Prognostic Meteorological Discussion
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FXUS24 KWNC 172006
PMDENS
EL NINO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
1000 AM EST THU 12 JAN 2017

NOTE: FIGURES MENTIONED IN THE DISCUSSION ARE AVAILABLE
ON THE INTERNET AT HTTP://WWW.CPC.NCEP.NOAA.GOV

ENSO ALERT SYSTEM STATUS: LA NINA ADVISORY

SYNOPSIS: A TRANSITION TO ENSO-NEUTRAL IS EXPECTED TO OCCUR
BY FEBRUARY 2017, WITH ENSO-NEUTRAL THEN CONTINUING THROUGH
THE FIRST HALF OF 2017.

LA NINA CONTINUED DURING DECEMBER, WITH NEGATIVE SEA SURFACE
TEMPERATURE (SST) ANOMALIES CONTINUING ACROSS THE CENTRAL AND
EASTERN EQUATORIAL PACIFIC (FIG. 1). THE WEEKLY NINO INDEX
VALUES FLUCTUATED DURING THE LAST MONTH, WITH THE NINO-3 AND
NINO-3.4 REGIONS HOVERING NEAR AND SLIGHTLY WARMER THAN -0.5DEG
C (FIG. 2). THE UPPER-OCEAN HEAT CONTENT ANOMALY WAS NEAR ZERO
WHEN AVERAGED ACROSS THE EASTERN PACIFIC (FIG. 3), THOUGH
NEAR-TO-BELOW AVERAGE SUBSURFACE TEMPERATURES WERE EVIDENT
CLOSER TO THE SURFACE (FIG. 4). ATMOSPHERIC CONVECTION REMAINED
SUPPRESSED OVER THE CENTRAL TROPICAL PACIFIC AND ENHANCED OVER
INDONESIA (FIG. 5). THE LOW-LEVEL EASTERLY WINDS WERE SLIGHTLY
ENHANCED OVER THE WESTERN PACIFIC, AND UPPER-LEVEL WESTERLY
ANOMALIES WERE OBSERVED ACROSS THE EASTERN PACIFIC. OVERALL,
THE OCEAN AND ATMOSPHERE SYSTEM REMAINED CONSISTENT WITH A
WEAK LA NINA.

THE MULTI-MODEL AVERAGES FAVOR AN IMMINENT TRANSITION TO
ENSO-NEUTRAL (3-MONTH AVERAGE NINO-3.4 INDEX BETWEEN -0.5DEG C
AND 0.5DEG C), WITH ENSO-NEUTRAL LASTING THROUGH AUGUST-OCTOBER
(ASO) 2017 (FIG. 6).   ALONG WITH THE MODEL FORECASTS, THE
DECAY OF THE SUBSURFACE TEMPERATURE ANOMALIES AND MARGINALLY
COOL CONDITIONS AT AND NEAR THE OCEAN SURFACE PORTENDS THE
RETURN OF ENSO-NEUTRAL OVER THE NEXT MONTH. IN SUMMARY, A
TRANSITION TO ENSO-NEUTRAL IS EXPECTED TO OCCUR BY FEBRUARY
2017, WITH ENSO-NEUTRAL THEN CONTINUING THROUGH THE FIRST HALF
OF 2017 (CLICK CPC/IRI CONSENSUS FORECAST FOR THE CHANCE OF
EACH OUTCOME FOR EACH 3-MONTH PERIOD).

EVEN AS THE TROPICAL PACIFIC OCEAN RETURNS TO ENSO-NEUTRAL
CONDITIONS, THE ATMOSPHERIC IMPACTS FROM LA NINA COULD PERSIST
DURING THE UPCOMING MONTHS (NOAAS 3-MONTH SEASONAL OUTLOOK
WILL BE UPDATED ON THURSDAY JANUARY 19TH). THE CURRENT SEASONAL
OUTLOOK FOR JFM 2017 FAVORS ABOVE-AVERAGE TEMPERATURES AND
BELOW-MEDIAN PRECIPITATION ACROSS MUCH OF THE SOUTHERN TIER
OF THE U.S., AND BELOW-AVERAGE TEMPERATURES AND ABOVE-MEDIAN
PRECIPITATION IN PORTIONS OF THE NORTHERN TIER OF THE U.S.

THIS DISCUSSION IS A CONSOLIDATED EFFORT OF THE NATIONAL OCEANIC
AND ATMOSPHERIC ADMINISTRATION (NOAA), NOAAS NATIONAL WEATHER
SERVICE, AND THEIR FUNDED INSTITUTIONS. OCEANIC AND ATMOSPHERIC
CONDITIONS ARE UPDATED WEEKLY ON THE CLIMATE PREDICTION
CENTER WEB SITE (EL NINO/LA NINA CURRENT CONDITIONS AND
EXPERT DISCUSSIONS). FORECASTS ARE ALSO UPDATED MONTHLY IN THE
FORECAST FORUM OF CPCS CLIMATE DIAGNOSTICS BULLETIN. ADDITIONAL
PERSPECTIVES AND ANALYSIS ARE ALSO AVAILABLE IN AN ENSO
BLOG. THE NEXT ENSO DIAGNOSTICS DISCUSSION IS SCHEDULED FOR
9 FEBRUARY 2017. 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.

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