Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
Versions:
1
2
939 FXUS06 KWBC 292049 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 29 2024 6-10 DAY OUTLOOK FOR JUN 04 - 08 2024 Todays model solutions are in good agreement on a moderately amplified 500-hPa circulation pattern across North America during the 6-10 day period. The manual 500-hPa height blend is based on the 0Z ensemble means from the GEFS, ECMWF, and Canadian ensemble models. The manual blend predicts an amplified trough and negative 500-hPa height anomalies over Alaska and the Gulf of Alaska. A ridge and positive 500-hPa height anomalies are predicted over the western contiguous U.S. (CONUS). Ensemble mean model forecasts from the GEFS and ECMWF predict positive 500-hPa height anomalies over the northeastern CONUS at the start of the 6-10 day period and negative 500-hPa height anomalies, associated with a developing trough, later in the period. Near zero 500-hPa height anomalies are predicted over the Southeast in the 6-10 day mean manual blend, while positive anomalies are predicted over the Northeast. Enhanced chances for above-normal temperatures are predicted over most of the CONUS due to the predicted mid-level ridge and generally positive 500-hPa height anomalies, and supported by most dynamical model temperature forecast tools. Probabilities favoring above-normal temperatures exceed 80 precent for parts of the central Great Basin. Probabilities for below-normal temperatures are enhanced over western and southern Alaska, including the Aleutians and Southeast Alaska, under the predicted trough and enhanced precipitation. Near-normal temperatures are favored for Hawaii, where temperature forecast tools are in disagreement. Above-normal precipitation is favored for most of Mainland Alaska and Southeast Alaska, with southerly flow ahead of a predicted trough over the Gulf of Alaska. A predicted anomalous mid-level ridge favors below-normal precipitation from parts of the southern Oregon and northern California coasts across the northern Great Basin and extending eastward to portions of the western Northern Great Plains. Above normal precipitation is slightly favored from eastern New Mexico and much of Texas into the Southern Plains and Ohio Valley, consistent with most dynamical model precipitation forecasts. Median precipitation accumulation predictions by the precipitation consolidation tool are as little as one or two millimeters during the 6-10 day period in semi-arid regions of the Southwest. However, any precipitation in arid regions would be considered above-normal. Above-normal precipitation is also favored for the Great Lakes region and the Northeast and Mid-Atlantic regions, consistent with most dynamical model precipitation tools. Probabilities of below-normal precipitation are slightly enhanced across Hawaii, consistent with the consolidation precipitation forecast tool. The official 6-10 day 500-hPa height blend consists of 35% of Today`s 0z 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 good agreement among model solutions and forecast temperature and precipitation tools. 8-14 DAY OUTLOOK FOR JUN 06 - 12 2024 Ensemble mean solutions for the 8-14 day period 500-hPa height forecast are consistent with the overall mid-level circulation pattern across North America in the 6-10 day period forecast. 500-hPa heights rise over Mainland Alaska during the 8-14 day period, with the center of negative 500-hPa height anomalies shifting southward into the North Pacific. An amplified ridge and associated positive 500-hPa height anomalies are predicted over the western half of the CONUS in the manual blend, while a trough and negative 500-hPa height anomalies are predicted to develop over the eastern CONUS during week 2. Below-normal temperatures continue to be favored for southern areas of Alaska, including the Aleutians and Southeast Alaska, associated with the predicted trough over the Gulf of Alaska. Above normal temperatures are slightly favored for northern Mainland Alaska, consistent with most temperature tools including the consolidation. A predicted ridge over the western CONUS and positive 500-hPa height anomalies favor above-normal temperatures for the western CONUS, with probabilities exceeding 80 percent over parts of the Great Basin, as in the 6-10 day period. Below-normal temperatures are favored over most of the eastern CONUS, under a predicted trough during the period. Above-normal temperatures continue to be likely for much of the Gulf Coast region, consistent with dynamical model forecast tools. Above-normal temperatures are slightly favored for parts of the Northeast under southerly flow ahead of the predicted trough, and consistent with temperature forecast tools. Near-normal temperatures continue to be favored for Hawaii, where temperature forecast tools are in disagreement. Above-normal precipitation continues to be slightly favored for most of Alaska, consistent with most dynamical model forecast tools, and under southerly flow. Below-normal precipitation is favored for the northern tier of the CONUS from the Pacific Northwest to the Northern Plains, under a predicted ridge. Above normal precipitation continues to be slightly favored from eastern New Mexico and much of Texas into parts of the Central Plains, consistent with most dynamical model precipitation forecasts. Median precipitation accumulation predictions by the precipitation consolidation tool are as little as one or two millimeters during the period in semi-arid regions of the Southwest. Above-normal precipitation is favored for much of the northeastern CONUS, ahead of a predicted trough. Near- to below-normal precipitation is favored for the Southeast, consistent with the precipitation consolidation. Below-normal precipitation is favored across Hawaii, consistent with the consolidation precipitation forecast tool. The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 0z GFS Ensemble Mean centered on Day 11, 35% 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 consistent evolution of the forecast pattern among ensemble mean model forecasts. FORECASTER: D Collins 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 June 20. 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: 19660514 - 19660520 - 20030513 - 20040529 - 19550527 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: 19660516 - 20030513 - 20040529 - 19840528 - 19890520 6-10 DAY OUTLOOK TABLE Outlook for Jun 04 - 08 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A B SRN CALIF A N IDAHO A B NEVADA A B W MONTANA A B E MONTANA A B WYOMING A B UTAH A B ARIZONA A N COLORADO A N NEW MEXICO A A N DAKOTA A B S DAKOTA A B NEBRASKA A N KANSAS A N OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA A A IOWA A N MISSOURI A N ARKANSAS A A LOUISIANA A N WISCONSIN A A ILLINOIS A N MISSISSIPPI A N MICHIGAN A A INDIANA A A OHIO A A KENTUCKY A A TENNESSEE N A ALABAMA A N 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 N S CAROLINA A N GEORGIA A N FL PNHDL A B FL PENIN A N AK N SLOPE N A AK ALEUTIAN B N AK WESTERN B A AK INT BSN N A AK S INT B A AK SO COAST B A AK PNHDL B A 8-14 DAY OUTLOOK TABLE Outlook for Jun 06 - 12 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A N SRN CALIF A N IDAHO A B NEVADA A N W MONTANA A B E MONTANA A B WYOMING A N UTAH A N ARIZONA A N COLORADO A N NEW MEXICO A N N DAKOTA B B S DAKOTA B B NEBRASKA B N KANSAS B N OKLAHOMA N N N TEXAS A N S TEXAS A N W TEXAS A A MINNESOTA B N IOWA B N MISSOURI B N ARKANSAS B N LOUISIANA A N WISCONSIN B N ILLINOIS B N MISSISSIPPI A N MICHIGAN B N INDIANA B N OHIO B N KENTUCKY B N TENNESSEE B N ALABAMA A N 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 N A NEW JERSEY N A W VIRGINIA B N MARYLAND N A DELAWARE N A VIRGINIA A N N CAROLINA A N S CAROLINA A N GEORGIA A N FL PNHDL A N FL PENIN A N AK N SLOPE A N AK ALEUTIAN B N 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. $$