708 FXUS06 KWBC 281902 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 28 2026 6-10 DAY OUTLOOK FOR MAY 04 - 08 2026 Dynamical models are in good agreement regarding a stable 500-hPa height pattern across North America during the 6-10 day period. A high latitude block associated with the negative phase of the North Atlantic Oscillation (-NAO) favors troughing reloading over the eastern CONUS. The manual height blend depicts the largest negative height anomalies (-120 meters) across portions of the Great Lakes and Northeast, with below-normal heights extending to the Gulf Coast. Upstream ridging is forecast across the northeastern Pacific into Southeast Alaska, with this feature slowly migrating into the northwestern CONUS later in the period where positive height anomalies are indicated in the manual blend. Shortwave troughing is predicted to undercut this ridge and progress across the southwestern CONUS and eventually become absorbed into the tough across the East. Troughing is forecast to move across the Aleutians resulting in below-normal heights. Closer to normal heights are favored across northern and western Mainland Alaska, with increasing positive height anomalies further south and east underneath the aforementioned ridge. Near-normal heights are forecast for Hawaii as troughing passes by to the northeast of the state, making a close approach during the first half of the period. Unseasonably cool weather is forecast to continue over much of the eastern U.S. during early May. While a brief moderation is possible across the Eastern Seaboard early in the period, the reloading trough is favored to bring another round of below-normal temperatures throughout much of the East. The 0z ECMWF ensemble has trended more amplified with the trough compared to yesterday and depicts a widespread area of temperature anomalies of -5 to -10 deg F for the period. Additionally, the analogs derived from the manual height blend support high probabilities for below-normal temperatures for much of the central and eastern CONUS with further support from teleconnections. Given strong tool support, today's forecast continues to indicate elevated chances for below-normal temperatures for most areas east of the Rockies. The exception is across south Florida where above-normal temperature probabilities are increased due to the influence of subtropical ridging. Ridging favors elevated chances of above-normal temperatures across the western CONUS, with support from the reforecast and uncalibrated 0z GEFS and ECMWF ensembles. Near- to slightly below-normal temperatures are favored across parts of the Southwest and Lower Four Corners as a shortwave trough moves across the region. A variable temperature pattern is forecast across Alaska. The highest confidence for above-normal temperatures is across Southeast Alaska underneath ridging. Troughing near the Aleutians favors near-to below-normal temperatures over portions of the Mainland and Aleutians, with above-normal temperatures more likely over the northwestern Mainland. Above-normal temperatures are forecast across most of the Hawaiian Islands, with slightly below-normal temperatures favored over Kauai. The troughing in the East and associated frontal boundary supports increased chances of unsettled weather across the region. The 0z ECMWF ensemble indicates a surface low developing across the Great Lakes and Northeast late in the period, with some evidence of this appearing in the GEFS and Canadian ensembles as well. As a result, probabilities for above-normal precipitation are increased across the Northeast. While reduced forcing decreases probabilities over the Ohio and Tennessee Valleys through the central Atlantic coast, probabilities for above-normal precipitation again increase across the Southeast and Gulf Coast tied to a shortwave trough nearing the region and interacting with the larger trough upstream over the East. The same shortwave trough also favors enhanced probabilities of above-normal precipitation across the Southwest where climatologies are low. Conversely, ridging favors increased chances for below-normal precipitation across the northwestern CONUS extending through the Upper Midwest with strong support from the analog guidance. For Alaska, tools generally favor enhanced odds for above-normal precipitation across the Mainland and Aleutians tied to troughing near the Aleutians. Below-normal precipitation probabilities are increased across Southeast Alaska due to more influence from ridging. Above-normal precipitation is slightly favored across Hawaii. 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: Above average, 4 out of 5, due to good model agreement regarding a stable blocking pattern across the East, offset by weaker precipitation signals over the CONUS, and a more variable pattern predicted across Alaska. 