329 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 Thu May 21 2026 6-10 DAY OUTLOOK FOR MAY 27 - 31 2026 Dynamical models are in good agreement regarding the 500-hPa height pattern across North America at the start of the 6-10 day forecast period, but begin to diverge toward day-10. An anomalous mid-level ridge (+180 meter positive height anomaly center) is predicted across central Canada with positive 500-hPa height anomalies extending southward into much of the northern and eastern CONUS in the manual height blend. Troughs are forecast on either side of this ridge axis, across southern Alaska and over the northwestern Atlantic, with below-normal heights tied to these features. Additional shortwave troughing and an associated closed low are forecast across the southwestern CONUS early in the forecast period favoring near-normal mid-level heights for the period as a whole. The 0z ECMWF and Canadian ensembles persist the strong ridge across Canada throughout the period, while the 0z GEFS is faster to weaken and broaden this feature across much of the northern CONUS. However, recent skill supports a lean toward the more amplified ECMWF and Canadian solutions. Near normal mid-level heights and southeasterly low-level flow are forecast across Hawaii. The highest confidence in the temperature outlook remains across portions of the Northern and Central Plains into the Midwest underneath the high amplitude mid-level ridge predicted across Canada. Probabilities for above-normal temperatures exceed 80 percent over portions of the Upper Mississippi Valley. However, uncertainty increases farther south, as ridging becomes less influential and enhanced precipitation and cloud cover supports less anomalous temperatures. The uncalibrated 0z ECMWF ensemble depicts elevated chances of below-normal temperatures across much of the Southern Tier, extending into portions of the Tennessee Valley and Mid-Atlantic. Its corresponding reforecast tool also shows a more expansive area of near-normal temperatures compared to yesterday, with a similar, but not as pronounced signal, in the Canadian reforecast tool. Analog guidance also supports a lean toward cooler temperatures. Therefore, probabilities of above-normal temperatures are largely reduced across the southern and southeastern CONUS relative to yesterday, with near-normal temperatures now being favored over many areas and a slight tilt toward enhanced chances of below-normal temperatures across parts of the Southern Plains. Florida continues to tilt toward above-normal temperatures tied to weak subtropical ridging over the southwestern Atlantic early in the period. A transitional temperature pattern is predicted across the western CONUS, with generally cooler temperatures underneath a closed mid-level low early in the period, followed by a warming trend late as the feature weakens. This generally supports near- to slightly below-normal temperatures over most of the West. Persistent cyclonic flow leads to elevated chances of below-normal temperatures across most of Alaska. Above-normal temperatures are favored for most of Hawaii, associated with observed above-normal SSTs in the adjacent Pacific. Shortwave troughing initially predicted across the southwestern CONUS favors enhanced southerly moisture flow from the Gulf, with much of the moisture becoming trapped underneath the ridge to the north. This favors a wet pattern persisting along the Gulf Coast, extending into portions of the Tennessee Valley, Southeast, and Mid-Atlantic at least into the early part of the forecast period. Above-normal precipitation probabilities are also elevated across much of the western CONUS into the Great Plains. By the second half of the period, models depict diminishing precipitation signals as the aforementioned trough over the Southwest weakens. Conversely, chances for below-normal precipitation are increased across portions of the Upper Mississippi Valley, Great Lakes, and Northeast tied to ridging along with support from the ECMWF and GEFS reforecast guidance and analogs. An active pattern is favored for most of Alaska underneath predicted cyclonic flow. Confidence is highest (greater than 40 percent chance) for above-normal precipitation across parts of the eastern mainland and Southeast Alaska, as predicted cyclonic flow promotes enhanced onshore flow. A weak tilt toward above normal precipitation is indicated for Hawaii, consistent with a skill weighted consolidation of calibrated precipitation amounts from the ECMWF and GEFS ensembles. The official 6-10 day 500-hPa height blend consists of 30% of Today's 0z GFS Ensemble Mean centered on Day 8, 35% of Today's 0z European Ensemble Mean centered on Day 8, and 35% of Today's 0z Canadian Ensemble Mean centered on Day 8 FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Average, 3 out of 5, due to decent model agreement early in the period, but offset by increasing spread with time, along with some mixed signals regarding the temperature outlook over the western and southern CONUS. 