JJAS SUMMER WEATHER FORECAST; Saturday, May 2, 2026; Part 1

[Larry Cosgrove]

ABSTRACT

Using a weighted selection of analog years bearing synoptic scale similarities to the period December 1, 2025 to March 17, 2026 , a forecast for temperature and precipitation was constructed on a month-by-month basis for May through September of this year. These are presented in order: WEATHERAmerica, choice of best numerical model, compiled analog for temperature, precipitation potential and 500MB heights. Outlines for temperature anomalies are shown for the European, Middle East and Asian theaters. There is also a discussion, and graphics, about the expected outcome of the 2026 tropical cyclone season in the Atlantic Basin. 

Sunspot Activity

The current past-peak trend of the sunspot cycle is a decent match for the summer of 1971. A more recent comparative season is from 2014.

500MB Comparison Test 

DJFM, 2025-26 is somewhat similar to the same time frame in 1993-94, albeit with much less cold advection and frozen precipitation. 

Surface Temperature Anomaly Similarity 

To look at seasonal shifts, first review the winter season comparison to the DJFM time frame for 2025-26. 2004-05 is a decent match with its cold eastern Canada and northeastern USA, vs. warmth inland.

Global Sea Surface Temperature Anomaly Review 

The Global Sea Surface Temperature Array of 2025 is generally close to the depiction of that from 2026. Key issues here: Will the Atlantic Basin warm as much as the Pacific Basin. I suspect yes, since the Main Development Region has a habit of warming rapidly after a cool (but not cold) start. Are some of the current public forecasts too extreme with comments like "Super El Nino"? Yes, as recent model guidance has backed away from hot outlooks for sector 3.4. But any well-entrenched El Nino will help to produce shearing westerly wind profiles aloft (as well as TUTT signatures in the Atlantic Basin). Many outlines feature a trans-ridge weakness from Florida and along the East Coast. So if a stronger tropical cyclone did form and fell into the 500MB gap, there might be a risk for a Hazel (1954), Agnes (1972) or Floyd (1999) scenario along the Eastern Seaboard.

Expected Outcome Of Tropical Cyclone Season In The Atlantic Basin

The early call for season storm totals in the Atlantic Basin: 13 Named Storms, 6 Hurricanes, 2 of which will be of major intensity. This is close to estimates by the National Hurricane Center and Colorado State University. The equatorial Pacific Basin from China to Central America should become active, but only when the very active polar + subtropical jet stream field moves north and weakens.

ENSO State Comparison Test:

YELLOW suggests MODERATE resemblance to current RONI; RED implies strong comparison

Comparison Year Analogs:

1971, 1976, 1985, 1996, 2001, 2009, 2012, 2017, 2018, 2022, 2023

There are any number of analogs of the RONI (Relative Oceanic Nino Index), but you will notice that there is not a striking/exact match for any year. Adding these to the synoptic climatology comparison list helps to point out where temperatures may be cooler or warmer than modeling, and also discern precipitation potential.

2026 North America Soil Moisture Profile

Two patterns have emerged since the turn of the year. One is for favoring warmth over cold (notice how the very cold Northeast has moderated with more cases of southwest flow aloft), and the other is a corridor from Texas into the Great Lakes that represents a split between two well-defined drought areas. That would mean a warm start to summer overall (once the evolving early May cold snap breaks down). If the Bermuda High weakens while the Sonoran heat ridge amplifies (favored by analogs, modeling, and synoptic climatology, northwest flow scenario with cold frontal passages and more frequent thunderstorms (some severe) will start to cool and moisten theMidwest/Great Lakes and Eastern Seaboard in later summer. The West and south central states, under the subtropical high, could see a fearsome heatwave like 2023.