8-14 DAY OUTLOOK FOR MAY 06 - 12 2026 The 500-hPa pattern during week-2 is very similar to that of the 6-10 day period. The 0z GEFS, ECMWF, and Canadian ensembles continue to depict troughing across the eastern U.S., with the ECMWF being the most amplified. The week-2 manual height blend indicates below-normal heights across the eastern CONUS, and above-normal heights across much of the western CONUS. However, the magnitude of the anomalies is reduced compared to the 6-10 day outlook. The GEFS and Canadian ensembles depict a more zonal mid-level pattern taking shape across the CONUS later in week-2, with the ECMWF ensemble persisting some degree of weak amplification associated with troughing over the Northeast and ridging persisting longer over the West. Troughing is forecast to drift to the south of the Aleutians and gradually weaken, but with near- to slightly below-normal heights remaining favored over the region. Ridging is forecast across southeastern Alaska favoring above-normal heights. There is a bit more uncertainty across Mainland Alaska where weakly above-normal heights continue to be indicated, although the 0z ECMWF ensemble has significantly reduced the amplitude of positive height anomalies compared to yesterday. Near-normal heights are forecast across Hawaii. There remains good confidence for a persistent period of unseasonably cool temperatures across the central and eastern U.S. during week-2, with elevated probabilities of below-normal temperatures east of the Rockies. This continues to be supported by the dynamical model guidance as well as a strong signal for below-normal temperatures in the analogs derived from the manual height blend. Some areas of the Northern Tier may continue to have overnight temperatures cold enough to support late season frosts, potentially delaying additional spring blooms or damaging existing vegetation. Stronger influence from subtropical ridging tilts much of the Florida Peninsula toward enhanced probabilities for above-normal temperatures, which is supported by the ECMWF and GEFS reforecast tools. Ridging over the West supports higher probabilities of above-normal temperatures across the region. While this ridge may ultimately flatten later in the period, the emergent zonal flow pattern would also continue to favor above-normal temperatures. A combination of weakening troughing near the Aleutians and uncertainty in the amplitude of downstream ridging leads to a more uncertain temperature forecast across Alaska, with near-normal temperatures forecast for much of the Mainland. Probabilities for above-normal temperatures are increased across Southeast Alaska and the coastal western Mainland. Above-normal temperatures are forecast across Hawaii consistent with the consolidation forecast tool. Troughing over the East continues to favor above-normal precipitation across the region. Surface low pressure early in the period leads to an enhancement of probabilities (above 40 percent) over the Northeast. Additional frontal activity and increasing southerly flow favors an uptick in above-normal precipitation probabilities across the Lower Mississippi Valley and Southeast. Increased odds for above-normal precipitation extend into the Southwest, consistent with the reforecast and uncalibrated GEFS and ECMWF guidance and also due to a low precipitation climatology. Analog guidance continues to favor enhanced chances for below-normal precipitation extending from the Pacific Northwest into the Upper Midwest. A variable mid-level pattern results in enhanced chances for near- to slightly above-normal precipitation across most of Alaska, except a slight tilt toward below-normal precipitation over Southeast Alaska. Above-normal precipitation chances are increased across Hawaii. 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: Above average, 4 out of 5, due to a fairly persistent pattern from the 6-10 day period and continued good tool agreement, offset by some increasing model spread later in the period and a more uncertain pattern across Alaska. 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 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: 19980415 - 20210413 - 20240503 - 19950417 - 20160511 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: 20190504 - 19980413 - 20160510 - 20100413 - 20120407 6-10 DAY OUTLOOK TABLE Outlook for May 04 - 08 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A N NRN CALIF A A SRN CALIF N A IDAHO A N NEVADA A A W MONTANA A B E MONTANA A B WYOMING A B UTAH A A ARIZONA N A COLORADO N A NEW MEXICO B A N DAKOTA B B S DAKOTA B B NEBRASKA B B KANSAS B N OKLAHOMA B A N TEXAS B A S TEXAS B A W TEXAS B A MINNESOTA B B IOWA B B MISSOURI B N ARKANSAS B A LOUISIANA B A WISCONSIN B N ILLINOIS B N MISSISSIPPI B A MICHIGAN B A INDIANA B A OHIO B A KENTUCKY B A TENNESSEE B A ALABAMA B 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 A NEW JERSEY B A W VIRGINIA B A MARYLAND B A DELAWARE B A VIRGINIA B A N CAROLINA B A S CAROLINA B A GEORGIA B A FL PNHDL B A FL PENIN B A AK N SLOPE N 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 A B 8-14 DAY OUTLOOK TABLE Outlook for May 06 - 12 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A N NRN CALIF A A SRN CALIF A A IDAHO A N 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 N A N DAKOTA B B S DAKOTA B B NEBRASKA B B KANSAS B N OKLAHOMA B A N TEXAS B A S TEXAS B A W TEXAS B A MINNESOTA B B IOWA B B MISSOURI B N ARKANSAS B A LOUISIANA B A WISCONSIN B B ILLINOIS B N MISSISSIPPI B A MICHIGAN B N INDIANA B N OHIO B A KENTUCKY B A TENNESSEE B A ALABAMA B 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 A NEW JERSEY B A W VIRGINIA B A MARYLAND B A DELAWARE B A VIRGINIA B A N CAROLINA B A S CAROLINA B A GEORGIA B A FL PNHDL B A FL PENIN A A AK N SLOPE N N AK ALEUTIAN N N AK WESTERN N N AK INT BSN N N AK S INT N N AK SO COAST N N AK PNHDL A 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. $$