Hurricane Evolution Status Fcsts 2006 Web

8/8/2019 Hurricane Evolution Status Fcsts 2006 Web

1/29

ENSO Cycle: RecentEvolution, Current

Status and Predictions

Update prepared by

Climate Prediction Center / NCEP

May 30, 2006


2/29

Outline

Overview

Recent Evolution and Current Conditions

Oceanic Nio Index (ONI) Revised 1 March 2004

Pacific SST Outlook

U.S. Seasonal Precipitation andTemperature Outlooks

Summary


3/29

Overview

The recent patterns of SST and upper-ocean heat content indicate a returnto near-average (ENSO-neutral) conditions in the tropical Pacific Ocean.

Statistical and coupled model forecasts indicate that ENSO-neutral

conditions are likely for the remainder of 2006.

Thus, ENSO-neutral conditions can be expected during the next 3-6

months.


4/29

Recent Evolution of Equatorial

Pacific SST Departures

Longitude

Time

During September 2005- January 2006

SST anomalies decreased and below-

average temperatures developed

throughout most of the central and

eastern equatorial Pacific.

In February 2006 positive SST

anomalies developed in the extreme

eastern equatorial Pacific, similar to

what occurred in 1999, 2000 and 2001

(La Nia years).

Recently, near average SSTs have been

observed throughout the equatorial

Pacific, except for 90-100W where

negative anomalies were observed and

for the region west of 180 where

positive anomalies greater than 0.5Cwere observed.


5/29

Nio Indices: Recent Evolution

The latest weekly SST anomalies are

slightly positive in the Nio 4 and 3.4

regions, near zero in the Nio 3 region,and negative in the Nio 1+2 region.

The weak anomalies in all regions

indicate ENSO neutral conditions.


6/29

Average SST Departures in the

Tropical Pacific: Last 4 WeeksEquatorial ocean surface temperatures were near average at most locations across the

equatorial Pacific, except for areas close to the South American coast where negative

anomalies are observed.

30 April 27 May 2006


7/29

Global SST Departures (Deg C):

30 Apr-27 May 2006

The subtropical Atlantic basin (5-25N) has been warmer than average for more than a

year. The equatorial Indian Ocean SSTs are above average. Positive anomalies

dominate the high latitudes in the North Atlantic Ocean and the subtropical and lower

mid-latitudes of the central Indian, South Pacific and western South Atlantic Oceans.


8/29

Evolution of SST Departure

Patterns in the Last 4 Weeks

During May 2006 basin-wide conditions were nearaverage. Negative anomalies were observed in theextreme eastern equatorial Pacific near the South

American coast.

Over this 4-week period warming was observed in

most of the equatorial Pacific.


9/29

Upper-Ocean Conditions in the Eq. Pacific

The basin-wide equatorial upper

ocean (0-300 m) heat content is

greatest prior to and during the

early stages of a warm (El Nio)

episode.

The upper ocean heat content is

least prior to and during the early

stages of a cold (La Nia) episode.

The slope of the oceanicthermocline is least (greatest) during

warm (cold) episodes.

The most recent values of the

upper-ocean heat anomalies and the

thermocline slope index are near

zero, indicating near average

conditions in the equatorial Pacific.

Cold Episodes

Warm Episodes

Themocline slope index is the difference in the anomalous depth of the 20C isotherm

between the western Pacific (160E-150W) and the eastern Pacific (90-140W).


10/29

Central & Eastern Pacific Upper-Ocean

Heat Content Anomalies

Decreasing upper-ocean heat content was observed during July 2005 through

January 2006. Since early February, upper ocean heat content has increased andis currently slightly positive.


11/29

Subsurface Conditions in the

Eq. Pacific

Time

During March early May 2006 positivesubsurface temperature anomalies spread

eastward, while the area of negative

anomalies became restricted to the extreme

eastern equatorial Pacific.

The most recent analysis shows negative

anomalies in the far eastern equatorial

Pacific and positive anomalies between 50and 250 m depth in the region to the west

of 100W.

