818 FXUS06 KWBC 041925 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Mon May 04 2026 6-10 DAY OUTLOOK FOR MAY 10 - 14 2026 The 0Z ECMWF, GEFS and Canadian ensemble mean forecasts agree on the overall average large-scale circulation pattern over North America for the 6-10 day period and on the evolution of the pattern during the period. Models predict a trough over the western Aleutians and Bering Sea, and a second trough to the north of Hawaii, at the start of the period. The trough over the Bering Sea is more amplified and persistent in the ECMWF ensemble mean than the GEFS, while the trough over the North Pacific quickly deamplifies in all model solutions. All models predict an amplified ridge over the western contiguous United States (CONUS), that flattens somewhat and progresses eastward with time. A trough is predicted over eastern Canada and the northeastern CONUS, which gradually deamplifies with time. The manual height blend of 500-hPa height forecasts is based on relatively equally weighted 0Z ensemble means from the ECMWF, GEFS and Canadian models. Above normal temperatures are favored over the western and central Aleutians, consistent with most temperature tools. Below normal temperatures are slightly favored for southwestern Mainland Alaska and parts of the North Slope, consistent with the consolidation of calibrated ECMWF and GEFS temperature forecasts. Above normal temperatures are very likely over the western half of the CONUS, under the predicted ridge, with probabilities exceeding 80 percent in some areas. Above normal temperatures are also favored for Texas, along the immediate Gulf Coast, and Florida, consistent with an automated consensus forecast and the temperature consolidation. Below normal temperatures are favored for the northeastern CONUS from the Central and Upper Mississippi Valleys eastward 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 Hawaii, excluding Kauai, consistent with the temperature consolidation. Above normal precipitation is favored for the Aleutians, most of Mainland Alaska excluding far northwestern areas, and Southeast Alaska, ahead of a predicted trough and consistent with most precipitation tools. Below normal precipitation is favored for most of the West, excluding climatologically dry areas of the Desert Southwest, under the predicted ridge. Probabilities slightly favoring below normal precipitation extend into parts of the Northern and Central Plains, consistent with the precipitation consolidation. Above normal precipitation is slightly favored for eastern areas of the Southwest, consistent with the consolidation of calibrated ECMWF and GEFS forecasts. Enhanced probabilities of above normal precipitation extend from Texas across the Gulf Coast region and Southeast and northward into the Ohio Valley, eastern Great Lakes region, and northeastern CONUS, ahead of a predicted trough. Above normal precipitation is favored for Hawaii, consistent with the precipitation consolidation. The official 6-10 day 500-hPa height blend consists of 33% of Today's 0z GFS Ensemble Mean centered on Day 8, 34% of Today's 0z European Ensemble Mean centered on Day 8, and 33% 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 good 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 12 - 18 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 over southwestern Mainland Alaska in the manual blend of 500-hPa height forecasts and the ECMWF ensemble mean. A ridge and positive 500-hPa height anomalies are predicted to flatten over the western CONUS in week 2, while progressing eastward into the central CONUS. The predicted trough and negative 500-hPa height anomalies persist over the northeastern CONUS while deamplifying slightly in week 2. Above normal temperatures continue to be favored for the western and central Alaeutians in week 2, and are slightly favored for far northwestern Mainland Alaska, consistent with the temperature consolidation and ECMWF bias-corrected temperature forecasts. Below normal temperatures are slightly 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 western and central CONUS in week 2, under expanding positive 500-hPa height anomalies. Enhanced probabilities of above normal temperatures extend across the Lower Mississippi Valley, the Gulf Coast region, and parts of the Southeast, consistent with the temperature consolidation. Below normal temperatures are favored over much of the northeastern CONUS in week 2, under a predicted trough, with lower probabilities relative to the 6-10 day period forecast. Above normal temperatures are likely for Hawaii, with positive sea surface temperatures in the vicinity. Above normal precipitation is favored for the Aleutians, Southeast Alaska, and Mainland Alaska, excluding parts of 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 northwestern CONUS, while near normal precipitation is favored for most regions. Above normal precipitation is favored for parts of the Southwest, Southern Plains, and Lower Mississippi Valley, consistent with the precipitation consolidation and supported by teleconnections from the center of positive 500-hPa height anomalies. Above normal precipitation is slightly favored across the eastern CONUS, consistent with the precipitation consolidation and southerly surface flow around high pressure to the east. Above normal precipitation is favored for Hawaii, consistent with the precipitation consolidation. The official 8-14 day 500-hPa height blend consists of: 35% of Today's 0z GFS Ensemble Mean centered on Day 11, 35% 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 general agreement on the overall 500-hPa height pattern forecast, offset by weaker anomalies in the manual blend of mid-level height forecasts 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: 20230430 - 20210510 - 20190507 - 20150421 - 20080518 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 - 20250415 - 19950517 6-10 DAY OUTLOOK TABLE Outlook for May 10 - 14 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 B ARIZONA A N COLORADO A N NEW MEXICO A A N DAKOTA N N S DAKOTA A B NEBRASKA A B KANSAS A N OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA B N IOWA B N MISSOURI B N ARKANSAS N A LOUISIANA A A WISCONSIN B N ILLINOIS B A MISSISSIPPI N A MICHIGAN B A INDIANA B A OHIO B A KENTUCKY B A TENNESSEE B A ALABAMA N A 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 B A MARYLAND B A DELAWARE B A VIRGINIA B A N CAROLINA B A S CAROLINA N A GEORGIA N A FL PNHDL A A FL PENIN A A AK N SLOPE B A AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A AK S INT N A AK SO COAST B A AK PNHDL N A 8-14 DAY OUTLOOK TABLE Outlook for May 12 - 18 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A N SRN CALIF A N IDAHO A N NEVADA A N W MONTANA A N E MONTANA A N WYOMING A N 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 N OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA N A IOWA A A MISSOURI A A ARKANSAS A A LOUISIANA A A WISCONSIN N A ILLINOIS N A MISSISSIPPI A A MICHIGAN B A INDIANA N A OHIO B A KENTUCKY N A TENNESSEE N A ALABAMA A A 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 A MARYLAND B A DELAWARE B A VIRGINIA N A N CAROLINA N A S CAROLINA N A GEORGIA A A FL PNHDL A A FL PENIN A A AK N SLOPE N A 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. $$