196 FXUS06 KWBC 181902 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Mon March 18 2024 6-10 DAY OUTLOOK FOR MAR 24 - 28 2024 Dynamical models are in good agreement today on the positioning of the mean 500-hPa height features during the 6-10 day period. There are two areas of positive 500-hPa height anomalies, one centered east of the Canadian Maritimes spreading into the northeastern contiguous U.S. (CONUS), and a second centered over Alaska with positive heights spreading towards the North Pole and into the central North Pacific. In southern Canada and the western half of the CONUS negative 500-hPa height anomalies are forecast with a trough digging into the central CONUS by the middle of the period. Below-normal temperatures are favored across the western CONUS east to the Upper-Mississippi Valley, Central Plains and parts of the Southern Plains along and behind the mean 500-hPa trough axis. The strongest chances for below-normal temperatures are forecast for the Northern Plains with chances exceeding 80% across this region. Meanwhile, east of the Mississippi River and extending along the Texas Gulf Coast, above-normal temperatures are forecast. There is lower confidence in the above-normal as the mid-level trough shifts eastward during the period and the raw dynamical tools are cooler relative to the reforecast and short term bias-corrected tools. In Alaska, with strong positive 500-hPa height anomalies forecast during the period, above-normal temperatures are strongly favored across most of the mainland, while in parts of Southeast Alaska, near to slightly-below normal is favored. For Hawaii, near to slightly below-normal temperatures are favored for the state. Above-normal precipitation is favored across most of the country during the 6-10 day period. The highest chances for above-normal precipitation are forecast in the southwestern CONUS and in the Mississippi Valley and Great Lakes. In the southwestern CONUS, a deep trough will be moving through the region early in the period bringing a period of unsettled weather to the area. Additionally, the precipitation climatology for this region for late March is relatively low, increasing chances for any precipitation to exceed normal. As this trough progresses inland, lee-side cyclogenesis is forecast to develop and will track into towards the Great Lakes and an associated frontal system may extend towards the Gulf Coast. In Alaska, above-normal precipitation is forecast across much of the Mainland with below-normal forecast in parts of Southeast Alaska as the above-normal 500-hPa heights may displace the storm track northwards. In Hawaii, near to below-normal precipitation is forecast. The official 6-10 day 500-hPa height blend consists of 20% of Today's 0z GFS Ensemble Mean centered on Day 8, 20% of Today's 6z GFS Ensemble Mean centered on Day 8, 40% of Today's 0z European Ensemble Mean centered on Day 8, and 20% of Today's 0z Canadian Ensemble Mean centered on Day 8 FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: About-average, 3 out of 5, due to fair agreement among all the model tools for much of the country offset by the very progressive nature of the pattern. 8-14 DAY OUTLOOK FOR MAR 26 - APR 01, 2024 The week-2 height forecast is less certain than the 6-10 day period. The ensemble dynamical tool means are less amplified relative to the earlier period with lesser agreement on the placement of the height anomalies. Generally, the tools maintain an area of negative 500-hPa height anomalies over the CONUS with positive 500-hPa height anomalies across much of Alaska and Canada. However, the weekly means dont tell the whole story due to the progressive nature of the pattern during the period. At the onset of the period, deep mid-level low pressure is forecast across the center of the CONUS with strong positive mid-level anomalies forecast for the Northeast. The negative 500-hPa height anomalies are forecast to progress eastward into the Great Lakes and weaken while shifting the positive 500-hPa anomalies over the Northeast offshore. Meanwhile, a second area of negative anomalies and associated troughing is forecast to move inland from the eastern Pacific; however, at this time, this trough is forecast to be less amplified relative to the trough early in the period. In Alaska, positive 500-hPa height anomalies at the onset of the period are likely to be displaced by negative 500-hPa height anomalies by the end of week-2. In Hawaii, tools are