LongitudeMost recent pentad analysis


12/29

Tropical OLR and winds: last 30 days

Negative OLR anomalies (enhanced convection and precipitation,

blue shading) were observed over portions of Indonesia and

northern Australia. Positive OLR anomalies (suppressed

convection and precipitation, orange shading) were observed overthe central and eastern equatorial Pacific.

Near-average low-level winds were observed over the equatorial

Pacific.

The patterns of anomalous OLR and wind during the last 30 days have weakened

considerably during the last month, but still continue to reflect weak La Nia conditions.Atmospheric conditions over the tropical Pacific often lag changes in the ocean state.

Weak cyclonic circulation anomalies (indicated by C in the figure)

were observed north and south of the equator over the central

tropical Pacific.

C

C


13/29

US Temperature and Precipitation Patterns

during the last 30 and 90 days

30-day (ending 29 May 2006) % of

average precipitation

30-day (ending 27 May 2006)

temperature departures (degree C)

90-day (ending 29 May 2006) % of

average precipitation

90-day (ending 27 May 2006)

temperature departures (degree C)


14/29

Intraseasonal Variability

Intraseasonal variability in the atmosphere (wind

and pressure), often related to the Madden-Julian

Oscillation (MJO), can have a significant impacton surface and subsurface conditions in the Pacific

Ocean.

Related to this activity

significant weakening of the low-level easterlywinds usually initiates an eastward-propagating

oceanic Kelvin wave.

Several Kelvin waves have occurred during thelast year (see next slide).


15/29

Heat Content Evolution in the

Eq. Pacific

The upper-ocean heat content gradually

decreased in the eastern and centralequatorial Pacific and increased in the

extreme western equatorial Pacific

during mid-2005. as a precursor to weak

La Nia conditions that developed in late

2005.

During March-April 2006 the upper-

ocean heat content increased as La Nia

conditions weakened and ENSO-neutral

conditions became established.

Time

Longitude

The downwelling (upwelling) phase of

Kelvin waves is indicated by the dashed

(dotted) lines. Downwelling (upwelling)

produces an increase (decrease) in upper-ocean heat content.


16/29

Low-level (850-hPa) Zonal (east-west)

Wind Anomalies (m s-1

)

Longitude

Time

Weaker-than-average easterlies(orange/red shading).

Stronger-than-average

easterlies (blue shading).

Low-level easterly wind

anomalies dominated the

central equatorial Pacific

during October 2005 April

2006.

Recently, low-level easterly

winds have again become

stronger than average over the

equatorial central Pacific.


17/29

200-hPa Velocity Potential

Anomalies (5N-5S)

Negative anomalies (green shading)

indicate favorable conditions for

precipitation.

Positive anomalies (brown shading)

indicate unfavorable conditions for

precipitation.

Longitude

Time From late December to late February,there was some eastward propagation,

indicating weak-to-moderate MJO

activity.

In early March the MJO activity

weakened and became incoherent.

Signs of strengthening MJO activity are

evident in May 2006.


18/29

Outgoing Longwave Radiation

(OLR) Anomalies

Wetter-than-averageconditions (blue shading)

Drier-than-average conditions

(orange/red shading)

Longitude

Time

From November 2005 through

April 2006 a persistent pattern of

suppressed convection was

observed near the date line(180W), while enhanced

convection, modulated by weak

MJO activity, was observed over

Indonesia (120-130E).

The overall pattern of anomalousconvection during this period is

consistent with La Nia conditions

in the tropical Pacific.


19/29

Oceanic Nio Index (ONI) Based on the principal measure for monitoring, assessment,

and prediction of ENSO (SST departures from average in

the Nio 3.4 region)

Three-month running-mean values of SST departures from

average in the Nio 3.4 region, based on a set of improved

homogeneous historical SST analyses (ExtendedReconstructed SST ERSST.v2). The methodology is

described in Smith and Reynolds, 2003,J. Climate, 16,

1495-1510.

