516 FXUS06 KWBC 211902 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Tue April 21 2026 6-10 DAY OUTLOOK FOR APR 27 - MAY 01, 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. However, there are some model differences and increasing uncertainty in underlying variations through the period. The manual height blend of 500-hPa height forecasts is based on 0Z ensemble means, weighting the ECMWF model greater due to recent model skill. All ensemble means predict an amplified trough over the Aleutians and the Bering Sea at the start of the 6-10 day period, that deamplifies and retrogresses over time. A ridge and associated positive 500-hPa height anomalies are predicted over the northeastern Pacific Ocean extending into Southeast Alaska and eastern Mainland Alaska, which is significantly more amplified in the ECMWF than the GEFS. The ECMWF ensemble mean predicts positive 500-hPa height anomalies to extend over the northwestern contiguous United States (CONUS) later in the period. A trough and associated negative 500-hPa height anomalies extend from near the California coast to the northern interior CONUS at the start of the period in all ensemble means. The ECMWF ensemble mean predicts the center of negative 500-hPa height anomalies further west over the Northern Rockies and High Plains on day 6, relative to negative anomalies centered over the Northern Plains in the GEFS ensemble mean forecast. During the period, the trough deamplifies somewhat over Southern California and the Southwest, while a trough amplifies over the northeastern CONUS. A ridge and positive 500-hPa height anomalies are predicted along most of the Gulf Coast by the ensemble mean forecasts and the manual blend. Below normal temperatures are favored for the far western Aleutians, under anomalous northerly flow behind a predicted trough. Above normal temperatures are favored for most of Mainland Alaska, excluding most of the southern Mainland, under southerly mid-level flow, and for Southeast Alaska, under positive 500-hPa height anomalies. Above normal temperatures are favored for parts of the Pacific Northwest, under a predicted ridge. Below normal temperatures are favored for parts of the Southwest across the Central Rockies, and are likely for much of the northern central CONUS, under a predicted trough early in the period. Above normal temperatures are likely for most of the Southern Plains and the Southeast, under weak ridging and consistent with the consolidation of calibrated ECMWF and GEFS temperature forecasts. Above normal temperatures are favored for far northern areas of the Northeast, under positive 500-hPa height anomalies early in the period. Above normal temperatures are likely for Hawaii, with positive sea surface temperature anomalies in the vicinity. Above normal precipitation is favored for the Aleutian Islands and Mainland Alaska, under and ahead of a predicted trough. Below normal precipitation is favored for southern areas of Southeast Alaska, consistent with most precipitation tools. Below normal precipitation is slightly favored for parts of northwestern Oregon and western Washington, under a predicted ridge. Above normal precipitation is favored from California eastward across most of the CONUS ahead of predicted troughs over Southern California and the northern central CONUS, excluding South Florida and much of the northern tier from the Pacific Northwest to the Northern Plains. Probabilities for above normal precipitation exceed 50 percent from central California into parts of the Great Basin, although predicted precipitation anomalies are relatively small. Probabilities favoring above normal precipitation exceed 50 percent from the central Gulf Coast states to the Ohio Valley and parts of the Northeast Atlantic coast, consistent with the precipitation consolidation. 