The spring has been very kind to most of us when it comes to moisture. This was something we thought would happen when we did our last update in mid April. I know that the epic blizzard back in late April really did a number on some folks, but it sure beats the alternative. An alternative that included drought, blowing dirt, and failed crops. Southeast Colorado weather is extreme, it always has been and always will be.
Here is the total precipitation for the last 60 days:
I can't underscore enough how important late winter and spring moisture is in keeping drought from developing and spreading. Currently, we aren't seeing any drought issues in Colorado:
El Niño Update
Here is a look at the latest sea surface temperature anomalies:
There is some pretty warm water just northeast of Australia, but most of the Central and Eastern Pacific do not scream El Niño at this time. The one area that I am watching is the Indian Ocean. Areas just west/northwest of Australia are cooler than normal. This may cause high pressure to intensify near that cooler water and create a relative pressure difference across the Pacific... high pressure west with lower pressure east. This may cause the trade winds to weaken or slightly reverse, and allow that warmer water northeast of Australia to push westward. The graph below shows what various models think will happen with El Niño development:
The yellow line is the mean of what the models think will happen, which just reaches weak El Niño criteria through he late summer and winter. Right now, a strong El Niño is not in the forecast. Most models show a weak El Niño developing by late summer and lasting through the winter.
While this event will likely not be a strong one, even a weak El Niño will have an impact. That impact will likely be the continuation of wetter than average conditions. This is especially true with the Pacific Decadal Oscillation remaining positive and the Atlantic Multidecadal Oscillation remaining negative.
In 2004, Gregory McCabe did some brilliant work on the relationship between the PDO (Pacific Decadal Oscillation) and the AMO (Atlantic Multidecadal Oscillation). The map below shows the relationship with each oscillation and phase and how it pertains to drought frequency:
We are currently seeing +PDO and -AMO. The blue in the upper right hand map represents reduced drought frequency. The red shaded areas represent higher than average chances for drought frequency. As of right now, we are dealing with a surplus of moisture for many areas of the Central, Western, and Southern Plains. As long as we keep the current oceanic setup, it is our thinking that Southeast Colorado will not have to worry about drought. When a phase shift occurs with the PDO/AMO, we will likely have to deal with drought again.
June - August Model Forecasts
CFSv2 Temperature Forecast
CFSv2 Precipitation Forecast
The CFSv2 keeps Southeast Colorado cooler than average with generally average rainfall. However, areas just to the south/southeast end up with above average rainfall.
NMME Temperature Forecast
NMME Precipitation Forecast
The NMME model pretty much agrees with the CFSv2 Model. It doesn't have quite as strong of a cool signal for temperature, but it still shows average temperatures and average rainfall during the next 3 months. Plus, it also has areas just southeast of Colorado staying wetter than average.
JAMSTEC Temperature Forecast
JAMSTEC Precipitation Forecast
The JAMSTEC is the only model to forecast above average temperature and above average rainfall. While the above average rainfall signal isn't a strong one, it is still there...
CAS Model (Constructed Analog on Soil Moisture)
The CAS Model shows a strong signal for cooler than average temperature. This is likely due to how much moisture is in the ground right now. Wet ground heats up much less efficiently than does dry ground. Plus, when moisture is evaporated from the ground it can act as fuel for thunderstorms. This in turn puts more moisture back in the ground, and the positive feedback mechanism continues... This is also likely why the model is forecasting above average rainfall too.
We do not see drought returning to Southeast Colorado through August. While there may be occasional drier times, we still continue to forecast average to above average rainfall with average to slightly below average temperatures.
Weather5280 June and July forecast maps