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 30 2025

Week 3-4 Forecast Discussion Valid Sat Jun 14 2025-Fri Jun 27 2025

The Weeks 3-4 Temperature and Precipitation Outlooks issued this week are based on dynamical model guidance, trends, soil moisture and sea surface temperature (SST) anomalies, and expected forcing from large-scale organized tropical convection.

SST anomalies in the equatorial Pacific are now very slightly below zero in the Niño-3.4 region. Cold anomalies can still be found in the Niño-3 region. Current and forecast Outgoing Longwave Radiation (OLR) anomalies indicate a very weak low-frequency positive anomaly over the central equatorial Pacific, indicating anomalously suppressed convection there, albeit with a very small anomaly; additionally, the El Niño/Southern Oscillation (ENSO) teleconnection is substantially weaker now than in winter, therefore, the current ENSO state largely does not factor into the Weeks 3-4 Temperature and Precipitation Outlooks.

The Madden Julian Oscillation (MJO) is currently active, having just exited Realtime Multivariate MJO (RMM) phase 4 and entered phase 5, with a precipitation minimum located over the eastern Indian Ocean, and a less pronounced maximum located over the Maritime Continent. Forecasts from ECMWF indicate that this wave will continue propagating eastward across the equatorial Pacific, passing through phases 6 and 7 in the first week of June, and entering phase 8 during the second week of June. The amplitude is expected to increase, especially while the wave is in phase 7, and these convective anomalies in the first two weeks of June may impact the extratropical circulation pattern in the weeks 3-4 period. Composites of the large-scale extratropical circulation two weeks following June MJO phases 7 and 8 during ENSO-neutral conditions indicate anomalous troughing over the Gulf of Alaska, anomalous ridging extending from the southwestern Contiguous United States (CONUS) to the northern Great Plains states, and anomalous troughing across the eastern CONUS, especially over the southeastern states.

Current coastal SST anomalies are generally below normal along California and the Alaskan Panhandle, with very warm SST anomalies located in the Gulf Coast states, and along the southeastern Atlantic seaboard. Additionally, Lake Michigan surface temperatures have dropped to slightly below average for this time of year.

Soil moisture anomalies indicate very wet conditions extending from northeastern New Mexico, northern Texas, southeastern Oklahoma, and most of Arkansas, Louisiana, Kentucky, Tennessee, Mississippi, and Alabama. Drier-than-normal soil moisture levels are currently seen across much of the southwestern CONUS, most of southern Texas, and in a band extending from Nebraska through northern Illinois. Soil moisture anomalies are likely to continue to evolve prior to the Weeks 3-4 period, though the wet conditions in parts of the south-central and southeastern CONUS gave a slight tilt towards cooler and wetter forecasts in those regions than might be indicated by the dynamical model consensus.

The newest suite of dynamical model guidance generally shows agreement on the large-scale circulation pattern, with the biggest region of uncertainty over the Pacific Northwest. Models show strong anomalous ridging centered near the Aleutian Islands, and anomalous ridging extending from the southwestern CONUS northeastward towards the northern Great Plains. Another anomalous local maximum is located over northern New England. Generally weaker, albeit still positive, anomalies are seen over the southeastern CONUS. A substantial weakness in the ridging, or even an anomalous trough, is seen in most model guidance downstream of the Aleutian ridge; however, the exact position and amplitude varies substantially from model to model. The ECMWF indicates a less well-defined weakness centered over southwestern Canada. The CFS and JMA indicate a slightly more well-defined weakness located over Oregon and Washington. Meanwhile, GEFS shows an even more pronounced weakness in the ridging, even with some negative height anomalies, centered just offshore of the Pacific Northwest, in the northeastern Pacific. Each of these scenarios would imply a different temperature and precipitation forecast for Oregon and Washington, leading to more uncertainty in the forecast over that region.

Given all of the factors mentioned above, the Temperature Outlook for the Week 3-4 period favors warmer than normal temperatures from south Texas, across the Rockies, and along the northern tier of CONUS, with highest probabilities over the central Rocky Mountains. This warm signal is consistent with the large-scale ridging indicated in the dynamical models. The increased uncertainty resulting from dynamical model discrepancies, and the cool SSTs along the California coast, result in a forecast of Equal Chances along the entire West Coast. Equal Chances are indicated for most of the southern Great Plains and southeastern CONUS, a result of taking both dynamical model guidance, and current and expected impacts from soil moisture, into consideration. Higher probabilities of warmer than normal temperatures associated with trends are also forecast for the north slope of Alaska, and a small region of enhanced colder than normal probabilities is indicated for parts of the Alaskan Panhandle, downstream of the Aleutian ridge.

The Precipitation Outlook for the Week 3-4 period favors below median precipitation across parts of the Great Basin and Northern Rockies, consistent with the western CONUS ridge at 500-hPa mentioned previously. Equal Chances are indicated in climatologically dry regions of the southwestern US. Below median precipitation is also favored over much of the Great Lakes region, under the influence of the large-scale 500-hPa ridging. Conversely, above median precipitation is forecast with enhanced probability in a region of the CONUS extending from the Oklahoma Panhandle eastward through the Tennessee Valley and to the Delmarva Peninsula, and extending southward to the Gulf Coast. In these regions, a combination of weaker ridging, anomalous upper-level easterly flow, high soil moisture anomalies, and the potential for tropical moisture from the Gulf, consistent with warm Gulf SSTs, all lend confidence to a general wet pattern. Slightly elevated probabilities of below median precipitation are also indicated for the southern coastline of Alaska, consistent with dynamical model guidance, and likely influenced by anomalous northerly flow and downsloping off the Alaska Range.

Probabilities of above normal temperatures are slightly elevated across the western Hawaiian Islands, with slightly elevated probabilities of below normal temperatures over the Island of Hawaiʻi, supported by anomalous ridging and warm SSTs to the north, and cooler SSTs to the south and east. Model guidance agrees on enhanced below median precipitation probabilities across the eastern Hawaiian Islands, with equal chances indicated for Oʻahu and Kauaʻi.

Temperature Precipitation

FCST FCST

Hilo B55 B60

Kahului EC B55

Honolulu A55 EC

Lihue A55 EC

Forecaster: Michael Goss

The next week 3-4 outlook will be issued on Friday, Jun 06, 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.