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, 45% of Today's 0z European Ensemble Mean centered on Day 8, and 25% 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 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 APR 29 - MAY 05, 2026 Ensemble mean forecasts for the 8-14 day period from the 0Z ECMWF, GEFS, and Canadian models predict some persistent large-scale features from the 6-10 day period forecasts, along with weakening of mid-level height anomalies and some changes in the pattern over the CONUS. A trough and negative 500-hPa height anomalies persist but deamplify and retrogress over the western Aleutians. A ridge persists into the week-2 period over Mainland Alaska and Southeast Alaska, while positive 500-hPa height anomalies weaken. With increasing uncertainty and differences among model ensemble means, weak troughing is present over California and parts of the Southwest in the manual blend for week 2. All ensemble means predict amplification of negative 500-hPa height anomalies associated with a trough over the West Coast late in week 2. A trough is predicted from the northern central CONUS across the Northeast and Mid-Atlantic, in all dynamical model forecasts, with some differences in the amplitude and extent of negative 500-hPa height anomalies between models. Above normal temperatures are favored for central and northern Mainland Alaska, as well as most of Southeast Alaska, under a predicted ridge and consistent with a consensus of model temperature tools. Above normal temperatures are favored for most of the Pacific Northwest, the Northern Rockies, and the California coast, consistent with calibrated ECMWF temperature forecasts. Below normal temperatures are favored for the Central and Northern Plains eastward across the Midwest to the Mid-Atlantic and most of the Northeast, excluding northern Maine, under a predicted trough. Above normal temperatures are favored for much of the Southwest border with Mexico, southern Texas and the Gulf Coast, consistent with the temperature consolidation. Above normal temperatures are likely for Hawaii, surrounded by positive sea surface temperature anomalies. Above normal precipitation is favored for the Aleutians and western Mainland Alaska in the 8-14 day period, under and ahead of the predicted trough. Below normal precipitation is favored for southern areas of Southeast Alaska, consistent with calibrated ECMWF model precipitation forecasts. Ahead of predicted troughing, above normal precipitation continues to be favored into the week-2 period across most of the western CONUS, excluding parts of the Pacific Northwest. Enhanced probabilities for above normal precipitation extend across most of the Central and Southern Plains into the Southeast, and northward through the Mid-Atlantic coast into the Northeast, consistent with the precipitation consolidation. 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, 45% of Today's 0z European Ensemble Mean centered on Day 11, and 25% 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: 20180502 - 20040417 - 20090424 - 20150405 - 20180427 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: 20180502 - 20040417 - 20210331 - 20020417 - 20150406 6-10 DAY OUTLOOK TABLE Outlook for Apr 27 - May 01, 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A N OREGON N N NRN CALIF N A SRN CALIF N A IDAHO N A NEVADA N A W MONTANA N N E MONTANA B N WYOMING B A UTAH B A ARIZONA B A COLORADO B A NEW MEXICO N A N DAKOTA B N S DAKOTA B A NEBRASKA B A KANSAS B A OKLAHOMA N A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA B A IOWA B A MISSOURI N A ARKANSAS A A LOUISIANA A A WISCONSIN N A ILLINOIS N A MISSISSIPPI A A MICHIGAN N A INDIANA N A OHIO N A KENTUCKY A A TENNESSEE A A ALABAMA A A NEW YORK N A VERMONT A A NEW HAMP N A MAINE A A MASS N A CONN N A RHODE IS N A PENN N A NEW JERSEY N A W VIRGINIA N A MARYLAND N A DELAWARE N A VIRGINIA N A N CAROLINA A A S CAROLINA A A GEORGIA A A FL PNHDL A A FL PENIN A N AK N SLOPE A A AK ALEUTIAN N A AK WESTERN A A AK INT BSN A A AK S INT N A AK SO COAST N A AK PNHDL A B 8-14 DAY OUTLOOK TABLE Outlook for Apr 29 - May 05, 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A N OREGON A A NRN CALIF N A SRN CALIF N A IDAHO N A NEVADA N A W MONTANA N A E MONTANA B N WYOMING N A UTAH N A ARIZONA N A COLORADO N A NEW MEXICO N A N DAKOTA B N S DAKOTA B A NEBRASKA B A KANSAS B A OKLAHOMA N A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA B N IOWA B N MISSOURI B A ARKANSAS N A LOUISIANA A A WISCONSIN B N ILLINOIS B N MISSISSIPPI N A MICHIGAN B N INDIANA B N OHIO B N KENTUCKY B N TENNESSEE B A ALABAMA N A NEW YORK B A VERMONT B A NEW HAMP B A MAINE N A MASS B A CONN B A RHODE IS B A PENN B N NEW JERSEY B A W VIRGINIA B N MARYLAND B A DELAWARE B A VIRGINIA B A N CAROLINA N A S CAROLINA N A GEORGIA A A FL PNHDL A A FL PENIN A N AK N SLOPE A A AK ALEUTIAN N A AK WESTERN A A AK INT BSN A A AK S INT N A AK SO COAST N A AK PNHDL A B 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. $$