339 FXUS06 KWBC 191912 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Tue May 19 2026 6-10 DAY OUTLOOK FOR MAY 25 - 29 2026 Today's numerical models are in relatively poor agreement with the 500-hPa flow pattern across North America and vicinity as the ECMWF and Canadian ensemble means depict a much more amplified solution relative to the GEFS. The period begins with a trough near southwestern Mainland Alaska. As time progresses, this trough is forecast by the ECMWF ensemble to progress eastward across the South Coast. A second, weaker trough is forecast downstream across the Pacific Northwest in the ECMWF and Canadian ensemble mean solutions early in the period. A trough in the southern stream is forecast over the southwestern CONUS but uncertainty is high on its evolution. A very strong ridge is forecast downstream over Hudson Bay, particularly in the ECMWF and Canadian ensemble solutions. The position of the ridge coupled with upstream cyclonic flow across the West is conducive to enhanced return flow from the Gulf across the Southern Plains and Lower Mississippi Valley. Near normal mid-level heights and southeasterly low-level flow are forecast across Hawaii. The anomalous ridge over eastern Canada is supportive of above normal temperatures across much of the north-central and northeastern CONUS. Confidence is high (greater than 70 percent chance) for above normal temperatures across the Upper Mississippi Valley and adjacent areas of the western Great Lakes and Northern Plains, consistent with teleconnections from the ridge anomaly center. A weaker transient ridge is forecast across parts of the Southeast during the early and middle parts of the period, supporting elevated probabilities of above normal temperatures across this region. Above normal temperatures are slightly favored for much of the interior West, ahead of a mean trough axis near or just inland of the West Coast. Near normal temperatures are favored along most of the West Coast and adjacent areas, due to the potential for mean troughing. Slightly enhanced probabilities of below normal temperatures were restricted to the Pacific Northwest, due to large model discrepancies across the West. Persistent cyclonic flow leads to elevated chances of below normal temperatures across Alaska. Above normal temperatures are favored for Hawaii, associated with observed above normal SSTs in the adjacent Pacific. Above normal precipitation is likely across the Gulf Coast, Lower Mississippi Valley, Southeast, Southern Plains, and adjacent areas of the Mid-Atlantic, Central Plains, and Southern and Central Rockies, around the periphery of predicted surface high pressure over the Great Lakes. Confidence is high (greater 60 percent chance) for above normal precipitation across parts of the western Gulf Coast, where enhanced moisture advection is most likely. Below normal precipitation is favored for much of the Great Lakes and surrounding regions, closer to the predicted ridge axis. An active pattern is favored for Alaska underneath predicted cyclonic flow. Confidence is high (greater than 50 percent chance) for above normal precipitation across parts of the South Coast, as a trough traverses the region. Above normal precipitation is modestly favored for the Pacific Northwest, due to predicted weak troughing early in the period. 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 20% of Today's 6z GFS Ensemble Mean centered on Day 8, 45% 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: Below Average, 2 out of 5, due to relatively poor agreement between the ECMWF/Canadian ensemble means and the GEFS. 8-14 DAY OUTLOOK FOR MAY 27 - JUN 02, 2026 During the week-2 period, strong anomalous ridging remains a dominant feature over Hudson Bay, particularly as depicted by the ECMWF and Canadian ensemble means. Early ridging across the Southeast is forecast to break down by the middle of the period in the ECMWF and GEFS ensemble solutions. Cyclonic flow is forecast across much of the west coast of North America, but uncertainty is very high regarding the evolution of individual shortwave features within this cyclonic flow. Early troughing over southern Alaska is forecast to weaken and retrograde toward western parts of the state with time, but uncertainty is very high