FXUS06 KWBC 012001 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Thu May 01 2025 6-10 DAY OUTLOOK FOR MAY 07 - 11 2025 Dynamical models are in good agreement regarding the 500-hPa height pattern across North America and the surrounding region. A broad area of positive 500-hPa height anomalies is forecast for the western contiguous U.S. (CONUS) and across the northern tier and southern Canada into eastern North America. An area of negative anomalies and mid-level troughing is forecast to undercut the ridge across the southeastern CONUS. Negative 500-hPa height anomalies are forecast across the Gulf of Alaska and much of the South Coast and the southern Mainland. However, with near to below normal heights favored across the remainder of Alaska, this favors increased onshore flow to parts of Southeast Alaska. Above normal temperatures are favored across much of the CONUS today, excluding portions of the south-central and southeastern CONUS. Strong positive mid-level height anomalies bring elevated chances for above-normal temperatures to much of the West, north-central, and northeastern CONUS. Meanwhile, a shortwave trough progressing across the southern tier will bring increased precipitation and cloudiness, bringing enhanced chances for below normal temperatures to the south-central CONUS. In Alaska, above-normal is favored for portions of southwest Alaska and the Aleutians. Below normal temperatures are slightly favored for portions of northern and eastern Mainland Alaska into Southeast Alaska, with near normal favored for the remainder of Mainland Alaska. In Hawaii, above normal temperatures remain favored for the island chain. Above normal precipitation is favored for much of the Four Corners, Southern Plains, and the southeastern CONUS as result of a shortwave trough progressing across the southern tier. Below normal precipitation is favored beneath the mid-level ridging and positive 500-hPa height anomalies across the northern tier of the CONUS and along much of the West Coast. Above normal precipitation is favored for southeastern Alaska, with onshore flow bringing enhanced probabilities to Southeast Alaska in particular. A slight tilt toward below normal precipitation is favored along parts of the North Slope. In Hawaii, above-normal precipitation chances are elevated with good agreement among the dynamical guidance. The official 6-10 day 500-hPa height blend consists of 10% of Today's 0z GFS Ensemble Mean centered on Day 8, 25% of Today's 6z GFS Ensemble Mean centered on Day 8, 35% 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: Above Average, 4 out of 5. Due to fairly good agreement in the model height pattern. 8-14 DAY OUTLOOK FOR MAY 09 - 15 2025 The dynamical models remain in good agreement heading into the week-2 period. Positive 500-hPa height anomalies remain forecast across the northern CONUS, with most guidance favoring above normal heights across the West for the week-2 mean, as well. Near to slightly below normal heights are again favored for the southeastern CONUS with a shortwave trough pushing through the region. In Alaska, most guidance forecasts near normal heights for week-2 with weak troughing favored in the Bering Sea and the Aleutian Islands. As with the 6-10 day period, above normal temperatures are favored across much of the CONUS during week-2, excluding the south-central and southeastern CONUS. Positive mid-level height anomalies bring elevated chances for above normal temperatures to much of the West, north-central and northeastern CONUS. Meanwhile, a shortwave trough progressing across the southern tier is associated with enhanced chances for below normal temperatures for much of the region. In Alaska, above normal is favored for much of the southwestern portions of the state with a slight tilt towards below normal along the North Slope. In Hawaii, above normal temperatures remain favored for the island chain. Above normal precipitation remains favored for portions of the Great Basin, Four