Sea Surface Temperature And Sea Ice Trends(2)

[Gavin P]

Yes, I'm getting increasingly interested in this evolving Atlantic SST pattern. I think we could do with a further increase in temperatures hrough the tropical Atlantic, but its going on the right direction, I think...

[summer blizzard]

Looking at the latest sea surface temperature anomoly chart, i have identified three main features which will effect on the weather in around a months time...

1) A Mid-Lattiude high in the central Pacific causing downstream amplification

2) A upper Low in the Tropical Pacific indicating the presence of a enhanced Sub-Tropical Jet Stream resulting in the Central Pacific Mid-Lattitude High

3) A strong Azores High ridging northward to be centred to the south west of the British Isles

In conclusion, sea surface temperature anomolies indicate winds probably from a north westerly direction, and dry and dull with high minima.

[Jack Wales]

Some subtle changes on the SST charts to note...

SST's

Growing warmer anomaly around the Azores could increase the strength of the HP cell and with the diminishing La Nina set up the SST's could be more of a driver for this summer.

Looking at the sub surface anomolies, it seems we could be heading into El Nino terriroty.

ENSO - Sub Surface

The warm anomolies over regions 1 & 2 have already propogated to the surface with the cold anomaly (undercut by warm) now diminishing in regions 3 & 4. With the slackening of the equatorial trade winds I expect to see an increase in warm anomalies over the next few months. I wouldn't be surprised to see an MEI above +.75C by the end of June.

Edited May 31, 2008 by Jack Wales

[Gray-Wolf]

Cheers JW! It would seem that NOAA are hedging with a forcast for the next 2 seasons of either a warming into El Nino or a re-intensification back to La Nina......................I could have guessed at that!

[Gavin P]

We appear to be in something of a negative PDO phase, which in the past has tended to make it diffcult for El Nino's to really become established. My suspicion is that this warming of the ENSO regions will struggle to get a real foot hold, and will gradually fizzle out, with renewed cooling taking place as we move towards autumn.

Edited June 1, 2008 by Gavin P

[summer blizzard]

Sea surface temperature anomolies continue to indicate the presence of high pressure over Greenland/Scandinavia in around a months time, this is been brought about by a large Pacific High breaking up the Jet Stream and in turn leading to the Azores High well south west of its average position.

[summer blizzard]

Sea surface temperature anomolies have developed interestingly recently, with a slightly +PNA indicated, this is likely to mean a stronger Azores High, but west of its usual position, leading to low pressure quite close to the south west of the British Isles in around a months time.

Looking at the latest sea surface temperature anomoly chart, i have identified three main features which will effect on the weather in around a months time...

1) A Mid-Lattiude high in the central Pacific causing downstream amplification

2) A upper Low in the Tropical Pacific indicating the presence of a enhanced Sub-Tropical Jet Stream resulting in the Central Pacific Mid-Lattitude High

3) A strong Azores High ridging northward to be centred to the south west of the British Isles

In conclusion, sea surface temperature anomolies indicate winds probably from a north westerly direction, and dry and dull with high minima.

I believed that high pressure would be closer to the British Isles, but in terms of wind direction, i believe that was a pretty good call.

[Gavin P]

Sea surface temperature anomolies have developed interestingly recently, with a slightly +PNA indicated, this is likely to mean a stronger Azores High, but west of its usual position, leading to low pressure quite close to the south west of the British Isles in around a months time.

That sounds like quite a cool and wet patterm SB?

[summer blizzard]

Sea surface temperature anomolies have developed interestingly recently, with a slightly +PNA indicated, this is likely to mean a stronger Azores High, but west of its usual position, leading to low pressure quite close to the south west of the British Isles in around a months time.

That sounds like quite a cool and wet patterm SB?

It does indicate a cyclonic circulation over the British Isles, however with low pressure to the south west, it could either mean a humid south easterly or cool north easterly.

[Gray-Wolf]

NOAA are still being rather cagey about the resurgence of El-Nino in the Pacific with warmer waters already just below the surface. If we do effectively switch from La-Nina to El-Nino over a 5 month period won't this lead to a difficult spell of forecasting? I'm still not ruling out a 6/7 week H.P. Block from mid-July onwards as conditions in the Pacific run their course.

Edited June 23, 2008 by Gray-Wolf

[johnholmes]

won't this lead to a difficult spell of forecasting?

what you mean; more difficult than it is already GW?

short or lrf all seem fraught with difficulties at the moment!