as to how fast and to what extent this retrogression and weakening will occur. Meanwhile, weak cyclonic flow is forecast across the Pacific Northwest in the ECMWF ensemble mean. All ensemble means forecast a trough in the southern stream over the southwestern CONUS but vary greatly on the timing, strength, and positioning of this feature. Adding to the uncertainty across the West is that model solutions predict the potential for weak transient ridging across parts of the West Coast in between the northern and southern stream troughs at various times during the period. Near normal heights continue to be forecast across Hawaii. The anomalous ridge over Hudson Bay is supportive of above normal temperatures across much of the north-central and northeastern CONUS. Confidence is high (greater than 70 percent chance) for above normal temperatures across the western Great Lakes and Upper Mississippi Valley, where positive height anomalies are largest. A weaker transient ridge is forecast across parts of the Southeast early in the period, supporting modestly elevated probabilities of above normal temperatures across this region. The potential for prolonged cyclonic flow across the West coupled with possible southern stream troughing near the southern High Plains, precluded favoring above normal temperatures across these regions. Persistent cyclonic flow leads to elevated chances of below normal temperatures across Alaska. Above normal temperatures are favored for Hawaii, associated with observed above normal SSTs in the adjacent Pacific. Above normal precipitation is favored for the Gulf Coast, Southeast, southern Mid Atlantic, and most of the Plains and Rockies, around the periphery of anomalous ridging over eastern Canada. Enhanced return flow moisture is forecast to persist into week-2 across the Gulf Coast and Southern Plains. Confidence is high (greater than 50 percent chance) for above normal precipitation across parts of the western Gulf Coast, where this enhanced moisture advection is most likely to occur. Conversely, below normal precipitation is more likely across the Great Lakes and Northeast, where surface high pressure is predicted. Above normal precipitation is modestly favored from the Great Basin to parts of California, associated with potential southern stream troughing. 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: 20% of Today's 6z GFS Ensemble Mean centered on Day 11, 45% 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: Below Average, 2 out of 5, due to relatively poor model agreement. FORECASTER: Scott H 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: 19910528 - 20250429 - 20250515 - 20170429 - 20060506 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: 20250501 - 20240531 - 20060506 - 20110506 - 20250515 6-10 DAY OUTLOOK TABLE Outlook for May 25 - 29 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N A OREGON N N NRN CALIF N N SRN CALIF N N IDAHO A N NEVADA A N W MONTANA A N E MONTANA A N WYOMING A A UTAH A A ARIZONA A A COLORADO A A NEW MEXICO A A N DAKOTA A N S DAKOTA A N NEBRASKA A A KANSAS A A OKLAHOMA A A N TEXAS N A S TEXAS N A W TEXAS N A MINNESOTA A N IOWA A N MISSOURI A N ARKANSAS A A LOUISIANA A A WISCONSIN A B ILLINOIS A B MISSISSIPPI A A MICHIGAN A B INDIANA A B OHIO A N KENTUCKY A N TENNESSEE A A ALABAMA A 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 A MARYLAND A A DELAWARE A A 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 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 27 - Jun 02, 2026 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N N OREGON N N NRN CALIF N A SRN CALIF N N IDAHO A A NEVADA N A W MONTANA A A E MONTANA A A WYOMING A A UTAH A A ARIZONA N N COLORADO A A NEW MEXICO A A N DAKOTA A A S DAKOTA A A NEBRASKA A A KANSAS A A OKLAHOMA A A N TEXAS N A S TEXAS N A W TEXAS N A MINNESOTA A N IOWA A N MISSOURI A N ARKANSAS A A LOUISIANA A A WISCONSIN A B ILLINOIS A B MISSISSIPPI A A MICHIGAN A B INDIANA A B OHIO A B KENTUCKY A N TENNESSEE A N 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 A N VIRGINIA A N N CAROLINA A A S CAROLINA A A GEORGIA A A FL PNHDL A A FL PENIN A A AK N SLOPE B A AK ALEUTIAN B N AK WESTERN B N AK INT BSN B A AK S INT B A AK SO COAST B A AK PNHDL B 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. $$