My Summer Outlook 2013

[Isotherm]

Factors/Expectations:

 

1)Neutral ENSO conditions should persist through the upcoming summer with sea surface temperature anomalies (SSTA) not far from normal in the tropical Pacific.

 

2)The negative Pacific Decadal Oscillation (PDO), or cold eastern Pacific, that we saw through winter has weakened somewhat, but will continue to be slightly negative/cold this summer season.

 

3)The Atlantic Multidecadal Oscillation (AMO) continues to run slightly positive/warm, with a SSTA profile of warmth near the East Coast, cold in the central Atlantic, and warm in the deep tropics.

 

4)The strong blocking pattern of negative North Atlantic Oscillation (NAO) and negative Arctic Oscillation (AO) that yielded a very cold late winter/early winter has since dissipated. Both indices have been predominately neutral to slightly positive over the past several weeks, and the historical tendency is for this to continue into the ensuing summer. There may be a one month period of –NAO/AO, but the overall signaling should be near neutral or slightly positive in terms of the NAO/AO blocking indicators.

 

5)The closest, most similar analog to the present conditions in terms of PDO, NAO, AO, PNA, ENSO, and other factors appears to be 2001. Note that analogs are utilized as tools to identify patterns and obtain clues from the past that may enable us to more accurately forecast the future. No one year is identical in pattern to another year.

 

6)Palmer Drought Index and Standardized Precipitation Index for the month of May have shown to be excellent foretellers of the June-July-August (JJA) temperature anomalies across the Continental United States (CONUS). The correlation is a strong one, when examining the past 20 years. Areas of drought/dry persistence in May tend to be the breeding grounds for heat in the summer and strong ridging. Likewise, areas of wetness / high soil moisture in the late meteorological spring tend to indicate an ensuing summer of coolness or at least less frequent heat spells.

 

7)Patterns of strong blocking in the late spring often foretell summers of strong USA heat while patterns devoid of blocking in late spring tend to yield summers of weaker USA heat.

 

Correlation of May Palmer Drought Index to JJA temp anomalies

 

Will provide a handful of examples, but the entire period 1995-2012 yielded a high correlation > 80% when we examine the following:

 

Dryness in May –> Warmer JJA

Wetness in May –> Cooler JJA

 

 

 

 

 

 

Precipitation Pattern over the past month:

2001 Analog Temp:

2001 Analog Precip:

NYC Specific Forecast – Temperature Departures:

 

June: -0.5 to +0.5

July: -0.5 to -1.5

August: +1 to +2

JJA: Near Normal

Precip: Above Normal

 

USA:

 

[Isotherm]

Had to delete quite a few images to get it to post. If you'd like to see the rest, go here:

 

http://www.lightinthestorm.com/archives/651

[uncle W]

nice work...I think the summer will be near average too...will it be a cool start and warm finish like 2001?...2001 had the fourth coolest July in 100 years and then August has a 103 degree heat wave...

[SACRUS]

Nice discussion Iso ( i was hoping you'd issue your forecast soon)!  I agree that we'll likely be closer to normal than the 10-11-12 trio but still warmer for the summer.  Interesting that 2011 July was so warm it skewed an otherwise avg/wet June and August.  I think we ride the neutral enso wave and 2001, 1961 become the best mei analogs.  I also agree about the pattern favoring wetter than normal conditions overall aided by large rainfalls rather consistent wet periods.  Anyway - I look fwd to tracking and discussing this summer with the crew.  

[Isotherm]

Thanks guys! Look forward to tracking this summer as well. I think T-storm wise we might be active too given the pattern of back and forth, occasional troughs into the Northeast.

[JBG]

I wonder if 1989 and 2003 and valid analogs since they are from the warm decadal cycle.

[SACRUS]

I wonder if 1989 and 2003 and valid analogs since they are from the warm decadal cycle.

 

2003 was a very wet and quite cool june until the last week of the month.

[Brian5671]

nice writeup-interesting with the wet/dry correlation to heat.  

