502 FXUS06 KWBC 221907 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Tue October 22 2019 6-10 DAY OUTLOOK FOR OCT 28 - NOV 01, 2019 Today's model solutions are in good agreement on certain areas of the large scale 500-hPa height pattern forecast over the U.S. during the 6-10 day period, though some disagreement exists for other parts of the country. All models predict very large positive height anomalies over Alaska (above 2 standard deviations in eastern Alaska and the Panhandle, early in the period, according to the 12z GFS) associated with a ridge extending from off the Pacific Northwest coast to the Arctic circle. Downstream, a trough is expected to deepen in the western CONUS and become positively tilted. This is where some larger differences come into play. The 0z ECMWF ensemble mean is forecasting the trough to dig further south and west, while the 06z GFS ensemble mean (and the last few deterministic GFS runs) predicts a slightly more progressive trough. The Canadian is inline with the ECMWF ensemble mean today, further supporting the solution with a slower trough. Today's manual 500-hPa blend is comprised entirely of the 0z ECMWF ensemble mean. Very large positive height anomalies strongly favor above normal temperatures across Alaska. Downstream the trough expected to impact the western and central U.S. favors below normal temperatures, particularly over the north central CONUS. Southerly low-level flow ahead of a forecast trough developing in the central CONUS increases the likelihood of above normal temperatures for the East Coast. One or more storm systems riding over the ridge predicted near western Canada and Alaska is expected to favor above normal precipitation for the Aleutians and Mainland Alaska. Downstream of this anomalous ridge, essentially zero precipitation is predicted by today's models, leading to very high probabilities of below normal precipitation for the Pacific Northwest, extending into parts of California, the Great Basin and the Four Corners Region. Upslope flow associated with some cyclogenesis expected in the lee of the Rockies increases chances of above normal precipitation for parts of the Central CONUS. The cold front predicted in the central U.S., ahead of the trough, may bring relatively large amounts of rain into the eastern U.S., favoring above normal precipitation there. The official 6-10 day 500-hPa height blend consists of FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Average, 3 out of 5, due to good model agreement in the western two thirds of the country, offset by large disagreements in the eastern U.S. between the latest GFS and ECMWF ensemble means. 8-14 DAY OUTLOOK FOR OCT 30 - NOV 05, 2019 For week-2, the pattern over the U.S. and surrounding areas is expected to become somewhat less amplified as the flow becomes more progressive over the western U.S. The mean trough over the CONUS is forecast to move eastward into the Great Lakes Region, while the Eastern Pacific ridge is predicted to retrograde slightly. There's still a great deal of uncertainty regarding the speed and position of the trough, with the 6z GFS ensemble mean still favoring a more easterly position, and the 0z ECMWF ensemble mean favoring a position farther west. Today's week 2 manual 500-hPa blend favors the 0z ECMWF ensemble mean. Temperatures are still likely to be above normal over all of Alaska since the positive temperature anomalies are predicted to be so high during the beginning portion of the week 2 period, and positive height anomalies still dominate over the state. Below normal temperatures are favored for most of the CONUS as troughing overtakes the majority of the lower 48 states. However, temperatures are expected to remain above normal along the Southeast coast and for Florida, associated with the larger positive temperature anomalies before the cold front moves off the East Coast. With a surface cyclone predicted to stall near the Alaska coast during the week 2 period, above normal precipitation is favored for Alaska. Downstream of the ridge over the Eastern Pacific, below normal precipitation is largely favored due to a relatively quiet storm track. The predicted storm system expected to bring upslope flow and above normal precipitation to the Northern Rockies will exit that area by the week 2 period, favoring near to below normal precipitation for the Central and Northern Plains. The above normal precipitation favored over for the Southern Plains, Southeast, and Mid-Atlantic is mainly supported by the 0z ECMWF ensemble's solution of a slower-moving trough in the Central CONUS and the potential for a strong surface cyclone to develop in the eastern U.S. The official 8-14 day 500-hPa height blend consists of: 40% of Today's operational 0z GFS centered on Day 11, and 60% of Today's 0z European Ensemble Mean centered on Day 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Average, 3 out of 5, due to good model agreement in the western two thirds of the country, offset by large disagreements in the eastern U.S. between the latest GFS and ECMWF ensemble means. 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 November 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: 19961023 - 19951002 - 20011011 - 19691002 - 19821007 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: 19961022 - 20011011 - 19951001 - 19951020 - 19601030 6-10 DAY OUTLOOK TABLE Outlook for Oct 28 - Nov 01, 2019 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B B OREGON B B NRN CALIF B B SRN CALIF B B IDAHO B B NEVADA B B W MONTANA B B E MONTANA B A WYOMING B A UTAH B B ARIZONA B B COLORADO B A NEW MEXICO B B N DAKOTA B A S DAKOTA B A NEBRASKA B A KANSAS B A OKLAHOMA B A N TEXAS B A S TEXAS B A W TEXAS B B MINNESOTA B A IOWA B A MISSOURI B A ARKANSAS B A LOUISIANA B A WISCONSIN B A ILLINOIS B A MISSISSIPPI B A MICHIGAN B A INDIANA B A OHIO B A KENTUCKY B A TENNESSEE B A ALABAMA A A NEW YORK N A VERMONT N A NEW HAMP A A MAINE A A MASS A A CONN A A RHODE IS A A PENN N 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 Oct 30 - Nov 05, 2019 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B B OREGON B B NRN CALIF N B SRN CALIF B B IDAHO B B NEVADA B B W MONTANA B B E MONTANA B N WYOMING B B UTAH B B ARIZONA B B COLORADO B B NEW MEXICO B B N DAKOTA B N S DAKOTA B B NEBRASKA B B KANSAS B B OKLAHOMA B N N TEXAS B A S TEXAS B A W TEXAS B N MINNESOTA B N IOWA B B MISSOURI B B ARKANSAS B N LOUISIANA B A WISCONSIN B N ILLINOIS B B MISSISSIPPI B A MICHIGAN B N INDIANA B N OHIO B A KENTUCKY B A TENNESSEE B A ALABAMA B A NEW YORK B A VERMONT B A NEW HAMP B A MAINE B A MASS B A CONN B A RHODE IS B A PENN B A NEW JERSEY B A W VIRGINIA B A MARYLAND B A DELAWARE B A VIRGINIA B A N CAROLINA B 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 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. $$