FXUS06 KWBC 192002 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EST Wed February 19 2025 6-10 DAY OUTLOOK FOR FEB 25 - MAR 01, 2025 A progressive flow pattern is forecast to take shape across North America during the 6-10 day period as the Arctic Oscillation (AO) becomes positive during the last week of February. However, the mean mid-level height pattern is predicted to remain broadly amplified, with ridging and above-normal heights favored across the western CONUS, and troughing and below-normal heights across the East. The 0z ECENS is less amplified with the troughing in the East compared to the 0z GEFS early in the period, but there is better model agreement toward the end of the period as a mid-level low shifts over northeastern Canada leading to decreasing heights over the eastern CONUS. Troughing is forecast across Alaska with an associated negative height anomaly center located to the south of the Aleutians in the manual blend. However, this feature is forecast to weaken with time, with more ridging building into Southeast and eastern Mainland Alaska by the end of the period. Below-normal heights are favored over southwestern Mainland Alaska and the Aleutians, with near- to above-normal heights forecast over the remainder of Alaska tied to the forecast mid-level pattern transition. Elevated probabilities for above-normal temperatures are favored across much of the western and central CONUS tied to ridging and consistent with the GEFS and ECENS reforecast tools. The highest probabilities (greater than 80 percent) are highlighted across parts of the southwestern CONUS. The ECENS reforecast tool is notably warmer across parts of the Northeast compared to its GEFS counterpart, and this is likely due to the weaker troughing depicted in the 0z ECENS. Most models indicate relatively warmer temperatures early in the period, followed by a cooling trend behind departing surface low pressure around day-9 (Feb 28). Near-normal temperatures are favored over much of the East for the period as whole. A slight tilt toward enhanced probabilities for above-normal temperatures is highlighted across coastal areas of the Northeast and northern Mid-Atlantic given support from the reforecast consolidation tool, some potential for enhanced southeasterly flow associated with surface low pressure, and a later start to the cooling trend. Probabilities for below-normal temperatures are increased across the Florida Peninsula due to better agreement in the reforecast tools compared to further north. Increased chances for above-normal temperatures are favored for much of Alaska underneath enhanced southerly flow upstream of troughing and due to increasing mid-level heights over eastern Alaska later in the period. Above-normal temperatures are strongly favored across Hawaii. Ridging over the western CONUS combined with a more progressive flow pattern favors elevated probabilities for below-normal precipitation over much of the western, south-central, and southeastern CONUS. There is good agreement in the models regarding a less active strom track during this period compared to earlier in the month with surface high pressure extending from the western CONUS to the Gulf Coast. The GEFS and ECENS reforecast tools support a tilt toward enhanced probabilities for above-normal precipitation across parts of the north-central and northeastern CONUS, with higher probabilities (greater than 40 percent) across New England given the elevated potential surface low development and associated enhanced precipitation around days 8 and 9 (Feb 27-28). Above-normal precipitation chances are increased across southern Alaska tied to an active surface low track over the north-central Pacific. Near- to below-normal normal precipitation is forecast across the northern Mainland further displaced from the mean storm track. A tilt toward elevated below-normal precipitation probabilities is favored across the Big Island of Hawaii, with near-to above normal precipitation chances increased across the remainder of the islands due to increasing influence from troughing over the central Pacific. The official 6-10 day 500-hPa height blend consists of 30% of Today's 6z GFS Ensemble Mean centered on Day 8, 40% 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 generally good agreement in the forecast tools, offset by some uncertainty due to a more progressive mid-level flow pattern and the temperature evolution in the East. 8-14 DAY OUTLOOK FOR FEB 27 - MAR 05, 2025 During week-2, the 500-hPa height pattern across western North America is forecast to weaken and retrograde, with a variable height pattern continuing across the East, although with a tendency toward more troughing. By the end of the period, troughing may also increase across portions