Used to place current conditions in historical perspective

NOAA operational definitions of El Nio and La Nia are

keyed to the index.


20/29

NOAA Operational Definitionsfor El Nio and La Nia

El Nio: characterized by apositive ONI greater than orequal to +0.5C.

La Nia: characterized by anegative ONI less than or

equal to -0.5C.

To be classified as a full-fledged El Nio or La Nia

episode these thresholds must be exceeded for a period of

at least 5 consecutive months.


21/29

ONI: Evolution since 1950

The most recent ONI

value (February-April

2006) is -0.4C.

El Nio

La Nia

neutral


22/29

Historical El Nio and La Nia episodes,

based on the ONI computed using ERSST.v2

AMJ 1997 MAM 1998 2.5

AMJ 2002 FMA 2003 1.5

JJA 2004 JFM 2005 0.9

SON 2000 JFM 2001 -0.7MAM 1994 FMA 1995 1.3

JJA 1998 MJJ 2000 -1.6FMA 1993 JJA 1993 0.8

ASO 1995 FMA 1996 -0.8AMJ 1991 MJJ 1992 1.8

AMJ 1988 AMJ 1989 -1.9JAS 1986 JFM 1988 1.6

SON 1984 MJJ 1985 -1.1AMJ 1982 MJJ 1983 2.3

ASO 1983 DJF 1983/84 -0.9ASO 1977 - DJF 1977/78 0.8

ASO 1974 AMJ 1976 -1.8ASO 1976 JFM 1977 0.8

AMJ 1973 JJA 1974 -2.0AMJ 1972 FMA 1973 2.1

JJA 1970 DJF 1971/72 -1.4ASO 1969 DJF 1969/70 0.7

SON 1967 MAM 1968 -0.9OND 1968 AMJ 1969 1.0

MAM 1964 JFM 1965 -1.1MJJ 1965 MAM 1966 1.6

ASO 1961 MAM 1962 -0.6JJA 1963 DJF 1963/64 1.0

ASO 1949 FMA 1951 -1.8

MAM 1954 DJF 1956/57 -2.1

JAS 1951 - NDJ 1951/52 0.7

MAM 1957 MJJ 1958 1.6

Cold Episodes minWarm Episodes max


23/29

Warm (red) and cold (blue) episodes based on a threshold of +/- 0.5 C for the Oceanic Nino

Index (ONI) [3 month running mean of ERSST.v2 SST anomalies in the Nino 3.4 region

(5N-5S, 120-170W)], based on the 1971-2000 base period. For historical purposes cold and

warm episodes (blue and red colored numbers) are defined when the threshold is met for aminimum of 5 consecutive over-lapping seasons.

Year DJF JFM FMA MAM AMJ MJJ JJA JAS ASO SON OND NDJ

1950 -1.8 -1.5 -1.4 -1.4 -1.4 -1.2 -0.9 -0.8 -0.8 -0.8 -0.9 -1.0

1951 -1.0 -0.8 -0.6 -0.4 -0.2 0.1 0.4 0.5 0.6 0.7 0.7 0.6

1952 0.3 0.1 0.1 0.1 0.0 -0.2 -0.3 -0.3 -0.1 -0.2 -0.2 -0.1

1953 0.1 0.3 0.4 0.5 0.5 0.4 0.4 0.4 0.4 0.4 0.3 0.31954 0.3 0.2 -0.1 -0.5 -0.7 -0.7 -0.8 -1.0 -1.1 -1.1 -1.0 -1.0

