Climate Prediction Center - Week 3-4 Outlook

Prognostic Discussion for Week 3-4 Temperature and Precipitation Outlooks
NWS Climate Prediction Center College Park MD
300PM EDT Fri May 15 2026

Week 3-4 Forecast Discussion Valid Sat May 30 2026-Fri Jun 12 2026

Dynamical model guidance favors coherent MJO activity through the end of May and into early June, with the enhanced convective phase potentially propagating across the Pacific and to the Western Hemisphere during the Weeks 3-4 period. This intraseasonal activity would constructively interfere with the evolving low-frequency state trending towards El Niño conditions, resulting in widespread low-level zonal westerly wind anomalies across the equatorial Pacific, expanding to the northeastern tropical Pacific by early June. While tropical-extratropical teleconnections tend to be weak during the boreal late spring and summer months, these signals may bring enhanced moisture to central America, Mexico, and the Gulf of Mexico, and may promote early season tropical cyclogenesis across the East Pacific.

A two-week average 500-mb height anomaly forecast for Weeks 3-4 was constructed from a manual blend of statistical and dynamical model guidance. Ridging over the northeastern Pacific favored during Week 2 is forecast to break down by Weeks 3-4, with anomalous ridging retrograding from the East to the northern Plains and Rockies. Positive height anomalies extend across almost the entire CONUS, with weaker heights favored for Alaska and western California. Most teleconnection signals such as the AO and PNA are favored to be weak at the start of the outlook period.

Given the positive height anomalies, the temperature forecast favors above-normal for much of the contiguous United States. The highest probabilities for above-normal temperatures extend across the north-central Rockies and Plains, where the mean ridge axis is placed in the manual blend. Equal chances are maintained across portions of the southern tier: in California due to the weakness in the height field, and across the south-central US due to a potential for enhanced precipitation. Higher probabilities for above-normal temperatures also extend across portions of the Southeast and mid-Atlantic, where current soil moisture content is extremely low. Despite the height anomaly pattern weakly favoring enhanced southerly flow, below-normal temperatures are forecast for southern Alaska, due in part to below-average sea-surface temperatures just offshore. Above-average temperatures are forecast across Hawaii, with enhanced ridging possible to the north of the enhanced ITCZ.

The Weeks 3-4 precipitation outlook favors below-average precipitation across the Pacific Northwest and far northern coastal California, where short term moisture deficits have been increasing. Above-average precipitation is forecast for a wide swath of the CONUS, extending from the Rockies eastward to the southern Ohio Valley and Southeast. Much of this signal is due to enhanced return flow from the Gulf of America, which would provide ample moisture for widespread convection, and organized convective systems in the presence of any shortwave systems. Equal chances are maintained for the Northeast and much of the Corn Belt, and a slight tilt towards below-average precipitation extends across parts of the Great Lakes region, where moisture availability is less certain. Above-average precipitation is favored for most of Alaska, with below-average precipitation forecast for southern areas of Southeast Alaska. Above-average precipitation is also favored for most of Hawaii, with reduced trade winds likely across the region. Dynamical model guidance indicates a potential for below-average precipitation across the far northwestern islands.

Forecaster: Adam Allgood

The next week 3-4 outlook will be issued on Friday, May 22, 2026

These outlooks are based on departures from the 1991-2020 base period

These are three category outlooks consistent with what is currently used for the monthly and seasonal forecasts.

The shading on the temperature map depicts the most favored category, either above-normal (A), below-normal (B), or near-normal (N) with the solid lines giving the probability ( >33%) of this more likely category (above, below, or near).

The shading on the precipitation map depicts the most favored category, either above-median (A), below-median (B), or near-median with the solid lines giving the probability ( >33%) of this more likely category (above, below, or near).

In areas where the likelihoods of 2-week mean temperatures and accumulated precipitation amounts are similar to climatological probabilities, equal chances (EC) is indicated.