La Nina
April
15, 2008
The current La Nina has weakened but will level off in the next two months.
It will remain weak until late fall 2008 then become stronger than it was last December through February then last until at
least next spring (Using ONI, Nino 3.4 region). Cool anomalies continue to arrive in the Nino 3.4 region from the vacinity
of Baja California which is preventing warm anomalies in the Nino 1 + 2 region from propagating west. Cool anomalies (and
high pressure) are expected to return to the South Pacific near South America and carry cool water into the Nino 1 + 2 region.
http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
UPDATE Nov 18:
The Oceanic Kelvin Wave is still moving eastward and has
progressed to between 140w and 120w. This caused warming in all Nino regions except 4, which is now behind the wave and showed
slight cooling in the last week. ONI for SEP/OCT/NOV should fall to –.1. SOI has been constant at about 13. In the east,
high pressure is still dominant off the South American coast but has shown less consistency over the last few weeks. The PSB
- EPS anomaly maps still indicate a healthy Peru Current. The most significant event in the past two weeks was that the 20-degree
thermo cline broke the surface at about 100w.
Update Nov 6:
The eastward moving oceanic kelvin wave has stopped the development of
La Nina conditions. ONI for the past 2 months was 0.0. The Kelvin wave should complete it's course within the next 3 weeks.
SOI is near 14. Ocean temperatures in the eastern equatorial Pacific are dropping slowly while holding steady in the west.
Update Oct. 13:
During the last two weeks temperatures in the Nino 3.4 region
reached the La Nina threshold (-.5) then dipped back to cool neutral conditions (-.4).
This was caused by an eastward moving Kelvin wave and a reduction in SOI, causing a slight slowing of the trade winds.
SOI was affected at Tahiti, as MSLP at Darwin has been steady. The reduction in MSLP in the vicinity of Tahiti was primarily
caused by a disorganization of high pressure in the area. SOI should remain steady or increase in the coming weeks. The real
news, however, are the cool subsurface anomalies (equatorial) that extend from 150E to 100W, to a depth of 500 ft. All warm
anomalies above this upward moving cool mass are gone and this mass of cool water will break the surface in the next few weeks.
The warm tongue is dissipating and the possible development of
El Nino conditions is no longer a concern.
ONI for July-August-September reached 0, this is the lowest
it will go before again rising to La Nina levels.
Update Sept. 30
Evolution toward ENSO negative conditions continue slowly.
Update Sept 15
There have been some significant developments in the past
two weeks. The two most recent anomaly maps show upwelling to the east of the Galapagos and SOI rose quickly to 17. Trade
winds have strengthened. ONI for June-July-Aug was -.1. Nino 3.4 had been at positive values for nearly six weeks and has
now switched back to negative values. Warm subsurface anomalies in the east are nearly depleted and a large body of cool anomalies
is headed for the surface.
Sept. 3
All Nino areas have cooled. SOI jumped to +9. The thermocline continued
to rise in the west and the 21 deg. isotherm broke the surface on Aug 21 near 100 west. Trade winds continue to strengthen.
Aug. 25
Following our last update we read a press release from NOAA, which
changed their hurricane prediction to nearly match ours, based on their prediction of a developing La Nina. At this point
we nearly threw up our hands and gave up, NOAA in this case would be a jinx (they never get it right). Sure enough, all Nino
areas began to warm, the cold upwelling at 100 west stopped it’s ascent, high pressure off South America became disorganized
for the first time in a month and the trade winds began to slow again.
Fortunately the NOAA jinx was short lived and all of those
conditions have reversed themselves, sharply. The anomaly map out today shows an increasing Peru Current and some very small
areas of cold upwelling on both sides of the Galapagos. Unfortunately the equatorial pacific cross section from Triton is
not a real time product so we will have to wait a week or two to see what the ocean is doing there.
Update Aug. 8-10-08
There have been some significant events in the last week or two
that have caught our attention.
There was a period early in the week where the trade winds slowed
down to nearly a crawl in the nino 3.4 and 4 regions, they have picked back up but are still weaker. At the same time, cloudiness
at the dateline increased but has again backed off.
