793 FXUS06 KWBC 141902 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Tue July 14 2020 6-10 DAY OUTLOOK FOR JUL 20 - 24 2020 All of today's models indicate three main large-scale features across the U.S. The feature with the largest amplitude is a strong ridge over the eastern Pacific, extending over parts of southern Alaska and the Pacific Northwest. Another feature is anomalous ridging forecast over the eastern half of the CONUS. Between these two features is a predicted region of weak troughing. Despite this region of troughing, positive 500-hPa height anomalies are forecast across most of the country. Above normal temperatures are favored for southern parts of Alaska (including the Aleutians, the southern Mainland coast, and the Panhandle) underneath predicted anomalous ridging. Forecast surface high pressure to the north of Alaska enhances the likelihood of below normal temperatures for the rest of the state. A weak forecast trough centered over Montana increases the likelihood of below normal temperatures over parts of the Northern Plains. Above normal temperatures are favored everywhere else in the country, particularly in the Northeast, where temperature tools are in very good agreement, and positive temperature anomalies are the most prolonged during the 6-10 day period. Several storm systems in the Gulf of Alaska are predicted to make landfall in southern Alaska, increasing chances of above normal precipitation there. Northern parts of Alaska are expected to remain dry, favoring below normal precipitation there. Downstream of the forecast East Pacific ridge, storm system activity is forecast to be limited, increasing the likelihood of below normal precipitation for much of the western quarter of the CONUS. Today's models are in less agreement on the Southwest Monsoon activity in the 6-10 day period, so near normal precipitation is favored in the Southwest Monsoon regions. A frontal system predicted to move from the Northern Plains to the East Coast during the 6-10 day period leading to increased chances of above normal precipitation for the Northern Plains, Upper and Middle Mississippi Valley, Great Lakes, and much of the eastern CONUS. Subtropical ridging is forecast to increase moisture flow into the Florida Peninsula, increasing chances of above normal precipitation there. Enhanced moisture flow into parts of coastal Texas and Louisiana also favor above normal precipitation in those areas. Relatively minimal storm system activity across parts of the central CONUS enhances the likelihood of below normal precipitation over parts of the Central and Southern Plains. The official 6-10 day 500-hPa height blend consists of 50% of Today's 0z European Ensemble Mean centered on Day 8, and 50% of Today's operational 0z ECMWF centered on Day 8 FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Above average, 4 out of 5, due to good model agreement among models and tools. 8-14 DAY OUTLOOK FOR JUL 22 - 28 2020 During the week-2 period, the eastern Pacific ridge is expected to weaken a bit, but still continue its influence on the surrounding regions' temperatures and precipitation. 500-hPa heights across the majority of the CONUS are expected to be near to above normal, leading to an anomalously warm pattern pretty much everywhere in the Lower 48. The highest probabilities of above normal temperatures run from the Central Plains northeast to the Great Lakes and Ohio Valley and into the Northeast and Mid-Atlantic, where temperature tools are in strong agreement and positive temperature anomalies are fairly persistent during the period. The only part of the country where below normal temperatures are favored is over much of Mainland Alaska due to surface high pressure forecast north of the state. The precipitation probability forecast during the week-2 period is similar to that in the 6-10 day period, with a few exceptions. The frontal system predicted over the Northern Plains near the beginning of the 6-10 day period is forecast to be in the eastern U.S. by the week-2 period, favoring near to below normal precipitation for theNorthwest CONUS and into the Rockies. Above normal Southwest Monsoon activity is still favored in parts of the Southwest by most of today's tools, favoring heightened above normal precipitation probabilities over parts of Arizona and New Mexico. The official 8-14 day 500-hPa height blend consists of: 1% of Today's operational 6z GFS centered on Day 11, and 99% of Today's 0z European Ensemble Mean centered on Day 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Above average, 4 out of 5, due to good model agreement among models and tools. FORECASTER: Mike C 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 1981-2010 base period means for temperature...precipitation...and 500-hpa heights as reference in the climate outlooks. The next set of long-lead monthly and seasonal outlooks will be released on July 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: 20020727 - 19810629 - 19540721 - 19980624 - 19730629 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: 19810629 - 20020727 - 19720626 - 19980623 - 19690723 6-10 DAY OUTLOOK TABLE Outlook for Jul 20 - 24 2020 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 B W MONTANA A B E MONTANA N N WYOMING A N UTAH A B ARIZONA A N COLORADO A N NEW MEXICO A N N DAKOTA B A S DAKOTA N A NEBRASKA A A KANSAS A N OKLAHOMA A B N TEXAS A B S TEXAS A A W TEXAS A B MINNESOTA N A IOWA A A MISSOURI A A ARKANSAS A N LOUISIANA A A WISCONSIN A A ILLINOIS A A MISSISSIPPI A N MICHIGAN A A INDIANA A A OHIO A A KENTUCKY A A TENNESSEE A 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 A S CAROLINA A A GEORGIA A A FL PNHDL A N FL PENIN A A AK N SLOPE B B AK ALEUTIAN A N AK WESTERN B N AK INT BSN B A AK S INT A A AK SO COAST A A AK PNHDL A A 8-14 DAY OUTLOOK TABLE Outlook for Jul 22 - 28 2020 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A N NRN CALIF A N SRN CALIF A N IDAHO A N NEVADA A N W MONTANA A N E MONTANA A N WYOMING A N UTAH A N ARIZONA A A COLORADO A N NEW MEXICO A B N DAKOTA A N S DAKOTA A N NEBRASKA A N KANSAS A B OKLAHOMA A B N TEXAS A B S TEXAS A A W TEXAS A B MINNESOTA A A IOWA A A MISSOURI A N ARKANSAS A N LOUISIANA A A WISCONSIN A A ILLINOIS A A MISSISSIPPI A N MICHIGAN A A INDIANA A A OHIO A A KENTUCKY A A TENNESSEE A 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 A S CAROLINA A A GEORGIA A N FL PNHDL A N FL PENIN A N AK N SLOPE B A AK ALEUTIAN A N AK WESTERN B A AK INT BSN B A AK S INT B N AK SO COAST A B AK PNHDL A B 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. $$