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 23 2025

Week 3-4 Forecast Discussion Valid Sat Jun 07 2025-Fri Jun 20 2025

ENSO neutral conditions are present. Equatorial sea surface temperatures (SSTs) are near average across most of the Pacific Ocean. ENSO neutral conditions are favored through the Northern Hemisphere summer of 2025 (74% chance during June-August), with chances exceeding 50% through August-October 2025.

The Madden Julian Oscillation (MJO) remains incoherent based on RMM observations and other fields. Kelvin Wave activity and a low frequency convection footprint near the Maritime Continent appears to remain the predominant mode of tropical variability since late March. There is broad agreement from the dynamical model RMM forecasts depicting an uptick in the amplitude of the MJO signal over the Maritime Continent in late May. However, any renewed activity is favored to be short-lived, and absent of a sustained, eastward propagation necessary to define an MJO event. There is some support in the extended range (>2 weeks) RMM forecasts favoring a more canonical eastward propagating MJO signal over the Western Pacific and into the Western Hemisphere. However, forecast confidence for a more coherent MJO developing remains low in the outlook, amidst an ENSO neutral background state.

The dynamical models broadly agree on above average 500hPa height anomalies across most of CONUS during the weeks 3-4 period. Over CONUS, slightly above average heights are forecast for much of the Western, Central, and Northeast U.S. The models also agree on a weakness in the above average height pattern over the Southeast. The models disagree most on the forecast height anomalies over Alaska. Most models agree on either near normal or below normal height anomalies over, and near, Alaska, but disagree on the placement and timing of below average heights during the 2-week period. CFSv2 leads the pack with the strongest and largest area of below average height anomalies, placing the trough over the Gulf of Alaska. Both ECMWF and ECCC place the trough north of Alaska. GEFS and JMA forecast near normal heights over Alaska.

The dynamical models agree on warmer than average conditions across most of CONUS with the highest chances for above average temperatures located between the Central Plains and the Intermountain West. Probabilities of above average temperatures are also elevated across the Great Lakes and Northeast. In the Southeast, models forecast either weakly above, or weakly below average temperatures. Given the mixed model guidance, Equal Chances are forecast in the Southeast. Equal Chances are also forecast along the West Coast in deference to both the model height pattern forecasts near the Northwest, and the below average SSTs along the West Coast. The models disagree the most on the temperature outlook for Alaska. ECMWF forecasts slightly cooler than average conditions for most of the state. JMA also forecasts cooler than average conditions but confines it to the South Coast of Alaska. Otherwise, CFSv2, GEFS, and ECCC forecast a slight chance of warmer than average conditions across the state. Given the mixed guidance, probabilities favor slightly elevated chances of warmer than average conditions for the North Slope and northern extent of the Interior Basin in Alaska, along with slightly elevated chances of below average temperatures along the Southern Interior to South Coast region.

The dynamical models agree on wetter than average conditions across the Southeast CONUS, with variation in the spatial distribution of precipitation among the models. The models also agree on a region of drier than average conditions with, again, variation in the location of the dry signal among the models. Given the variation in position across the models, forecast probabilities are only slightly above average in the Southeast and only slightly below average for the Northern and Central Rockies and Intermountain West. The precipitation forecast for Alaska was also mixed. Given the guidance of a blended dynamical forecast, with ECMWF and JMA weighted more than CFSv2, GEFS, and a statistical tool, slightly elevated chances of wetter than average conditions are forecast for most of Alaska with an area of Equal Chances carved out for the Southern Interior and South Coast.

For Hawaii, surrounding SST anomalies continue to be warmer than average. The temperature outlook favors near normal temperatures for all islands except Hilo where chances of below normal temperatures are slightly elevated. Chances for precipitation are forecast to be near normal for Lihue and Honolulu, slightly wetter than normal for Kahului, and drier than normal for Hilo.

Temperature Precipitation

FCST FCST

Hilo B55 B60

Kahului EC A55

Honolulu EC EC

Lihue EC EC

Forecaster: Emerson LaJoie

The next week 3-4 outlook will be issued on Friday, May 30, 2025

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

These are two category outlooks and differ from official current three category outlooks currently used for the monthly and seasonal forecasts.

The shading on the temperature map depicts the most favored category, either above-normal (A) or below-normal (B) with the solid lines giving the probability ( >50%) of this more likely category (above or below).

The shading on the precipitation map depicts the most favored category, either above-median (A) or below-median (B) with the solid lines giving the probability ( >50%) of this more likely category (above or below).

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