Forecast Forum
The canonical correlation analysis (CCA) forecast of
SST in the central Pacific (Barnett et al. 1988, Science, 241,
192‑196; Barnston and Ropelewski
1992, J. Climate, 5, 1316‑1345), is shown in Figs. F1 and F2. This forecast is produced routinely by the
Prediction Branch of the Climate
Prediction Center.
The predictions from the National Centers for
Environmental Prediction (NCEP) Coupled Forecast System Model (CFS03) are
presented in Figs. F3 and F4a, F4b.
Predictions from the Markov model (Xue, et al.
2000: J. Climate, 13, 849‑871) are shown in Figs. F5 and F6.
Predictions from the latest version of the LDEO model (Chen et al. 2000:
Geophys. Res. Let., 27, 2585‑2587)
are shown in Figs. F7 and F8. Predictions using linear inverse modeling (Penland and Magorian 1993: J.
Climate, 6, 1067‑1076) are shown in Figs. F9 and F10. Predictions from the Scripps / Max Planck
Institute (MPI) hybrid coupled model (Barnett et al. 1993: J. Climate, 6,
1545‑1566) are shown in Fig. F11.
Predictions from the ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea.
Forecasting, 12, 633‑652) are shown in Fig. F12. Niño 3.4 predictions are summarized in Fig.
F13, provided by the Forecasting and Prediction Research Group of the IRI.
The CPC and the contributors to the Forecast Forum caution
potential users of this predictive information that they can expect only modest
skill.
ENSO Alert System Status: El Niño Watch
Outlook:
El Niño conditions are likely to develop during
August or September 2012.
Discussion:
ENSO-neutral conditions
continued during July 2012 despite above-average sea surface temperatures (SST)
across the eastern Pacific Ocean (Fig. T18). Reflecting this warmth, most of the monthly
Niño index values remained near or greater than +0.5°C (Table T2). The
oceanic heat content anomalies (average temperature in the upper 300m of the
ocean) also remained elevated during the month, consistent with a large region
of above-average temperatures at depth across the equatorial Pacific (Fig.
T17). Although
sub-surface and surface temperatures were above average, many aspects of the
tropical atmosphere were inconsistent with El Niño
conditions. Upper-level and
low-level trade winds were near average along the equator, while tropical
convection remained enhanced over Indonesia (Figs. T20 and T25). However, convection increased near and just
west of the International Date Line, which may eventually reflect a progression
towards El Niño. The lack of a clear
atmospheric response to the positive oceanic anomalies indicates ongoing
ENSO-neutral conditions.
Nearly all of the
dynamical models favor the onset of El Niño beginning in July- September 2012 (Figs.
F1-F13). As in previous months, several
statistical models predict ENSO-neutral conditions through the remainder of the
year, but the average statistical forecast of Niño-3.4 increased compared to
last month. Supported by model forecasts
and the continued warmth across the Pacific Ocean, there is increased
confidence for a weak-to-moderate El Niño during the Northern Hemisphere fall
and winter 2012-13. El Niño conditions
are likely to develop during August or September 2012.
Weekly
updates of oceanic and atmospheric conditions are available on the Climate
Prediction Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).