[kold weather]

There is indeed warmer waters below the surface out there Graywolf but until something can upwell them then El Nino is still some ways away. If the upwelling does try to occur then we may eventually find ourselves in an El nino but we shall have to wait and see.

By the way just for those interested the only year that saw that sort of change from strong La nina in the winter to weak El nino by the next Autumn is....1976....and we all remember what happened that summer...

Edited June 24, 2008 by kold weather

[Gavin P]

The synoptic evolution of that summer had already been set by this point, Kold - Indeed, it was really late June that the heatwave got going. Of course, we could always find a hot set up developing later on, but to me the Atlantic looks much to active this year for prolonged high pressure cells to get established.

As far as El Nino goes, I have my doubts to be honest. I *think* the warm waters are really going to struggle to get a foot hold. My suspicion is neutral and if anything trending back to weak La Nina through autumn.

Edited June 24, 2008 by Gavin P

[Jack Wales]

It appears we could be heading into El Nino territory very soon, look at the SST banding and strong +'ve anomalies in regions 1, 2 and 3...

Unisys SST

This is not just a surface feature as it is backed up by +'ve sub surface anomalies...

CPC Sub Surface

Also looking at the time series you would expect the trend towards +'ve to continue, especially for regions 3 & 4...

CPC Time Series

The question is what will be the synoptic effects of migration to El Nino conditions? Well, as said in a previous post the last time the enso went from strongly negative to positive was during summer 1976! I think it's safe to say that we are not going to see a repeat of that summer but we should continue to lose heights to our north thus enabling the jet to take a more n'ly track. I believe this will allow greater scope for the Azores high to ridge towards the UK in August and September.

Edited July 12, 2008 by Jack Wales

[Gavin P]

NCEP discussion is for ENSO to remain neutral through the remainder of summer and through to winter 2009.

http://www.cpc.ncep.noaa.gov/products/anal...s-fcsts-web.pdf

This discussion is updated every Monday though, so it will be interesting to see whether they move towards a positive ENSO state tomorrow.

Edited July 13, 2008 by Gavin P

[Gray-Wolf]

NCEP discussion is for ENSO to remain neutral through the remainder of summer and through to winter 2009.

http://www.cpc.ncep.noaa.gov/products/anal...s-fcsts-web.pdf

This discussion is updated every Monday though, so it will be interesting to see whether they move towards a positive ENSO state tomorrow.

They keep qualifying their forecasts with the 'things can alter very quickly over the northern summer...' line though and I've thought the Nino signal has been building with warmer waters amassing not very far down over some sectors since April.

[summer blizzard]

Sea surface temperature anomolies have developed a lot recently, into something we have not seen in quite some time in the Atlantic. What this means for the UK is that mid-lattitude ridging is indicated for the USA and western Atlantic (possibly leading to an active monsoonal trough - hurricanes?), however in the eastern Atlantic, low pressure looks to take a southerly track with the Azores High well south of its normal position and high heights to the north.

[Gavin P]

When do you anticpiate that from SB? September/October or sooner?

[summer blizzard]

When do you anticpiate that from SB? September/October or sooner?

SST lag is just short of a month however i hav'nt seen the anomolies in a while, so i would suggest around the beggining of August.

[J10]

SB. Looking at recent SST, what would be your thoughts on the weather in August.

[summer blizzard]

For the first ten days at least would suggest low pressure dominant to the south and south west of the UK, so cool and wet, especially for the south.

[Gavin P]

Thanks mate.

So, if your correct, thats as good as August written off!

[BLAST FROM THE PAST]

Thanks mate.

So, if your correct, thats as good as August written off!

Looks like the cold phase PDO is strengthening again. Talk of El Nino conditions I have read around the forum are for me premature...I think neutral for a while with La Nina kicking in for Autumn again.

BFTP

[Glacier Point]

Looks like the cold phase PDO is strengthening again. Talk of El Nino conditions I have read around the forum are for me premature...I think neutral for a while with La Nina kicking in for Autumn again.

BFTP

Indeed Fred, and those cold water anomalies extend to some depth in the central-eastern Pacific north of the equator. We should also remember how the last Nino event completely collapsed within this PDO regime, so neutral ENSO with a possible Nina by spring 09.

[Gray-Wolf]

Thanks guys, the surface SST's look remarkably Nino with warm waters piled up from central America back into the Pacific so i'm glad you've put me straight .