The 20-degree thermocline has risen quite a bit and is less than
50 meters from breaking the surface at 100 W. We do not know if this is a result of the cool upwelling caused by the high
pressure that has stabilized off the South American coast or a rebounding of a Kelvin wave that started in late May, or a
combination of the two.
Cool anomalies from the northwest, what we call the “Baja
Express” have weakened and seem to be coming from farther up the coast of California. However, our initial forecast;
that these cool anomalies will stop the westward propagation of the warm tongue seems to be correct. The warm tongue has stopped
its westward propagation and has cooled slightly in the southeastern portion. The cool anomalies appear to be aided by high
pressure that has stabilized northeast of Hawaii.
Cool, anomalies still persist between 160w and the dateline.
CPC still reports that the atmospheric circulation still
reflects lingering La Nina conditions.
Update August 4:
ENSO conditions in the equatorial Pacific are currently neutral.
ONI for May, June, July is -.4 and indicates the official end to the La Nina. Warming in each of the 4 Nino regions has stopped.
As expected, high pressure has developed and stabilized off the South American coast in the last week causing upwelling to
increase. Trade winds continue to move cooler water westward at the equator. SOI is slowly trending upward from it’s
low in late May and now stands at 3.1.
Update July 26: Little has changed since the last update. The warm tongue
has stopped its westward propagation and winds along the South American west coastline continue to shift north and south preventing increases
or decreases in upwelling. Sea level pressure off the South American coast remains unstable. Atmospheric circulation
in the west equatorial pacific continue to reflect lingering La Nina conditions. Overall ENSO is neutral.
Update July 14: Cool water extending from the vacinity of Baja California
to the Nino 3.4 area has nearly stopped. This has allowed warm water to propagate westward from the nino 1 + 2 area resulting
in a warm tongue extending to about 150W. SOI dropped in the last week and is currently about -.5 High pressure systems off
the coast of Southern Peru were almost non-existent last week resulting in a lack of cool water in the Southeast
Pacific from moving northward into the nino 1 + 2 area. The 20C thermocline slope reflects ENSO neutral conditions. The
effect of these conditions on global temperatures is a reduction in the amount of cold water masses upwelling
from the deep ocean and cold Arctic Ocean surface water that reach the Equatorial Pacific. April-May-June ONI was -.5,
this figure is expected to continue downward and will signal the official end of the La Nina. HOWEVER, 10 meter and 850 hpa
winds (trade winds) in the equatorial Pacific still reflect La Nina conditions.
Update July 7: Since the last update cold anomalies from Baja California
to the Nino 3.4 regeon have warmed. Cool anomalies in the Nino 1 + 2 regeon also began to level out. Winds in the Nino 3.4
weakened last week. High pressure in the Pacific off Southern South American coast also weakened reducing the strength of
the Peru current. All of these indices indicate a weakening of the La Nina. CPC reports that the atmospheric and convective
circulation in the equatorial Pacific reflect "lingering" La Nina.
UPDATE June 25, 2008:
As predicted, the LaNina has weakened to near neutral levels.
ONI at time of prediction was -1.4 and is down to -.7.
High pressure in the Southeast Pacific is strengthening causing cold anomalies
to move northward along the South American coastline bringing cooler waters into the Nino 1 + 2 region. This will continue and strengthen
as the southern hemisphere winter developes.
Cool anomalies continue in the Pacific between Baja California and
the Nino 3.4 region. This condition has prevented warm anomalies in the Nino 1 + 2 region from propagating westward,
preventing warm anomalies from developing in the Nino 3.4 region.
2008 Global Temperatures
The La Nina that is expected to continue through the rest of the year will
keep global temperatures down. 2008 temperatures will continue the cooling trend to between .270C and .296C above anomaly (using
HadCRUT3).
http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt
Ocean temperatures will continue cooling to between .209C and .219C
above anomaly (using HadSST2)
http://www.cru.uea.ac.uk/cru/data/temperature/hadsst2gl.txt
Nov 18 Update:
Jan - Oct Anomaly: Global: .315C above anomaly
Ocean: .251C above anomaly
2008 Atlantic Hurricanes
2008 Hurricane season: 18 named storms with 10 being Hurricanes. This is
based on something we discovered and will remain private for now. : )
Predicted and current count:
Named storms: 18 Hurricanes 10
(predicted)
17 8
(current count)
KBSF ROCKS!