generally mixed but lean towards positive 500-hPa height anomalies during the period. In week-2 as the mid-level trough progresses eastward, displacing the 500-hPa height anomalies across the northeastern CONUS in the 6-10 day, below-normal temperature chances extend eastward into the Ohio, Tennessee, Lower-Mississippi Valley, and parts of the Southeast while maintaining coverage across the western CONUS. Probabilities are slightly reduced across the Northern Plains relative to the 6-10 day period but chances continue to exceed 60% for below-normal temperatures across this region. In the Northeast, probabilities exceed 50% for above-normal temperatures ahead of the trough. In Alaska, with 500-hPa height anomalies relaxing and forecast to turn negative by the end of the period, the strong chances for above-normal temperatures forecast in the 6-10 day period are significantly reduced and focused in the southwestern Mainland. Near- to below-normal temperatures are forecast for the North Slope, eastern Mainland and Southeast Alaska. In Hawaii, below-normal temperatures are slightly favored. During week-2, above-normal precipitation remains most likely for much of the country, although with weaker probabilities relative to the 6-10 day period, as Pacific flow continues to bring moist air into the CONUS. In the southwestern CONUS, slightly elevated chances of above-normal precipitation are forecast due to continued unsettled weather and potential for a second area of troughing to move onshore during the period. Meanwhile, in the East a baroclinic zone is likely to become established as the trough progresses eastward. This slightly enhances chances for above-normal precipitation across the East Coast. In parts of the Northern and Southern Plains near to below-normal precipitation is favored for areas displaced from the main storm track. In Alaska, above-normal precipitation is slightly favored for central and southern Mainland Alaska along with Southeast. As the strong ridging across the state breaks down it may allow for more precipitation to work into southern Alaska. Near-normal precipitation is favored for Hawaii consistent with the blend of tools and consolidation tools. The official 8-14 day 500-hPa height blend consists of: 20% of Today's 0z GFS Ensemble Mean centered on Day 11, 20% of Today's 6z GFS Ensemble Mean centered on Day 11, 40% of Today's 0z European Ensemble Mean centered on Day 11, and 20% of Today's 0z Canadian Ensemble Mean centered on Day 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Average, 3 out of 5, due to fair agreement between the dynamical tools on the 500-hPa height pattern and in the sensible weather tools offset by the continued progressive pattern FORECASTER: Ryan Bolt 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 March 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: 20000331 - 19920311 - 19920330 - 19880312 - 19620330 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: 20000330 - 19920311 - 19920329 - 20050311 - 19880311 6-10 DAY OUTLOOK TABLE Outlook for Mar 24 - 28 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B A OREGON B A NRN CALIF B A SRN CALIF B A IDAHO B A NEVADA B A W MONTANA B A E MONTANA B A WYOMING B A UTAH B A ARIZONA B A COLORADO B A NEW MEXICO B A N DAKOTA B A S DAKOTA B A NEBRASKA B A KANSAS B A OKLAHOMA B A N TEXAS N A S TEXAS A A W TEXAS B A MINNESOTA B A IOWA B A MISSOURI B A ARKANSAS N A LOUISIANA A A WISCONSIN B A ILLINOIS N 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 A FL PENIN A A AK N SLOPE A A AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A AK S INT A A AK SO COAST A A AK PNHDL A B 8-14 DAY OUTLOOK TABLE Outlook for Mar 26 - Apr 01, 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B A OREGON B A NRN CALIF B A SRN CALIF B A IDAHO B A NEVADA B A W MONTANA B A E MONTANA B A WYOMING B A UTAH B A ARIZONA B A COLORADO B A NEW MEXICO B A N DAKOTA B A S DAKOTA B A NEBRASKA B A KANSAS B A OKLAHOMA B A N TEXAS B N S TEXAS B B W TEXAS B N MINNESOTA B A IOWA B A MISSOURI B A ARKANSAS B A LOUISIANA B N WISCONSIN B A ILLINOIS B A MISSISSIPPI B A MICHIGAN N A INDIANA B A OHIO N A KENTUCKY B A TENNESSEE B A ALABAMA B 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 N A MARYLAND A A DELAWARE A A VIRGINIA N A N CAROLINA N A S CAROLINA N A GEORGIA N A FL PNHDL N A FL PENIN N A AK N SLOPE N N AK ALEUTIAN A N AK WESTERN A N AK INT BSN N N AK S INT A A AK SO COAST A 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. $$