of the west-central CONUS as the ridging shifts further upstream. For the period as a whole, near- to below-normal heights are favored across much of the CONUS east of the Rockies. Above-normal heights are forecast across the western third of the CONUS, although the positive anomalies are reduced compared to the 6-10 day period. The retrogression of the trough-ridge pattern over the Pacific supports below-normal heights across the Aleutians, with above-normal heights over the remainder of Alaska. The GEFS and ECENS reforecast tools continue to support increased probabilities for above-normal temperatures across the western CONUS tied to ridging early in the period. However, these probabilities are reduced compared to the 6-10 day period, and a cooling trend late in the period tilts the odds toward near-normal temperatures over the Northern Rockies. The temperature forecast is more uncertain across the East, with the GEFS (ECENS) reforecast tool depicting enhanced chances for below (above) normal temperatures. Today’s outlook leans toward higher chances of below-normal temperatures given the projected extension of negative height anomalies throughout the East, along with support from the uncalibrated model guidance and statistical (teleconnection and analog) tools. Above-normal temperature probabilities are increased over most of Alaska as ridging builds across the state. Above-normal temperatures also remain favored across Hawaii. The largest shift relative to the 6-10 day period is in the precipitation forecast across the CONUS. As the ridging initially over the West retrogrades, with a more cyclonic mid-level flow pattern in its wake, a more active storm track may begin to develop across the central CONUS by the end of week-2. Forecast tools support enhanced chances for near- to above-normal precipitation from the Rockies eastward to the Atlantic Coast. Probabilities are higher (greater than 40 percent) across northern New England due to potential impacts from surface low pressure at the outset of the period, and across the Gulf Coast where the week-2 precipitation totals in the 0z GEFS and ECENS are highest. Conversely, below-normal precipitation probabilities are increased along the West Coast tied to decreased onshore flow as the ridging becomes centered over the eastern Pacific. Enhanced chances for above-normal precipitation remain favored for most of Alaska underneath enhanced southerly flow and an active storm track, especially early in the period. Near-to above normal precipitation is favored across Hawaii due to continued influence from troughing extending across the central Pacific. The official 8-14 day 500-hPa height blend consists of: 25% of Today's 6z GFS Ensemble Mean centered on Day 11, 50% of Today's 0z European Ensemble Mean centered on Day 11, and 25% 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 generally good tool agreement, offset by some uncertainty due to a transitioning mid-level pattern. FORECASTER: Thomas Collow 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 February 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: 20070212 - 19570304 - 19780215 - 19800208 - 19570217 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: 20070212 - 19800210 - 19570304 - 19980302 - 19780214 6-10 DAY OUTLOOK TABLE Outlook for Feb 25 - Mar 01, 2025 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A B SRN CALIF A B IDAHO A B NEVADA A B W MONTANA A N E MONTANA A N WYOMING A B UTAH A B ARIZONA A B COLORADO A B NEW MEXICO A B N DAKOTA A A S DAKOTA A N NEBRASKA A B KANSAS A B OKLAHOMA A B N TEXAS A B S TEXAS A B W TEXAS A B MINNESOTA A N IOWA A N MISSOURI A B ARKANSAS N B LOUISIANA N B WISCONSIN A N ILLINOIS N N MISSISSIPPI N B MICHIGAN N A INDIANA N N OHIO N N KENTUCKY N N TENNESSEE N N ALABAMA N B NEW YORK N A VERMONT N A NEW HAMP A A MAINE N A MASS A A CONN A A RHODE IS A A PENN N A NEW JERSEY A A W VIRGINIA N N MARYLAND A A DELAWARE A A VIRGINIA N N N CAROLINA N N S CAROLINA N N GEORGIA N N FL PNHDL N B FL PENIN B N AK N SLOPE A N AK ALEUTIAN A A AK WESTERN A A AK INT BSN A N AK S INT A A AK SO COAST A A AK PNHDL A A 8-14 DAY OUTLOOK TABLE Outlook for Feb 27 - Mar 05, 2025 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A B SRN CALIF A N IDAHO N N NEVADA A B W MONTANA N A E MONTANA A A WYOMING N A UTAH A N ARIZONA A N COLORADO A A NEW MEXICO A A N DAKOTA A N S DAKOTA A N NEBRASKA A A KANSAS N A OKLAHOMA N A N TEXAS N A S TEXAS N A W TEXAS A A MINNESOTA B N IOWA N N MISSOURI B N ARKANSAS B A LOUISIANA N A WISCONSIN B N ILLINOIS B N MISSISSIPPI B A MICHIGAN B A INDIANA B N OHIO B A KENTUCKY B N TENNESSEE B N 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 B A GEORGIA B A FL PNHDL B A FL PENIN B 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. $$