361 FXUS06 KWBC 151904 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Wed May 15 2024 6-10 DAY OUTLOOK FOR MAY 21 - 25 2024 Todays model solutions are very similar to yesterdays and the GEFS, ECMWF, and CMCE all depict a similar synoptic picture over the 6-10 day forecast period, although differences still remain when considering the strength and location of various features. Todays manual blend features widespread positive height anomalies over the North Pacific, a weak subtropical ridge centered over southeastern Texas, and troughing over the northwestern and north-central CONUS. Weak troughing is also favored near the East Coast. Subtropical ridging favors above-normal temperatures for much of the southern and eastern contiguous U.S. (CONUS), with probabilities exceeding 80% for portions of South Texas. Troughing over the West Coast favors below-normal temperatures for much of the CONUS west of the Rockies as well as the Northern Plains, especially the Northern Rockies and southern California where probabilities exceed 60%, consistent with most forecast tools. For Alaska, increased northwesterly flow aloft favors increased cloudiness and below-normal temperatures for much of the southwestern Mainland, while the North Slope tilts slightly towards above-normal temperatures, as indicated by the GEFS and ECMWF reforecast tools. The Hawaii ERF consolidation (CON) favors above-normal temperatures for the entire state, with odds increasing from southeast to northwest. Troughing over both coasts and positive height anomalies centered over northern Mexico develop a stronger than normal jet stream for this time of year, favoring a more active pattern which tilts the odds toward above-normal precipitation for most of the northern and eastern CONUS. The subtropical ridge favors below-normal precipitation for portions of the southern CONUS, especially for portions of southern New Mexico and southwestern Gulf Coast. Much of Alaska tilts towards above-normal precipitation with weak troughing favored over eastern Siberia although model solutions generally keep the enhanced potential for precipitation confined to the Mainland and below-normal precipitation is slightly favored for the Panhandle of Alaska. The Hawaii CON indicates above-normal precipitation for the whole state, with odds increasing from southeast to northwest. The official 6-10 day 500-hPa height blend consists of 33% of Today's 0z GFS Ensemble Mean centered on Day 8, 34% of Today's 0z European Ensemble Mean centered on Day 8, and 33% 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, with good run-to-run continuity among forecast models, offset by differences between models regarding strength and position of various synoptic features. 8-14 DAY OUTLOOK FOR MAY 23 - 29 2024 During week-2, positive 500-hPa height anomalies persist over the North Pacific and the south-central and southeastern CONUS, while weak troughing continues over the coasts. This persistence of the synoptic pattern rEnsemble mean solutions for the 8-14 day (week-2) period predict a de-amplification of the 500-hPa circulation pattern relative to the 6-10 day period across North America and the surrounding regions. Height anomalies are weaker relative to the 6-10 day period as the synoptic pattern becomes more zonal although spread among ensemble mean solutions decreases relative to the 6-10 day period results in similar outlooks between forecast periods for both temperature and precipitation. Above-normal temperatures continue to be favored for the southern CONUS east of the Rockies. Continued troughing over both coasts favors an eastward expansion of chances for below-normal temperatures as far as the Great Lakes, while near-normal temperatures become most likely for the northeastern CONUS. In Alaska odds for below-normal temperatures expand further into the Mainland with northwesterly flow aloft continuing, while reforecast tools continue to favor a slight tilt towards above-normal temperatures for the North Slope, and near-normal temperatures most likely for southeastern Alaska. The western half of Hawaii continues to be favored for above-normal temperatures, although near-normal temperatures are now most likely for the group of islands around Maui as well as the Big Island, consistent with todays autoblend and Hawaii CON tool. Subtropical ridging over the southern CONUS continues to favor below-normal precipitation for portions of the Four Corners, southeastern Texas, and south Florida, while the weak troughing present on both coasts results in a tilt towards above-normal precipitation for much of the rest of the CONUS, supported by the majority of forecast tools. Continued troughing over Siberia favors above-normal precipitation for the whole state of Alaska, further supported by the consensus of forecast tools. Above-normal precipitation continues to be favored for Hawaii, especially Kauai and Oahu. The official 8-14 day 500-hPa height blend consists of: 33% of Today's 0z GFS Ensemble Mean centered on Day 11, 34% of Today's 0z European Ensemble Mean centered on Day 11, and 33% 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, with good run-to-run continuity among forecast models, offset by differences between models regarding strength and position of various synoptic features. FORECASTER: Daniel Barandiaran 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 16. 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: 19990528 - 19520524 - 19660519 - 19980426 - 19690507 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: 19990527 - 20010522 - 19660520 - 19520523 - 19690507 6-10 DAY OUTLOOK TABLE Outlook for May 21 - 25 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B A OREGON B A NRN CALIF B A SRN CALIF B N IDAHO B A NEVADA B A W MONTANA B A E MONTANA B A WYOMING B A UTAH B A ARIZONA B N COLORADO B N NEW MEXICO A B N DAKOTA B A S DAKOTA B A NEBRASKA N A KANSAS A A OKLAHOMA A N N TEXAS A N S TEXAS A B W TEXAS A B MINNESOTA N A IOWA N A MISSOURI A A ARKANSAS A A LOUISIANA A B WISCONSIN N A ILLINOIS A A MISSISSIPPI A A MICHIGAN A A INDIANA A A OHIO A A KENTUCKY A A TENNESSEE A A ALABAMA A A NEW YORK A A VERMONT A A NEW HAMP A A MAINE A A MASS A A CONN A A RHODE IS A A PENN A A NEW JERSEY A A 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 N FL PENIN A B AK N SLOPE A A AK ALEUTIAN N A AK WESTERN B A AK INT BSN N A AK S INT B A AK SO COAST B A AK PNHDL N B 8-14 DAY OUTLOOK TABLE Outlook for May 23 - 29 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B A OREGON B A NRN CALIF B A SRN CALIF B N IDAHO B A NEVADA B N W MONTANA B A E MONTANA B A WYOMING B A UTAH B N ARIZONA N N COLORADO N N NEW MEXICO A B N DAKOTA B A S DAKOTA B A NEBRASKA B A KANSAS A A OKLAHOMA A A N TEXAS A N S TEXAS A B W TEXAS A N MINNESOTA B A IOWA B A MISSOURI A A ARKANSAS A A LOUISIANA A B WISCONSIN B 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 N A NEW HAMP N A MAINE N A MASS N A CONN N A RHODE IS N A PENN N A NEW JERSEY N A W VIRGINIA A A MARYLAND N A DELAWARE N A VIRGINIA A A N CAROLINA A A S CAROLINA A A GEORGIA A A FL PNHDL A N FL PENIN A B AK N SLOPE A 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 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. $$