The expectation for a neutral to weak LA NINA episode in the Pacific Ocean this Summer and Fall is a major input to the outlook for average weather over the next 3-4 months, but the -ENSO (La Nina) is not the sole input to the outlook. Ocean patterns in the Atlantic and Caribbean along with recent solar and atmospheric trends are also inputs.
A list of analog years is composited to show what years in past history suggest could be the outcome for the coming Summer.
NATIONAL MODELS BLEND ENSO FORECAST:
INTERNATIONAL MODELS BLEND ENSO FORECAST:
MULTI MODEL SYSTEM SEA-SURFACE TEMPERATURE FORECAST ANOMALY:
HISTORICAL LA NINA TRENDS FOR SUMMER:
NORTH AMERICAN MODEL CONSENSUS:
INTERNATIONAL MODEL CONSENSUS:
MULTI NATIONAL SYSTEM BLEND:
So the models generally agree on above-normal rainfall but are split on temperatures being warmer than normal or just normal.
I will lean more on my analog years list for my outlook...
ANALOG LIST CONSIDERED:
ANALOG SUMMER TEMPERATURE AND RAINFALL OUTLOOK:
Above-normal air-conditioning demand is expected in much of the country. In terms of precipitation the wettest area is the Upper-Midwest and the driest areas are the center of the country to Louisiana and in the Mid-Atlantic states. The later is subject to being thrown off if multiple tropical systems reach there as many indicators point to happening.
For the Atlanta area near-normal rainfall is suggested along with temperatures a little warmer than normal. No drought is indicated by the analogs and is supported by the model blends. A long brutally hot summer is also not indicated for our area but warmer than normal none-the-less.
That does NOT mean there will be no heat waves, it just means steady un-ending extreme heat is not expected as of now.
Remember the outlook covers the average of June-September temperatures and rainfall, it does NOT describe every day or every week.
If data from May or early June indicates a need for a revision then I will update the outlook.
For more follow me on Twitter @MellishMeterWSB.