Corners, Southern Plains, and the southeastern CONUS as result of a shortwave trough progressing across the southern tier. Below normal precipitation is favored beneath the mid-level ridging and positive 500-hPa height anomalies across the Upper Mississippi Valley and adjacent areas of the Great Plains eastward to the Great Lakes and interior Northeast. Near normal precipitation is favored for portions of the northwestern CONUS with slightly more onshore flow into the region relative to the 6-10 day period. Above normal precipitation is favored for the southern portions of Alaska, with onshore flow bringing enhanced probabilities to Southeast Alaska in particular. A slight tilt toward below normal precipitation is favored along the west coast of Mainland Alaska. In Hawaii, above-normal precipitation chances are favored for much of the state, excluding the Big Island, with good agreement among the dynamical guidance. The official 8-14 day 500-hPa height blend consists of: 25% of Today's 0z GFS Ensemble Mean centered on Day 11, 40% of Today's 0z European Ensemble Mean centered on Day 11, and 35% of Today's 0z Canadian Ensemble Mean centered on Day 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Above average, 4 out of 5. Very good agreement among the temperature and precipitation dynamical and statistical tools is offset by differences in ensemble mean 500-hPa height anomalies. FORECASTER: Ryan Bolt Notes: Automated forecasts are issued on Saturday and Sunday. Occasionally manual intervention is necessary to address quality control and consistency issues. In these cases, forecasts are manually drawn but a full discussion is not issued. 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 (unshaded, "N"). Historical average values for the calendar period of the forecast (dashes, "f"). 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 (unshaded, "n"). Historical median values for the calendar period of the forecast (dashes, "inches"). 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 15. 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: 19560513 - 20040422 - 19660424 - 19820425 - 19940411 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: 19640410 - 20040421 - 19660425 - 19560513 - 19610514 6-10 DAY OUTLOOK TABLE Outlook for May 07 - 11 2025 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A N NRN CALIF A N SRN CALIF A N IDAHO A N NEVADA A N W MONTANA A B E MONTANA A B WYOMING A N UTAH A A ARIZONA A A COLORADO B A NEW MEXICO B A N DAKOTA A B S DAKOTA A B NEBRASKA A N KANSAS N A OKLAHOMA B A N TEXAS B A S TEXAS B A W TEXAS B A MINNESOTA A B IOWA A B MISSOURI N N ARKANSAS N A LOUISIANA N A WISCONSIN A B ILLINOIS A B MISSISSIPPI N A MICHIGAN A B INDIANA A B OHIO A B KENTUCKY A N TENNESSEE N A ALABAMA N A NEW YORK A N VERMONT A N NEW HAMP A N MAINE A N MASS A N CONN A N RHODE IS A N PENN A N NEW JERSEY A N W VIRGINIA A N MARYLAND A N DELAWARE A N VIRGINIA A A N CAROLINA A A S CAROLINA A A GEORGIA A A FL PNHDL A A FL PENIN A A AK N SLOPE B N AK ALEUTIAN A N AK WESTERN N N AK INT BSN N N AK S INT N A AK SO COAST N A AK PNHDL B A 8-14 DAY OUTLOOK TABLE Outlook for May 09 - 15 2025 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A N OREGON A N NRN CALIF A N SRN CALIF A N IDAHO A A NEVADA A A W MONTANA A N E MONTANA A N WYOMING A A UTAH A A ARIZONA A N COLORADO A A NEW MEXICO B A N DAKOTA A B S DAKOTA A N NEBRASKA A N KANSAS N N OKLAHOMA B N N TEXAS B A S TEXAS B A W TEXAS B A MINNESOTA A B IOWA A B MISSOURI N B ARKANSAS B N LOUISIANA B A WISCONSIN A B ILLINOIS A B MISSISSIPPI B A MICHIGAN A B INDIANA A B OHIO A B KENTUCKY N N TENNESSEE N N ALABAMA B A NEW YORK A B VERMONT A B NEW HAMP A N MAINE A N MASS A N CONN A N RHODE IS A N PENN A N NEW JERSEY A N W VIRGINIA A N MARYLAND A N DELAWARE A N VIRGINIA A A N CAROLINA A A S CAROLINA N A GEORGIA N A FL PNHDL N A FL PENIN N A AK N SLOPE B N AK ALEUTIAN A N AK WESTERN A N AK INT BSN N N AK S INT A A AK SO COAST A 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. $$