[Isotherm]

Well another summer has come and gone already...feel free to give any feedback/grade etc...

 

http://www.lightinthestorm.com/archives/651

 

Verification

USA Temperature Departures for June-July-August:

USA Precipitation Departures for June-July-August:

The call for a very warm Western US relative to normal and a cooler/near normal East worked out well, and the precipitation expectation for a wet/very wet East Coast with dryness for most of the rest of the Nation transpired as anticipated.

Local NYC Metro June-July-August Temp Departures:

Central Park: +1.3
Newark, NJ: +1.1
LGA, NY: +1.7
JFK, NY: +1
Overall NYC metro: +1.3

Precipitation was above normal at all sites for June-July-August.

Temperatures were a touch cooler than expected in the OH Valley, and slightly warmer than expected in the Northeast, otherwise, the outlook turned out well precip/temp wise.

Overall Summer 2013 Outlook Grade: B/B+

[uncle W]

Well another summer has come and gone already...feel free to give any feedback/grade etc...

 

http://www.lightinthestorm.com/archives/651

 

Verification

USA Temperature Departures for June-July-August:

USA Precipitation Departures for June-July-August:

The call for a very warm Western US relative to normal and a cooler/near normal East worked out well, and the precipitation expectation for a wet/very wet East Coast with dryness for most of the rest of the Nation transpired as anticipated.

Local NYC Metro June-July-August Temp Departures:

Central Park: +1.3

Newark, NJ: +1.1

LGA, NY: +1.7

JFK, NY: +1

Overall NYC metro: +1.3

Precipitation was above normal at all sites for June-July-August.

Temperatures were a touch cooler than expected in the OH Valley, and slightly warmer than expected in the Northeast, otherwise, the outlook turned out well precip/temp wise.

Overall Summer 2013 Outlook Grade: B/B+

good job...the summer will be remembered for it's stretch of heat in July and rains in June...reverse it for the winter and January would be very cold while the other months were above average...

[Isotherm]

good job...the summer will be remembered for it's stretch of heat in July and rains in June...reverse it for the winter and January would be very cold while the other months were above average...

 

 

Thanks man. Yeah I think the high humidity was the big story this summer. Hopefully this winter will be as easy to forecast but probably not..

[forkyfork]

NYC Specific Forecast – Temperature Departures:

 

June: -0.5 to +0.5 C+

July: -0.5 to -1.5 F

August: +1 to +2 D

[JBG]

This was the summer of blown forecasts. There were innumerable times where flooding rains were expected and only a minor freshet, or no rain at all, occurred.  There was a forecast for a repeat of the early June rains in late June, which fortunately didn't happen.

Another big story was the number of retrograding WAR's.

[winterwarlock]

It wasnt cooler to normsl in the east this summer overall so how do yougive yourself that grade

[Isotherm]

It wasnt cooler to normsl in the east this summer overall so how do yougive yourself that grade

 

 

You have to look at the entire picture. The idea for a hotter west / closer to normal East and very dry Plains/West and very wet East worked out quite well. Yes, the monthly progression July-Aug was off, but most places in NJ/NYC area finished around +0.5 to +1.5 for JJA which is slightly above normal. Most of the East actually finished cooler than I thought. Certainly not a nailed fcst but good overall.

[nzucker]

You have to look at the entire picture. The idea for a hotter west / closer to normal East and very dry Plains/West and very wet East worked out quite well. Yes, the monthly progression July-Aug was off, but most places in NJ/NYC area finished around +0.5 to +1.5 for JJA which is slightly above normal. Most of the East actually finished cooler than I thought. Certainly not a nailed fcst but good overall.

You missed the temperature gradient in the East, though... The cold was in the south, not the north.

[Isotherm]

You missed the temperature gradient in the East, though... The cold was in the south, not the north.

 

Yeah ended up being more of a Nino signature w/ the coolest anomalies in the lower MS valley, SE US.

 

Maybe we can luck out and get a weak nino this winter though I'm leaning neutral atm