QBO Invesigation

Staying on the topic of the QBO, I decided to look back at all years since 1979 that had a September 30mb QBO number within 5.00 of our monthly anomaly this september (21.36). These years also had to fall within 2 months of the westerly QBO peak. Keep in mind that all these years were in the westerly shear phase going into winter, which is where we are headed currently. Here is the corresponding 500mb pattern for the following Dec-Feb periods. 

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OLR anomalies have the MJO mainly in phases 5-8 for the DEC-FEB period.

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Precipitation

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North Pacific Pattern is Key

Couple important things we may want to keep an eye on over the next few months:

1. A batch of much warmer then normal SST's east of Japan favours stronger jet streaks over the north pacific. This sets up a +WPO pattern with zonal flow across Central/Eastern north america and a trough over Alaska/Pacific NW.
250mb Wind Speed and GPH forecast illustrate this pattern

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We need to see the GOA remain warmer then normal with cooling taking place across the bering sea and NW pacific. The ECMWF monthlies support this although the west coast cools some with the GOA warm pool shifting west.

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If we look at past torchy winters in the east we notice similar trends with a Ring of cold in the GOA and warm SST anomalies east of japan.
Sept 2011:

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The good news is, with the MJO currently over the W PAC, the tropics are responding over there with more recurving TC's helping to cool off the GOA/waters East of Japan. Obviously not the only factor to consider but something to keep an eye on...

A quick note on the QBO... we are quickly headed towards the +QBO peak and are expected to head into the westerly shear phase by winter which favours phases 7, 8 and 1 of the MJO.  This bodes well for winter weather lovers as it favours cold and snowy conditions over the eastern two thirds of north america.

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Winter Ramblings

Couple Interesting developments with regard to the GWO phase spacing over the last few months. Notice the gradual but significant shift to positive phases since june/july. The GEFS forecast continues this trend with propagation into phases 5-8 by late sept/early oct. 

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Definitely goes to show the significant recovery from what looked to be at least a weak la nina for a time in early to mid summer. 

The latest weekly SST departures valid sept 16th:
Niño 4 0.0ºC 
Niño 3.4 0.0ºC
Niño 3 -0.2ºC
Niño 1+2 -0.4ºC

With a neutral ENSO signal we will have to turn to other factors...starting with the atlantic. Here is the ideal SST setup for a -NAO in DEC-FEB.

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If we look at our current SST setup we notice a southerly displaced warm belt, positioned off the coast of NL and NS. Cooler SST's are evident south of greenland and iceland. This doesn't bode well for a consistently negative NAO and leans more towards a +NAO pattern in the cold season with a SE ridge.

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H5 anomalies from the past month illustrate this well. Will be interesting to see where we head in the fall.

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In terms of the pacific, +QBO la nada's or la nina's favour a stronger and northerly displaces bering sea ridge. With the GOA expected to cool off, this type of pattern keeps height falls east of the west coast with a SE ridge in place and wave breaking events/troughiness across E CAN, New England and the maritimes. This would keep the mean storm track across the great lakes with above normal precip in the west as well. The Mid ATL/SE would stay warm and dry in this setup. This is how I see the mean pattern setting up for the first half of winter. We should see more enhanced blocking in JAN-FEB and may even see a SSW event with the low solar regime in place. 2001-02 is a good example of how this can happen, despite a +QBO event. 

El Nino Looking More Likely... Implications On Winter Pattern

Starting to notice subsurface anomalies really warming up now with yet another push of warmer then normal anomalies towards nino regions 1,2 and 3 below the surface. 

Surge of warmth was caused by a Kelvin wave that passed through the west pacific in the first few days of september allowing SOI values to drop significantly.

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Euro and NMME suite staying in the el nino or at least warm biased neutral camp and have been pretty consistent for several runs now. With this type of SST profile, positioning will be critical as a basin wide or east based warm event does not produce the goods in the east.

Euro SST profile not ideal with core of warmth near 120W.

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In coldest el nino years we notice the core of warmth west of 130w. For example, 1963 in december was very cold in the east and had that type of setup.

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In 2002 and 1957 we have a basin wide nino in december and a very warm month across much of NA with the exception of the SE in 2002.

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Positioning of warm sea surface temperatures will be key... but could bear fruit if we see a favourable setup.

May Verification and June Forecast

May Temperature Forecast Verification:

Here was my may forecast:

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Actual temperature departures for may:

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For my June temperature forecast I am going with a cold eastern/central part of the u.s. Their are several reasons why I am so aggressive on the cold when CPC has equal chances for june. 