1955 -1.0 -0.9 -0.9 -1.0 -1.1 -1.0 -1.0 -1.0 -1.5 -1.8 -2.1 -1.7

1956 -1.2 -0.8 -0.7 -0.6 -0.6 -0.6 -0.7 -0.8 -0.9 -0.9 -0.9 -0.8

1957 -0.5 -0.1 0.2 0.6 0.7 0.8 0.9 0.9 0.8 0.9 1.2 1.5

1958 1.6 1.5 1.1 0.7 0.5 0.5 0.4 0.1 0.0 0.0 0.1 0.3

1959 0.4 0.4 0.3 0.2 0.0 -0.3 -0.4 -0.5 -0.4 -0.4 -0.3 -0.3

1960 -0.3 -0.3 -0.3 -0.2 -0.1 -0.1 0.0 0.0 -0.1 -0.2 -0.3 -0.21961 -0.2 -0.2 -0.2 -0.1 0.1 0.1 0.0 -0.3 -0.6 -0.6 -0.5 -0.5

1962 -0.5 -0.5 -0.5 -0.5 -0.4 -0.3 -0.2 -0.3 -0.4 -0.6 -0.7 -0.7

1963 -0.6 -0.3 0.0 0.1 0.1 0.3 0.6 0.8 0.8 0.9 1.0 1.0

1964 0.8 0.4 -0.1 -0.5 -0.7 -0.7 -0.8 -0.9 -1.0 -1.1 -1.1 -1.0

1965 -0.8 -0.5 -0.3 0.0 0.2 0.6 1.0 1.2 1.4 1.5 1.6 1.5

1966 1.2 1.1 0.8 0.5 0.2 0.1 0.1 0.0 -0.2 -0.3 -0.3 -0.4

1967 -0.4 -0.5 -0.6 -0.5 -0.3 0.0 0.0 -0.2 -0.4 -0.5 -0.5 -0.6

1968 -0.7 -0.9 -0.8 -0.8 -0.4 0.0 0.3 0.3 0.2 0.4 0.6 0.9

1969 1.0 1.0 0.9 0.7 0.6 0.4 0.4 0.4 0.6 0.7 0.7 0.6

1970 0.5 0.3 0.2 0.1 -0.1 -0.4 -0.6 -0.8 -0.8 -0.8 -0.9 -1.2

1971 -1.4 -1.4 -1.2 -1.0 -0.8 -0.8 -0.8 -0.8 -0.9 -0.9 -1.0 -0.9

1972 -0.7 -0.3 0.0 0.3 0.5 0.8 1.1 1.3 1.5 1.8 2.0 2.1

1973 1.8 1.2 0.5 -0.1 -0.5 -0.8 -1.1 -1.3 -1.4 -1.7 -1.9 -2.0

1974 -1.8 -1.6 -1.2 -1.1 -0.9 -0.7 -0.5 -0.4 -0.5 -0.7 -0.8 -0.7

1975 -0.6 -0.6 -0.7 -0.8 -1.0 -1.1 -1.3 -1.4 -1.6 -1.6 -1.7 -1.8


24/29






1976 -1.6 -1.2 -0.9 -0.7 -0.5 -0.2 0.1 0.3 0.5 0.7 0.8 0.8

1977 0.6 0.5 0.2 0.1 0.2 0.3 0.3 0.4 0.5 0.7 0.8 0.8

1978 0.7 0.4 0.0 -0.3 -0.4 -0.3 -0.4 -0.5 -0.5 -0.4 -0.2 -0.1

1979 -0.1 0.0 0.1 0.2 0.1 0.0 0.0 0.2 0.3 0.4 0.5 0.51980 0.5 0.3 0.2 0.2 0.3 0.3 0.2 0.0 -0.1 0.0 0.0 -0.1

