Evolution toward weak El Nino conditions continue...

[RNS]

Over the course of the past few months...many operational climate models continue to indicate the progression toward El nino Conditions sooner rather than later.

As most of us know...the criteria (established by NOAA) needed in order for El nino conditions to officially be declared is for SSTA anomalies in the ENSO region 3.4 to average at least 0.5C above normal for at least three months. This criteria has NOT yet been met. The data below illustrates this:

2003 8 20.14 -.66 25.04 .08 29.05 .60 26.85 .15
2003 9 20.00 -.48 24.97 .14 29.02 .54 26.96 .32
2003 10 20.99 .08 25.33 .43 29.22 .81 27.19 .60

The values in bold represent the Nino 3.4 anomalies over the past three months...and as we can see...the ENSO 3.4 anomaly has only warmed above 0.50C in one of the past three months...and eventhough this Novembers anomalies in the 3.4 region (not shown) should also average above 0.50C, we would only be left with 2 months of SSTA anomalies above 0.50C. therefore (officially speaking) El nino conditions will not be declared until late december...providing that we also observe SSTA above the critical value in december as well.

SSTA data:

ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52 ... oi.indices

This afternoons run of the NCEP ENSO climate model Supports the trend toward El nino:

Monthly SSTA:



Three Season mean:



As we can see the modelis forecasting the greatest warm anomalies relative to normal to be located in the western pacific...on the order of +0.6 to +1.0C above normal.

The NCEP ENSO model has support from the latest (NOV) run of the AGCM as well:

http://www.emc.ncep.noaa.gov/cmb/atm_fo ... urrent.gif

Note the similar placement of the warm SSTA. furthermore...another surge in the MJO is about to occur...

http://www.cpc.ncep.noaa.gov/products/p ... nthly.html

note the area of increased convection just to the west of the dateline in the equatorial pacific. this convection is likely being enhanced by the very warm SSTA locatedin that particular region. normally the MJO is less active in El Nino winters, although when one has the greatest anomalies relative to normal located in that region...it promots increased convection and a more active MJO. remember that the MJO is described by the westward movement of areas of increased and supressed convection across the tropical pacific. normally the MJO cycles last 30 to 60 days. This feature can be used to assess the fluctuations in the strength of the pacific jet. when the MJO becomes active...the pacific jet becomes enhanced.

this latest surge in the MJO will likely result in the enhancement of the paciifc jet over the next week to 10 days.

furthermore...concerning the evolution of equatorial pacific SSTA...the latest sub-surface temperature analysis (mean and anomaly) would indicate a relatively shallow layer of sub-surface temperatures greater than 20C in the equatorial regions.



this would not support the development of anything more than a weak El nino in the short term. and one which is centered in the western pacific.

SSTA Nino regions(graphic):

http://www.cpc.ncep.noaa.gov/products/a ... gions.html

[JCT777]

So long as the El Nino does not become moderate-to-strong prior to March, I would think it should not be a detriment to cold or snow this winter.

[weatherlover427]

Next winter ... BRING ON THE EL NINO!!! I want my rain! Hardly anything this month and it's already Nov. 25th!

[cycloneye]

RNS not a topic in this forum but if a weak el nino develops next year it will make the 2004 hurricane season somewhat less active but then comes the other factors that may balance things in favor or against an active hurricane season.

[RNS]

fixed some broken links and inserted the rest of the discussion...

[RNS]

RNS not a topic in this forum but if a weak el nino develops next year it will make the 2004 hurricane season somewhat less active but then comes the other factors that may balance things in favor or against an active hurricane season.

Considering the potential for the development of El Nino conditions and the QBO switch to west...im thinking more along the lines of a near normal to very slightly above normal season with reagrd to activity. i doubt we will see another active season such as this past one.

[Anonymous]

What the CPC model shows for summer 04, I'd call a moderate El Nino...not weak. A moderate El Nino like that would probably result in a below average hurricane season. Though I agree with RNS about the slow developing El Nino conditions now to remain weak through the winter.

[NEwxgirl]

what he was talking about was the winter, not the moderate El nino that may be developing for the summer. our best guess right now would be for a near to slightly above normal season. Closer to 2002.

[Stormsfury]

El Niño is definitely on the way unless we see a remarked cooling in the SST's depths, especially ENSO West Regions ... a large pool of warm anomalies continues to slowly intensify and spread across the EPAC and the SST's above 150 meters all across the Equatorial Pacific continue to warm as shown by this loop ...

ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52 ... kxzteq.gif