8-14 DAY OUTLOOK FOR MAY 29 - JUN 04, 2026 During the week-2 period, amplified ridging initially across central Canada is forecast to broaden and retrograde slightly toward western Canada and the northwestern CONUS, with the 0z GEFS being quicker with this evolution compared to the 0z ECMWF and Canadian ensembles. As a result of the broader ridge axis, positive 500-hPa height anomalies of at least +30 meters are indicated across the northern two-thirds of the CONUS in the manual height blend, increasing to greater than +90 meters across the Upper Midwest and Northern Plains. A weakness remains favored across the Southern Tier and along the Gulf Coast and Southeast where near-normal heights are forecast. Troughing over southern Alaska and the northeastern Pacific favors enhanced cyclonic flow over western North America early in the period. However, this trough is forecast to slowly retrograde toward the Aleutians with time as the upstream ridge expands westward, leading to increasing heights over the western CONUS by the middle of the period, and near-to above-normal heights across much of Alaska. Near normal heights continue to be forecast across Hawaii. Above-normal temperatures probabilities are forecast to increase over the western CONUS during week-2 as the mean ridging retrogrades, with stronger signals for warmer temperatures relative to the 6-10 day period in the dynamical models supporting probabilities above 40 percent extending to the Pacific Coast. The broad ridge axis also favors elevated chances of above-normal temperatures over much of the eastern and northern CONUS. Areas of the coastal Mid-Atlantic, Southern Plains, and Lower Mississippi Valley maintain a tilt toward near- to slightly below-normal temperatures based on the analogs and a lingering of the wetter pattern discussed in the 6-10 day period into week-2. Troughing retrograding across southern Alaska favors elevated chances of below normal temperatures across the southern Mainland, Southeast Alaska, and parts of the Aleutians. Near- to above-normal temperatures are more likely across the northern half of the Mainland tied to increasing mid-level heights. Above-normal temperatures are favored for Hawaii, associated with observed above-normal SSTs in the adjacent Pacific. Above-normal precipitation remains favored across much of the interior western CONUS, Great Plains, and into the southeastern quadrant tied to a continued weakness in the 500-hPa height field underneath the ridging to the north and lingering return flow out of the Gulf. Relative to the 6-10 day period, there is a notable eastward shift in the strongest precipitation signals toward portions of the Southeast and Florida where probabilities for above-normal precipitation have been increased above 50 percent over some areas. Surface high pressure continues to favor increased odds for below-normal precipitation across the Great Lakes and Northeast. A drying trend is also likely across the West Coast as ridging expands into the region, with near- to below-normal precipitation becoming favored across portions of California, the Pacific Northwest, and the northern Great Basin. Near to above-normal precipitation is favored for Alaska, underneath predicted mean cyclonic flow. A weak tilt toward above-normal precipitation is indicated for Hawaii, consistent with a skill weighted consolidation of calibrated precipitation amounts from the ECMWF and GEFS ensembles. 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: Average, 3 out of 5, due to good model agreement regarding the mid-level pattern evolution, offset by diminishing signals regarding temperature and precipitation. FORECASTER: Thomas Collow 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 June 18. 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: 20250515 - 20200523 - 19910528 - 20170501 - 20250604 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: 20120528 - 20250501 - 20250515 - 19910528 - 20060506 6-10 DAY OUTLOOK TABLE Outlook for May 27 - 31 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N N OREGON N N NRN CALIF N N SRN CALIF N N IDAHO A A NEVADA N A W MONTANA A A E MONTANA A A WYOMING A A UTAH N A ARIZONA N N COLORADO A A NEW MEXICO B A N DAKOTA A A S DAKOTA A A NEBRASKA A A KANSAS A A OKLAHOMA N A N TEXAS N A S TEXAS N A W TEXAS B A MINNESOTA A N IOWA A A MISSOURI A A ARKANSAS N A LOUISIANA N A WISCONSIN A N ILLINOIS A N MISSISSIPPI N A MICHIGAN A B INDIANA A N OHIO A N KENTUCKY A A TENNESSEE N A ALABAMA N A NEW YORK A B VERMONT A B NEW HAMP A B MAINE A B MASS A B CONN A B RHODE IS A B PENN A B NEW JERSEY A B W VIRGINIA A N MARYLAND A N DELAWARE N N VIRGINIA N N N CAROLINA N A S CAROLINA N A GEORGIA N A FL PNHDL N A FL PENIN A A AK N SLOPE B A AK ALEUTIAN B A AK WESTERN B A AK INT BSN B A AK S INT B A AK SO COAST B A AK PNHDL B A 8-14 DAY OUTLOOK TABLE Outlook for May 29 - Jun 04, 2026 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 N NEVADA A A W MONTANA A N E MONTANA A A WYOMING A A UTAH A A ARIZONA A A COLORADO A A NEW MEXICO N A N DAKOTA A A S DAKOTA A A NEBRASKA A A KANSAS A A OKLAHOMA N A N TEXAS N A S TEXAS N A W TEXAS N A MINNESOTA A N IOWA A N MISSOURI A A ARKANSAS A A LOUISIANA N A WISCONSIN A N ILLINOIS A N MISSISSIPPI A A MICHIGAN A B INDIANA A N OHIO A N KENTUCKY A A TENNESSEE A A ALABAMA A A NEW YORK A B VERMONT A B NEW HAMP A B MAINE A B MASS A B CONN A B RHODE IS A B PENN A B NEW JERSEY A B W VIRGINIA A N MARYLAND A N DELAWARE N N VIRGINIA A N N CAROLINA N A S CAROLINA A A GEORGIA A A FL PNHDL A A FL PENIN A A AK N SLOPE N A AK ALEUTIAN B A AK WESTERN B N AK INT BSN N A AK S INT B A AK SO COAST B A AK PNHDL B N 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. $$