682
FXUS24 KWNC 141403
PMDENS
El Nino/Southern Oscillation (ENSO) Diagnostic Discussion
NWS Climate Prediction Center College Park MD
900 AM EST Thu 14 Nov 2024

NOTE: figures mentioned in the discussion are available on
the internet at HTTP://WWW.CPC.NCEP.NOAA.GOV

ENSO Alert System Status: La Nina Watch

Synopsis: La Nina is most likely to emerge in October-December
2024 (57percent chance) and is expected to persist through
January-March 2025.

Over the past month, ENSO-neutral continued, as evidenced
by overall near-average sea surface temperatures (SSTs)
observed across the central and eastern equatorial Pacific Ocean
(Fig. 1). Similar to last month, the latest weekly Nino indices
ranged from +0.2degC (Nino-4) to -0.3degC (Nino-3.4; Fig. 2).
Below-average subsurface temperatures persisted (Fig. 3) across
the east-central and eastern equatorial Pacific Ocean (Fig. 4).
For the monthly average, low-level wind anomalies were easterly
over a small region of the east-central equatorial Pacific, and
upper-level wind anomalies were near average. Convection was
suppressed over the Date Line and was weakly enhanced over
eastern Indonesia (Fig. 5). The traditional and equatorial
Southern Oscillation indices were positive. Collectively,
the coupled ocean-atmosphere system reflected ENSO-neutral.

The IRI plume predicts a weak and a short duration La Nina,
as indicated by the Nino-3.4 index values less than -0.5degC
(Fig. 6). The latest North American Multi-Model Ensemble (NMME)
forecasts are cooler than the IRI plume and predict a weak
La Nina. Due to this guidance and La Nina-like atmospheric
circulation anomalies over the tropics, the team still favors
onset of La Nina, but it is likely to remain weak and have
shorter duration than other historical episodes. A weak La Nina
would be less likely to result in conventional winter impacts,
though predictable signals could still influence the forecast
guidance (e.g., CPC`s seasonal outlooks). In summary, La Nina
is most likely to emerge in October-December 2024 (57percent
chance) and is expected to persist through January-March 2025
(Fig. 7).

This discussion is a consolidated effort of the National
Oceanic and Atmospheric Administration (NOAA), NOAA`s National
Weather Service, and their funded institutions. Oceanic and
atmospheric conditions are updated weekly on the Climate
Prediction Center website (El Nino/La Nina Current Conditions
and Expert Discussions). Additional perspectives and analyses
are also available in an ENSO blog. A probabilistic strength
forecast is available here. The next ENSO Diagnostics
Discussion is scheduled for 12 December 2024. To receive
an e-mail notification when the monthly ENSO Diagnostic
Discussions are released, please send an e-mail message to:
ncep.list.enso-update@noaa.gov.



$$