Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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150 FXUS06 KWBC 061902 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Mon May 06 2024 6-10 DAY OUTLOOK FOR MAY 12 - 16 2024 Today`s model solutions are in good agreement on the predicted amplified 500-hPa circulation pattern across North America and surrounding regions during the 6-10 day period. The manual 500-hPa height blend is based primarily on the ensemble means from the GEFS, ECENS, and Canadian models due to recent model skill. The resultant manual blend features a 500-hPa trough and negative 500-hPa height anomalies across the eastern contiguous U.S. (CONUS). A ridge and associated positive 500-hPa height anomalies are forecast over the northwestern CONUS, while a weak trough is forecast over the southwestern CONUS. A trough is forecast over Alaska. Weak troughing with negative 500-hPa height anomalies are favored for Hawaii. Mid-level ridging and positive 500-hPa height anomalies across the western CONUS bring elevated chances for above-normal temperatures over much of the western CONUS extending eastward through the High Plains, the Upper and Middle Mississippi Valley, and into the Upper Great Lakes region. The strongest chances are forecast over parts of Oregon, California, Nevada, and Utah with probabilities exceeding 70% in this region. Anomalous mid-level troughing favors near- to below-normal temperatures across much of the Southern Plains and the eastern CONUS, except for Maine and southern Florida where above-normal temperatures are indicated. In Alaska, weakly below-normal 500-hPa height anomalies lead to chances for below-normal temperatures across the state. In Hawaii, above-normal temperatures are forecast consistent with the consolidation of tools. In the Pacific Northwest, below-normal precipitation is likely beneath the positive 500-hPa height anomalies. The below-normal chances overspread the northern Rockies and into the Northern Plains. Along the southern and eastern edge of the trough above-normal precipitation is slightly favored as a surface frontal boundary is likely to become established that may help to focus precipitation along the East Coast and Gulf Coast. Areas of surface low-pressure may develop in the southern Rockies and a weak trough predicted over the Southwest that may bring precipitation to the region. In Alaska, above-normal precipitation is forecast over much of Alaska as troughing may bring onshore flow. In Hawaii, above-normal precipitation is favored due to a weak trough over the region. The official 6-10 day 500-hPa height blend consists of 40% of Today`s 6z GFS Ensemble Mean centered on Day 8, 30% 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 MAY 14 - 20 2024 Ensemble mean solutions for the 8-14 day period maintain a fairly persistent and less amplified 500-hPa circulation pattern relative to the 6-10 day period across North America and the surrounding regions. During week-2, a ridge is forecast over the western CONUS. A weak trough with negative anomalies is forecast over the eastern CONUS. Another weak trough is predicted over Alaska, while ridging and above-normal 500-hPa heights are forecast over the Aleutians. A weak trough with slightly below-normal 500-hPa heights continued to be predicted over Hawaii. A weak mid-level trough and negative 500-hPa height anomalies supports near-normal temperature for much of the eastern CONUS, excluding portions of the Northeast and Florida peninsula where above-normal temperatures are indicated. Elevated probabilities of above-normal temperatures are forecast over much of the central and western CONUS due to the forecast ridging and above-normal 500-hPa heights. In Alaska, below-normal temperatures are slightly favored with continued weak troughing impacting the state. In Hawaii, slightly above-normal temperatures are forecast consistent with the consolidation of tools. Below-normal precipitation is favored for parts of the Pacific Northwest and the Northern Rockies with ridging over the region. Near- to above-normal precipitation is forecast over the remainder of the CONUS due to southerly return flow associated with mean surface high pressure over the Southeast and the mid-level trough expected to linger in the region through much of the period, and supported by most of the dynamical precipitation forecast tools. In Alaska, above-normal precipitation is generally favored across the state with unsettled weather beneath a mid-level trough continuing. Meanwhile, above-normal precipitation is slightly favored for Hawaii consistent with the consolidation of tools. The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 6z 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: About average, 3 out of 5, with good agreement in the overall circulation pattern for the period, offset by weaker signals and some disagreement among precipitation and temperature tools. FORECASTER: Luke H 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: 19980514 - 19750430 - 20030420 - 19640501 - 19980519 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: 19980516 - 19980511 - 19750428 - 20030420 - 19640430 6-10 DAY OUTLOOK TABLE Outlook for May 12 - 16 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A N SRN CALIF A A IDAHO A B NEVADA A N 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 A N S DAKOTA A N NEBRASKA A N KANSAS A A OKLAHOMA N A N TEXAS B A S TEXAS B A W TEXAS B A MINNESOTA A N IOWA A N MISSOURI N N ARKANSAS B N LOUISIANA B A WISCONSIN A N ILLINOIS N N MISSISSIPPI B A MICHIGAN N N INDIANA N N OHIO N N KENTUCKY B N TENNESSEE B A ALABAMA B A NEW YORK N A VERMONT N A NEW HAMP N A MAINE A A MASS N A CONN N A RHODE IS N A PENN N A NEW JERSEY N A W VIRGINIA B A MARYLAND N A DELAWARE N A VIRGINIA N A N CAROLINA N A S CAROLINA B A GEORGIA B A FL PNHDL B A FL PENIN A A AK N SLOPE B A AK ALEUTIAN B N 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 14 - 20 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A N OREGON A B NRN CALIF A N SRN CALIF A A IDAHO A N NEVADA A N W MONTANA A N E MONTANA A A WYOMING A A UTAH A A ARIZONA A A COLORADO A A NEW MEXICO A N N DAKOTA A A S DAKOTA A A NEBRASKA A A KANSAS A A OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A N MINNESOTA A A IOWA A A MISSOURI A A ARKANSAS A A LOUISIANA A A WISCONSIN A A ILLINOIS A A MISSISSIPPI N A MICHIGAN N A INDIANA N A OHIO N A KENTUCKY N A TENNESSEE N A ALABAMA N A NEW YORK N A VERMONT N A NEW HAMP N A MAINE A A MASS N A CONN N A RHODE IS N A PENN N A NEW JERSEY N A W VIRGINIA N A MARYLAND N A DELAWARE N A VIRGINIA N A 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 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. $$