As the calendar turns from July to August, we really begin to increase the amount of research into the upcoming winter season. While still a couple months out from publishing our official Winter Outlook, we did want to touch base on a couple of items.
The early “baseline” of our ideas focuses on the likelihood of El Nino returning for the upcoming winter season. As we’ve stated many times in the past, each Nino event is different from one another and other ingredients (highlighted above) can play a significant role in ultimately determining the eventual outcome.
- Weak Modoki (central-based) Nino is expected this winter
- SST configuration in the NPAC (north Pacific) is perhaps the most “intriguing” item at the moment
- Low solar/ QBO
Somewhat of a surprise is that the majority of longer range, seasonal data is aligning for a cold, stormy eastern winter. Included in the cold, stormy camp are the JAMSTEC, European, and CanSIPS. A few snap shots are included below…
JAMSTEC Sea Surface Temperature Anomalies for meteorological winter (December through February).
JAMSTEC Surface Temperature Anomalies for meteorological winter.
CanSIPS 500mb for meteorological winter.
The CFSv2 is siding with a warmer winter, but it appears as if the model is struggling with the coming Nino and “over-hyping” things. Accordingly, the model results in a blow torch winter. Again, remember, we’re leaning towards a weak, central-based event.
That sea surface temperature configuration in the northern Pacific argues for western Canada ridging and downstream troughiness such as the JAMSTEC, European, and CanSIPS would imply.
Just wanted to touch base briefly on our early thinking before we release our official 2018-2019 IndyWx.com Winter Outlook in October.
At the surface, all three major global models agree on warmth in the long range period, including the GEFS, EPS, and CFSv2:
Guidance suggests below average precipitation during the period. With broad scale ridging in place, we agree on a drier theme compared to normal. While trying to put our finger on the flip from the prolonged cold to warmer was difficult to nail down from March and April, May always looked like a drier than average month from several weeks out. (One note is the potential of active times across the Great Lakes region as “sudden summer” gains steam to the south and stubborn chill refuses to let go to our north. The gradient would promote heavier than normal precipitation relative to average).
Given the agreement in the data, along with some additional pattern drivers, we continue to believe the medium to longer term period (including mid and late May) will feature an overall warmer than average pattern along with drier than normal conditions.
More specific to Indianapolis, here’s the monthly temperature breakdown so far for 2018:
While we have conflicting temperature ideas, both suggest a drier than average month emerging:
At the end of the day, our call on May’s forecast from mid-April would be for an early cooler than average start before flipping towards more of a seasonable to slightly warmer than normal regime. Our idea all along this spring has been that when this pattern flips, the potential is present to jump right to a summery feel. In the face of the new European Weeklies, we still feel this warmer idea mid and late May is on the table. We’re in agreement with the data of a drier than average month.