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1. Over the past few weeks we have been seeing wetter than normal conditions over the american midwest and western great lakes region. This means that when warm shots come racing out of the plains they will pack less of a punch then if the ground was already dry.

2. The MJO is headed into phase 2-4 over the next two weeks which favours a trough over the central and eastern part of the u.s. This will make it very difficult for temps to recover later on.

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3. Euro weeklies are strongly supporting a colder than normal june with the first 25 days of the month looking much cooler then normal in the midwest, great lakes and east with wet conditions along the gulf coast.

4. ENSO anomalies have turned much cooler in eastern ENSO regions relative to western ENSO regions. This will keep the core of the heat confined to the SW U.S and western rockies. I think B.C stays transient as systems move through and heights fall later in the month. Temps may end up slightly above normal.


It does look like we will see some very warm days in june across Ontario/quebec it just means that we will see more cloud cover and precipitation holding back departures in southern ontario. In eastern canada, northern ontario and the prairies temps look to average near to above average. This month should also feature above normal severe weather in the great lakes region with more clashes between warm and cool air masses. 

2013 Hurricane Season Outlook

Welcome to my 2013 hurricane outlook. This year will be a challenge for forecasters as we have a neutral ENSO state, moderation in the -PDO and warm AMO pattern.  Lets get right into my analog package.
Top 3 Analogs 

The top year I have been looking into is 2003 which had a weak el nino summer and a warm AMO. The 500mb pattern in the summer featured a trough in the east and a ridge in the west which is what I am expecting this summer. The european is consistent with this type of pattern setting up. Notice the cluster of tracks east of florida and in the western gulf.

1996 is my second best match which had a weakening moderate la nina, similar to this year. It also had eastern troughiness in the JJA 500mb pattern. We also see the spray of tracks originating off of Africa and spreading towards the eastern caribbean and carolinas. This was another active year along the eastern seaboard with a +AMO pattern.

1952 has a nice ENSO match with a similar spread of tracks. Several systems may have went unnoticed in the North Atlantic with the lack of satellite data.

Here is my full analog package SST blend:

If we compare it to this year, notice the similarities with the cool western gulf and warm AMO tripole. There is also cool water in nino 1 and 2.

ENSO

ENSO will be a very key driver for this years hurricane season. The european and canadian guidance suggest a weak modiki el nino throughout the summer with dryness around florida/cuba. The euro monthlies has a trough over the great lakes with a near normal hurricane season in the atlantic basin. It is suggesting two spreads of tracks, one extending from the MDR towards the gulf states and a second one along the eastern seaboard late in the season. Given the overall pattern in place, I agree with the overall tracks advertised by the european but disagree on ENSO state. Currently, we have an area of warmer then normal subsurface SST anomalies between 140E and the dateline. These anomalies may make an attempt to upwell in the central ENSO regions but in a modified form. 

We continue to see OLR anomalies clustering around the maritime continent/eastern IO which supports a neutral ENSO/weak la nina pattern. The atmosphere is not headed towards an el nino very quickly given the lack of a strong subsurface warmth which.

Mid tropospheric easterlies west of the date line and subsequent SOI rises will prevent an incoming el nino. A la nada or very weak el nino is what I am expecting by late summer. This should not prohibit hurricane development given the lag effect involved with a changeable ENSO state. With this being said, we need to look at other factors that can influence the hurricane season.

QBO

Currently we are experiencing a downwelling easterly QBO state which should strengthen into a westerly state by the summer. A downwelling easterly QBO will help promote easterly winds in the stratosphere with lower heights over the caribbean and an increased hurricane threat in the atlantic basin this summer. Notice how the easterlies are already beginning to strengthen in the subtropics around 50mb which is consistent with my analogs (1964 and 1969).

Hurricane Track Forecast

Within a positive AMO period we should always be on the lookout for hurricane tracks up the eastern seaboard. I think this year will be no different with several threats from the carolinas to New England and towards the eastern caribbean. Several of my analog years are pointing towards east coast storm tracks such as Isabel, Juan, Fran and Dora. Many systems may end up tracking just to the east of the northeast coast. In august and september several central caribbean and gulf of mexico tracks are likely as storms shift southwestwards and the bermuda high weakens. Florida will be in the middle of this  track spread which means that it is also at risk of several land falls. I don't feel as if this is a hurricane season like 2005 or 2004 but an above normal season is in the works with a -NAO likely this may with a build up of warm SST's in the MDR.