ENSO Region 3.4 status to a likely moderate event of +1.0 to +1.2C by late fall.
• The GWO Radii Model continues to allude to cooler temperatures over the Midsection and Eastern U.S. while the West Coast should be above normal temperature wise during July/August. This summer cool pattern is something we haven't seen since 2009.



Summer of 2014 Forecast Based On The Global Wind Oscillation

It seems the Atmospheric Base State is still in a La Nina like mode, the Equatorial Pacific is quickly transitioning to an El Nino, but sometimes there is a lag in the coupling between the Oceanic ENSO Pattern and Atmospheric Base State. That lag is occurring now and should sort itself out by the end of the Summer. Here is the latest forecast created from Global Wind Oscillation analogs:

Principal Component Analysis of Winter 2013-2014 - Finding the Predominant Modes

Using the predominant signals of the Winter 13-14 (defined by NDJF), Extremely Warm Mean NPAC SST's, Very High Bering Sea/Alaskan Mean 500mb Heights, Very Low S.E. Canada/Hudson Bay Mean 500mb Heights, and High Pressure dominant Sea Level Pressure over the North Central Plains. These 4 Datasets since 1948 were put through Rotated Principle Components Analysis.

Two Principal Components had significant Eigenvalues of 1 or above and explained 79% of the Winter (NDJF) Pattern. The 1st Principle component explained 43.4% and was determined to be the predominant boreal mode of the East Pacific Oscillation (EPO). The 2nd Principle component explained 35.6% and was determined to be the Tropical/Northern Hemiphere (TNH) teleconnection.