724 FXUS06 KWBC 061909 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Wed May 06 2026 6-10 DAY OUTLOOK FOR MAY 12 - 16 2026 The 0Z ECMWF, GEFS, and Canadian ensemble mean forecasts generally agree on the overall average large-scale circulation pattern over North America for the 6-10 day period, with some differences between models on the evolution of the pattern during the period and in the phase and amplitude of 500-hPa height anomalies. Models predict a trough over the Bering Sea, and a second trough over the North Pacific to the northeast of Hawaii, at the start of the period. The trough over the Bering Sea deamplifies with time in model solutions, while the trough over the North Pacific progresses eastward towards the California coast. The GEFS and Canadian ensemble means predict a greater amplitude trough and negative 500-hPa height anomalies closer to California than the ECMWF. All models predict an amplified ridge over the western contiguous United States (CONUS), that flattens somewhat and progresses eastward with time. The GEFS ensemble mean predicts progression of the ridge further eastward into the central and eastern CONUS, while the ECMWF ensemble mean predicts persistent positive 500-hPa height anomalies over the western CONUS in the 6-10 day period and progression later in week 2. The GEFS and Canadian models predict a trough over eastern Canada and the northeastern CONUS, which deamplifies and progresses eastward with time, while the ECMWF model predicts reamplification of a trough over the northeastern CONUS later in the period. The manual height blend is based on 0Z ECMWF, GEFS, and Canadian model 500-hPa height forecasts, weighting the ECMWF ensemble mean slightly more due to recent model skill. Above normal temperatures are favored over the central Aleutians, consistent with most temperature tools. Below normal temperatures are favored for southern and northeastern Mainland Alaska, consistent with the consolidation of calibrated ECMWF and GEFS temperature forecasts. Above normal temperatures are very likely over the western CONUS, from the Pacific Coast across most of the Great Plains and parts of the Lower Mississippi Valley, under the predicted ridge, with probabilities exceeding 80 percent over parts of the southwestern CONUS. Above normal temperatures are also favored for the Florida Peninsula, consistent with most temperature tools. Below normal temperatures are favored for the northeastern CONUS from the eastern Great Lakes region to the Mid-Atlantic and Northeast, under the predicted trough, with differences among tools on the southward extent of below normal temperatures. Above normal temperatures are favored for most of Hawaii, excluding Kauai, consistent with the temperature consolidation. Above normal precipitation is favored for the Aleutians, Mainland Alaska, excluding the North Slope, and Southeast Alaska, ahead of a predicted trough and consistent with most precipitation tools. Below normal precipitation is favored for the northwestern CONUS, under the predicted ridge. Above normal precipitation is favored for eastern areas of the Southwest, the Southern Plains, the Lower Mississippi Valley, and the Florida Peninsula, consistent with the consolidation of calibrated ECMWF and GEFS precipitation forecasts. Above normal precipitation is slightly favored for northeastern areas of the CONUS, as troughing progresses through the region in model forecasts. Above normal precipitation is favored for Hawaii, consistent with the precipitation consolidation. The official 6-10 day 500-hPa height blend consists of 30% of Today's 0z GFS Ensemble Mean centered on Day 8, 40% of Today's 0z European Ensemble Mean centered on Day 8, and 30% of Today's 0z Canadian Ensemble Mean centered on Day 8 FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: About average, 3 out of 5, due to general agreement among ensemble means on the predicted 500-hPa height pattern, offset by a changing circulation pattern and some differences among model temperature and precipitation tools. 8-14 DAY OUTLOOK FOR MAY 14 - 20 2026 Ensemble mean forecasts for the 8-14 day period from the 0Z ECMWF, GEFS, and Canadian models predict some eastward progression of large-scale features from the 6-10 day period forecasts, with weakening of mid-level height anomalies and increasing differences among ensemble mean forecasts. A weak trough is predicted centered near the coast of western Mainland Alaska in the manual blend of model 500-hPa height forecasts. A ridge and positive 500-hPa height anomalies are predicted to flatten and spread over almost the entire CONUS in week 2. The ECMWF ensemble mean predicts positive 500-hPa height anomalies over the western CONUS at the start of the period and progression of the ridge into the eastern CONUS later in week 2, compared to the GEFS ensemble mean forecast. In week2, the predicted trough over the northeastern CONUS slightly deamplifies and progresses eastward, relative to the 6-10 day period manual blend. Above normal temperatures continue to be favored for the central Aleutians, consistent with most model temperature tools. Below normal temperatures are favored for the south coast of Mainland Alaska, consistent with raw model temperature forecast probabilities and the temperature consolidation. Above normal temperatures are likely for most of the CONUS in week 2, excluding the northern Great Lakes region and the Northeast, under expanding positive 500-hPa height