1981 -0.3 -0.4 -0.4 -0.3 -0.3 -0.3 -0.4 -0.3 -0.2 -0.1 -0.1 -0.1

1982 0.0 0.1 0.2 0.4 0.6 0.7 0.8 1.0 1.5 1.9 2.2 2.3

1983 2.3 2.0 1.6 1.2 1.0 0.6 0.2 -0.2 -0.5 -0.8 -0.9 -0.8

1984 -0.5 -0.3 -0.2 -0.4 -0.5 -0.5 -0.3 -0.2 -0.3 -0.6 -1.0 -1.1

1985 -1.0 -0.8 -0.8 -0.8 -0.7 -0.5 -0.4 -0.4 -0.4 -0.3 -0.2 -0.3

1986 -0.4 -0.4 -0.3 -0.2 -0.1 0.0 0.2 0.5 0.7 0.9 1.1 1.2

1987 1.3 1.2 1.1 1.0 1.0 1.2 1.5 1.6 1.6 1.5 1.3 1.1

1988 0.8 0.5 0.1 -0.3 -0.8 -1.2 -1.2 -1.1 -1.3 -1.6 -1.9 -1.9

1989 -1.7 -1.5 -1.1 -0.9 -0.6 -0.4 -0.3 -0.3 -0.3 -0.3 -0.2 -0.1

1990 0.1 0.2 0.3 0.3 0.3 0.3 0.3 0.4 0.3 0.3 0.3 0.4

1991 0.5 0.4 0.4 0.4 0.6 0.8 0.9 0.9 0.8 1.0 1.4 1.7

1992 1.8 1.7 1.6 1.4 1.1 0.8 0.4 0.2 -0.1 -0.1 0.0 0.1

1993 0.3 0.4 0.6 0.8 0.8 0.7 0.5 0.4 0.4 0.3 0.2 0.2

1994 0.2 0.3 0.4 0.5 0.6 0.6 0.6 0.6 0.7 0.9 1.2 1.3

1995 1.2 0.9 0.7 0.4 0.2 0.1 0.0 -0.3 -0.5 -0.6 -0.7 -0.8

1996 -0.8 -0.7 -0.5 -0.3 -0.2 -0.2 -0.1 -0.2 -0.2 -0.2 -0.3 -0.4

1997 -0.4 -0.3 0.0 0.4 0.9 1.4 1.7 2.0 2.3 2.4 2.5 2.5

1998 2.4 2.0 1.4 1.1 0.4 -0.1 -0.8 -1.0 -1.1 -1.1 -1.3 -1.5

1999 -1.6 -1.2 -0.9 -0.7 -0.8 -0.8 -0.9 -0.9 -1.0 -1.2 -1.4 -1.62000 -1.6 -1.5 -1.1 -0.9 -0.7 -0.6 -0.4 -0.3 -0.4 -0.5 -0.7 -0.7

2001 -0.7 -0.5 -0.4 -0.2 -0.1 0.1 0.2 0.1 0.0 -0.1 -0.2 -0.2


25/29






2002 -0.1 0.1 0.3 0.4 0.7 0.8 0.9 0.9 1.1 1.3 1.5 1.3

2003 1.1 0.8 0.6 0.1 -0.1 0.0 0.3 0.4 0.5 0.5 0.6

2004

20052006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

20252026

2027

0.5

0.4 0.2 0.2 0.2 0.3 0.4 0.7 0.8 0.9 0.9 0.9 0.8

0.6 0.5 0.3 0.4 0.5 0.3 0.2 0.0 0.0 -0.2 -0.4 -0.7-0.8 -0.7 -0.4


26/29

Most statistical and coupled model forecasts indicate ENSO-neutral

conditions through the end of 2006.

Pacific Nio 3.4 SST Outlook

Figure provided by the

International Research

Institute (IRI) forClimate and Society

(updated 17 May 2006).


27/29

SST Outlook: NCEP CFS

29 May 2006

The CFS ensemble mean (blue line) indicates

slightly warmer-than-average conditions for theremainder of 2006.


28/29

U. S. Seasonal Outlooks

June-August 2006

Temperature Precipitation

Outlooks combine long-term trends and soil-moisture effects,

with typical ENSO cycle impacts, when appropriate.


29/29

Summary

The recent patterns of SST and upper-ocean heat content indicate a returnto near-average (ENSO-neutral) conditions in the tropical Pacific Ocean.

Statistical and coupled model forecasts indicate that ENSO-neutralconditions are likely for the remainder of 2006.

Thus, ENSO-neutral conditions can be expected during the next 3-6

months.

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