Long Range Forecast: A bit more patience, please; Wetter times ahead


It’s been very difficult to break this dry pattern. However, over the past few weeks, we have seen some changes across the Mid-Atlantic. Some areas are not ‘as dry,’ while other places continue to see little, if any rainfall. We are at least in the right direction, in regards to temperatures. It’s nice to know that 90’s and near 100-degree temperatures from early October are now a thing of the past!

While the forecast in the long term DOES NOT show any ‘drought breaking’ rainfall, wetter times ARE ahead any long range models are picking up on these changes.

There are a few ways that we can tell.

First up, the MJO, or ‘Madden–Julian Oscillation,’ is a tool many forecasters use. It’s the largest element of the intraseasonal (30 to 90-day) variability in the tropical atmosphere. It is an eastward progression of large regions of both enhanced and suppressed tropical rainfall. It’s origin usually begins in the Indian Ocean. As these thunderstorms develop, they circle the tropical areas of the globe and can change the odds of wetter or drier conditions.

MJO Phases diagram

There are eight phases. Depending on the time of year, each phase could mean cold, wet, warm, or dry. Each phase can greatly differ by the month, season, and location.

Here is the current MJO Index Forecast, using the European model and ensembles.

MJO Index Forecast October 8 – October 22

If you follow the lines all the way around from September to October, you’ll see that we are in phase 1. This model wants to take us into phase 2.

MJO Precipitation composites (October-December)

If we look at the precipitation composites, You can see that Phase 2 for OND (October, November and December) favors wetter conditions.

MJO temperature composites (October-December)

For MJO temperature composites, Phase 2 shows cooler temperatures for the Eastern United States.

Super Typhoon Hagibis could be another reason for cooler and wetter times ahead. Hagibis is equivalent to what we know as Category-5 strength. Wind speeds and categories are different in the Western Pacific.

Super Typhoon Hagibis Forecast

By Saturday afternoon, ‘Hagibis’ could make direct landfall across portions of Japan.

Re-curving typhoons often bring troughs across the East-Central and United States, which means cooler and potentially unsettled weather conditions. In time, this may open the door for more increased precipitation chances.

European Weeklies, Courtesy: WeatherBell, European Centre ECMWF

The European Weeklies show wetter times ahead for the Eastern United States. This may be a combination from coastal storms, or systems along cold fronts and pass through the region.

Bottom Line:
– Mild conditions are expected to continue through early next week.
– We should start seeing more rainfall closer to October 15 and beyond.
– Additional rain chances will likely result in cooler temperatures.