anomalies and consistent with calibrated ECMWF temperature forecasts. Near normal temperatures are favored over much of the northeastern CONUS in week 2, under a deamplifying trough. Above normal temperatures are likely for Hawaii, with positive sea surface temperature anomalies in the vicinity. Above normal precipitation is favored for the Aleutians, Southeast Alaska, and Mainland Alaska, excluding the North Slope, ahead of a predicted trough and consistent with the precipitation consolidation. With weaker positive 500-hPa height anomalies and eastward progression of a ridge over the western CONUS, below normal precipitation is only slightly favored for parts of the northern Rocky Mountains and northern High Plains, while near normal precipitation is favored for most of the northwestern and northern central CONUS. Above normal precipitation is favored for most of California into Nevada, ahead of a predicted trough that approaches the coast later in the period. Above normal precipitation is favored for the Southwest, Southern Plains, Lower Mississippi Valley, and eastern Gulf Coast, consistent with the precipitation consolidation and calibrated ECMWF precipitation forecasts. Above normal precipitation is slightly favored for the Great Lakes region and parts of the northeastern CONUS, consistent with the consolidation precipitation anomalies. Above normal precipitation is favored for Hawaii, consistent with the precipitation consolidation. The official 8-14 day 500-hPa height blend consists of: 30% of Today's 0z GFS Ensemble Mean centered on Day 11, 40% of Today's 0z European Ensemble Mean centered on Day 11, and 30% of Today's 0z Canadian Ensemble Mean centered on Day 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Below average, 2 out of 5, with increasing model differences on the 500-hPa height pattern forecast and uncertainty among the temperature and precipitation tools. FORECASTER: D Collins Notes: The notation for the categorical forecast indicated on the maps is the same as that in the tables: A-above N-near normal B-below The temperature map shows regions with > 33% chance of being warmer (orange, "A"), colder (blue, "B"), or close to (gray, "N") normal. Labels on the shaded lines give the probability (> 33%) of the more likely category (B or A). Probability of N is always < 40%. The precipitation map shows regions with > 33% chance of being wetter (green, "A"), drier (tan, "B"), or close to (gray, "N") normal. Labels on the shaded lines give the probability (> 33%) of the more likely category (B or A). Probability of N is always < 40%. In the southwest and other climatologically dry regions - there will be a greater than 33.3% chance of no precipitation and occasionally even a normal (i.e. Median) value of zero - especially during the dry seasons. In such cases a forecast of near normal is effectively a forecast of little or no precipitation. The climate prediction center uses 1991-2020 base period means as reference in the climate outlooks. The next set of long-lead monthly and seasonal outlooks will be released on May 21. Analogs to the 5 day mean observed pattern centered 3 days ago (D-3) for the region from 20N to 70N latitude and 175E to 60W longitude include the 5 day periods centered on the following dates: 20190507 - 20080518 - 20210509 - 20250416 - 20200416 Analogs to the 7 day mean observed pattern centered 4 days ago (D-4) for the region from 20N to 70N latitude and 175E to 60W longitude include the 7 day periods centered on the following dates: 20190508 - 20230430 - 20150421 - 20080519 - 20210510 6-10 DAY OUTLOOK TABLE Outlook for May 12 - 16 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A B SRN CALIF A N IDAHO A B NEVADA A B W MONTANA A B E MONTANA A B WYOMING A B UTAH A N ARIZONA A N COLORADO A A NEW MEXICO A A N DAKOTA A N S DAKOTA A N NEBRASKA A N KANSAS A A OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA N N IOWA A N MISSOURI A A ARKANSAS A A LOUISIANA A A WISCONSIN N A ILLINOIS N A MISSISSIPPI N N MICHIGAN B A INDIANA N A OHIO B A KENTUCKY N N TENNESSEE N N ALABAMA N N NEW YORK B A VERMONT B A NEW HAMP B A MAINE B A MASS B A CONN B A RHODE IS B A PENN B A NEW JERSEY B A W VIRGINIA N N MARYLAND B A DELAWARE B A VIRGINIA N N N CAROLINA N N S CAROLINA N N GEORGIA N N FL PNHDL N N FL PENIN A A AK N SLOPE B N AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A AK S INT B A AK SO COAST B A AK PNHDL N A 8-14 DAY OUTLOOK TABLE Outlook for May 14 - 20 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A N OREGON A N NRN CALIF A A SRN CALIF A A IDAHO A B NEVADA A A W MONTANA A B E MONTANA A B WYOMING A N UTAH A A ARIZONA A A COLORADO A A NEW MEXICO A A N DAKOTA A N S DAKOTA A N NEBRASKA A N KANSAS A A OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA A N IOWA A A MISSOURI A A ARKANSAS A A LOUISIANA A A WISCONSIN A A ILLINOIS A A MISSISSIPPI A A MICHIGAN N A INDIANA A N OHIO A N KENTUCKY A N TENNESSEE A N ALABAMA A A NEW YORK N N VERMONT N A NEW HAMP N A MAINE N A MASS N N CONN N N RHODE IS N N PENN A N NEW JERSEY N N W VIRGINIA A N MARYLAND A N DELAWARE A N VIRGINIA A N N CAROLINA A N S CAROLINA A N GEORGIA A A FL PNHDL A A FL PENIN A A AK N SLOPE N N AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A AK S INT B A AK SO COAST B A AK PNHDL N A LEGEND TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN B - BELOW B - BELOW THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE. FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS PMDMRD. $$